УДК 622.06 ...

ИЗВЕСТИЯ УРАЛЬСКОГО ГОСУДАРСТВЕННОГО ГОРНОГО УНИВЕРСИТЕТА МАРТ 2021 | ВЫПУСК 1 (61) 17

Известия Уральского государственного горного университета. 2021. Вып. 1 (61). С. 17-24

УДК 622.06

Determination and quality classification of rock mass of the Diatomite mine, Algeria

Abdessattar LAMAMRA1*,Dmitriy Leonidovich NEGURITSA2**

Samir BEDR3***

Ariant A. REKA4****

1Peoples’ Friendship University of Russia (RUDN University), Moscow, Russia2Sergo Ordzhonikidze Russian State Geological Prospecting University, Moscow, Russia3National Center for Applied Research in Earthquake Engineering Algiers, Algeria4University of Tetovo, Tetovo, Republic of North Macedonia

Abstract Research relevance. Most ground movements are generally due to rock instability, this natural phenomenon poses a risk to humanity. The properties of the rock mass directly influence the type of movement especially in underground structures.Research aim. Our goal is to characterize and classify the rock mass of diatomite from the sig mine using geomechanical classification systems such as the RQD and RMR in order to determine the quality of the rocks in the sig mine Western Algeria from the determination of the physical and mechanical properties.Methodology. In this article, the characterization analysis of the diatomite rock mass of the sig mine was carried out. First, determinations of the physical properties and carried out the triaxial test to determine the mechanical properties (young’s modulus, the friction angle, the dilatancy angle, the cohesion, the poisson’s ratio). Secondly to classify the deposit and give a recommendation to avoid stability problems.Research results. The results from physical and mechanical analyzes, it can be said that the nature of the rock present in the diatomite (underground mine) does not have enough resistance.Conclusion. Our study definitively proves that the rock mass of sig diatomite is of very low quality and it will be very dangerous for the underground mining work of the mine especially in places where the mineralized layer is very deep. And we suggest to replace the mining technique room and pillar currently used in the diatomite mine and put another mining method which includes roof support system to ensure the safety both of the miners and the equipment.

Keywords: Diatomite, RQD, RMR, triaxial test, physical and mechanical analysis.

https://doi.org/10.21440/2307-2091-2021-1-17-24

[email protected]**[email protected]***[email protected]**** [email protected]

Introduction Diatomite is a siliceous sedimentary rock of biogenic origin

because it is formed by the accumulation of diatom skeletons (unicellular brown algae). Generally, between 10 and 50 mi-crons in size [1–4], the skeletons (or frustules) consist of hydrat-ed amorphous silica (opal). Other constituents are present in variable proportions, such as organic matter, classical elements, even clay minerals. Diatomite is also called “kieselguhr” [5], or “diatomaceous earth” in the Anglo-Saxon world; in Denmark, “molar” means a diatom clay containing up to 30% smectites [6]. There are a large variety of diatoms, some are of the sponge type with small elements that are more or less fragmented, oth-ers are on the contrary of the more or less elongated type made up of small rod-shaped elements. Currently geologists identify more than 12,000 species of diatomite [7, 8]. Diatomites find use filter media, absorbents, fillers, abrasives, production of construction materials and many other purposes [9–12].

Silica is found in nature in crystalline (quartz, cristobalite and tridymite), cryptocrystalline (chalcedony) and amorphous

(opal) forms; its density and melting point vary depending on the crystalline form. Crystalline silica is the most common of all minerals. It is present in most rocks. The most common form of sand is found on beaches around the world. Sandstone, a sedimentary rock, is made up of quartz grains agglomerated with various clays. Silica is a raw material for the manufacture of ordinary glass and most refractory bricks.

Location and topography of the study areaThe location of the sig deposit is strategic; it is located 390

km west of the capital of Algeria [13], in the center between 4 major cities; Two coastal cities (Oran 54 km and Mostaganem 70 km) and two inland cities (Mascara 50 km and Sidi Bel Abbes 80 km). The diatomite deposit, as shown in (Fig. 1), is located 15 km southeast of the town of Sig [14]. X = 240600; Y = 240500.

