Screening and Modelling of Pilot Sites - Sardinia Symposium 2017
17
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 641988 SMART data collection and inteGRation platform to enhance availability and accessibility of data and infOrmation in the EU territory on SecoNDary Raw Materials Efficient methods for screening and modelling of potential landfill sites for collection of SRM´s G14 - "WORKSHOP | ENHANCED LANDFILL MINING" Sardinia Symposium 2017 2 – 6 October 2017 Forte village/S. Margherita di Pula, Cagliari, Italy Heikki Särkkä South-Eastern Finland University of Applied Sciences (XAMK)
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Transcript of Screening and Modelling of Pilot Sites - Sardinia Symposium 2017
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 641988
SMART data collection and inteGRation platform to enhance availability and accessibility of data and infOrmation in the EU territory on
SecoNDary Raw Materials
Efficient methods for screening and modelling of potential landfill sites for collection of SRM´s
G14 - "WORKSHOP | ENHANCED LANDFILL MINING"
Sardinia Symposium 2017
2 – 6 October 2017
Forte village/S. Margherita di Pula, Cagliari, Italy
Heikki Särkkä
South-Eastern Finland University of Applied
Sciences (XAMK)
Contents
1. Landfill screening methods
2. Case Aijala tailings pond in Finland
3. Advantages of screening methods for LM
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1. Landfill screening methods
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Geophysical methods are non-destructive and provide information about physical properties of ground (magnetic properties, density, electrical conductivity, seismic properties and gamma radiation). These properties are used for classification and characterization of waste areas.
Usually two or three, or even more, different methods are used together in order to get the best result. For example, magnetic data locates buried metallic objects, but contain very limited information about the layering structure of ground and groundwater, which can be efficiently mapped using the electrical techniques. The best combination of methods depends on the site to be studied.
Geophysical methods:
1. Landfill screening methods
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Main geophysical methods:
Method Description
Electrical resistivity sounding (ERT) Layers, or smaller parts of waste material having specific electrical conductivity can be defined.
Magnetic method Magnetic measurements are used to find out and locate the magnetizing material (metal objectives) of landfill.
Electromagnetic method The EM methods are used for mapping the electrical conductivity of ground in different scales and depths. They are used especially for fast mapping of large areas for example the whole landfill area. EM methods can be used also for studies of deep structures.
Gravity method The gravity instrument measures the density differences of landfill. The average thickness of the waste pile can be calculated in convenient conditions.
Multi-frequency Electrical Impedance Tomography (mfEIT)
By using EIT for measuring on the surface, it is possible to record high resolution impedance images of waste body
1. Landfill screening methods
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Terrestrial Laser Scanning is the use of a ground based device that uses a laser tomeasure the 3D coordinates of a given region of an object’s surface automatically,in a systematic order at a high rate in near real time.
This survey technique is capable of surveying thousands of X,Y,Z points per second,getting 3D points with their associated laser intensity and it allows thecontemporaneous acquisition of geometrical data and information about thephysical and structural properties of the investigated surface.
Outputs
• 3D modelling of slopes, infrastructures, naturaland man-made cavities
• Mesh, DTM, contourmaps, orthoimages
1. Landfill screening methods
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Example of point cloud:Spacing: 6cm
Distance: 300 – 400m
EXAMPLE OFLASER SCANNER
SURVEY
1. Landfill screening methods
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Photogrammetry obtains reliable information about the properties of surfaces and objectswithout physical contact with the objects (typically with photographs), and of measuring andinterpreting this information. The output of photogrammetry is typically a map, drawing,measurement, or a 3D model of some real-world object or scene.
Aerial photogrammetry is often replaced by Structure for Motion (SfM) techniques where thecamera is mounted on a helicopter or a UAV, “Unmanned Aerial Vehicle” and is usuallypointed vertically towards the ground.
Multiple overlapping photos of the ground are taken as the aircraft flies along a flight path.These images are later processed to obtain, for example, geometric corrected images(orthophotos) and Digital Elevation Model (DEM).
Flights
Photo Shoots
1. Landfill screening methods
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N° pictures: 830Overlap. long/trans. 90% / 60%Ground Pixel: 3 cm
UAV FLIGHT PLANNING
PHOTOGRAMMETRIC 3D MODEL MESH
EXAMPLE OFPHOTOGRAMMETRIC SURVEY
Includes tailings from Aijala, Metsämonttu and Telkkälä Geophysical and geochemical investigations
• 5 new samplig wells were drilled and collected samples wereanalyzed for metals
• Dimensions and different layers of landfill were identified(originality of waste/SRM´s)
• Estimation of SRM potential was done
2. Case Aijala tailings pond in Finland
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Magnetics and GEM 2To find out the magnetic and conductiveparts of the tailings pond.GEM2: the conductivity distibution1-10 m downward.
Electrical ResistivityTomography (ERT)Layers of differentconductivities fromsurface to thebottom of tailings.
GravityThe bottom surfaceof tailings pond and bedrock topography
Line map of geophysical methods in Aijala
2. Case Aijala tailings pond in Finland
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Magnetic susceptibility indicates the Ni-consisting areas (red)
Electrical conductivity (mS/m) indicates the sulphide consistingareas (red)
2. Case Aijala tailings pond in Finland
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Gravity interpretation: Depth of the bottom of tailings (red) Depth of bedrock Bounded to drilling data
ERT interpretation: Depth of layers of different resistivity Depth of bedrock
3D interpretation of ERT lines
2. Case Aijala tailings pond in Finland
2. Case Aijala tailings pond in Finland
Drone mapping by IMAGEO, Aijala in September 2016
Area: 20 ha(500m x 400m)
Drone: DJI Phantom4 Camera: internal 12 MpixelFlight H: 70m Speed: 3 m/sTime: 3 flights 25’
2. Case Aijala tailings pond in Finland
N° pictures: 430
Overlap long/trans.80% / 60%
Ground Pixel: 3cm
CLASSIFIED POINT CLOUD
3D MODEL
PHOTOGRAMMETRIC 3D MODEL MESH
2. Case Aijala tailings pond in Finland
Gravity method was used to determine the bedrock level and the thickness of thetailings.
Electrical resistivity tomography (ERT) showed the conductive areas, differentlayers and the bottom level of the tailings pond.
GEM-2 was tested to get more detailed picture of the distribution of conductivematerial, but in this case it was not effective enough. We found ERT to be bettermethod for conductive environment.
Magnetic method helped to detect the different type of Ni-consisting areas.
UAV was used to obtain a detailed reconstruction of the topographic surface ofsite
INTEGRATING GRAVITY AND ERT RESULTS WITH GEOCHEMISTRY RESULTS A ROUGHMINERAL RESOURCE ESTIMATE OF THE TAILINGS POND COULD BE DONE
Summary:
3. Advantages of screening methods for LM
Geophysical methods are especially useful tools when structures ofthe landfill sites are investigated and modelled. Modelling resultscan be adopted for the estimation of the SRMs potential of bothMSW and EW facilities.
In photogrammetry based surveys, a consumer-grade UAV can beused to provide professional quality high resolution aerial imagesand elevation models of landfill site surfaces. It also seems to be acost-effective method for areas in these scales.
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