Efficient methods for Screening and Modelling of Potential Landfill Sites for collection of SRMs

1. 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)

2. Contents
1. Landfill screening methods
2. Case Aijala tailings pond in Finland
3. Advantages of screening methods for LM
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3. 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:

4. 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

5. 1. Landfill screening methods
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Terrestrial Laser Scanning is the use of a ground based device that uses a laser to
measure 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 the
contemporaneous acquisition of geometrical data and information about the
physical and structural properties of the investigated surface.
Outputs
• 3D modelling of slopes,
infrastructures, natural
and man-made cavities
• Mesh, DTM, contour
maps, orthoimages

6. 1. Landfill screening methods
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Example of point cloud:
Spacing: 6cm
Distance: 300 – 400m
EXAMPLE OF
LASER SCANNER
SURVEY

7. 1. Landfill screening methods
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Photogrammetry obtains reliable information about the properties of surfaces and objects
without physical contact with the objects (typically with photographs), and of measuring and
interpreting 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 the
camera is mounted on a helicopter or a UAV, “Unmanned Aerial Vehicle” and is usually
pointed 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

8. 1. Landfill screening methods
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N° pictures: 830
Overlap. long/trans. 90% / 60%
Ground Pixel: 3 cm
UAV FLIGHT
PLANNING
PHOTOGRAMMETRIC
3D MODEL MESH
EXAMPLE OF
PHOTOGRAMMETRIC SURVEY

9.  Includes tailings from Aijala, Metsämonttu and Telkkälä
 Geophysical and geochemical investigations
• 5 new samplig wells were drilled and collected samples were
analyzed 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

10. www.smart-ground.eu
Magnetics and GEM 2
To find out the magnetic and conductive
parts of the tailings pond.
GEM2: the conductivity distibution
1-10 m downward.
Electrical Resistivity
Tomography (ERT)
Layers of different
conductivities from
surface to the
bottom of tailings.
Gravity
The bottom surface
of 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 consisting
areas (red)
2. Case Aijala tailings pond in Finland

12. www.smart-ground.eu
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

13. 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 Mpixel
Flight H: 70m Speed: 3 m/s
Time: 3 flights 25’

14. 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

15. 2. Case Aijala tailings pond in Finland
 Gravity method was used to determine the bedrock level and the thickness of the
tailings.
 Electrical resistivity tomography (ERT) showed the conductive areas, different
layers and the bottom level of the tailings pond.
 GEM-2 was tested to get more detailed picture of the distribution of conductive
material, but in this case it was not effective enough. We found ERT to be better
method 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 of
site
INTEGRATING GRAVITY AND ERT RESULTS WITH GEOCHEMISTRY RESULTS A ROUGH
MINERAL RESOURCE ESTIMATE OF THE TAILINGS POND COULD BE DONE
Summary:

16. 3. Advantages of screening methods for LM
 Geophysical methods are especially useful tools when structures of
the landfill sites are investigated and modelled. Modelling results
can be adopted for the estimation of the SRMs potential of both
MSW and EW facilities.
 In photogrammetry based surveys, a consumer-grade UAV can be
used to provide professional quality high resolution aerial images
and elevation models of landfill site surfaces. It also seems to be a
cost-effective method for areas in these scales.
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17. Project Coordinator
Marco de la Feld
ENCO s.r.l.
m.delafeld@enco-consulting.it
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