Its average length is 1.5 km, its average width of 1.39 km and its surface of 209 ha. It is divided into two mining regions: the Ghana region to the northwest and the Morin region to the

НАУКИ О ЗЕМЛЕ А. Ламамра и др. / Известия УГГУ. 2021. Вып. 1(61). С. 17-24

18 A. Lamamra et al. Determination and quality classification of rock mass of the Diatomite mine, Algeria//Известия УГГУ. 2021. Вып. 1 (61). С. 17-24. DOI 10.21440/2307-2091-2021-1-17-24

southeast. In 2019, using the S-GeMS 2D software, the reserves of diatomite were calculated by A. Lamamra, which amount to about 5.2 million tons [15, 16].

Rock Quality Designation RQDProposed by Deere in 1964 and obtained from geologi-

cal drill core, it is an index representing the evaluation of the percentage of cores recovered over a specific stroke length [17, 18]. To determine the RQD, the International Society of Rock Mechanics (ISRM) recommended using an NX size carrot (54.7 mm) and it have to be drilled by a double tube using the diamond bit.

RQD calculation principle: Based on a qualitative process, only the sum of the lengths of pieces over 10 cm (4 inches) is kept as shown in (Fig. 2) [19, 20]. This sum is divided by the stroke length of the drill core. This parameter is defined as follows:

⋅∑ length of core drilling

= 100.Total length of extracted core drilling

RQD (1)

Palmström (1982) suggested that, when core drill are not available but the discontinuities are visible on the display sur-face (free face), the RQD can be estimated from the number of discontinuities per unit of volume.

For example, for a negative exponential distribution of discontinuity spacings, Priest and Hudson (1976) derived the following relationship between RQD and linear discontinuity frequency λ:

( ) ( )t t− l l + 1= 100 exp .RQD (2)Where t is the length threshold. For t 1/4 0.1 m as for the

conventionally defined RQD, Eq (2) can be expressed as:

( ) ( )−= 100 exp 0,1λ 0,1 λ + 1 .RQD (3)

Priest and Hudson (1976) [21] presented the relation-ships between the value of RQD and λ were obtained, and the

Figure 1. Geological map of the Western region with the main deposits.Рисунок 1. Геологическая карта Западного региона с основными месторождениями.

Figure 2. Procedure for determination of RQD using coring (after Deere, 1989). Рисунок 2. Процедура определения RQD с использованием керна (по Диру, 1989).

A. Lamamra et al / News of the Ural State Mining University. 2021. Issue 1(61), pp. 17-24 EARTH SCIENCES

A. Lamamra et al. Determination and quality classification of rock mass of the Diatomite mine, Algeria//Известия УГГУ. 2021. Вып. 1 (61). С. 17-24. DOI 10.21440/2307-2091-2021-1-17-24

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calculated values based on Eq (2) (3), as shown in (Fig. 3). An approximate value of RQD was determined according to the following relationship:

(4)

Rock Mass Rating RMRRMR was established by Bieniawski (1973) to evaluate

the quality of rock masses for underground projects [22]. The RMR system consists of five basic parameters that represent different conditions of the rock and the discontinuities [23, 24]. The discontinuity orientation parameter (B) is ignored. The retained system reverts to the RMR basic [25]. This cor-rection is made mainly to ignore the environmental conditions resulting in a classification dependent on the rock mass only.

Constraints are ignored as a parameter of the RMR system. Bieniawski, 1989 considers the RMR system adequate for a civil project up to a vertical stress of 25 MPa. Often in the mining sector, underground mines operate at higher stress levels.

This classification does not take into account the in-situ stress state or the roughness of the fractures and the friction angle of the filling material. Swelling rocks are also not treated there. The application of this classification is limited to cases of massifs whose matrix has good resistance and whose behavior is governed by discontinuities.

However, RMR remains a powerful tool, when used well. This system has succeeded in identifying almost universal geo-logical parameters making it possible to record quickly and simply any experience of excavations in the rock mass [17]. In this way, the application of the RMR classification system

Figure 3. Relationship between RQD and discontinuity frequency λ (after Priest and Hudson, 1976). Рисунок 3. Связь между RQD и частотой разрыва λ (по Присту и Хадсону, 1976).

successfully extends to foundation design, slope stability, strip-ping assessment, as well as many mining applications.

RMR = A1 + A2 + A3 + A4 + A5. (5)

Determination of physical and mechanical propertiesTo reach our objective of rating and classifying the di-

atomite rock mass of the sig mine west Algeria, we had to de-termine the physical and mechanical properties by carrying out several laboratory experiments, which was the only tool to determine the resistance of the rock in the underground mine and find out how safe the mine is, and whether it guarantees the safety of workers and equipment against sudden collapse. All results obtained are summarized in the following (Table).

