nr. 1 EN/2011

SUMMARY

Grigore BUIA, Csaba LORINŢ Li, Te, Se, Nb-Ta – 21st Century Metals 2

Silvia IONESCU PETRE Geographic Information Systems Technology 7

Roland Iosif MORARU, Gabriel Bujor BĂBUŢ Explosion and/or Fire Risk Assessment Methodology: a Unified Approach, Structured for Underground Mine Environments 14

Ciprian NIMARĂ Assessment Methods of Anthropic Impact on the Terrain Features of a Region 19

Ilie ONICA, Eugen COZMA, Dacian Paul MARIAN Ground Surface Deformation Using the Finite Element Method, in Conditions of the Longwall Mining of the Coal Layer no. 3 - Livezeni Mine 24

Emil TEODORESCU, Iuliana TEODORESCU, Toma PRIDA, Nicolae GIURGIU, Carmen SOCACIU Complex Technological System of Crushing – Fine Grinding – Pneumatic Sizing for Industrial Minerals with Low and Medium Hardness for the Manufacturing of Cosmetic Products and Food – Supplements 34

Eugen TRAISTĂ, Emanoel ANDRONACHE Study on Restoration of Topsoil on the Waste Dumps in Jiu’s Valley 37

Vasile ZAMFIR, Horia VÎRGOLICI Synthesis of Mechanisms by the Interpolation Method 42

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Li, Te, Se, Nb-Ta – 21st CENTURY METALS

Grigore BUIA*, Csaba LORINŢ**

The third millennium started under the new information era. Revolution IT (Information Technology) is dependent on new mineral resources that have become viable since 2000. Metals such as Li, Te, Se, Nb-Ta, through their properties and uses into the modern technology, generates an increasingly demand on the market, also being a challenge for the mining industry. Keywords: lithium, tellurium, selenium, niobium, tantalum, application, resources, reserves, producing countries.

Motivation

According to a European Commission report published on 17 June 2010, European Union will have lower access to some mineral resources essential to the manufacture of high technology and current use products, such as mobile phones, solar panels with thin-layer cells, Li-ion batteries, cables with optical fiber or synthetic fuels. Forecasts go to 2030 and show a group of 14 elements and materials are considered critical [9].

This is generated by economic growth in developing countries and new emerging technologies. The issue of ensuring the supply of these raw materials is mainly due to the fact that they exist in only a few countries in the world (Ex.: Democratic Republic of Congo for cobalt and tantalum, Brazil for niobium and tantalum etc..). In many cases, besides the concentration of production, a low degree of substitution and a low recycling rate can be remarked. Moreover, many emerging economies have adopted the strategy of industrial development based on commercial, tax and investment instruments so as to use only local resources [9].

Application and uses

As stated, the demand on the market of these elements mostly dues the latest generation technologies, especially in the field of IT and communications. Every element among these has different uses, derived from their properties. Thus:

Lithium Although lithium and its compounds find utility in several applications (for example in industry - ____________________________________ *Prof. eng. Ph.D University of Petrosani ** Asist. eng. Ph.D University of Petrosani

for heat-resistant glass and ceramics, high strength alloys and lightweight aircraft used, in nuclear physics - through the fission of lithium atoms, the use of deuterium as lithium and as a fuel for thermonuclear weapons) its main use in the context mentioned above, is related to the manufacture of batteries and accumulators. Banal and ubiquitous: mobile phone, laptop, digital camera, mp3 player, even the clock at our hand, all use batteries or rechargeable batteries. For several years, batteries / lithium batteries have seized the world market with a majority share in growth at the expense of those based on nickel-cadmium (Ni-Cd) or nickel-metal hybrid (Ni-MH). Visionaries, however, argue that the future of this metal will be in the auto industry, by manufacturing electric or hybrid cars. Naval and aviation industry where miniaturization of circuits and electrical energy storage devices are essential should not be neglected.

Tellurium Until recently considered waste material in the

mining industry, tellurium is recently widely used in various fields, including: energy industry (thermoelectric devices), steel processing, coloring glass and plastics, manufacture of metal alloys (due to its ductility). Its most important using in terms of economic implications, however, remains manufacture of solar panels and semiconductors. Underlying solar cells as basis for the solar panels are used as semiconductor materials especially Si and also CdTe, GaAs combinations or CdTe cells use very expedient CBD technology (deposition of thin layers on large surfaces in the environment of pH, temperature and concentration of reagent control) which reached a yield of 16% in the laboratory, and less than 10% for modules produced so far [10].

Selenium Beyond the essential character that this element

plays in the functioning of the human body, selenium has many uses, from manufacturing photovoltaic cells, photocopiers and cameras / cameras etc. to the recovery of electricity. It is obtained from: refining lead, copper, nickel. Selenium increases its conductivity easily a thousand times when it is moved from darkness to strong sunlight, which is used to build magnetic flow-meters. Selenium salts (selenite mercury for example) use in medical analysis laboratories for determination of total nitrogen in blood/serum.

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Revista Minelor - no. 1 / 2011

Niobium and Tantalum These two metals, with antimony, beryllium,

cobalt, fluorine, gallium, germanium, graphite, indium, manganese, platinum metals, rare earths and tungsten are considered "critical" for European industry, according to data presented by the first report so far in the EU on access to mineral raw materials [9].

From the world production of niobium and tantalum, 60% is used in the manufacture of mobile phones, and the rest, at everything that is last generation electronics: TVs, video games, batteries / accumulators, laptops, airplanes, GPS, optic fiber guided weapons, MP3 players, artificial satellites, cameras / digital video, medical devices.

Tantalum chemical inertia makes it extremely valuable for laboratory equipment and a replacement for platinum, but its main use is in implementing powdered tantalum capacitors and electronic equipment industry. By alloying with other metals, tantalum is used to create high-quality alloys used in nuclear reactors, missile components, jet engines production, etc. Because it does not cause irritation to the body, being a nonalergic a material, tantalum is widely used in the manufacture of surgical instruments and implants, and for jewels newly, mounted with gold [11].

Niobium is extracted by electrolysis or other complex processes, from niobium and tantalum, these minerals being, first, converted into double fluoride of niobium and potassium.

It is a silvery-gray metal, which possesses the property of easily absorbing gases, making it usable in absorbent compositions (getters) for tubes. It is also used in the preparation of alloy steels (as feroniobiu), or other alloys.

GEOCHEMICAL Li, Te, Se, Nb-Ta

Lithium

Lithium is part of the alkali metals with sodium, potassium, rubidium and cesium, one of the rarest elements in the bark and having a strong lithophile character. Lithium contents of the various classes of magmatic rocks show that it tends to be concentrated in the latest products during crystallization, especially in granite rocks, while remarking “repulsion” toward the feldspatic structures.

Lithium however is concentrated in the mice, amphibole and pyroxene. With lithium fluoride, chlorine, phosphorus and manganese are often so focused on border and sientic nepheline pegmatite-forming minerals that are independent: criolitionit, trifilit, litiofilit, ambligonit, petalit, and its product spodumen encriptit alteration, micelles of lithium - lepidolit, and coockeit zinawaldit, lithium

tourmaline, amphibole very rare - holmquistit etc. Minerals of the pegmatite, ambligolit (8-10% Li2O) spodumen (4,6 - 7,5% Li2O) and lepidotit (3-10% Li2O) are important sources of lithium [7].

Tellurium and Selenium Tellurium and selenium are calcofile elements

(have high affinity for sulfur). In lava rocks selenium and tellurium come together with sulfur in separated sulfides of magma. After Noddack, selenium content of primary magmatic sulphides is 200 g/t and tellurium 2g/t.

Like sulfur, selenium and tellurium elements are pronounced sulfofile in the upper lithosphere. The average ratio S:Se in the early magmatic sulphides is 2.000:1 - 20,000:1 (Goldschmidt and Hefter, 1933) and in the sulphides pneumatolitic arsenide and high-temperature hydrothermal ratio is 400:1 - 20,000:1 (Goldschmidt and Strock, 1935). On the other hand selenium is less abundantly in rocks and hydrothermal minerals formed at intermediate and low temperatures in this report S:Se being 70.000:1 - 250.000:1 (Goldschmidt and Strock, 1935). The values of the S: It is shown that selenium is preferentially concentrated in sulphides and hydrothermal arsenide formed at high temperatures.

Tellurium also forms, in hydrothermal rocks, telluride of the mentioned elements and other elements. In addition, he has a tendency to combine with gold, which he accompanies in many mineral strands.

Among the products resulting from oxidation of terrestrial minerals there are known different telluriums, ex.: durdenitum- Fe2 (TeO3)-4H2O; feroteluritum - Fe (TeO4) teinitum - With [(Te, S) O4] 2H2O (all being rare minerals).

Like sulfur, selenium and tellurium elements are found in nature and natural state. In addition, they form mixed crystals of selenium-tellurium (Se, Te). Selenolitum oxides (SeO2) and tellurite (TeO2) are produced by oxidation of native elements or selenide and telluride. Selenium accompanies sulfur in volcanic emanations S:Se report of the sublimation of sulfur in volcanic regions varies between 600:1 and 140.000:1 S: Se (Goldschmidt and Hefter, 1933) so it is similar to the ratio in sulfides from magmatic rocks. Native sulfur content of selenium in volcanic regions may exceed 5%.

After Scerbina (1937), tellurium metal affinity decreases in minerals in the next order (gold, having the highest affinity): Hg-Au-Ag-Bi-Pb-Cu-Ni [7].

Niobium and tantalum From the geochemical point of view, niobium

and tantalum elements form a pair of pretty consistent elements, being separated by hardly by chemical analysis; in spite of this, the two elements

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are slightly separated in nature. Nb and Ta medium contents in magmatic rocks are 24 g/t Nb and 2.1 g/t Ta (Rankama, 1944, 1948), so the average of abundance Nb:Ta is 11.4.

In magmatic rocks it is known that Nb and Ta crystallize in the last stages of magmatic differentiation.

The concentration is very strong in the borders Ta presents the maximum concentration, while Nb, although appears in borders, has maximum concentration in syenite and nepheline – syenite.

Although in the basic and ultrabasic rocks the content of the two elements are smaller than those in the borders, in ultrabasic rocks sometimes we find remarkable amount of columbium (Niggli, 1932).

The dominant and typical feature in the Nb and Ta geochemistry is their pronounced concentration in pegmatite The most common minerals in the pegmatite Nb and Ta are columbitum and tantalitum [7].

In genetically terms, these elements are concentrated in magmatic deposits or the alteration

products and their mechanical and physical concentration [2,4,5].

Reserves and producing countries

A report by the U.S. Agency for Mineral Resources shows that the total resources of lithium in the world by the end of 2008, would approach 30 million tones, of which around 750,000 tones would be in the United States, especially in Nevada. About 14 million tons in the global reserves would be exploitable resources. Almost half of what can exploited, 5.4 million tons, would be found in Bolivia, under Salar de Uyuni, a salt desert of 10,000 km2. There are also, according to those estimations, reserves in Chile - 3 million tons (from which Americans massively import), 1.1 million tons in China and about one million in Brazil. The rest, 0.5 million tons as reserves, would be in Argentina, Australia, Canada, Zimbabwe and Portugal.

Table 1 World production of lithium (according to WMD, 2010) [8]

Country / Year 2004 2005 2006 2007 2008 Chile 17977 17900 20700 24111 22997 Australia 5922 8682 11105 9613 11976 SUA 3200 3200 3200 3230 3230 China 2700 2820 2820 3010 3100 Canada 650 630 700 707 707 Brazil 497 473 437 430 430 Portugal 346 311 339 372 375 Spain 30 20 42 45 0 Zimbabwe 1450 937 900 0 0

Total 32772 34973 40243 41518 42815

And in the case of this metal so wanted, paradoxes are evident. Although Chile has reserves be estimated as 250 times lower compared with the U.S., production records a seven times higher production, with a weight of more than 53% of world the production. The next state in order of production volume is Australia, with values that are

approx. 28% of the world production. Tellurium and selenium are found in small quantities in the anode mud resulting from the copper electrolysis process. Unfortunately copper producers use only a part of the mud results for the extraction of tellurium and selenium.

Table 2 World production of tellurium (according to WMD, 2010) [8]

Country / Year 2004 2005 2006 2007 2008 Peru 29 33 34 35 28 Canada 40 28 11 8 19 Japan 33 23 24 41 4 Mongolia 2 1 0 0 0

Total 104 65 69 84 87

Economically exploitable reserves of selenium, however, are estimated at only 82,000 tones and 43,000 tones at tellurium opposite of copper which is estimated at 550 million tons. Many production

processes use gallium, indium, selenium and tellurium in uneconomic ways. Unlike copper, where the recycling process is developed, at gallium, indium, selenium and tellurium recycling

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is not possible because these elements are included in finely distributed multilayer structures, where the

recovery, apparently, even in future shall be impossible.

Table 3 World production of selenium (according to BGS, 2010) [1]

Country / Year 2004 2005 2006 2007 2008 Japan 599 625 730 806 754 Belgium 200 200 200 200 200 Canada 277 107 117 144 158 Sweden 131 122 135 126 130 Russia 85 100 110 110 110 Poland 83 84 87 85 82 Finland 65 66 70 52 65 China 65 65 65 65 65 Philippines 48 68 65 65 65 Peru 76 70 75 59 60 Kazakhstan 100 60 70 155 56 Uzbekistan 20 20 20 20 20 Germany 14 12 12 12 12 India 0 8 0 0 0

Total 3767 3612 3762 3906 3785

– estimated production

In addition to the table, it is considered that countries like Australia, Chile, Korea and Zimbabwe are also producing selenium.

About niobium and tantalum, R.D. Congo on the border with Burundi and Rwanda holds 80% of the world reserves, it records an annual production of only 0.21% of the global production. This state,

situated at the end of 2008 on the 5th position from a total of 11 producers of niobium and tantalum, with a slightly increase of production. Brazil doubled its production of these metals in recent years, reaching at the end of the same year at a weight overreaching 93% of the world production.

Table 4 World production of niobium and tantalum (according to WMD, 2010) [8]

Country / Year 2004 2005 2006 2007 2008 Brazil 39296 56287 68850 81922 82000 Canada 3450 3704 4157 4368 4432 Australia 350 340 330 435 680 Ruanda 117 148 100 242 298 R.D. Congo 37 61 26 132 186 Mozambic 256 101 34 70 138 Etiopia 52 68 81 89 93 Nigeria 40 35 40 70 60 Burundi 10 17 6 19 33 Bolivia 11 4 3 2 2 Zimbabwe 4 0 0 0 0

Total 43623 60765 73627 87349 87922 As shown, there are many situations in

which the main holders of these resources are not the major producers. Because the statistics shown above refer to the leading manufacturers of Li, Te,

Se, Nb and TA in the following graphic the main areas of major economic interest will be highlighted (Fig. 1.).

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Figure 1 Areas of major economic interest for the elements Li, Te, Se, Nb and Ta

Therefore lithium reserves are outlined in the

U.S., Bolivia, Chile, China, Brazil, Canada, Australia, Spain, Portugal, Argentina, Zimbabwe, tellurium in the U.S., Canada, Japan, Peru, Romania, selenium in Peru, Chile, Russia, Canada, USA, Japan, Philippines, Poland, Zimbabwe, Romania, and niobium and tantalum in Brazil, RD Congo, Australia, Canada, Mozambique, Ethiopia, Nigeria.

References 1. Brown T.J., Bide T., Hannis S.D., Idoine N.E., Hetherington L.E., Shaw R.A., Walters A.S., Lusty P.A.J., Kendall R. World mineral production 2004/2008, Britsh Geological Survey, Keyworth, Notingham, 2010; 2. Buia G., Lorinţ C. Zăcăminte de substanţe minerale utile solide, Editura Focus Petroşani, 2005;

3. Buia G. Geografie economică mondială, Ediţia a II-a revizuită, Ed. Focus Petroşani, 2003; 4. Lorinţ C. Geologie economică, lucrări practice de laborator, Ed. Universitas Petroşani, 2009; 5. Lorinţ C., Buia G. Geologie economică, detreminator pentru lucrări practice de laborator, Ed. Focus Petroşani, 2009; 6. Popescu C. G., Neacşu A. Metalogenie aplicată şi prognoză geologică, Ed. Universităţii din Bucureşti, 2009; 7. Rankama K., Sahama G. Th. Geochimie, Ed. Tehnică, Bucureşti; 8. Weber L., Zsak G., Reichl C., Schatz M. World Mining Data, Volume 25, International Organizing Committee for the World Mining Congresses, Vienna 2010; 9. http://ec.europa.eu/commission_2010-2014/tajani/hot-topics/raw-materials/index_ro.htm 10. http://ro.wikipedia.org 11. http://www.tantalul.ro

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GEOGRAPHIC INFORMATION SYSTEMS TECHNOLOGY

Silvia IONESCU PETRE* This article presents the importance of using the Geographic Information System technology. It describes the activities of gathering and processing the spatial and descriptive data, both from the general perspective and by presenting the functionality of the software developed in this purpose. There are also presented the technology's characteristics and future possibilities for development. Keywords: Spatial data, Geographic information system, technology, software Introduction

Geographical information systems have first appeared in 1970. Initially they could only be used by companies or universities that had expensive hardware and software. Today, any person who owns a computer can use geographic information systems technology. Over time, GIS programs have become easier to use, compared to previous periods, when in order to work with GIS software a preparation in advance was needed. As I will describe below, GIS software is not just a product but incorporates all aspects of management and use of digital geographic data. The volume of information collected by any man of our time is growing due to the almost unlimited possibilities for managing and operating the retention of the information provided in digital form, in relational databases. One can appreciate that a percentage of 85 percent in databases in use contain one or more components regarding the geographical location of objects in inventory. Where cadastral databases can say that all the information is related in some way or another to the geographical location of the property defined by geographic boundaries of the land base unit. Creating and joint exploiting in a Geographic Information System of the information with spatial reference to the graphical representation of objects in surface or underground can bring great benefits to users or administrators of such information, primarily due to the existence of an operational data structures and well defined - primary requirement for any information system. ____________________________________ * Academy of Economic Studies Bucharest, Faculty of Statistical Cybernetics and Informatical Economics

When all information is ordered by relational rules to geographic reference – in digital format - and is administered by a system of programs designed for this purpose, this opens up new possibilities for management and use increasingly by a large group of users.

