System frequency of substation is dependant on active load of power grid. when system frequency exceeds allowable limits load shall be regulated immediately for stabilization of system frequency.

It is significative to accelerate the stabilization of landfill and alleviate the load of the treatment facilities of leachate, furthermore it provides a feasible way to utilize the alkaline slag.

In the second phase, after the mining subsidence is gradually stabilization, we bring into bear different load in the different location of subsiding basin, and we study ground stability with goaf.