SSHE

SURFACE SUBSIDENCE

One of the most concerned impacts from any underground mining operation is surface subsidence. The Company has put this issue as top priority ensuring that the surface subsidence induced by our operation shall be very well within standard recognized by global mining community.

The Project recognized that the impact on surface subsidence from operation, so it has studied the methods to reduce such impact start from the mining design. It has studied and tested the physical properties of potash and rock mechanical strength by sending the project potash to be tested in Germany. The derived results that found the design of the mine have safety by more than > 100% safety factor.

 

Before start the trial mining in 1999, the Project had installed monitoring stations for a surface subsidence at the trial mine area. It monitored since 1999 up to present, found that the result of the rate of surface subsidence is well within acceptable standard that will not cause any unmanageable damage to the environment.

 

Prognosis of surface subsidence

 

“To prognosis possible surface subsidence over the period of 50 years after the mining operation is creased. The result show that 90 percent of mining area, the maximum subsidence of 16 centimeters so it will not cause any damage to the building structure on the ground surface whatsoever”

The geomechanics research unit, engineering office, Suranaree University of Technology has studied and forecast the surface subsidence by the computerized simulations to prognosis of surface subsidence over the mining operation period. After the operation, 90 percent of mining area , the maximum subsidence of 16 centimeters and 10 percent of the remaining area found  the maximum subsidence of 18 centimeters, while the soil subsidence would occur gradually and will not cause any impact on the building on the ground surface, as well as will not cause any change of natural water flow direction.

 

Mitigation Measurements 

  • Mine Design and support system to have high safety standard and  internationally accept and is wildly used in international potash mining. Since 1999, the Project has monitored surface subsidence at the trial mine which  found that no any impact from a surface subsidence at the trial mine.
  • Backfill the tailings in the underground mine to ease the tailings piles from the tailings pond and support the stability for the underground mine.
  • Install the standard system of monitoring the movements of the underground mining. 
  • Monitor the movements of the soil surface arise from mining such as,Install a device to measure the stretch of rock mass in the drilling holes to measure the change of the tunnel roof shape and inspect the support pillars on swelling.
    • Install convergence meters.
    • Install vibrating wire strain gauge
    • Install micro seismic detectors consists of the receiver of the vibration signals with high sensitivity on the soil surface of the mine area in the drilling holes and the underground mine.
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