GIS is a computer system for capturing, storing, checking, integrating, manipulating, analyzing and displaying data related to positions on the Earth's surface. Typically, a Geographical Information System is used for handling different types of maps. These could be represented as several different layers where each layer holds data about a specific type of facility. Each feature is linked to a graphic image on a map and a record is retained in a table of attributes. GIS can reveal such hidden patterns, relationships, and trends that are not easily observed in spreadsheets or statistical packages, new information often existing data sources.

GIS technology integrates common database operations such as query and statistical analysis with unique visualization of geographic analysis benefits offered by maps. These abilities distinguish GIS from other Geographical Information Systems and capitalize it on a wide range of public and private enterprises in explaining events, predicting outcomes and planning strategies.

Representing an application that works with graphical components, likeness with computer assisted design (CAD) is natural. The perception of many is that GIS is a sub domain of the CAD's, in fact; among the first major CAD systems is GIS software.

Using GIS technology has many advantages over traditional geo-spatiality expense. Optimal structuring of data, accuracy of representations, calculations, faster access to information, current data, assisting decision-making in the short term, the possibility of performing complex studies and analysis are just some of the many advantages of using GIS.

Designing such a system brings in addition to designing a database application, the care for graphic components. A geographical component is often hidden in a data source: an address, postal code, city, county, or coordinates of latitude / longitude. With GIS, you can explore the elements of spatial data to display soil types, find the best location for a business expansion, create a path model for air pollution, and make decisions for many types of complicated issues. GIS involves complete understanding of models,

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space, and processes or methodology needed to address a problem. It is a tool that acts as a means to achieve certain objectives quickly and efficiently. Its applicability is realized when the user fully understands the whole concept of space in which a particular GIS is established and examines the application in light of the established parameters.

Before the implementation of GIS must be taken into account the objectives, both short and long term. Since the effectiveness and efficiency (benefits bigger then cost) of GIS depends largely on the quality of the original captured data, the organization of the application must be set to maintain this data flow continuously.

Fields and methods of use of geographic information systems technology

GIS technology is used by a multitude of

categories of users (managers, academics, professionals in the field) depending on their specific needs. Each user group has its own educational and cultural background is associated with various companies, magazines, conferences, traditions, therefore each is identified with particular ways of approaching the problem. Finally, all the user-groups share the same technology to address specific problems.

The main areas of use of GIS technology can be classified as follows: • Developed technologies that interact with GIS, interchange functions and supply data for GIS

- Mapping - Topography and Engineering - Remote sensing

• Resource management and management decisions - Inventory and resource management - urban planning (Urban Information

Systems) - record of land for property taxation and

control (Land Information Systems) - facilities management (AM / FM) - planning and retail marketing - routing and scheduling

• Science and research activities of university and government laboratories

GIS technology can be used in mapping by two perspectives: automating the process of map making and creating different types of maps from the data analysis and manipulation. The undeniable advantage of automating the process of map making is that objects can be moved easily into the map without having to recreate them and work to change the scale and projection are easily accomplished.

Topography’s main concern is measuring the objects’ locations on Earth's surface, in particular the property boundaries. Locations of a limited number of fixed points are extremely accurate, with precision instruments and measurements. These are monuments and landmarks. Using these specific benchmarks for reference, a large number of locations can then be accurately determined relative to fixed monuments. Topography is a leading provider of GIS data. However, it is not directly concerned with the role of GIS decision-making tool. Some engineers use GIS technology, particularly using digital elevation models and associated functionality to help in the planning and construction. For example, for calculations of earth quantities to be moved in construction projects such as building highways or to see the effects of major construction projects, such as dams.

As topography, remote sensing is a field producer for GIS data, it receives information about the earth's surface from airborne or space platforms. Remote sensing has well developed techniques and technologies in terms of data capture - high spatial and spectral resolution, transmission, processing, and archiving data, and interpretation, classification of images. By using remote sensing, GIS technology is provided with important roles such as increasing product quality and value using additional data to improve the accuracy of classification and assist in decision making by combining the product with other less observed layers in space, such as political borders. This area continues to be an area of active research in view of the fact that new tools must be evaluated for applications in various fields, careful research is needed to realize the enormous potential of technology and the volume of data accumulated is growing rapidly.

Applications for inventory and management of resources have dominated the providers’ sales in the early 1980’s. Many systems have been used by state governments, federal and industry resources, especially forestry, oil and gas. Among the most popular and successful applications developed for this purpose include: forestry applications - inventory timber, watershed management, infrastructure development (roads), forest regeneration, applications in agriculture - agricultural pollution studies, inventories of land capability, studies of productivity applications for land use - land use planning, zoning, impact assessments, applications for wildlife - habitat management.

Programs for urban planning involves developing file Dime (street axes locations, address ranges for each block, census reporting zones). An example of urban planning using is GIS community

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risk assessment. This example shows the modeling of community vulnerability to hazardous materials and is designed to reduce potential impacts.

Governments, developers and landowners require and use land use information every day. The most information which the Government uses and records refers to specific geographic locations under its jurisdiction: property lines, easements, utility and sewer lines, and more spatial data. The ability to store, retrieve, analyze, and report efficiently and accurately display this information public about the land is of great importance, since requests for information from a database that stores information about the land can reach a total of 1,000 applications per day. Legal description of land is based on precise measurements, points with precisely known location, and descriptions such as mid-evil (the river may change its course), marks on trees, etc... To prevent inconsistencies, the source of information about land and its accuracy can be as important as the information itself, such a database containing information on land may need not only the lands’ coordinates. To increase the amount of information that there is need for the use of software becoming more sophisticated, GIS functionality is required. The question in this case the use of a powerful management system, relational database structured topologically. For some projects of land management, GIS technology characteristics are the essential: urban and regional planning - the ability to merge information with statistical information about geographic boundaries, resulting in the rapid creation of thematic maps in support of project planning, use of overlays to support the space search for feasible areas to meet the project requirements, community development - fast updates of area records , the rapid display of paper using the plot-space operations, public works - a use of 3D capabilities to the engineering calculations, utilities: hydrological modeling - using network modeling capabilities for predicting urban leakage, the effects of changes in fluvial system, schools: models -population forecasting to go to school in small towns based on population migration, housing development patterns, to obtain populations balanced schools.

Initially, interest in automation was simply recognition of the need for immediate automatic mapping as a way to record and process changes. However, during the planning system were also identified many other potential applications and other information. With control over various layers of information, facilities management offers a variety of ways to present existing information in a single database. A major advantage of using automated mapping is a better possibility of their

maintenance, productivity increased to 10 times more than the manual methods of making maps. There is no question of physical deterioration or the content of the map as they are created as needed or updates. The increasing use of computers also offers easier access and better control over the maps, producing and distributing copies when necessary.

Location factor is critical for success in retail business. Exact knowledge of the spatial distribution is essential for advertising online campaign. GIS technology is useful in the design of sales areas, analyzing trade areas of stores. Although still in an early stage, similar applications appear in politics: for example, planning voting centers has a major impact on elections results. GIS technology is very useful for routing and planning, which includes car navigation systems, help systems, emergency vehicle routing, and scheduling delivery vehicles. Functionality resulting from the use of GIS in this area is represented by the following aspects: simple data retrieval and display for vehicle navigation systems, finding the optimal route (requires a fast algorithm, intelligent), finding a location specified by address. Lately there is growing interest given the use of GIS technology to support scientific research: science supporting global-environmental-global investigations, epidemiology, to search for factors that cause disease-models, anthropology, demography, social geography - for understanding the changes of the population structure, distribution of population groups in cities, landscape ecology, to understand relationships between species distribution and habitats. Unlike statistical package, GIS development was related to applications other than scientific research. Lack of spatial analysis tools has meant that the role of location in explaining phenomena has been difficult to assess. Tracking data are available in libraries are difficult to map interfered with other information that are not part of the digital research environment. GIS has a great potential in scientific research by allowing space as an analysis of statistical packages can create statistical analysis.

Geospatial and descriptive data

GIS data represent real objects (such as roads,

lands use, trees, waterways, etc.) with digital data. Real objects can be abstracted in two ways: discrete objects (ex. a house) and continuous fields (such as precipitation, increases in debt). Traditionally, there are two methods widely used to store data in a GIS for both types of mapping abstractions: vector and raster images.

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The graphic entities that compose digitally the map are usually vectorially defined, this way an entity on a map is represented staring from the Cartesian Coordinates of its points. An alternative to this representation are the raster images that represent bitmap images, where an entity is defined by several colored dots. Unlike the vector representation, which can define single entities, in a raster image are represented several entities, the colors through these entities are represented helping them to differentiate from other.

Raster images may come from multiple sources like scanning existing maps on a physical medium, aerial photography of the land, from specialized satellites, drawing etc. Data capturing and introducing data into the system occupies a large part of GIS users time. There are several ways of collecting and processing data.

A first way of producing vectorial data is using and processing field measurements. A main objective of the field measurement process is to generate the coordinates of several points processing distances and determinate angles using a measuring device. GPS (Global Positioning System) is a specialized technology based on a set of specialized satellites that allow the continuous determination of the position points on Earth’s surface. The existing data on physical medium can be scanned or photographed, resulting raster images, which can also be processed after that in order to produce vectorial data. In GIS’ view

important is not the modality of collecting data, but getting coordinates that define the graphic vectorial entity and additional information for this.

For obtaining raster images there are also several ways: scanning maps or plans in physical format, aero-photographic imagery, satellite images. The aero-shooting represents the process of photographing the land from an aircraft that flies over the territory. This way of obtaining the raster images brings in addition to documents’ scanning the characteristics of unity and actuality, but for a perfect accuracy of these characteristics, the data collected in this way will require some adjustments. The images from specialized satellites are obtained by shooting the earth's crust seen from the satellite’s orbits. Images obtained like this are then put to a process of analysis and processing in order to achieve optimal results.

The geo-referential process is a process by which a raster image that represents a ground coordinate system is transformed into the coordinates of the current project system, so that each entity contained in it reaches the positions corresponding to reality. Geo-referencing makes sense when the raster image is combined with vector data representation from the area. Therefore, the simultaneous achievement of precision given by the vector representation and the achievement of meaning given by the raster image. In (Figure 1) is presented a raster image after the process of geo-referencing.

Figure 1 Raster image after geo-referencing

Geo-coding involves placing unpretentiously

the geospatial entities having as a landmark some alphanumeric attributes from the associated database. The fact that geo-coding offers pure geographical information, rather generating than

asking for spatial data, extends amazingly the GIS functionality.

The key of GIS applications is the connection between the vectorial entities and the descriptive attributes, which also represents the distinction

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from digital cartography. The analysis and decisions’ assistance skills are based mainly on descriptive data. Since relational databases dominate the market for more than three decades,

most GIS applications use this model of data storage. In (Figure 2) is shown how the connection between a graphic entity and a record in the database is created.

Figure 2 Connection graphic entity - registration table

Descriptive data collection can be done by

explicit synchronous collecting, asynchronous or by importing data from databases related thematic to the GIS application. Explicit synchronous data collection involves placing data into the system by the designer with the creation of graphical entities. Asynchronous explicit collection involves creating the links between the table and the thematic layer and then introducing the attributes visually identifying each entity or working in groups, in which case consideration should be given to the unique identification codes of the graphic entities.

Using a GIS product reveals its true capacity, presuming frequently the engage of alphanumeric data in analysis and queries. GIS user should be able to quickly access the descriptive information associated to the graphic domain, but also should be able to aggregate them in more complex studies. In addition to descriptive data, lately the GIS software manufacturers also store the vectorial entities into the database, so in many cases the model for databases transformed from relational to object-relational or pure object. When constructing and using complex GIS projects, with multiple ways of access for enterprises, the control and the synchronization of their development is a key issue to be taken into account, traditional solutions being limited because they are forced to work at file level. Storing graphic data into relational databases adds, by conducting internal management to a project component level. This approach substantially affects productivity in complex projects.

Description and use of MapSys software

MapSys focuses powerful features, but easy to use for the producing and using the digital plan, functions for geo-referenced and management of spatial referenced information. Efficient exploitation of MapSys geo-data created or imported from other systems is provided by standard GIS functions such as those of geo-reference, collection of attributes, topological overlay layers, creating user queries or generating buffer area, but also specific functions by parceling cadastre duplication and mailing address search. Defining the right of access to program functions and data, and the possibility of cataloging operations performed, enabling better tracking and protecting data consistency. MapSys COM Interface offers the possibility of extending the functionality of the program by creating their own applications with available programming language functions and internal MapSys functions. MapSys Internet Map Server Map optional module allows authorized users to query information from databases MapSys work in an Intranet or the Internet.

To generate graphical data, the user can take advantage of the usual import duties, digitization / vectorization and graphic design functions. There are specialized functions for creating, searching, selecting and modifying of points, lines, curves, texts and symbols. Multiple specialized functions for building graphical geometric topographic and cadastral plans, generating cross longitudinal profiles. The targeted plans can be scanned, cut or

11


merged and displayed in order to be digitized. For digital plan printing are standard functions for plan sheet generation, multiple overlapping plans or placing on worksheet open graphics windows. The features import / export permit graphic and alphanumeric information transfers in the most popular graphic formats, or GIS, such as DXF, SQD, SHP, MIF, E00, etc...

MapSys work units are called Works. They contain all the information entered or created by a given time. Graphics functions create information like dot, line, arc, curve, text or symbol. Generates topological features with spatial reference objects of type point, line or polygon. These objects are composed of graphics, object identifier and object attributes. In the Works, graphic and alphanumeric information are kept in their own formats in the form of files. MapSys is a Geographic Information System that allows the creation, management and use of spatial reference information.

Keeping them in relational databases requires very broad definition of categories of objects that satisfy the minimum conditions of consistency andpositioning graphics. These objects are called topological objects, and can be summarized in three categories. In (Table 1) are three categories oftopological objects.

Table 1 Definition of topological objects

In MapSys, each object type has a

corresponding topological structure built database. In (Table 2) presents the structure of topological objects in the database. Table 2 Structure of topological objects in the database

Nr. topological objects basic attributes attribute type

1 point NRCAD, X,Y,Z Text, Num, Num, Num

2 line (arc) NRCAD, length, average share

Text, Num, Num

3 polygon NRCAD, area,

perimeter, average share

Text, Num, Num, Num

Structure given above is automatically created

when MapSys topology generation for a class of

graphic and alphanumeric objects contained in a combination of graphic layers. Standard structure can be expanded by the user, creating new fields, or creating tables or relational databases.

Topological information and related attributes are maintained in Database Management Systems such as those listed above. Working on multiple workstations with specific update operations of a functional GIS system is ensured by management functions the statements of Works extras that can be distributed to the workstations will that after completion, can be integrated into the basic Works. Database query functions allow creating, saving and running complex SQL queries, view query results or creating thematic representations. There are special functions of graphic search features of postal address, buffer zone generation, and analysis overlay plot (re-plotting), generation of thematic representation.

Functions and data access can be restricted so that each registered user can access only those functions and data that have been granted by an authorized person named administrator, who has authority to access and modify all functions and all data. Users are identified by name and password system.

By using Internet Map Server Mapsys, geo-information data value is multiplied by the fact that they are made available to potential users where and when they need them as soon as data manager and potential customers are connected to the Internet. For Intranet users connect through a local network configuration and user functions are the same as for the Internet.

The information provided in the network are MapSys normal Works located on a server which may have a degree of detail set by the user. Configured MapSys Works may be the original set - which are constantly changing - or copies of theirs. Thus there is a permanent control over the “news” factor of the information provided.

Future development trends for geographic information systems technology

The Geographic Information Systems already offer more precision than the basic mapping scales. A first future trend would be to redefine some of the data collection methods and their levels of accuracy. At one time GIS technology can be influenced by the possibility of multimedia data storage and that of networks’ creation. The ability to display text, maps, data, photos, video, and sound for locations from a multitude of sources from the network will give a new definition of what constitutes a spatial database.

