Technological Study Of Resonably Determining The Upper Limits Of Mining On Shallow Embedding Coal Seam

A study on increasing the upper minable limits when mining under waterbody at qi-wu colliery was systematically carried out by reprospecting the hyhrography and geology in testing section, testing mechanical properties of rock, and using physical simulation, FEM and in situ measurement. The mining program of 3_up and 3_down coal seams and the upper minable limits in the testing section were determined, and more than 200 thousand tons of coal in the first sub-layer of 3_up seam was excavated. The result of observing the subsection water height in upward holes under mine was basically in accordance with the conclusion of prediction.