Mining is a truly global activity with operations at uncountable locations around the world, comprising both subsurface and open-pit mines. These activities are seldom static or short-lived but grow and evolve over long periods of time, often impacting upon their surroundings.
A typical mine will see much development during its life-cycle, as the operation grows and as new shafts, larger pits, additional infrastructure, new waste material handling etc. are implemented, efficient ground investigation is essential. Today, much of the ground investigation work is done by traditional point-by-point geotechnical drilling and sampling. But this can be tough in an already crowded environment, with subsurface installations of utilities and structures and surface infrastructure and waste piles. Instead, different geophysical tools can be used to assist in the understanding of the subsurface within and around an expanding mine.
There is also a heavy schedule of maintenance work, tending to the infrastructure such as processing plants and haulage roads and monitoring the stability of waste deposits, dams and embankments. If applied correctly, geophysics can provide invaluable insights into the ‘health’ of the mining infrastructure and early warnings of potential problems.
GPR measurements in a tunnel to see the depth to bedrock. The size of mining vehicles increased so the tunnel needed to be increased in height and this was done by lowering the asphalt level.
Solutions
Guideline Geo´s wide range of geophysical investigation techniques can solve a number of the most common questions that arise during mining operations. They will give a non-destructive and cost-efficient way of gaining a better understanding of the ground conditions both for subsurface and open-pit mines, providing a good data coverage across the investigated volume.
GPR, resistivity, IP (induced polarization) and seismics can be used for mine operations. These methods are suitable for both surface and in-mine measurements, as well as for borehole investigations. GPR can also be used for analysis of the state of existing structures such as concrete hard-standing and structures.
Watch the webinar covering our solutions for the mining industry.
GPR IN RELATION TO MINING
As introduced above, GPR is useful for many different applications during mining, both for geological purposes and for structural investigations; some common applications are:
Tunnel inspection – investigation of concrete (e.g. thickness, number and positioning of rebars), voids, fractures, loose stones
Pre-investigation of the rock volume (e.g. groundwater-bearing fractures) ahead of tunnel boring (with borehole GPR)
Investigation of rock quality, such as fractures within marble or clay layers in limestone
Mapping of the infrastructure around a mining area, including utilities and other underground structures
Investigation of geology, in particular depth to bedrock prior to expansion of open-pit mines
Investigating, and potentially monitoring, dam constructions containing e.g. leachate
Additionally, GPR can be used for a number of different geotechnical applications needed for new infrastructure, including roads and other construction projects.
One major consideration with GPR is that the ground around mining sites can be quite conductive due to the high degree of alteration and mineralization. This may adversely affect the GPR results.
MALA Ground Explorer
MALÅ GX is an easy-to-use and field proven GPR solution for a wide range of different applications, amongst them tunnel inspection, depth to bedrock,and investigations of underground structures.
Resistivity measurements during the operation of a mine are often suitable for:
Monitoring of infrastructure e.g. tailings dams and embankments
Mapping/monitoring pollution plumes and other contamination from the mine
Geotechnical information for mine development/expansion
Mapping of potential slip planes in / beneath waste heaps
Mapping of aquifers and aquitards in geohydrological investigations
Resistivity and IP surveys are most often carried out in combination. The same equipment is used for both and to measure the two parameters instead of one does not necessarily prolong field acquisition times to any great extent. The IP will provide additional complementary information to the resistivity which can be very useful when differentiating between materials which might present a similar range of resistivity values (such as clay and groundwater).
Resistivity measurements to determine the thickness of the soil prior to the expansion of an open-pit marble mine.
ABEM Terrameter LS 2
Flexible, easy to use and boasting a number of innovative features the ABEM Terrameter LS 2 is the ideal partner for geotechnical, groundwater, mineral or environmental surveys and research work
Seismic investigations during the operation of a mine can be for:
Material stability e.g. embankments, earth dams and waste heaps
Geotechnical information for active mine development/expansion such as depth to bedrock and rippability (a measure of how hard a rock will be to excavate)
Testing the level of vibration at the perimeter of the mining operation during specific activities to assess the potential for damage to neighboring properties and infrastructure
Mining operations is just one of many different application areas that Guideline Geo offer solutions for. Visit our applications area page to read more.