Nr. topological objects definition conditions

1 point ID, point coordinates -

2 line (arc) ID, point coordinates without interruption

3 polygon polygon identifier,

coordinates splitting points

to be a closed contour

be defined uniquely *

12


Creating 4D GIS geographic information systems (XYZ and time) is the next major challenge. Currently, time is treated as a series of stored map layers that can be animated for visualizing the changes on the landscape. Adding predictive modeling along with the actions proposed by the management (ex, timber harvesting and subsequent growth of vegetation) can be introduced as methods for looking into the future.

Data structures will host tomorrow's time for a fully integrated size and thus will change the paradigm of conventional mapping.

Conclusions

GIS technology has greatly changed the

perspective about map’s utility. This perspective has moved from classical mapping to an active and vital ingredient in making decisions. The professionalism of nowadays is challenged to understand the new environment and to formulate innovative applications that fulfill the complexity and the ever-changing needs. Bibliography 1. Clarke, K. Analytical and Computer Cartography, Prentice Hall, Englewood Cliffs, 290, 1995 2. Chang, K.T. Introduction to geographic information systems, McGraw Hill, New York, 348, 2002 3. DeMers, M. Fundamentals of Geographic Information Systems, John Wiley & Sons, New York, 498, 2000 4. Reuter, A., Zipf, A. Geographic Information Science: Where Next?, Blackwell Publishing Ltd, Malden, 609, 2008 5. Knoblock, C.A., Shahabi, C Geospatial Data, Blackwell Publishing Ltd, Malden, 196, 2008

6. Maantay, J., Ziegler, J. GIS for the Urban Environment, ESRI Press, Redlands, 600, 2006 7. Frigerio, S., Van Westen, C.J. RiskCity and WebRiskCity: Data Collection, Display, and Dissemination in a Multi-Risk Training Package, Cartography and Geographic Information Science, vol. 73, no. 2, pp. 119-135, 2010 8. Jimenez, J.J., Feito, F.R., Segura, R.J. A new hierarchical triangle-based point-in-polygon data structure, Computers & Geosciences, vol. 35, no. 9, pp. 1843-1853, 2009 9. Zhan, F.B. Three Fastest Shortest Path Algorithms on Real Networks: Data Structures and Procedures, Journal of Geographic Information and Decision Analysis, vol. 1, no. 1, pp. 70-82, 1997 10. Di Giacinto, V. On vector autoregressive modeling in space and time, Journal of Geographical Systems, vol. 12, no. 2, pp. 125-154, 2010 11. Murray, A. Advances in location modeling: GIS linkages and contributions, Journal of Geographical Systems, vol. 12, no. 3, pp. 335-354, 2010 12. Dangermond, J. GIS in the Web-A Big Step, 2010, http://www.vector1media.com/vectorone/?p=5211 13. Foote, K.E., Lynch, M. Geographic Information Systems as an Integrating Technology: Context, Concepts, and Definitions, 2009, http://www.colorado.edu/geography/gcraft/notes/intro/intro_f.html 14. Keenan, J. Falling Off the Edge of the Map, 2010, http://www.directionsmag.com/articles/falling-off-the-edge-of-the-map/142735 15. Bartling, W.C., Schleyer, T.K.L. An Application of Geospatial Information Systems (GIS) Technology to Anatomic Dental Charting, 2003, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1480180/ 16. Păunescu, C. Curs de Geodezie şi Topografie, Editura Universităţii Bucureşti, 2001.

13


EXPLOSION AND/OR FIRE RISK ASSESSMENT METHODOLOGY:

A UNIFIED APPROACH, STRUCTURED FOR UNDERGROUND MINE ENVIRONMENTS

Roland Iosif MORARU*, Gabriel Bujor BĂBUŢ*

In order to meet statutory requirements concerning the workers health and safety, it is necessary for mine managers within Valea Jiului coal basin to address the potential for underground fires and explosions and their impact on the workforce and the mine ventilation systems. Highlighting the need for a unified and systematic approach of the specific risks, the authors are developing a general framework for explosion risk assessment in gassy mines, based on the quantification of the likelihood of occurrence and gravity of the consequences of such undesired events and employing Root-Cause analysis method. It is emphasized that even a small fire should be regarded as being a major hazard from the point of view of explosion initiation, should a combustible atmosphere arise. The developed methodology, for the assessment of underground fire and explosion risks, is based on a known underground explosion hazards, fire engineering principles and fire test criteria for potentially combustible materials employed in mines. Keywords: methane, spontaneous combustion, explosion, risk, prevention, protection Introduction

Hard coal exploitation in Valea Jiului basin is conducted in difficult mining and geological conditions, causing numerous hazards relating to the health and safety of underground personnel. To the most serious mining hazards belong underground fires and firedamp explosions, which far too many times were the reason of mining catastrophes [8, 9].

The implementation into the practice of scientific principles of fire and explosion prevention contributed to significant decrease of the fire/explosion hazard in coal mines [2]. ____________________________________ * Assoc. prof. eng. Ph.D University of Petrosani

However, in spite of many achievements of science and technology in this field, fires and explosions still occur, creating a potential hazard for miners and contributing to the generation of considerable costs of fire-fighting and rescue actions, temporary output suspension or loss of longwalls.

This concerns both spontaneous and open fires. Mine methane is also one of the main concerns, as a risk factor in coal mining [7]. To improve the precision and reliability in assessing fire/methane hazard in working face of coal mine, it is more and more considered that an integrated approach is required. The principles and general framework of the explosion risk assessment in methane gassy mines

The basic principles and the general

framework of the explosion and fire risk assessment process in the underground workings within methane gassy collieries are common, as a consequence of the complex interactions between the specific parameters and, even, of the involved substances [3]. So, a methane – air mixture explosion can raise airborne coal dust particles, which previously were settled on the floor and walls, enriching in this manner the explosive mixture involved in the burning process. On the other hand, one of the direct consequences of methane explosions can be an open – fire, which magnifies the gravity of consequences generated. Likewise, the explosion’s ignition trigger can be a spontaneous combustion.

Consequently, we consider that the risk assessment approach should be carried out in an integrated manner, propounding the entire set of influence factors, funded on an arborescent causality approach, as depicted in figure 1 [4, 10].

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Figure 1 Reduced Tree – Cause tree for the undesired event „Collective injury induced by a methane explosion“

A risk assessment procedure for the

assessment and management of explosions/fires in underground mine workings should always be developed based on several main principles issued from the past work and acquired experience [1, 5, 6]. For reasons related to the brief character of this paper, we are presenting only the basic principles on which the general assessment framework is grounded, as it is set up below: a. Identification of materials present and method of material selection.

Identify and list materials present, quantify and location;

Review tests used as a basis for selection of such materials and their shortcomings;

Consider how fire resistance changes in use, for instance due to contamination with coal dust or other combustible material.

b. Establish possibility of ignition. Review acceptance criteria, e.g. flame size or

maximum permissible temperatures allowed under tests, to establish case of ignitability;

Collective injury

induced by a

METHANE EXPLOSION

METHANE EXPLOSION

WORKERS IN THE

SITE

Methane-air

explosive mixture

Ignition source

Unable to escape and leave the

hazardous area

Alarm ignored

Lack of alarm

Methane emission increase

Deficient ventilation

Mechanical and electrical

sparks

Flames

Blasting operations

Lack of systems

CTT malfunction

Lack of awareness

Misperce-ption

Deliberate ignoring

Inadequate escapeways

Emergency response failure

Methane drainage sytem’s malfunction

Faulty ventilation project

High aerodynamic resistance

Damaged data cable of the monitoring

system

Smoking requisites

Fire

Spontaneous combustion

Welding, vulcanization

Methane sensor located improperly

Burned Wheatstone balance

Obstructed methane sensor inlet

Barometric pressure variation

Fault interception (methane blower)

Mining depth increased

Opened airlock

15


Establish maximum permissible temperatures under regulations applied to the mine;

Review method of use of materials: consider possible fault conditions or other scenarios which may lead to higher temperatures being achieved.

c. Consider possibility of explosion/fire growth. Establish likelihood of fire spreading beyond

source; Include size of original fire and material

involved; Include consideration of fire resistance data for

items which may be subject to flame impingement.

d. Availability of explosion/fire detection systems.

Will personal be able to detect a fire; Use of environmental monitoring; Use of smoke detectors, infrared detectors or

other measuring systems and devices to look for hot spots.

e. What fire suppression systems are present? Are any fire detection systems in place? What is the method of warning control staff of

fire, in order to start the emergency procedure? What type are the fire suppression systems and

how effective are they? Consider nature of possible fuels and typical

extinguishing media; How are extinguishing substances to be

applied (injection into engine compartments, deluge etc.)?

Do any standards exists specifying details of fire suppression systems, if not how is the system to be installed?

f. Communication and evacuation. Are reliable communication systems in place

to coordinate fire and rescue operations? Are practice drills undertaken? How will the spread of post-explosion or post-

combustion gasses and smokes affect fire suppression and rescue measures?

Can the ventilation system be used to assist fire suppression and rescue operations? Is there a residual risk for ventilation reversal?

By applying the above synthesized basic principles it should be possible to identify the prevention safety barriers for unwanted events like methane and coal dust explosions and/or mine fires in the underground environment.

The structure of the integrated risk assessment methodology for explosion/fire risk assessment

Basically, the integrated methodology proposed for implementation in the specific

conditions of the underground environment of Valea Jiului collieries, involves the completion of the steps described below. STEP 1: Identification of fuels and ignition sources (others then methane gas) which can be involved in the dynamic phenomenon propagation, simultaneously with considerations given to workplace activities, job tasks and equipments characteristics to the analyzed unit (face, sector, ventilation circuit, etc). STEP 2: Establishing the potential for ignition of fuels.

Consider the likelihood of a fire or explosion occurring for all combinations of fuels and ignition sources identified and assign an overall risk rating. Also to be considered at this stage are any effects local air flow may have on hindering fire detection, or increasing the spread of fire.

Also, consideration must be given to the movement of a body of gas by the mine ventilation system into areas where sparks or flames may be present. For example, around mineral cutting or drilling equipment, shot firing, areas of coal seams undergoing spontaneous combustion, failed items of electrical or mechanical equipment generating sparks etc.

Risk reduction measures will be required for any area having a combined risk rating exceeding a present value. STEP 3: Risk reduction measures – reducing ignition probability. Methods for reducing risk in areas identified as having a high fire or explosion potential will include both means of reducing the likelihood of ignition and reducing the quantity of fuel present. Such measures may include:

Equipment design – evaluate design to determine if risk can be reduced through design changes;

Operating procedures – the threat of explosion/fire can be reduced through effective implementation of company policies and procedures; the safety philosophy should be grounded on the dualism resulting from the connection of top management commitment with an adequate level of safety culture (in correlation to the standard ISO 31000: Risk management – Principles and guidelines for implementation) [11];

Review of maintenance intervals; Reduction in the amount of combustible

materials through use of low flammability alternative;

Design, installation and maintenance of systems to limit the range of an explosion consequences. For example, in the case of

16


Valea Jiului collieries stone dust/water through barriers, explosion doors etc.

STEP 4: Identification of fire/explosion protection and warning systems, installation and accessibility. This stage is divided into three phases:

Phase 1 – Considerations of fire/explosions types. This entails using information from STEP 1 on fuel types and quantities to determine type of suppression system, how the agent is to be applied, the method of detection and areas where rapid fire spread may occur, requiring early detection and system activation.

Phase 2 – Fire detection equipment. The purpose of this section is to ensure consideration of all relevant areas, not just sitting of detectors. Also important is correct routing of signal cables from detectors, accessibility of enunciation panels etc. Explosion detection equipment–concerns environmental monitoring including firedamp measurements or hand-held instruments used by officials etc.

Phase 3 – Visibility and use of fire fighting equipment. Here the purpose is to ensure adequate signage of fire fighting equipment, case of accessibility, staff training etc. At each stage a column will be included to highlight where further action is required.

STEP 5: Means of escape. Considerations will be given to the means of escape given a fire or explosion, and the choice of self rescuer given the nature and toxicity of anticipated smoke. Establish how many people are at risk and method of notifying personnel of choice of escape route. STEP 6: Establish residual risk. To be completed for those areas for which a high risk rating was derived. This is a basic stage, which often is missing in the Valea Jiului collieries practice, in which the information regarding the residual risk is gathered and transmitted to workers. For example, they can be notified that when the self rescuer’s hose is damaged, the worker can breathe directly from the filtering cartridge. The final stages of the assessment are referring to issues for emergency plan, ongoing requirements and outstanding actions, as it follows: STEP 7: Prepare a table summarizing areas where fire or explosion is though possible, the main fuel and toxicity of smoke, evacuation routes considered (including the case of ventilation flow reversal) and the effects of possible disruption of communications. STEP 8: Prepare a table or list of ongoing safety

requirements and further measures which must be met for systems put in place to remain operational and effective, e.g. staff training, testing of fire fighting equipment, regular stone dusting etc. STEP 9: Prepare and act upon a list of outstanding actions identified during the assessment to ensure that systems put in place are effective. This involves the prioritization of risks, resource allocation and practical implementation of identified measures.

During the risk assessment and management process, it is of major importance the real (not formal) involvement of the key workers, following a well-established communication-consultation procedure. Conclusions

As fire is not the only underground hazard of

significance, the proposed methodology has been developed by combination of the principles outlined above, with additional consideration of explosion. The methodology will involve the completion of a number of check sheets to allow the user to establish the likelihood of fire or explosion, the number of personnel at risk, methods of evacuation and areas where a more detailed examination is required. Having identified prime areas for investigation, a more detailed analysis should be undertaken as part of the mine’s emergency preparedness documentation.

The first stage is concerned with establishing the potential for fire and explosion, either through workplace activities, or accidental ignition of combustible material. The first stage is to study the areas or operation of concern to identify combustible materials and potential ignition sources (either permanent or arising through fault conditions). The likelihood of fire/explosion occurrence is then evaluated by: • Noting the coexistence of potential ignition

sources ; • Noting the likelihood of an explosive

atmosphere occurrence; • Study of past fire and explosion incidents in a

particular operation, as they may have a high probability of reoccurrence;

• Study of maintenance routines – are they being met, is maintenance of an adequate standard, could maintenance operations themselves lead to an increased fire/explosion risk, are there any changes in the frequency of faults which may indicate either inadequate maintenance or the equipment is coming to the end of its lifetime, are replacement parts those recommended by the equipment supplier;

17


• Establish if the risk of fire/explosion is affected by standards of housekeeping. As stated above it is also of importance to give

practical consideration of workplace activities which could a fire/explosion, as well as identifying potential fuels and ignition sources. Such activities may include obvious areas such as mineral extraction/cutting, hot works such as grinding, cutting, welding, or possibly smoking, along with less obvious hazards such as working on electrical equipment where electrical fires may result from accidental shorting or damage to equipment, or working on methane drainage systems, where methane leaks could result in fire or explosion.

When undertaking a risk assessment it is of importance to consider the range of hazards proposed by personnel of all disciplines present in the affected area. This may include the mine manager, with whom ultimate responsibility lies, electrical and mechanical engineers, mine safety personnel and worker’s representatives. Depending on the perceived severity of the hazard difficulty in fire fighting or the length of the escape route, it may also be prudent to consult the Mine Rescue Service, or other emergency service who may attempt to undertake rescue or fire fighting underground. References 1. Cioca, L.I., Moraru, R., Băbuţ, G. Occupational Risk Assessment: A Framework for Understanding and Practical Guiding the Process in Romania, Proceedings of the International Conference on RISK MANAGEMENT, ASSESSMENT and MITIGATION (RIMA ’10), pp. 56-61, Bucharest, Romania, 20-22.04.2010, WSEAS Press, 2010; ISSN: 1790-2769, ISBN: 978-960-474-182-3, http://apps.isiknowledge.com 2. Matei, I.,Bǎbuţ, G., Moraru, R.,Hanna, C. The use of the FOCUS program for the assessment of safety conditions with the reopening of areas isolated as a result of spontaneous combustions in the Valea Jiului coal basin, Proceedings of the 3rd Canadian Conference on Computer Applications in the Mineral Industry (CAMI 95), pag. 720-724, Montreal, Canada, 22-25.10.1995, http://apps.isiknowledge.com. 3. Mitchell, D. W. Mine Fires: Prevention Detection and Fighting, Third Edition, 82-83 p (Intertec Publishing: Chicago), 1996. 4. Moraru, R., Băbuţ, G. Analiză de risc, Editura Universitas, Petroşani, 2000 5. Moraru, R., Băbuţ, G., Matei, I. Ghid pentru evaluarea riscurilor profesionale, Editura Focus, Petroşani, 2002 6. Moraru, R., Băbuţ, G. Managementul riscurilor: abordare globală - concepte, principii şi structură, Ed. Universitas, Petroşani, 2009

7. Moraru, R., Băbuţ, G.Cioca, L.I. Human Reliability Model and Application for Mine Dispatchers in Valea Jiului Coal Basin, Proceedings of the International Conference on Risk Management, Assessment and Mitigation (RIMA ’10), pp. 45-50, Bucharest, Romania, 20-22.04.2010 WSEAS Press, 2010; ISSN: 1790-2769, ISBN: 978-960-474-182-3 http://apps.isiknowledge.com 8. Moraru, R., Băbuţ, G. Managementul stresului de căldură în mediul cald şi umed specific activităţii de salvare minieră din bazinul carbonifer Valea Jiului/Management of heat stress in a hot, humid,underground environment specific to mine rescue activities in Valea Jiului coal basin Revista Minelor, vol. 16, nr. 2/2010, pag. 18-21 9. Moraru, R., Băbuţ, G. Modul de interpretare a deficienţei în oxigen din componenţa indicilor de apreciere a evoluţiei combustiilor spontane / Oxygen deficiencies interpretation for use in ratios assessing spontaneous combustion activity, Revista Minelor, vol. 16, nr. 3/2010, pag. 15-19 10. Moraru, R., Băbuţ, G. Evaluarea şi managementul participativ al riscurilor: Ghid practic, Editura Focus, Petroşani, 2010, ISBN:978-973-677-206-1. 11. x x x ISO 31000: Managementul riscului – principii şi linii directoare privind implementarea, ASRO, 2010

18


ASSESSMENT METHODS OF ANTHROPIC IMPACT ON THE TERRAIN FEATURES OF A REGION

Ciprian NIMARĂ*

Assessment of human impact on the relief is a challenge, because the assessment methods are very rare, due to the priority of assessing the human impact on other environmental components (water, air, soil, human communities) which are often ineffective when the term "relief" is considered synonymous with the term "landscape." Keywords: anthropogenic impact, evaluation, morphology, geomorphological diversity. Introduction

By economic activities, human society has imposed on the territory the emergence of relations between anthropogenic and environmental elements based on exploiting natural resources, in order to satisfy the needs. The result of this relationship, most often, highlighted by the appearance of an anthropogenic landscape, characterized by forms of relief that has not any geological or geomorphological process, genetically speaking, with an unpredictable evolution.