Results and discussionAccording to laboratory tests for physical characteristics,

we find that our rock has an average porosity of 7% as shown in the (Table), with average water absorption. We can say that the diatomite rock mass is moderately saturated with water. And according to the results of the compression resistance test which is equal to 1.23 mРa × s we can say that the rock mass presents very low resistance < 5 as shown in (Fig. 6) which shows the three tests were carried out. And we were also able to calculate the tensile compression value from the Brazilian test which gives us 0.23 MРa which considered very low <0.4 by standard. And according to the triaxial test as shown in (Fig. 5), we were also able to calculate the modulus of young from the orientation coefficient between the axial deformation (%) and the stress deviator: is equal to 533 kРa which presents the rock of Very strong deformation according to the standard <1000.

Physical and mechanical properties of diatomite ore from the Sig mine.Физико-механические свойства диатомитовой руды с шахты Сиг.

Sample g, kg/m3 r, % Rc, MРa Eref, MРa Rt, MРa y, grade n j, grade Cref, MРa RQD RMR

Diatomite 700–1265 7 1.23 0.533 0.23 0 0.3 23.5 204.87 23.10 34

Eref – Young’s modulus, Cref – cohesion, g – Unit weight, j – friction angle, n – Poisson’s ratio, y – dilatancy angle, r – propsity.



Figure 4. Photos made to estimate the number of cracks per 1 m2.Рисунок 4. Фотографии, сделанные для оценки количества трещин на 1 м2.

Figure 5. Triaxial compression under effective stress, consolidated drained.Рисунок 5. Трехосное сжатие в условиях эффективного напряжения.

The massive shear parameters (C and φ) according to the calculations based on the Hoek and Brown and Mohr-Cou-lomb criteria as shown in (Fig. 5), show that our massive has very low shear strength which is respectively 204.87 MРa, 23.5°. And in view of the absence of core drill in our case we were able to calculate the values of RQD by the equation (3). For this we have drawn windows of 1 m² to calculate the number of joints as shown in (Fig. 4), to get good results we did several calculations of l after we did the average. l = 28 joints/m² which gave us the value of RQD is 23.10% < 25%, so we can say that we have very poor rock quality.

From the results we obtained from the RMR method, revealed the presence of two categories of rock, namely class IV, with a minimum score of 32 and a maximum score of 36. So, we were able to classify the massif being that poor rock or low-quality rock (class IV).

Conclusion and RecommendationsThe physical and mechanical tests carried out, despite

their complexities, allowed the simple and sharp assess-ment of the quality of the rock mass. Using available data, Our study definitively proves that the rock mass of sig di-atomite is of very low quality and it will be very dangerous



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Figure 6. The curves of the destruction of the sample by compression.Рисунок 6. Кривая разрушения образца путем сжатия.

for the underground mining work of the mine especially in places where the mineralized layer is very deep and in the light of the will of the ENOF company to increase the production rate and the complete recovery of the pillars in the mine, we recommend putting another extraction method which consists in applying a roof support sys-

tem to protect the workers and equipment against sudden collapse.

AcknowledgmentWe are very grateful to the company ENOF, which pro-

vides us with all the necessary information on this research and all the necessary analyses.

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The article was received on August 11, 2020



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УДК 622.06

Определение и классификация качества горной массы диатомитовой шахты Cиг, АлжирАбдессаттар ЛАМАМРА1*, Дмитрий Леонидович НЕГУРИЦА**2

Самир БЕДР***3

Ариант А. РЕКА****4

1Российский университет дружбы народов, Москва, Россия2Российский государственный геологоразведочный университет им. Серго Орджоникидзе, Москва, Россия3 Национальный центр прикладных исследований в области сейсмостойкости Алжира, Алжир4 Тетовский государственный университет, Тетово, Республика Северная Македония