Human process of redesigning the original land is a vital social and economic development of human society. Induced land transformations consist of disruption a significant volume of materials, relocation and storage them in anthropogenic various forms of relief. Thus, the initial land form suffers a change of shape and function, the final result is the generation of a complex with an increased sensitivity to anthropogenic hazards. As technological development and spatial extent of the anthropogenic areas, has been produced a contradictory relationship with the natural environment. Anthropogenic shaping differs from the natural one by the rate of intensity during the event, complexity and shape of the products, offering irreversible changes to the land. Thus, areas with positive landforms, subject to human shaping, have been transformed from its original shape to a form almost horizontally and flat surfaces have been raised tens of meters. Following this feedback, morphological and structural changes are generated ____________________________________ * Ph.D student University of Petrosani

and the result would be a landform inversion and the appearance of critical environments. Assessment of human impact on the morphology and structure of the relief

A component of the concept of "sustainable development" is the management of impacts of social and economical activities on the environment.

Impact management requires detailed knowledge of the phenomenon, which involves going through stages of identification and estimation.

It is well known that any human activity has a wide range of implications which can be seen in various areas. In general, we need to take into account the full range of implications for indirect effects in some cases exceeding those of direct importance.

In a brief definition, evaluation of human impact on the morphology and structure of the landforms follows the scientific investigation of complex geomorphological effects resulting from the impacts of human activities on the structure and morphology of the original land.

By estimating the effects induced by anthropogenic impact on the morphology of land means the quantitative and / or quality assessment of geomorphological processes and phenomena. Many times, the novelty of problems, lack of previous or similar data, highly diverse nature of the effects of uncertainty and multiplicity of interactions with other environmental factors, the qualitative estimation may be the only solution, and the quantitative estimation may require the use of mathematical and physical models to provide a basis for interpreting the results.

The proposed assessment methods Assessment method of geomorphological quality depreciation

Geomorphological quality depreciation (DC) is calculated by summing the two parameters: geomorphologic type (Rg) and diversity of geomorphological features of interest (D) created from human activities, in order to highlight the severity of the impact on the terrain features from a region (table 1).

19


DC = Rg + D

Geomorphological type may have the following values of interest: local (1), regional (2), national (3) and global (4).

The diversity of geomorphological features of interest is given by the number (subtypes) of elements with geomorphological significance (table 2).

Regarding the type of affected geomorphological resource, the matrix can be filled with the landforms and the type of modelling system that created it, depending on the specific region. Ex: glacier modelling system (landforms: fjord, moraine, fjard, etc), marine and oceanic modelling system (landforms: cliffs, headland, bay, delta), etc.

After mapping, it can be identified the number of significant items created by the human activity (forms of accumulation, hollows, accumulation of water) in the natural landform, noting in table 1.

It will total all the elements created by human activity and pass the result obtained in section D, thereby achieving the diversity of geomorphological features of interest.

The obtained parameter will be introduced in the above formula and filled in table 1 as well, and according to the relation, the depreciation of geomorphological quality will be obtained (DC).

Depending on the coefficient of geomorphologic quality depreciation obtained, it can be made the following classification:

0 unaffected geomorphological environment;

1-3 less affected geomorphological environment;

4-6 moderately affected geomorphological environment;

7-10 strongly affected geomorphological environment;

≥ 10 intense modified geomorphological environment.

Table 1 Assessment matrix for geomorphologic quality depreciation

Name of affected geomorphological

resource

Cons.

no.

Modelling

system

Name of landform

Geomorphological

type

(Rg)

Diversity of

geomorphological features of interest

(D)

Quality

depreciation

(Dc)

Table 2 Diversity of geomorphological features of interest

Types of geomorphological elements

Cons.

no.

Name of geomorphological

resource Accumulation forms

Hollows Water accumulation

Diversity of geomorphological

features (D)

Total

Assessment method based on the relationship surface exhibition - solar radiation

This method takes into account the potential of climatic parameters to influence the vegetation growth on the surfaces of new landforms created by human activities.

Basis on the premise that areas with southern exhibition receive a larger amount of solar radiation, and the northern areas receive a lesser amount, it has been used a model for grades of creditworthiness, based on the use of values grouped into classes bounded by values - obtained through the threshold of Jenks optimization method (the method of optimal limits).

20


Thus, were awarded the following grades of creditworthiness (table 3):

Table 3 Grades of creditworthiness for the exposure of surfaces Grade of creditworthiness The range of values

quantitative qualitative

North 2 shaded North – East 3 shaded North – West 4 semi-shaded Horizontally 5 semi-shaded

East 6 semi-shaded West 7 semi-sunny

South –East 8 semi-sunny South – West 9 sunny

Exposure (versants

orientation)

South 10 sunny

As mentioned previously, the grades of creditworthiness were given according to the characteristics of areas in terms of quantity of solar radiation received (Filip S., 2008).

Thus, the orientation of the slopes is characterized as follows:

1 – 3 shaded slopes: North, North - East, is characterized by a lack of solar radiation, humidity and frequency of extra winds from a northerly direction;

4 – 6 semi-shaded slopes: East, North - West, horizontal surface is characterized by a significant contribution of solar radiation, especially in the early hours of the morning and a lack of moisture; are influenced by the general circulation of air masses from the east direction;

7 – 8 semi-sunny slopes: West, South - East, are sometimes considered to be similar to the eastern slopes, in terms of climate, but it has certain features, such as extra rain and heat in afternoon;

9 – 10 sunny slopes: South, South - West is characterized by an important contribution of solar radiation, humidity deficit and presents a specific climate, protected from cold winds. Assessment method “alteration – reuse”

I designed this method as a product of three parameters namely: the strategic level of the affected area, type of human activities and the ability of affected geomorphological environment to recover (resilience).

MR = Ns · Ta · R Strategic level (NS) indicates the importance

of the area or landform under anthropic activity in terms of economic importance, accessibility, distance from the attractions, location (inside or outside the city), etc. (table 4).

This parameter can have the following values: • 1 - low importance • 2 - medium importance • 3 - high importance

Table 4 Strategic level of landform Landform or area potential Strategic

level Ns

Low economical potential, unincorporated area, open to natural processes (sloughing, landslides, concentrated erosion), poor accessibility, low productive land uninhabitable area.

1

Medium economical potential, within incorporated area or unincorporated area, not subject to active geomorphological processes, areas occupied by forests, grassland or meadow, approachable, temporary living area (seasonal or recreational activities).

2

High economical potential, within incorporated area, land for building, areas occupied by agricultural land, roads, the land is not subject to active geomorphological processes, high accessibility, continuously inhabited area (residential centers).

3

21


Type of human activities (Ta) is represented by how the anthropogenic factor involved in changes of geomorphological environment (table 5). It is classified as: • constructive and / or accumulation human activities (anthropogenic accumulations like: waste dumps or landfills, local accumulations of water, concrete surfaces, buildings and yards, mud flows); • destructive and / or remodeling human activities (surface excavations, underground holes, terracing the slopes, products of compaction processes, subsidence processes, concentrated erosion, landslides);

For the type of human activities (constructive or destructive) was given a score depending on the impact on the geomorphological environment.

I started from the premise that the resulting products like dumps, excavations and accumulation of water are those which affect the geomorphological environment the most, both in terms of the quantity of mass circulated material (excavation, relocation), processes and phenomena that arise due to the combined action of external agents and in terms of occupied area.

The other products can be considered as related products, some of them are part of a particular process (terracing the slopes or reshaping a versant for a coal pit or quarry) or the result of primary process (erosion products developed on dumps or the landslides; geomorphological processes caused by gravity, for coal pits or quarries, but also for dumps: declines, rolls, or landslides).

Recovery capacity (R), represent the ability of the geomorphological system to return by itself or man-induced through rehabilitation to the state it was before the commencement of human activity, or to a state similar to the original. Starting from this idea a value for each case will be given: • R = 5, no possibility of recovery, 0%; • R = 4, reduced capacity for recovery, <25%; • R = 3, average capacity of recovery, 25-50%; • R = 2, high capacity of recovery, 50-75%; • R = 1, very high capacity for recovery, 75-

100%;

Table 5 Type of anthropogenic activity

Products of anthropic activities Grade Ta

h – anthropogenic accumulations (dumps, ash pit)

2,5

a – local water accumulations 2 sb – concrete surfaces 0,15

ci – buildings and yards 0,15 cn – mud flows 0,2

ex – excavations 2

gs – underground holes 0,2 tv – benches, platforms 1,5 pt – products of compaction processes 0,15

ps – products of subsidence processes 0,15

pec – products of concentrated erosion 0,2 dtm – landslides 0,8

Total 10

After applying the formula for assessing the impact on the morphology of a given area, the final outcome may fall, according to the scale, between 0 and 150, where:

0 – unaffected geomorphological environment, no human intervention, natural environment;

0-25 – less affected geomorphological environment;

25-50 – moderately affected geomorphological environment;

50-100 – strongly affected geomorphological environment;

100-150 – very strongly affected geomorphological environment due to overall change.

Using the table 4 and 5 in conjunction with the formula M = Ns · Ta · R, we obtain the coefficient of impact on landforms, later to be passed in the last column of the matrix of impact, table 6 (Nimară C., 2010).

Tab. 6 Matrix for human impact assessment on the relief

Name of the geomorphological

resource

No.

Natural modeling

system

Affected landform

Products of human activity

Strategic level

(Ns)

Type of activity (total)

(Ta)

Recovery capacity

(R)

Value of the final rate

(MR)

22


Conclusions

The impacts on environmental components are part of the "price" that human society and the environment are forced to pay for the benefits of natural resource consumption. From this point of view it is unrealistic to say that the exploitation of such resources will be made without damaging the environment.

The papers refer to the assessment of human impact on the landforms are very rare and the conceptual and methodological base is diverse and sometimes remote.

It is curious that, an important element of the environment is unvalued when it comes to assess human impact, given that the relief represents the base of the other geospheres: biosphere, hydrosphere, pedosphere, atmosphere (troposphere), landscape and human society (social and economical activities).

The base character, the role of physical base for organizing the environment, that gives a certain spaciousness of the other environmental components, proved to be decisive in their mode of action.

I would like to mention that, by using these methods of anthropic impact assessment to the morphology and structure of a geographical region, I wanted to highlight the impact generated by human activities, specific to a landform, named "geomorphological resource" and not to the entire region.

Assessment method of geomorphological quality depreciation is a more simplified method and it can be used for anthropic impact assessment in regions where the anthropogenic pressure on the landforms is not so significant in terms of diversity of anthropic products. This method takes into account only the major interventions and the

resulting products such as dumps, pits, ravines, considerable land subsidence and water accumulation (ponds or lakes).

Assessment method based on the relationship surface exhibition - solar radiation can be used in those cases where the affected area which will be reincorporated into the natural landscaping. The intent of creditworthiness grades is to support the decisions taken for the type of vegetation chosen. I mention that this method takes into account only the climate variability, created by the new exposure and not the type of soil.

The assessment method "alteration - reuse" is a complex method and can be used for regions which present a high anthropogenic pressure and a high geomorphological diversity, as well. This method is presented as a product of three parameters: the strategic level of the affected area, type of human activities that take into account both, human primary products, products that can be considered the "base" (dumps, quarries, coal pits and water reservoirs), but also secondary products, considered "related" (landslides, mud flows, products of subsidence, squeeze etc.) and recovery ability. References 1. Filip, S. Depresiunea şi Munceii Băii Mari, Studiu de geomorfologie environmentală, Ed. Presa Universitară Clujană, Cluj-Napoca, 2008; 2. Mac, I. Geomorfosfera şi geomorfosistemele, Ed. Presa Universitară Clujană, Cluj-Napoca, 1997; 3. Nimară, C. Evaluarea impactului antropic asupra morfostructurii Depresiunii Petroşani, raport de cercetare doctorat, Petroşani, 2010.

23


GROUND SURFACE DEFORMATION USING THE FINITE ELEMENT METHOD, IN CONDITIONS OF THE LONGWALL MINING OF THE

COAL LAYER NO. 3 - LIVEZENI MINE

Ilie ONICA*, Eugen COZMA*, Dacian Paul MARIAN** The Livezeni Mine is situated in eastern part of the Jiu Valley coal basin (Romania) and produces about 0.5 million tons of hard coal (presently, in totality from coal layers no.3). In the case of this thick and gentle coal layer, the mining methods are by use of the longwall mining technologies with roof control by rocks caving. In this paper, it is presented the analysis of the complex deformations of ground surface, as a consequence of superposed effect of three mining panels. Also, it is analysed the ground surface subsidence phenomenon using the 2D finite element method. The modelling is made in the elasticity and the elasto-plasticity behaviour hypothesis. The obtained results are compared with the in situ measurements data basis. Keywords: subsidence, horizontal displacement, stress, finite elements. Generalities

The Petroşani Hard Coal Basin, under the

management of the Hard Coal Company of Petroşani, contains the most important hard coal deposit of Romania, with a balance reserve about on billion tons of coal. This coal deposit was known and mined since the year 1788, as far back as the Austro-Hungarian Empire [1]. But, the intensive coal mining of this deposit began in the same time with the Romania’s industrialisation, after the Second World War, reaching after 1980 the over 9-10 millions tons of coal per year [1]. Due to Romanian industry reorganisation, after the year 1990, in conformity with the new demands of the market economy, the coal production of this basin was reduced to about 3.5 millions of tons per year, from which 0.5 million are obtained from the Livezeni mining field. From the beginning this ____________________________________ *Prof. eng. Ph.D University of Petrosani ** Eng. Ph.D student University of Petrosani

coal deposit was split into 16 mining fields, from which following several successive reorganisation and closing stages, only 7 mining fields are left in activity.

The complicated deposit tectonics determines the delimitation in geological blocks of reduced extent (most of them varying between 200 and 300 m) and an equally technical difficulty in mining. Moreover, there occurs a methane gas emission (of over 10 to 15 methane m3/coal ton) and there is a marked tendency of coal self-ignition [1], [2].

In this mining perimeter, through the geological research works, there was identified a number of 18 coal layers, of which the most economical importance having the coal layer no.3 (48%) and coal layer no.5 (12%). The sedimentary rocks complex, in which these coal layers are present, consists in rocks deposits which belong to Superior Cretaceous, Neocene and the Quaternary [12].

The subject of this study consists in the underground mining influence analysis on the ground surface of three adjacent mining panels (panel (3-4), panel 5 and panel 6), situated on the coal layer no.3, block VI A. Coal layer no.3, for these panels, was mined in inclined slices (about 2.5m thickness) with the longwall mining system, complexly-mechanized (powered support SMA-P2H, shearer 2K52-MY and armoured conveyer TR-7) and roof control by caving [2].

The underground excavations sizes results from the coal mining corresponding of these panels are presented into Table 1.

Table 1 The average sizes of the mining panel of the coal layer no.3, block VI A

Panel Slices number

Mined total thickness (m)

Longwall face length (m)

Panel extent (m)

Panel (3-4) 4 10 119 346

Panel 5 5 12.5 87 440

Panel 6 1 2.5 137 362

24


Figure 1 The monitoring station of ground displacement and deformation of Livezeni Mine

Geo-mechanical characterization

As the deposit genesis is sedimentary, the most frequent rocks in the basin are: limestones, marls, argillaceous or marly sandstones, conglomerates, etc., their strength ranging between 15–16 MPa up 50–60 MPa, sometimes even more. Mainly, they are rocks of relatively low stability [8]

The main factors that contribute at the definition of the stress and strain state surrounding the excavations generated by the coal layers mining with the roof rocks caving, in the Jiu Valley coal

basin, are the following: the excavation sizes, the layer dip, the coal and surrounding geo-mechanics characteristics, the mining depth, the face supports characteristics, the face advancement speed, the distance from the adjacent panels, the distance from nearby coal layers, etc [4], [8].

The average values of the main mechanical and elastic characteristics of the rocks used in the ground surface deformation analysis, in the Livezeni Mine conditions, are shown in the Table 2 [3], [11].

Table 2 The average values of the geo-mechanical characteristics of the roof and floor rocks

of the coal layer no.3 [3], [11]. Rocks

Rocks characteristics UM roof floor

Coal layer no.3

Apparent specific weight, aγ kN/m3 26.63 27.01 14.5

Module of elasticity, E kN/m2 5 035 000 5 268 000 1 035 000 Poisson ratio, ν - 0,19 0,20 0,13

Compressive strength, cσ kN/m2 43 500 46 000 12 500

Tensile strength, tσ kN/m2 4 600 4 950 1 000

Cohesion , C kN/m2 6 130 6 630 1 300 Internal friction angle, ϕ o 55 56 50

As a result of the measurement analysis made on the ground surface under the underground mining influence, so as to find the optimum design parameters of the main safety pillars, the limit

angles of subsidence have been set for the different coal mining fields of the Jiu Valley coal basin [9].

25


The values of the limit angles of influence ( γβ , andδ ), depending on the mining depth H (m), for the Livezeni mining field, in conformity with the instructions elaborated by the ICPMC Petroşani are expressed by the following relations:

8,560309,0 +⋅= Hβ ; 133,560261,0 +⋅= Hγ ;

867,51146,0 +⋅= Hδ Also, in the same conditions, the average

failure angles, recommended by ICPMC are the following:

orupere 5545 ÷=β ;

orupere 6055 ÷=γ ;

orupere 75=δ [9].

Ground surface deformation monitoring

Now, the monitoring of the ground surface deformation parameters under the underground mining influence at the Livezeni Mine is made

using a monitoring (surveying) station that consists in 50 benchmarks. The benchmarks’ emplacement is along the access road toward the Parâng Mountains tourist area [10]. The topographical measurements were made every three months, beginning with the year 2001. This monitoring station provides data concerning the ground subsidence area affected by the mining of the coal layer no.3, block IV A, panel (3-4), 5 and 6. Taking into account the values of the measured parameters, with the aid of the known calculus relations, there were determined the main parameters of the subsidence basin, namely: subsidence or vertical displacement, horizontal displacement, horizontal strain and the slope [5], [6].

The subsidence basin from the Figure 2 is a composed basin, resulted from the superposition influence of the three panels. This subsidence basin has an irregular shape due the fact that the three individual basin are intersected, and also because the monitoring station is situated toward the mining boundaries of the panels (Fig.1), area where the transversal deviations are maximum.

-400

-200

0

200

400

600

800

1000

0 200 400 600 800 1000 1200 1400 1600

Distance x (m)

Subs

iden

ce W

(mm

)

Month 6 - 2001 Month 9 - 2001 Month 12 - 2001 Month 3 - 2002Month 9 - 2002 Month 12 - 2002 Month 3 - 2003 Month 6 - 2003Month 9 - 2003 Month 12 - 2003 Month 3 - 2004 Month 6 - 2004Month 9 - 2004 Month 12 - 2004 Month 6 - 2005 Month 12 - 2005Month 6 - 2006 Month 12 - 2006 Month 6 - 2007 Month 12 - 2007Month 6 - 2008 Month 12 - 2008 Month 6 - 2009 Polynomial regression for MONTH 6 - 2009Subsidence - FEM modeling

W = 89,13568279-4,55910336x+0,05084368x2-0,17912987E-3x3+0,31353123E-6x4-0,2940696E-9x5+0,140039E-12x6-0,26E-16x7+0,00000x8

R = 0,8167

Figure 2 The subsidence profiles at the Livezeni Mine

In this case, the accuracy of the values that

characterise the obtained subsidence basin is lower because the fact that, it is not only the result of the ground subsidence but also the result of the displacement of it, and the deviations were corrected in conformity with the following methodology. Even if the transversal deviations that act on this subsidence profile are approximately equal in all the points situated inside the goaf, the difference level between every point benchmark at the base measurement and the their level at the final measurement is not the same,

because the ground surface elevation mark is different (Fig. 3).

Figure 3 The displacement and the subsidence of a point A

26


In these conditions, we are considering the points A and B that belong to a displacement and subsidence monitoring profile and the following parameters are defined: DAB –distance between the points A and B; ΔDX – displacement following the X axis (horizontal displacement); ΔDY – displacement following the Y axis (transversal deviation); SA – displacement following the Z axis (real subsidence of the point A); SA`m – the measured subsidence in the point A`. SA``m – the measured subsidence in the point A`` ; SA```m – the measured subsidence in the point A```;ΔHAA`` - initial level difference between the point A and the point A``; ΔHAA``` - initial level difference between the point A and the point A```.

Because the displacement is under few meters we can consider that the subsidence in the point A is equal to the subsidence in the point where that was displaced (the points A`, A``, A```), that is SA = SA` = SA`` = SA```.

The subsidence and the vertical displacements, previous mentioned, are calculated with the relation: Wi = H*i - Hi (mm) (where: H*i is the level of the point “i” at the zero measurement; Hi – the level of the point “i” measured at a given moment).

Analysing the in situ measurements situation, we can conclude that, taking into account the ground surface subsidence and displacements there are three cases of the correction determination of the measured values, namely:

1) Case when the point A, with the level HA, is displaced in the point A`, having the initial level equal to the level of the point A. In this case, there is no correction because the ground slope is zero, and by consequence, the measured subsidence is equal to the real subsidence (SA = SA`m);

2) When the point A, having the level HA, is displaced in the point A``, having the level HA``>HA . In this case the measured subsidence is less then the real subsidence (SA``m < SA) and, as a consequence, must be applied a correction equal to the initial difference level between the point A and the point A`` (ΔHAA``), namely: SA = SA``m+ HAA``;

3) When the point A, having the level HA, is displaced in the point A```, having the level HA``` < HA, the measured subsidence is greater than the real subsidence (SA```m > SA) and, as a consequence, must be applied a correction equal to the initial difference level between the point A and the point A``` (ΔHAA```), namely: SA = SA```m - ΔHAA```.

These adjustments of the measured values are necessary only in the case when the horizontal displacement and (or) the transversal deviation are significant and when the ground surface is inclined.

In the case of this monitoring (surveying) station, the maximum measured subsidence is of Wmax = 924mm and the horizontal displacement

ranges between the value of U = + 3712mm and U = - 3625mm. The average of maximum subsidence is Wmax = 524mm (the reference value in the case of numerical modelling).

Numerical modelling of the subsidence phenomenon

Models description

To build the 2D finite element calculus models the CESAR-LCPC finite element code was used. The CESAR software, development of which began in 1981, is the successor of the ROSALIE system developed by the Central Laboratory of Bridges and Roads of Paris, between 1963 and 1983. CESAR is a computational general code, based on the finite element method, addressed to the following areas: structures; soils and rocks mechanics; thermo-mechanics; hydrogeology. The CESAR-LCPC code, version 4, which involves the Cleo2D processor, completed with the C0 option (linear and non-linear static mechanics & diffusion) was used in this work, to perform the following models.

To determine the displacement and the ground surface deformation in the case of Livezeni Mine, where the ground is affected by the three panels, there were made two different models, in the plane strain hypothesis, namely: 1) the model “with mining voids” resulted as a consequence of underground coal mining; 2) the model “with caved zones” (on a height equal to eight times the mined height), due the roof rocks caving in the goaf (Figure 4).

The calculus for these two models was performed in two hypotheses: a) in the elastic behaviour of the rock massive and b) in the Mohr-Coulomb elasto-plastic without hardening behaviour. In view of finding the influence degree of every panel on the entire subsidence basin, generated by mining all of these three panels, maintaining the geo-mechanical conditions constant, there were made certain models where the coal layer mining was simulated with every independent panel.

In all of the modelling cases, both rocks and coal layer no.3 were supposed to be continuous, homogenous and isotropic and the geo-mechanical characteristics taken into the calculus having the average values (Tab.2).

The natural state of stresses was estimated being geostatic, characterized by the vertical stress

Hv ⋅= γσ and horizontal stress vh σ

ννσ ⋅−

=1

(because of the lack of the real values in situ measured).

27


To fit on the models in function of the measured values of the maximum vertical displacements and to correct the rocks and coal characteristics in laboratory obtained (Tab.2) toward the in situ values, the calculus of the models was made successively using the values reduced by

0%, 30%, 50% and 70% (respectively multiplied with a reducing coefficient K = 1; 0.7; 0.5; 0.3 - structural weakness coefficient). Because the numerical models were significantly sensitive only to the modulus of elasticity variation, only the reduction of this parameter was taken into analysis.

Figure 4 The finite element model “with caved zones”

Modelling achievement

2D modelling achievement, in the plane strain

hypothesis, for every previous defined model the following steps were necessary: a) establishment of boundaries, interest zones and meshing of the model; b) determination of zones (regions) and computational hypothesis and the geo-mechanical characteristics input; c) boundaries conditions establishment; d) initial conditions and loading conditions establishment; e) achievement of calculus and stoking of results [5].

Establishment of boundaries, interest zones and meshing of the model

For a better precision of the calculus, the

models were performed with sizes X=1500m and Y = 690m. Also, the sizes of the interest zone around underground excavations were established so as to involve the model surface where the stress and strain variation is maximum. Model meshing, respectively of every region, was made by triangle finite elements with quadratic interpolation. Respectively, the model meshing was performed with a total number of nodes of 23448 and surface elements of 11661.

Determination of regions and computational hypothesis and the geo-mechanical characteristics input

In order to make a qualitative description of the models, there were taken into consideration 3 regions with various geo-mechanical characteristics, in the case of the models “with mining voids”, respectively 4 regions in the case of the models “with caved zones”, adequate at the roof and floor rocks, coal layer and the caved rocks of the goaf.

The rocks characteristics, considered to be homogenous and isotropic, are presented in Table 2, and taken in the calculus in the elastic behavior hypothesis, respectively elasto- plastically without hardening behavior Mohr-Coulomb hypothesis, were reduced successively, taking into account the structural weakness coefficient.

The caved rocks of the goaf was considered being a very compressible elastic body, characterized by the elasticity modulus of 5000kN/m2, Poisson ratio of 0.4 and specific density of 1800kg/m3. Boundaries conditions establishment

The superior side of the model is considered

free and the lateral sides, blocked (for the inferior side the vertical displacements v = 0 and the horizontals 0≠u and for the lateral sides 0≠v şi u = 0).

Initial conditions and loading conditions establishment

Initial loading conditions of the model were

considered as geostatic [ ]oσ , corresponding to an

28


average mining depth of H=337m, namely: the vertical geostatic stresses

87819=⋅⋅= Hgsoy ρσ kN/m2=87.8MPa and the

horizontal geostatic stresses

=⋅=⋅−

= oyooyox k σσν

νσ1

21076kN/m2=21.076MPa

(where: 24.01

=−

=ν

νok ). The induced stress by the

excavation presence was [ ]eσ , respectively the stresses variation represented by the horizontal stress xeσ = -21.076MPa and the vertical stress

yeσ =-87.8MPa. Thus, the loading of the model

was performed in the total stresses: [ ] [ ] [ ]eoT σσσ −= [5].

Achievement of calculus and stoking of results

The calculus was made taking 60 iterations per increment and a tolerance of 1% of the results, using for the resolution the initial stress method

with non-linear behaviour of geo-mechanical problem. The calculus results were stocked in the graphical form on the model surface (isovalue, vector and tensor representation) and in the predefined sections following the ground surface. The results obtained are corresponding to the subsidence W (mm) and horizontal displacement U (mm).

Analysis of the numerical modeling results

Analyzing the obtained results from the numerical modeling it is observed that the surface basin has a simple shape, different by report to the real basin, because of their emplacement toward the goaf boundaries. In contrary, in the case of FEM modeling, the profile is situated in the middle part of the subsidence basin.

The maximum subsidence and displacements values obtained from the numerical modeling, in elasticity and elasto- plasticity, previous presented, are shown in Table 3.

Table 3 Maximum subsidence and displacements obtained from the numerical modelling for individual mining panel

and for grouped mining panels ELASTICITY - Models “with mining voids”

Panel 6 Panel 5 Panel (3-4) Panel (3-4) +5+6 W U W U W U W U Coef. Max.

Max. Min. Max

. Max

. Min. Max.

Max. Min. Max. Max

. Min.

mm mm mm mm mm mm mm mm mm mm mm mm K=1 132 39 -39 66 24 -19 110 41 -28 237 78 -71

K=0,7 189 56 -56 95 34 -27 157 58 -40 339 111 -101K=0,5 264 78 -79 133 48 -37 219 82 -55 474 156 -142K=0,3 440 130 -131 222 80 -62 365 136 -92 790 260 -237

ELASTO - PLASTICITY - Models “with mining voids” Panel 6 Panel 5 Panel (3-4) Panel (3-4) +5+6

W U W U W U W U Coef. Max.

Max. Min. Max

. Max

. Min. Max.

Max. Min. Max. Max

. Min.


K=0,7 192 57 -57 97 35 -27 157 58 -40 344 113 -103K=0,5 269 80 -80 135 48 -38 220 82 -56 482 158 -144K=0,3 448 133 -133 225 81 -63 367 136 -93 803 264 -240

ELASTICITY - Models “with caved zones” Panel 6 Panel 5 Panel (3-4) Panel (3-4) +5+6


Max. Min. Max

. Max

. Min. Max.

Max. Min. Max. Max

. Min.


K=0,7 184 53 -56 147 36 -57 207 59 -66 430 92 -169K=0,5 248 72 -76 203 50 -80 286 82 -91 590 125 -231K=0,3 380 110 -117 332 81 -129 463 132 -147 942 193 -370

29


ELASTO - PLASTICITY - Models “with caved zones” Panel 6 Panel 5 Panel (3-4) Panel (3-4) +5+6


Max. Min. Max

. Max

. Min. Max.

Max. Min. Max. Max

. Min.


K=0,7 177 52 -53 147 36 -57 207 59 -66 431 93 -169K=0,5 237 69 -72 203 50 -80 286 82 -91 592 125 -232K=0,3 360 105 -110 332 81 -129 463 132 -147 943 193 -370

From the previous table it could be observed

that, there are very small differences between the models computed in elasticity and the same ones in elasto-plasticity behaviour (the rocks having behaviour to the limits between these). The results more appropriate to the in situ measurement are for the “caved zones” models, in elasto-plasticity behaviour, for a structural weakness coefficient of K = 0.5.

In Figure 5 are represented the subsidence basins obtained for the models “with caved zones”, in elasto-plasticity (for K=0.5), as result of three panels mining, as well as the subsidence basin generated by the every singular panel and various combinations between them, and the horizontal displacements curves are shown in Figure 6.

-600

-500

-400

-300

-200

-100

0

100

0 200 400 600 800 1000 1200 1400 1600

Distance x (m)

Sub

side

nce

W (m

m)

Panel 6Panel 5Panel (3-4)Panel (3-4)+5+6Panel 5+6Panel (3-4)+6Panel (3-4)+5

Figure 5 The subsidence basins obtained from the numerical modelling

-250

-200

-150

-100

-50

0

50

100

150

0 200 400 600 800 1000 1200 1400 1600

Distance x (m)

Hor

izon

tal D

ispl

acem

ent U

(mm

)

Panel 6Panel 5Panel (3-4)Panou (3-4)+5+6

Figure 6 The horizontal displacement graphics obtained from the numerical modelling

30


The subsidence basins obtained from the numerical (FEM) modelling on the model “with mining voids” and on the model “with caving zones”, for all that three mining panels, in elasticity

and elasto-plasticity, for a structural weakness coefficient of K = 0.5 are presented in the Figure 7 and the horizontal displacement curves in the Figure 8.

-600

-500

-400

-300

-200

-100

0

100

0 200 400 600 800 1000 1200 1400 1600

Distance x (m)

Subs

iden

ce W

(mm

)

Model "with mining voids" ElasticityModel "with mining voids" Elasto-plasticityModel "with caved zones" ElasticityModel "with caved zones" Elasto-plasticity

Figure 7 The subsidence basins obtained from numerical modelling in elasticity and elasto-plasticity rocks behaviour

-250

-200

-150

-100

-50

0

50

100

150

200

0 200 400 600 800 1000 1200 1400 1600

Distance x (m)

Hor

izon

tal D

ispl

acem

ent U

(mm

)

Model "with mining voids" Elasticity

Model "with mining voids" Elasto-plasticity

Model "with caved zones" Elasticity

Model "with caved zones" Elasto-plasticity

Figure 8 The horizontal displacement graphics obtained from numerical modelling

From the Figure 7 can be concluded the fact

that between the model “with mining voids” and the model “with caved zones” there is a small difference, about of 200mm. Also, between the same type models, computed in elasticity and elasto-plasticity, the difference is very small (negligible).

The surface zones affected by the compressions (a), tractions (b) and shears (c),

where there could appear the opening phenomenon of the natural fissures or the new ones arising by exceeding the strength limits of the rocks, are shown in the fig. 9. The general state of stresses, developed in the rock massive, represented by the maximum stress 1σ (a) and minimum stress 2σ (b), under the underground excavations influence, are represented in fig. 10.