АннотацияАктуальность. Большинство движений земной поверхности обычно происходит из-за нестабильности горных пород, это естественное явление представляет опасность для человечества. Свойства массива горных пород напрямую влияют на тип движения, особенно в подземных сооружениях.Цель работы состоит в том, чтобы охарактеризовать и классифицировать горную диатомитовую массу в шахте, используя геомеханические системы классификации, такие как RQD и RMR, чтобы определить качество горных пород в шахте Западного Алжира на основе определения физико-механических свойств. Методология. Проведен анализ характеристик массива пород диатомитовой шахты вблизи г. Сиг. Были определены физические свойства и проведено испытание на трехосное сжатие для определения механических свойств (модуль Юнга, угол трения, угол дилатансии, сцепление частиц горной породы, коэффициент Пуассона), а также классифицированы месторождения и даны рекомендации во избежание проблем со стабильностью.Результаты исследования. По результатам физико-механического анализа можно сделать вывод, что порода, присутствующая в диатомите (подземная шахта), не имеет достаточного сопротивления.Выводы. Исследование окончательно доказывает, что горная масса диатомитовой шахты Сиг имеет очень низкое качество, и это будет опасно для подземных горных работ, особенно в местах, где минерализованный слой очень глубокий. Мы предлагаем заменить метод добычи камеры и столба, который в настоящее время используется в диатомитовой шахте, и использовать другой метод добычи, который включает систему поддержки крыши для обеспечения безопасности как горняков, так и оборудования.

Ключевые слова: диатомит, RQD, RMR, испытание на трехосное сжатие, физико-механический анализ.

ЛИТЕРАТУРА1. Kawamoto M., Murakami T., Hanao M., Kikuchi H., Watanabe T. Mould powder consumption of continuous casting operations // Ironmaking and Steelmaking. 2002. Vol. 29. № 3. Р. 199–202. https://doi.org/10.1179/0301923022250041512. Sprynskyy M., Kovalchuk I., Buszewski B. The separation of uranium ions by natural and modified diatomite from aqueous solution // Journal of Hazardous Materials. 2010. Vol. 181, issues 1-3. P. 700–707. https://doi.org/10.1016/j.jhazmat.2010.05.0693. Lamamra A., Neguritsa D. L., Eremenko V. A. Justification of Longwall Mining Technology for the Development of Kieselguhr Deposit in Sig Mine, Algeria // IOP Conf. Series: Earth and Environmental Science. 2020. Vol. 609. Article number 012002. https://doi.org/10.1088/1755-1315/609/1/0120024. Ламамра А., Негурица Д. Л. Основные направления развития геотехнологии на Кизельгурском месторождении (Алжир) // Проблемы освоения недр в XXI веке глазами молодых: материалы 14 Междунар. науч. школы молодых ученых и специалистов. М.: ИПКОН РАН, 2019. С. 202–206. URL: www.spsl.nsc.ru/FullText/konfe/ПрОсвНедр2019.pdf5. Elden H., Morsy G., Bakr M. Diatomite: Its Characterization, Modification and Applications // Asian Journal of Materials Science. 2010. Vol. 2 (3). P. 121–136. https://doi.org/10.3923/ajmskr.2010.121.1366. Gómez J., Gil M. L. A., de la Rosa-Fox N., Alguacil M. Formation of siliceous sediments in brandy after diatomite filtration // Food Chemistry. 2015. Vol. 170. P. 84–89. http://dx.doi.org/10.1016/j.foodchem.2014.08.0287. Nakkad R., Ezbakhe H., Benmoussa A., Ajzoul T., El Bakkouri A. Contribution à l’étude morphologique et thermique des diatomites utilisées dans l’isolation. 12émes journées internationales de thermique, 15–17 nov. 2005. Tanger, Maroc. (In French)8. Zhao Y.-H., Geng J.-T., Cai J.-Ch., Cai Yu-F., Cao Ch.-Y. Adsorption performance of basic fuchsin on alkali-activated diatomite // Adsorption Science and Technology. 2020, May. Р. 1–17. https://doi.org/10.1177/02636174209220849. Reka A. A., Pavlovski B., Ademi E., Jashari A., Boev B., Boev I., Makreski P. Effect of Thermal Treatment of Trepel At Temperature Range 800–1200 ºC // Open Chemistry. 2019. Vol. 17, issue 1. P. 1235–1243. https://doi.org/10.1515/chem-2019-013210. Reka A. A., Pavlovski B., Makreski P. New optimized method for low-temperature hydrothermal production of porous ceramics using diatomaceous earth // Ceramics international. 2017. Vol. 43, issue 15. P. 12572–12578. http://dx.doi.org/10.1016/j.ceramint.2017.06.132

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https://doi.org/10.21440/2307-2091-2021-1-17-24



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