31


Figure 9 Compressive stresses (a), tensile stresses (b) and shear stresses (c) at the ground surface

calculated in the elasto-plasticity hypothesis

a)

b)

Figure 10 Isovalue representation of the maximum stress 1σ (a) and minimum stress 2σ (b), in the rock massive, affected by the underground excavations

Conclusions

The subsidence and displacement monitoring (surveying) station, in the case of Livezeni Hard Coal Mine, that consists of 50 benchmarks, where there are measured the ground surface subsidence and displacement every three months. This ground surface is affected by the coal underground mining

of three panels, mined with longwall faces and roof control by total caving. Thus were determined the main parameters of the subsidence basin (subsidence or vertical displacement, horizontal displacement, horizontal strain, slope and the curvature).

The subsidence basin has a very complicated shape, being the result of coal layer no.3 mining

32


with three neighbouring panels, and the monitoring (surveying) station is situated towards the boundaries of these three mining panels (where the deviations are considerable).

In this case, for a better understanding of the subsidence phenomenon, the 2D modelling with finite element method was used. Thus, with the aid of CESAR-LCPC code was generated two models groups, namely: “with mining voids” and “with caved zones”. The calculus was performed in the elasticity rock behaviour and in the elasto-plasticity behaviour Mohr-Coulomb hypothesis.

After the analysis of the obtained results we can conclude the fact that the model with the more appropriate values by the in situ reality is the one “with caved zones”, computed in the elasto-plasticity Mohr-Coulomb hypothesis, for a structural weakness coefficient K=0.5 (the maximum obtained subsidence is of Wmax = - 592mm and the horizontal displacements ranging between of U = + 125mm and of U= - 232mm).

References 1. Almăşan, B. Exploatarea zăcămintelor minerale din România, Volumul I, Editura Tehnică, Bucureşti, 1984, pag. 70-291. 2. Covaci, St. Exploatări miniere subterane, Vol.I, Editura Didactică şi Pedagogică, Bucureşti, 1983, pag.424. 3. Hirian, C. Mecanica rocilor, Editura Didactică şi Pedagogică, Bucureşti, 1981, pag. 322 4. Oncioiu, G., Onica, I. Ground Deformation in the Case of Underground Mining of Thick and Dip Coal Seams in Jiu Valley Basin (Romania),Procedeengs of 18th International Conference on Ground Control in Mining, 3-5 August, 1999, Morgantown, WV, USA, 1999, pag.330-336.

5. Onica, I. Introducere în metode numerice utilizate în analiza stabilităţii excavaţiilor miniere, Editura Universitas, Petroşani, 2001, pag. 156. 6. Onica, I. Impactul exploatării zăcămintelor de s.m.u. asupra mediului, Editura Universitas, Petroşani, 2001, pag.173-198. 7. Onica, I., Cozma, E., Goldan, T. Degradarea terenului de la suprafaţă sub influenţa exploatării subterane, Buletinul AGIR, anul XI, nr.3, 2006, pag.14-27. 8. Onica, I., Cozma, E. Stress and Strain State Developed Around the Longwall Faces in the Jiu Valley Coal Basin, Proceedings of the 21 World Mining Congress & Expo –Session 6: Coal Mining – Chances and Challenges, Krakow, 2008, pp.153-163. 9. Ortelecan, M. Studiul deplasării suprafeţei sub influenţa exploatării subterane a zăcămintelor din Valea Jiului, zona estică, Teză de doctorat, Universitatea din Petroşani, 1997, pag.195 10. Ortelecan, M., Pop, N. Metode topografice de urmărire a comportării construcţiilor şi terenurilor înconjurătoare, AcademicPres, Cluj-Napoca, 2005, pag. 256 11. Todorescu, A. Proprietăţile rocilor, Editura Tehnică, Bucureşti, 1984, pag. 676 12. Petrescu, I. ş.a. Geologia zăcămintelor de cărbuni. Zăcăminte din România, Vol.2 Editura Tehnică, Bucureşti, 1987, pag.81-106.

33


COMPLEX TECHNOLOGICAL SYSTEM OF CRUSHING – FINE GRINDING – PNEUMATIC SIZING FOR INDUSTRIAL MINERALS WITH

LOW AND MEDIUM HARDNESS FOR THE MANUFACTURING OF COSMETIC PRODUCTS AND FOOD – SUPPLEMENTS

Emil TEODORESCU*, Iuliana TEODORESCU*, Nicolae GIURGIU*,

Toma PRIDA*, Carmen SOCACIU** This project was proposed by a consortium that includes S. C. MINESA MINING RESEARCH AND DESIGN INSTITUTE S.A. Cluj – Napoca and AGRICULTURAL SCIENCE AND VETERINARY MEDICINE UNIVERSITY (USAMV) Cluj-Napoca. The main objective was the design and the implementation of a complex system of crushing / fine grinding and pneumatic sizing of industrial minerals, used in the manufacture of cosmetic products and food supplements. The technology designed and implemented in the Project consists of several modules: inter-phase transport, crushing and grinding of raw ore, drying in a temperature and time-controlled environment, crushing / fine grinding and pneumatic sizing, physical and chemical analysis and quality control, packaging, calibration and labeling, temporary storage of finite products before delivery to the beneficiary. With minimal technological changes, the process can produce fine grinded products that are chemically inert and sterile and have strictly controlled granulometric structures ranging from 0 – 15 microns to 0 – 60 microns. Under certain conditions, up to 140 microns can be obtained. Keywords: fine grinding, cosmetic products, fibroblasts Introduction

The paper presents the final stage of the

researches performed in the Project “Research regarding the manufacturing of fine grinded competitive industrial minerals, requested in the cosmetics and food industries, by designing and implementing of performing processing systems”, project which is part of the NATIONAL PLAN FOR RESEARCH – DEVELOPMENT AND INNOVATION II 2007 – 2013, INNOVATION ____________________________________ * Eng. S.C. MINESA ICPM S.A. Cluj-Napoca ** Prof. Ph.D USAMV Cluj-Napoca

PROGRAM NO. 5, coordinated by AMCSIT – POLYTECHNIC UNIVERSITY Bucharest, developed in 2007 – 2009, with the economical effects finalization in the 2010, and it is a following of the article (1) published in the Mining Magazine no. 1/2009.

Since 2000, at the economic agent continuant request, whit holds an important position in the internal market of cosmetics industry, SC MINESA Mining Research – Design Institute SA Cluj – Napoca, has started to produce 3 – 4 types of fine grinded clay, with well defined granulometric structures, in the Micro production Station,. The economic agent as beneficiary uses these types of fine grinded clay for manufacturing a wide range of cosmetic products and some food supplements. Unfortunately, because of the advanced rate of ware of the technologies equipment, overcome both physical and moral, obtaining the clay types at the strict qualitative conditions requested by the beneficiary, was accomplished with great efforts and high costs. The beneficiary has continued soliciting higher quantities, practically very hard to obtain given the existent endowment (the fine grinded clay solicited had exponentially grown, reaching from 5,000 kg in 2000, at 50,000 kg in 2007). Because of the high costs requested for processing these types of clay, the benefit was insufficient for obtaining, if not the endowment with modern technology, at least modernization of the existent one.

Having a supplementary benefit as part of a co-financed budget Project, SC MINESA Mining Research – Design Institute SA Cluj – Napoca, has proposed to obtain a processing technology for industrial minerals, with the final purpose of obtaining fine grinded products, used in the cosmetic industry and the manufacturing of food supplements.

The technology was especially based on the field of obtaining fine grinded final products as clay and volcanic tuff, this approach was not limitative, and it was ended with achieving a technology that could also be used, with minimum accommodation, for fine grinding other industrial minerals with similar physical – chemical properties, and with adjacent use area like talc,

34


calcite, dolomite and limestone, kaolin, diatomite, etc.

Technology description

The processing technology founded, designed

and accomplished according to the Project, is a modular technology comprised of the following functional modules: inter-phase transport, crushing and grinding of raw ore, drying in a temperature and time-controlled environment, crushing / fine grinding and pneumatic sizing, physical and chemical analysis and quality control, packaging, calibration and labeling, temporary storage of final products before delivery to the users. Based on the specific requests of the consumers, with minimal technological changes, the process can produce fine grinded products that are chemically inert and sterile and have strictly controlled granulometric structures ranging from 0 – 15 microns to 0 – 60 microns, and under certain conditions, up to 140 microns can be obtained.

Emplacement, installation and operation of the technological equipment

The technological equipment was located into

an existing building, out of service, in a space limited by closing up with full and glassware panels, used for separating the surrounding spaces. There where installed two dusting installations, equipped with performance hardware for capturing and retaining mineral dusts. By applying the last two measures there was created the optimum condition for performing the productive process, assuring the safety and microclimate conditions and for manufacturing the necessary raw materials and obtaining the cosmetic and food supplements products, and with positive impact on the environment and health of the working staff.

Fig. 1 and 2 are pictures of the drying installation, and the fine grinding and pneumatically sizing installation.

After finalizing the processing equipment installation and the run on empty and on load, there where performed technical adjustment works for the optimum work parameters determination. So, the technical parameters and the production capacity where determined for manufacturing three types of clay (Type I with 0 – 20 microns granulosity, Type II with 0 – 40 microns granulosity, Type III with 0 – 60 microns granulosity).

The production capacity accomplished by the technology implementation, based on the fineness requested by the final products, varies between 50 – 80 kg / h, and is dictated by the fine grinding –

sizing modulus capacity. The installation may function for 3 shifts – 7 working hours per day, with approx. 1 hour break per shift, for control, repairs and technological adjustments.

Figure 1 Drying installation

Figure 2 Fine grinding and classing installation

The no. 1 Partner, AGRICULTURAL SCIENCE AND VETERINARY MEDICINE UNIVERSITY (USAMV) Cluj-Napoca, has accomplished the particles spectroscopic print characterization Uv – Vis FT – IR, such as and in different types of suspensions; particles size and dispersion degree assessment in cellular culture mediums (fibroblast), by microscopically methods, cyto-toxicity in vitro study on leukocyte and fibroblast cellular cultures, for the fine grinded mineral products obtained on the designed and implemented technology, according to the Project. There were performed analyzes on clays response, in natural and fine grinded form on the cellular systems by measuring up the cyto-toxicity markers. The cyto-toxicity in vitro study was realized on leukocyte cultures (experimental variant for oral administration). For testing the bio-stimulating capacity, or the cell proliferation inhibition due to the fine grinded clays, fibroblastic – epithelial (RPE – D407) cells where used. The tests performed on two clay samples (fine grinded in two different variants Type I with 0 – 20 microns granulosity, Type III with 0 – 60 microns granulosity), have demonstrated, both on the leukocyte cells and fibroblastic cells, the lack of cyto-toxicity. So, the conclusion is that these clays can be used as ingredients and additives in the orally and direct dermal

35


administrated products (cosmetic and dermatological products). The industrial lot production

After the optimum processing conditions

determination and according to the results obtained in the laboratory research stage, and with the tests results for the potential users of the technology’s products, the finale products lot was started.

For 2009 there was a firm order for the production of 50,000 kg fine grinded clay, Type III, use in manufacturing cosmetic and food supplement products. As a result, the production of this type of clay was initiated, using the complex technology of crushing, graining, drying, fine grinding and pneumatic sizing, designed and performed according to the Project. By the end of the last stage of the Project, there where 6,900 kg Type III fine grinded clay manufactured and delivered to the beneficiary. The fine grinded clay production has continued until the end of 2009, with a total quantity about 42,000 kg.

The fine grinded clay lot production has testified the optimum processing parameters determined in the technological adjustment stage, the differences from those parameters being insignificant, with values below 1% in regard to the optimum values. So far, the beneficiary had no complains related to the quality of fine grinded clays lot delivered.

As an additional advantage and very important for the research beneficiary - SC MINESA Mining Research – Design Institute SA Cluj – Napoca – is the acquisition and the implementation of a modular complex technological line for crushing – fine grinding – pneumatic sizing, under strict condition related to the food and cosmetic products safety for human use, which will serve as a research base for future developments.

As a result of the Project specific Innovative process, the invention proposal no. A/00587/28.07.2009 was registered at OSIM Bucharest, with the title: “Modular fine grinding technology for industrial minerals with low and medium hardness”, applicant: SC MINESA Mining Research – Design Institute SA Cluj – Napoca and

titular: SC MINESA Mining Research – Design Institute SA Cluj – Napoca. Conclusions 1. The processing technology, founded, designed,

and implemented according to the Project, is a modular technology, comprised of several functional modules, the number of the modules and their activation sequence depends on the processed mineral materials, and on the finale products quality.

2. Based on the consumers specific requests, with minimum technological changes, fine grinded industrial minerals can be obtained and these minerals are chemically inert and sterile, and have strictly controlled granulometric structures ranging from 0 – 15 microns to 0 – 60 microns, and even up to 140 microns, under certain conditions

3. Following up the performed studies, USAMV Cluj – Napoca has established that these clays can be used as ingredients and additives in the orally and direct dermal administrated products (cosmetic and dermatological products).

References 1. Teodorescu, E. ş.a. Obţinerea de substanţe nemetalifere micronizate competitive, solicitate de industria produselor cosmetice şi industria alimentară, prin elaborarea şi implementarea unor sisteme performante de procesare. Revista Minelor nr. 1/2009, pag. 17 – 20. 2. Wiegel, O. Zeolith Kristallography. 1925. 3. Bărbat, A. Tufurile vulcanice zeolitice Editura Dacia Cluj-Napoca, 1989. 4. Timbuş, I. Miracolele tratamentelor cu rocă de argilă naturală Editura Cartimpex, Cluj-Napoca, 2001. 5. Ghizdavu, L. Chimie bioanorganică Ed. Polirom, Cluj-Napoca, 2000. 6. Wroblewski, F., LaDue, J. S. Lactic dehydrogenase activity in blood 1995 Proc. Soc. Exp. Biol. Med. 90:210–213

36


STUDY ON RESTORATION OF TOPSOIL ON THE WASTE DUMPS IN JIU’S VALLEY

Eugen TRAISTĂ*, Emanoel ANDRONACHE**

This paper presents a descriptive study on vegetal soil restoration on waste dumps from Jiu’s Valley. The introduction refers to the activation of nitrogen. The article content presents nitrogen fixation and amonia formation. There are also presented considerations on anthropogenic soils and a comparative study between waste dumps from Ukraine and Jiu’s Valley. The paper ends with conclusions regarding anthropogenic soils, enzymatic activities and the existance of bacteria in soils. Keywords: anthropogenic soil, enzymological analysis, waste dump Introduction

Altough nitrogen forms many compounds, the nitrogen molecule, N2, is very little reactive.

Very low rate of all reactions of nitrogen is influenced on the one hand, by the strength of N ≡ N connections and therefore a higher activation energy is necesary to break this bond, and on the other hand low polarized action of N2, which prevents the formation of high polarity transition states, states which usually occur in replacement reaction of electrophilicity and nucleophiles agents.

In this sense, a way to fix nitrogen, which must be taken into account in the future, is based on the observation that bacteria can convert atmospheric N2, at room temperature, into a series of compounds. The main underlying process of fixing nitrogen in the soil is catalytic conversion of dinitrogen in NH4

+ in the presence of an enzyme called nitrogenase, located in the root nodules of legumes. Nitrogenase contains in active site Fe and Mo ions. These discoveries have led to the conclusion that catalysts can be obtained in which the metal ions can be coordinated to N2, resulting in its reduction.

In this way many N2 complexes were prepared. In some cases, preparation is very simple, consisting of N2 bubbling through an aqueous solution of a complex:

[Ru(NH3)5(OH)]+2

(aq) + N2 (g) → [Ru(NH3)5(N2)]+2

(aq) + H2O (l) ____________________________________ * Assoc. prof. eng. Ph.D University of Petrosani ** Ph.D student University of Petrosani

N2 molecule can function as linking, beeing linked to the metal as the isoelectronic molecule of CO. In the Ru(II) complex, the N ≡ N connection is very little modified. However, when N2 is coordinated to a metal center with strongly reducing character, the nitrogen-nitrogen connection considerably lengthens by retrodonation of orbital π electrons of N2. Although no catalysts were obtained for N2 reduction, there is hope in this regard because it is possible that the N2 bounded in some of these complexes may be transformed in NH4

+:

cis – [W(N2)2{P(CH3)2(C6H5)}4] ⎯⎯⎯ →⎯ 4SO2H N2 + NH +

4 + W(IV) compounds

The nitrogen fixation

Nature uses a way of obtaining NH3 completely different from the industrial way, but much more complicated. The reducing agent used by nature is ATP and the reaction can be represented as:

N2 + 16MgATP + 8e- + 8H+ → 2NH3

+16MgADP +16Pi + H2, where Pi is inorganic phosphate. This process is

probably much less effective than the Haber process, because the energy consumption required for reduction of hydrogen, as well as for protectection against atmospheric oxygen of the biological system with a high reducing potential.

The special characteristic, attractive, of such a process is that it occurs at room temperature and pressure in Rhizobium organisms living in the roots of vegetables (alfalfa, beans, clover, peas etc.), as well as in some bacteria or blue-green algae. Nitrogenase enzyme catalyzes the reaction under anaerobic conditions, being able to destroy the high inertia of the N ≡ N molecule.

The mechanical details of N2 fixation are still unclear, but it id known that nitrogenase uses for this purpose an iron-sulfur protein and a molybdenum-sulfur protein.

37


Figure 1 Coupling made between dephosphorylation of ATP to ADP and reduction of molecular nitrogen (N2) to NH4

+

The structure of complexes containing

molecular nitrogen is well known in inorganic chemistry, but this one is completely different from the proposed structure of biological compounds. In the presence of a strong acid, N2 in some inorganic complexes undergo a reduction proces, induced by protons, to ammonium ion:

( )( )[ ] ( ) .....VIMoNNH2H8NPRMo 24223 +++↔+ ++

The idea that multiple binding sites containing metals may facilitate the reduction of N2 echoed in organometallic chemistry, where it was shown that metal clusters facilitate proton-induced reduction of the CO molecule - isoelectronic molecule with N2.

Anthropogenic soils

Anthropogenic soils are soils formed from mining-technical biological recultivation of overburden materials, waste dumps and other residues of the open pit and underground mining and other industrial activities. Also, all these residues constitute a dangerous source of environmental pollution.

By definition, the evolution of anthropogenic soils is the transformation of all these residues in agricultural or forest soils or land used for other purposes (parks, playgrounds etc.). Simultaneously, this process is accompanied by the reduction or elimination of the polluting effects of waste on the environment. The practical importance of this process is growing because of the development of mining and other industries leading to increasing quantities of waste and, therefore, recultivation of degraded land is becoming a major economic necessity. It is estimated that by 1980 on the surface of the earth there have been accumulated

about 1,600 billion m3 of waste dumps and the volume has increased annually by about 40 billion m3. As a comparison we remember that water erosion affects a smaller volume of soil, that does not exceed 13 billion m3 per year. According to some estimates, in order to extract a million tonnes of coal about 40 to 50 hectares of farmland are put out of the normal circuit.

The evolution of anthropogenic soils presents a theoretical importance, related to a deeper knowledge of landscape development looked upon as a whole.

The evolution of anthropogenic soils, which reflects recultivation efficiency, is studied by various methods including a series of physical, chemical and biological methods. Enzymological methods, have also been applied and found that the enzyme activity is a good indicator for anthropogenic soils evolution.

Chemical methods who include the determination of humus, base exchange capacitie and hydrogen exchange capacitie, nutrients such as N, P, K, B does not lead to results that can be directly correlated with fertility and implicitly crop production made on those soils .

For a better assessment of the ability of land to be vegetated some analysis are needed to be performed to reflect the enzymatic activity of bacteria existing in soil.

Of interest for enzyme activity, is catalase, urease, invertase etc.

Catalase can be measured by the ability to cleave hydrogen peroxide by the soil. It was found that the ability to cleave H2O2, in particular its termolabile component, always give higher values in well-developed plots with plants than in plots where plant growth was inhibited. Recultivated

38


waste dumps properties to make possible for forest species to grow can be assessed by measuring the catalytic activity.

Urease is the proces of decomposition of urea by soil enzymes. Urease is measured by the amount of ammonium formed in 100 g soil in 40 hours.

Invertase is a process of hydrolysis of sugar with the formation of fructose and glucose. Invertase is measured by the amount of inverted sugar by a gram of soil in 40 hours.

Studies of the mine waste dumps recultivate at Iurkov in Ukraine determined invertase, urease and catalase activities in the soils of plots planted with lupine and black alder compared with fallow plots. The results in table 1 show that the enzyme activities decreased with depth in all plots from

which samples were collected. Under the action of recultivation, enzymatic activities were clearly increased, sometimes several times, compared with activities recorded in control plots. Perennial lupine effect was stronger than that of black alder. Because lupine the humus content and total nitrogen content also increased, from 2.94 - 2.87 times, respectively 2.94 - 3.30 times. In alder plots, the humus content and total nitrogen content increased 1.95 times, respectively 1.81 times.

The results show that the recultivation with black alder and in particular with the green fertilizer plant (perennial lupine) makes it possible to increase the fertility levels of anthropogenic soils in a relatively short period of time.

Table 1 Plantation and its age Depth Invertase Urease Catalase

Perennial lupin(5 years) 0 - 2

2 - 10 10 - 20

39,48 17,57 6,45

136,9 97,4 61,5

209,8 135,5 84,7

Black alder (5 years) 0 - 2

2 - 10 10 - 20

30,82 16,76 3,68

125,6 74,6 42,7

168,2 106,2 74,3

Control (fallow) 0 - 2

2 - 10 10 - 20

6,56 2,65 1,56

70,5 45,2 15,2

124,0 90,1 59,4

Waste dumps from Iurkov recultivated with

different species of trees and shrubs have become fertile soils in a relatively short time (9-14 years)

already having a layer of humus and N content and a high enzymatic potential (table 2).

Table 2

Plantation and its age Depth (cm)

Humus (%)

N (%)

N in humus (%)

Invertase Urease

Sylva pine(14 years)

0 - 2 2 - 5

5 - 10 10 - 20 20 - 30

4,74 2,33 1,20 0,41 0,36

0,24 0,12 0,07 0,02 0,02

6,0 5,1 5,8 5,0 5,5

29,70 10,00 6,62 4,42 0,60

1,96 0,56 0,45 0,34 0,26

Acacia(9 years)

0 - 2 2 - 5

5 - 10 10 - 20 20 - 30

2,08 1,02 0,73 0,16 0,11

0,18 0,09 0,07 0,01 0,01

8,6 9,0 9,6 6,2 9,9

22,30 8,03 4,90 1,12 0,60

1,64 0,62 0,33 0,28 0,15

Sea buckthorn (9 years)

0 - 2 2 - 5

5 - 10 10 - 20 20 - 30

1,65 0,75 0,43 0,26 0,18

0,19 0,06 0,04 0,02 0,02

11,0 8,0 9,5 8,0

11,1

44,50 11,20 2,25 1,71 1,02

3,68 0,72 0,37 0,16 0,11

Black alder (9 years)

0 - 2 2 - 5

5 - 10 10 - 20 20 - 30

1,30 1,03 0,84 0,17 0,19

0,13 0,12 0,08 0,03 0,03

10,0 11,6 9,5

17,6 15,8

28,50 13,50 7,50 4,70 0,80

2,86 0,84 0,42 0,32 0,25

Control (fallow)

0 - 2 2 - 5

5 - 10 10 - 20 20 - 30

0,72 0,43 0,24 0,23 0,21

0,05 0,02 0,01 0,01 0,01

6,9 4,6 4,1 4,3 5,0

10,80 5,20 2,35 0,10

0

1,08 0,71 0,32 0,20

0

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Waste dumps, consisting predominantly of loess from the brown coal open pit mining from Baidakov - Ukraine were also studied multilaterally. It was found, among others, that the invertase, urease and respiration activities (CO2 production) are very low in the loess forming the quarry’s walls and in the waste dumps of loess uncovered with vegetation. Enzymatic activities

and respiration increased dramatically in parallel with the age of vegetation spontaneously installed on the loess consisting dumps. However, activity and respiration values were lower in waste dumps covered with 23 years old spontaneous vegetation, than the values measured in the soil area unaffected by mining (Table 3).

Table 3

Studied material Invertase Urease Respiration Material from the quarry walls Material from the fallow waste dump Material from the dump with spontaneous vegetation: 1 year 2 years 4 years 23 years Soil in the area (chernozem)

0.3 0.3

1.2 2.2 4.1 7.0

20.5

1.1 1.4

1.5 2.0 2.3 4.5

15.6

4.4 4.6

5.1 -

28.7 35.3

217.0

Also it was studied the enzyme activity and chemical composition of surface layer (0-50 cm) away from the ground and stored in heaps, before total overburdening and coal exploitation. Piles whose height was 1.5 - 4 m, were used after 3-5 years of storage to cover the leveled waste dumps for their recultivation. In the stored surface soil, catalase activity remained almost the same level as in the 0-50 cm layer of leached chernozem from the area unaffected by mining (native soil). However, urease activity decreased and proteinase activity increased somehow in the stored surface soil. The quantity and qualitative composition of humic substances I the stored soil had values close to those recorded in native soil.

The deposited soil, after it was placed on the leveled dumps and its recultivation with perennial grasses, showed catalase and urease activities similar to activities of the seasonal average of the 0-50 cm layer of native soil, while proteinase activity was 3 times higher in the soil placed on the dumps than in native soil.

To verify the possibility of using these parameters for the waste dumps in from Jiu’s Valley a series of tests were conducted on soil samples collected from waste dumps and their surrounding areas.

The obtained results are given in tables 4 and 5:

Table 4

Nrcrt Sample name Invertase Urease Catalase

1 M.E. Petrila– control soil sample 37,213 3,383 6,089 2 M.E. Petrila–waste dump soil sample 14,536 1,264 2,300 3 M.E. Aninoasa – Tericon dump 9,200 0,800 1,472 4 M.E. Aninoasa – Tericon dump 8,291 0,721 1,326 5 Petrila processing plant– fertile soil 25,334 2,203 4,031 6 M.E. Livezeni – PA 3 dump 26,542 2,308 4,223

7 M.E. Aninoasa – Piscu dump 28,048 2,439 4,463 8 M.E. Aninoasa – Piscu dump 33,476 2,911 5,327 9 M.E. South Aninoasa – control sample 28,957 2,518 4,607 10 M.E. North Aninoasa – control sample 51,931 4,721 8,545

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Table 5

Parameter 1 2 3 4 5 6 7 8 9 10

pH 5,4 6,1 7,6 5,8 5,4 7,6 7,2 5,8 5,4 6,1 Combustible parts 17,3 7,5 8,6 15,4 15,3 6,5 8,5 19,5 14,1 12,5 Coarse sand 54,39 56,69 66,67 14,48 42,64 42,64 62,64 46,51 59,89 18,23Fine sand 32,48 21,58 20,28 39,59 29,25 29,25 21,80 27,47 17,24 35,46Powder I 9,62 7,78 4,21 21,17 14,60 14,60 5,83 15,49 6,93 21,15Powder II 2,36 1,63 0,63 12,38 4,73 4,73 1,75 4,00 1,59 10,69Clay 1,15 12,32 8,21 12,38 8,78 8,78 7,98 6,53 14,35 14,47Humidity 5,2 2,1 7,85 5,23 4,6 2,4 7,85 5,58 6,3 4,75 Humus 16,5 0 2,5 13,4 14,8 0,5 1,8 17,5 12,3 10,5 Exchange Bases 4,69 0 3,60 20,21 5,19 0 2,75 8,47 16,78 18,60Hydrogen exchange 21,63 0 2,55 22,57 15,82 0,15 1,90 46,95 23,56 21,35Total exchange capacity 26,32 0,00 6,15 42,78 21,01 0,15 4,65 55,42 40,34 39,95Assimilable N 0,85 0 0,10 0,69 0,51 0,12 0,05 0,91 0,78 0,75 Assimilable P 16,2 0,6 0,15 12,12 14,7 0 0,25 13,6 15,60 16,30Assimilable K 23,6 5,8 2,15 8,20 12,1 2,35 2,25 7,9 14,35 8,9

Conclusions 1. Anthropogenic soils are soils formed by recultivation of materials such as overburden, waste dumps and other residues of the open pit and underground mining and other industrial activities. 2. The evolution of anthropogenic soils, which reflects recultivation efficiency, is studied by various methods including a series of physical, chemical and biological methods. 3. Among the enzymatic activities, catalase, invertase, urease and nitrogenase are of interest The pathway for nitrogen fixation, which should be considered in the future, is based on the observation that bacteria can produce at room temperature the convertion of atmospheric N2 into a series of compounds. 4. The main process underlying the N2 fixation in soil is catalytic conversion of dinitrogen in NH4

+ in the presence of an enzyme called nitrogenase. 5. Although no catalysts were obtained for N2 reduction, there is hope in this regard because it is possible that the N2 bounded in some of these complexes may be transformed in NH4

+

6. Determination of nutrient such as N, P, K and B does not lead to results that can be correlated with fertility and crop production performed on anthropogenic soils. 7. For a better assessment of the ability of land to be vegetated some analysis are needed to be performed to reflect the enzymatic activity of bacteria existing in soil. References 1. Shriver, D. F., Atkins, P. W., Langford, C. H. Inorganic Chemistry, Oxford University Press, translation from English, Technical Publishing House, Bucharest 1998. 2. Collman, J., Hutchinson, J. E., Lopez, M. A., Guilard, R., Reed, R. A., J. Am. Soc., 113, 2794 (1991) 3. Orme, W. H. Johnson, Science, 257, 1639 (1992) 4. Chan, M. K., Kim, J., Ress, D. C. Science, 260, 792 (1993) 5. Brezeanu, M., Spacu, P. Complex Combinations Chemistry, Second edition, Didactic and Pedagogic Publishing House Bucharest, 1974.

41


SYNTHESIS OF MECHANISMS BY THE INTERPOLATION METHOD

Vasile ZAMFIR*, Horia VÎRGOLICI**

The paper presents aspects of designing simple planar linkages as component parts of mining machines and equipment. Keywords: mechanism synthetics, interpolation method, interpolation nodes

Introduction

The most common practical requirements for the design (synthesis) of a mechanism are: - Creating a motion law demanded at a mechanism element, as a rule at one of the working elements; - Plotting a given trajectory by one of the points of a mechanism’s elements.

The accurate solving of the two types of problems is possible only with mechanisms with higher pairs (for example cam mechanisms), at which the synthesis is called exact.

With low pair mechanisms, due to the limited motions the low pairs allow (rotations and translations), the conditions imposed by the two synthesis aspects can be fulfilled only approximately and therefore their synthesis is called approximate.

Nevertheless, the low pair mechanism can create the law or the required trajectory accurately for a limited number of positions and with deviations for the remaining positions in the approximation interval.

On the synthesis of a mechanism, in order to create a given motion law at the working element it is required that depending on the working element motion law (1) defined by the relation φ1 = F1(t) (in the case of the element with rotating motion) or by S1=G1(t) (in the case of the element with translation motion), figure 1, we should design a mechanism at which the working element n is to have, on a certain working interval [ ]n110 ,ϕϕ , respectively [ ]nSS 110 , a required motion, defined by the functions φn = Fn(t) or Sn=Gn(t).

Removing parameter t from the functions φ1(t), S1(t) and φn(t), sn(t), the positional relations, shown in Table 1 are obtained. ____________________________________ * Prof. eng. Ph.D University of Petrosani ** Lect. Ph.D University „Spiru Haret” Bucharest

Figure 1 Defining the motion of the input element and

that of the output element: a) the input element with rotating motion;

b) the input element with translation motion; c) the output element with rotating motion;

d) the output element with translation motion

Table 1 Output element motion Input element motion Rotation Translation

Rotation φ1=F1(t) φn=F(φ1) Sn=F(φ1) Translation S1=G(t) φn=G(S1) Sn=G(S1)

The time function defining the motion of the

working output element (n) in relation to the input element (1) can be rendered graphically or analytically.

Let us consider the case of correlating the rotations of two cranks in order to illustrate it figure 2.

Figure 2 Designing a mechanism according to the input

and output elements positions

The driving input element AB has its angular coordinate φ in relation to the arbitrary reference

42


axis A-α, while the working output element CD has the angular coordinate ψ, considered in relation to the arbitrary reference axis D-β. The two reference axes A-α and D-β are oriented to the direction of the fixed element AD by the angle φ0, respectively ψ0.

The connection between the driving element AB and the working element CD can be made either by the connecting rod BC or, in a general case, by a kinematic chain made up of a certain number of links.

The mechanism will have n elements in all, which also include elements AB and CD.

The positional synthesis conditions require that the diagram of the mechanism positional function should pass through a series of points Q1(φ1,ψ1), Q2(φ2,ψ2), ... , figure 3. In some cases, in the points Q1, Q2, ..., the function shape is also defined by the transmission ratio

ϕψ

ddi = and its derivative

2

2

ϕψ

ϕ dd

ddi

= .

Figure 3 The diagram of the position function

Each point Qj, j=1,2,...,n represents associated positions of the driving element and of the working element.

The problem can be solved either graphically or analytically. With the analytical solution, the number of equations that can be written should be equal to the number of unknowns.

For n mechanism positions can be written 2n scalar contour equations, obtained by projecting the mechanism vectorial contour in its n positions onto the two axes of the reference system the mechanism is related to. Thus, for the four-bar linkage it is necessary to have 5 parameters: the relative lengths a, b, c and the coordinates α and β which position the reference axes of the driving element AB, respectively the working one CD, that is

52 += nn (1)

It results that in the case of the four-bar linkage no more than 5 positions relatively associated to the cranks (levers) AB and CD can be given.

Therefore, in the positional synthesis it is required to find that mechanism structure which, for a given structure of the working element

ψ=F(φ) (2)

continues on the given interval [φ0, φm], figure 4, to be approximated as faithfully as possible.

This function will be rendered only approximately (in a limited number of positions) by the designed low pair mechanism.

Figure 4 Approximating a given function F(φ) by the

function f(φ)

The function the mechanism can create for certain chosen or calculated parameters (called position functions) has the following appearance in the case of the four-bar linkage:

),,,,;( 00 ψϕϕψ cbaf= (3)

Approximation error

The function given by relation (3) has to be as close as possible to the one given by relation (2) for the four-bar linkage. The degree of closeness between the two functions can be appreciated by the difference Δψ:

)()( ϕϕψ Ff −=Δ (4)

called deviation (error) of the position function f(φ) from the function F(φ), Figure 5.

This deviation can be considered on any direction. In most cases, for simplification, it is considered on the directions of the coordinating axes.

Figure 5 The diagrams of the functions f(φ) and F(φ)

and the diagrams of errors

43


Thus, the vectors *QQ=Δψ , equal in magnitude to the distance between the diagram of the approximating function f(φ) and that of the approximated function F(φ) on the direction of the axis ψ and oriented from the diagram of the given function F(φ) towards the diagram of the mechanism position function f(φ) (figure 5 a), give the deviation (error) of the position function f(φ) from the given function F(φ) in any interval point.

The equation (3) shows the deviation Δψ is dependent on the coordinate φ of the driving element, that is:

)(ϕψ Δ=Δ (5)

The diagram of the deviations Δψ depending on the position angle of the driving element is rendered in figure 5.b.

From figure 5 we deduce the following: a) The diagrams f(φ) and F(φ) have two

categories of contact points: intersection points (contact of 0 order) and multiple contact points (of higher order than zero);

b) The intersection point gi of the deviation diagram Δ(φ) with abscissae axis corresponds to the intersection point Qi of the diagrams f(φ) and F(φ);

c) The tangent point gj of the diagram Δ(φ) with abscissae axis corresponds to the tangent point (contact point of order 1) Qj of the two diagrams.

Writing down with Δψmax and Δψmin the maximum deviation, respectively the minimum deviation reached by the deviation diagram in h´ and h´´ on the interval [φ0,φm] and making their mean value, we get:

2

minmax ψψψ

Δ+Δ=Δ y (6)

Figure 6 Rotating the axes with a view to equalizing

deviations

If the axis D-β (see figure 6) is rotated round the point D with the angle Δψy (counterclockwise) it can be seen that the new coordinate of the axis D-β is:

yy ψψψ Δ+= 0 (7)

and the coordinate of the working element CD against the new axis D-βy is:

yy ψψψ Δ−= (8)

Consequently, the diagram of the position function f(φ) being dependent on the parameters of the mechanism kinematic structure, will move on the ordonate axis direction on the distance (-Δψy) to the position f(φ)y (see Figure 5b, dotted line). The curve of the given function does no depend on the mechanism parameters and it remains in the same position. Therefore, the error curve will have a displacement of the same magnitude (-Δψy) on the ordonate direction to the position Δy(φ) plotted by a dotted line in Figure 5b.

The maximum and minimum points of the error curve h´ and h´´ will move to positions hy´ and hy´´ and will show new maximum and minimum values of the errors:

2)( minmax

maxmaxψψ

ψψψΔ−Δ

+=Δ−Δ=Δ yy (9)

2)( minmax

minminψψ

ψψψΔ−Δ

−=Δ−Δ=Δ yy (10)

of equal magnitude:

2

minmax ψψ Δ−Δ=L (11)

The displacement Δψy is called equalizing error and its diagram Δy(φ) is called equalized error curve.

The magnitude value of the equalized errors (L) is used for estimating the accuracy of approximating the mechanism position function f(φ) against the given function F(φ). All the synthesis problems in which the magnitudes of the maximum (Δψmax) and minimum (Δψmin) errors are not equal between them are the cases most commonly met in practice.

Besides the errors of the linkage kinematic structure mentioned above, the machining and setting errors as well the clearance in the kinematic pairs, the rigidity of the elements etc. have obvious influence. In this paper we shall not deal with this kind of errors. The problem of choosing the interpolation nodes

In the mechanism synthesis problems we use various analytical methods of approximating the functions [1,2,3,5,6,10,11]. The interpolation method is widely applied among these.

Within the calculus method by interpolation, some problems arise referring to the interpolation nodes:

44


- how many interpolation nodes have to be chosen?

- what kind of nodes, simple or multiple? - where are they to be chosen in the imposed

approximating interval so that the approximation error should be minimum?

Interpolation with simple nodes

Let us approximate the continuous function ψ=F(φ) on the interval [φ0,φm] with a four-bar linkage. For example, for a four-bar mechanism, the problem lies in finding such values of the parameters a, b, c, φ0 and ψ0 and of the kinematic structure for which the position function

),,,,;( 00 ψϕϕψ cbaf= of the linkage on a given interval [φ0,φm] should deviate as little as possible from the imposed function ψ=F(φ).

Practically, for the case of determining five parameters, we shall choose five points Q1, …, Q5, of abscissae φ1, …, φ5 on the approximating interval [φ0,φm], where the two functions intersect. These are called simple interpolation nodes.

Figure 7 Interpolation with simple nodes P-P-P-P-P

The diagrams of the two functions and the plot of the approximation error Δψ are shown in figure 7. As the two plots F(φ) and f(φ) intersect, the error plot appears both on the positive side and the negative side of the axis ψ. Therefore the errors, in the case of interpolation with simple nodes, have different signs between the nodes on the approximation interval.

Interpolation with multiple nodes

Besides simple nodes, the interpolation method also uses multiple nodes, in which the plots f(φ) and F(φ) have common points of a certain

established multiplicity order. When multiple nodes, which are equivalent to 2, 3, … simple nodes, are used, the number of precision points (nodes) on the approximating interval [φ0,φm] diminishes from five with the multiplicity sum of the multiplicity nodes.

For example, in the case of the four-bar mechanism synthesis, for all the five parameters of the kinematic structure, two double nodes and a simple one can be chosen (in which case the nodes number on the approximating interval falls from 5 to 3 – 2 being the multiplicity sum of the two double nodes – as a double node has multiplicity one, figure 8) or other combinations of multiple or simple nodes.

Figure 8 Interpolation with two double and a simple one

(PP-PP-P)

The possible combinations between multiple and simple nodes for determining all the 5 geometric parameters of the four-bar mechanism structure are:

P-P-P-P-P; PP-P-P-P; P-PP-P-P; PP-PP-P; PP-P-PP; PPP-P-P; P-PPP-P; PPP-PP; PPPP-P; PPPPP The symbols used [7,8,9] have the following

significance: PP – double node or of multiplicity one, in

which two conditions k=2 are fulfilled: the value equality of the functions and the admission of the same tangent;

PPP – triple node or of the multiplicity two, in which three conditions are fulfilled k=3: value equality, the admission of the same tangent and of the same curvature;

PPPP – quadruple node or of multiplicity three, in which four conditions are fulfilled k=4: value equality of functions and the admission of the same tangent, curvature and supercurvature 1;

45


PPPPP – quadruple node or of the multiplicity three, in which all the conditions of the preceding case are fulfilled and besides the admission of supercurvature 2, k=5.

The above symbols have the following expression in the error function (4):

⎪⎪⎩

⎪⎪⎨

⎧

=Δ==Δ=Δ=Δ

=Δ=Δ=Δ=Δ=Δ

− 0)(...)('')(')(

0)('')(')(;0)(')(

)1( ϕϕψϕϕψ

ϕψϕϕψϕϕψ

k

(12)

From Figure 8 it results that in the double nodes Q1 and Q2 the diagrams of the two functions are tangent. This is shown by two points infinitely close (one point for one condition) marked in each of the points Q1 and Q2. The simple node Q3, the condition marking an intersection of two diagrams, is represented by a single point.

In the error diagram, there are the points g1 and g2 corresponding to the nodes Q1 and Q2. In them the error diagram is tangent to the abscissae axis; they are shown in the same way, by the two infinitely close points.

As we have only double nodes inside the interval, the errors on the wholes interval are of the same sign.

What is the difference between the interpolation with double nodes and the interpolation with simple nodes?

From the viewpoint of approximation accuracy, which we have agreed to estimate by mean error, the two situations are equivalent.

From the viewpoint of the amount of calculus (determining the five parameters of the four-bar linkage) the case of using double nodes is more advantageous.

The use of double nodes, for example, reduces the synthesis problem of the four-bar linkage for five relatively associated positions to three relatively associated positions.

This can be easily shown in the following. Let us approximate the function ψ=F(φ) with

the help of the four-bar linkage on the interval [φ0,φm], using the interpolation with two double nodes and a simple one.

Choosing the abscissae of the nodes Q1 and Q2 so that mϕϕϕ <<< 210 and the abscissa of the simple node φ3=φm, the ordinates of the given function are calculated:

3,2,1),( == iF ii ϕψ (13)

The difference between the abscissae and the ordonates of the nodes Q2 and Q1, respectively Q3 and Q1 is calculated:

)()(; 12121212 ϕϕψϕϕϕ FF −=−= (14)

)()(; 13131313 ϕϕψϕϕϕ FF −=−= (15)

Let us suppose that we have found the parameters a, b, c, φ0 and ψ0 of the kinematic structure of the four-bar linkage for which the position function fulfills the conditions shown in Figure 9.

Let be the mechanism thus found in the three positions AB1C1D, AB2C2D, AB3C3D, corresponding to the three abscissa nodes Q1, Q2, Q3: φ1, φ2, φ3, see figure 9.

Figure 9 The results of the four-bar linkage positional synthesis by the interpolation method with two double

nodes and a simple one

As the diagrams of two functions in the nodes Q1 and Q2 have order 1 contact, it means that the transmission ratio i1 and i2 in the points of abscissa φ1 and φ2 are also to be considered:

)(');(' 2211 ϕϕ FiFi == (16)

It is evident that the four-bar linkage synthesis, under the conditions mentioned, can be accomplished calculating the angles of the relative position of the driving and working elements with relations (14) and (15) and the transmission ratios corresponding to the first and the second positions with relation (16).

Interpolation with double nodes

At the arbitrary choice of abscissae φ1 and φ2 for the double nodes Q1 and Q2, the maximum errors Δψ1 and Δψ2 in the points h1 and h2 are not obtained equal as a rule.

If the abscissa φ3 of node Q3 is maintained unchanged abscissae φ1 and φ2 are modified so that the errors in the maximum points become equal: ]

210 ψψψ Δ=Δ=Δ (17) These are the least ultimate deviations that can

appear on the given interval [φ0,φm] for any other abscissae of the nodal points Q1 and Q2.

In figure 10 is shown the case where the conditions (18) are fulfilled.

By equalizing the diagram represented by broken line is obtained. It has six ultimate deviations, equal among them, in absolute value, but alternative as sign on the mentioned interval.

46


The greatest magnitude of these equalized deviations (L) is less than the greatest mean magnitude of the approximation deviations with other abscissae φ1 and φ2 for the double nodes Q1 and Q2.

In the Chebyshev polynomial theory we find very useful suggestions for choosing the abscissae φ1 and φ2 for which deviations Δψ0, Δψ1 and Δψ2 differ the least among themselves on the interval [φ0,φm].

Figure 10 Equalizing the deviations at the interpolation

with two double nodes and a simple one (PP-PP-P)

Based on what Chebyshev has established, the deviation of the approximating function f(φ) in relation with the given function F(φ) on the interval [φ0,φm] can be expressed by a polynomial of n degree:

011

1 ...)()()( aaaFf nn

n ++++=−=Δ −− ϕϕϕϕϕϕ (18)

whose coefficients an-1, an-2, ..., a1, a0 are determined from the conditions of the uniform approximation. From figure 11 it can de deduced that the deviation diagram Δψ has (n+1) points on the interval [φ0,φm] where the deviations have boundary values. These points, like those intersecting the abscissae axis, have a strictly logical spacing along the abscissae axis.

The abscissae of these points can be found geometrically by the construction in figure 11, where the case n=5 is illustrated. For this case, Chebyshev polynomial has degree 5, that is:

014

45 ...)( aaa ++++=Δ ϕϕϕϕ (19)

For simplification the interval [0,φm] and not

the interval [φ0,φm] has been taken into account. The interval [0,φm] is considered the diameter

of a circumference divided into n=5 equal parts through the points 0, 1, 2, 3, 4, 5.

The abscissae of the points h0, h1, h2 where the deviations are maximum are the same with those of the points 0, 2, 4, while the points where the deviations are minimum have the same abscissae as the points 1, 3, 5. The points on the circumference that indicate the middle of the arcs obtained through the points 0, 1, 2, 3 ,4, 5 have the abscissae with the intersection points of the diagram with abscissae axis, that is with the zero points on the deviations Δψ diagram.

Figure 11 The choice of interpolation nodes by

Chebyshev spacing

From figure 11 it can be noticed that in the case of uniform approximation, the points where the deviations take boundary values and the zero points of the deviations function alternate among themselves and towards the interval ends become more crowded.

Geometrically, from the construction shown in figure 11, the formulas are deduced:

⎪⎪⎪

⎩

⎪⎪⎪

⎨

⎧

=

=⎟⎠⎞

⎜⎝⎛ −=

=⎟⎠⎞

⎜⎝⎛ −=

m

mm

mm

ϕϕ

ϕϕπϕ

ϕϕπϕ

3

2

1

6545,05

3cos121

0955,05

cos121

(20)

for the interval [0,φm]. For the interval [φ0,φm], the formulae are:

⎪⎩

⎪⎨

⎧

=−+=−+=

m

m

m

ϕϕϕϕϕϕϕϕϕϕ

3

002

001

)(6545,0)(0955,0

(21)

47


Corresponding to them, the abscissae of the points h1 and h2 are given by the formulae:

⎪⎪⎩

⎪⎪⎨

⎧

=⎟⎠⎞

⎜⎝⎛ −=

=⎟⎠⎞

⎜⎝⎛ −=

mm

mm

ϕϕπϕ

ϕϕπϕ

9045,05

4cos121

3455,05

2cos121

'2

'1

(22)

for the interval [0,φm] and

⎩⎨⎧

−+=−+=

)(9045,0)(3455,0

00'2

00'1

ϕϕϕϕϕϕϕϕ

m

m (23)

for the interval [φ0,φm].

Conclusions

The problem of designing a plane linkage with low pairs, which has to comply with the motion law of the output working element, defined by the function F (φ) expressed graphically, tabularly or analytically, lies in finding the n constant dimensional parameters contained in function f(φ), which have to be as close to possible to the given function F(φ).

If the number of parameters that determine the approximating function in the case of the four-bar linkage ψ=f(φ;a,b,c,φ0,ψ0) is equal to the number of points chosen for the interpolation (n+1), then, generally speaking, the function f(φ) could be chosen so that the error relation (4) should become zero in the (n+1) points:

niFf iii ,...,2,1,0);()( =−=Δ ϕϕϕ (24)

The function f(φ) can be written as a generalized polynomial of the type:]

)(...)()()( 1100 inniii fpfpfpf ϕϕϕϕ +++≡ (25)

where p0, p1, …, pn are explicit functions with m unknown mechanism parameters (the functions fj(φi) are known depending on the independent φi parameter).

The system (25) becomes a system of linear equations in pj; j=0,1,…,n:

ni

Ffpfpfp iinnii

,...,1,0);()(...)()( 1100

==+++ ϕϕϕϕ

(26)

From the system (26), in the case the number of (n+1) positions of the mechanism is equal to the number of dimensional parameters m, the parameters pj (j=0,1,2,…,n) can be found, whereby the m parameters of the mechanism are obtained.

For the case when mnr <+= 1 , m-r parameters are chosen, that is m-r coefficients pj can be chosen arbitrarily, the remaining r coefficients being determined from the system (26) of r equations with r unknowns. References 1. Artobolevski, I.I., Levitski, N.I., Cercudinov, S.A. Sintez ploskia mehanizmov, Fizmatigiz, Moskva, 1959. 2. Beleţki, V. Rasciot mehanizmov maşin avtomatov piscevâh proizvodstv, „Vişa scola”, Kiev, 1974. 3. Cercudinov, S.A. Sintez ploskih şarnirnorîciajnîh mehanizmov, Iz-vo Academii Nauk S.S.S.R., Moskva, 1959. 4. Dancea, I. Programarea calculatoarelor numerice pentru rezolvarea problemelor cu caracter tehnic şi de cercetare ştiinţifică, Ed. Dacia, Cluj-Napoca, 1973. 5. Hartenberg, R.S., Denavit, I. Kinematic Synthesis of Limkage, McGraw-Hill Series in Mechanical Engineering, New York. 6. Lazaride, Gh., Stere, N., Niţă, C. Mecanisme şi organe de maşini, Ed. Didactică şi Pedagogică, Bucureşti, 1970. 7. Sarkisean, Iu.L, Cecean, G.S. Optimalnîi sintez peredatocinovo cetîrzvenika, Maşino-beledenie, nr.3, 1969. 8. Tesar, D. The Generalized Concept of Three Multiply Separated Positions in Coplanara Motion, Journal of Meechanisms, vol.2, 1967, p.461-474. 9. Tesar, D. The Generalized Concept of Four Multiply Separated Positions in Coplanara Motion, Journal of Meechanisms, vol.3, 1968, p.11-23. 10. Zamfir, V., Albăstroiu, P. Mecanisme şi organe de maşini. Partea I. Mecanisme, Litografia Institutului de Mine, Petroşani, 1975. 11. Zamfir, V. Sinteza mecanismelor cu bare articulate plane (Note de curs), fasciculele 1-5, Litografia Institutului de Mine, Petroşani, 1976, 1977.

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