Numerical modelling results show that the response characteristics of transient electromagnetic method of high resistivity goaf
are weaker than that of low resistivity goaf
Drilling log table of anomaly YC7 in No.80101 workface Drilling Parameter Location Log Azimuth Dip Dcplij Number ([degrees]) ([degrees]) (m) H19-1 313 37 129 H19-2 277 46 125 No.18 H19-3 221 41 130 drilling field of H19-4 136 157 No.80101 H19-5 237 -1 141 return airway H19-6 221 1 133 H19-7 229 -10 130 H19-S1 238 35 111 H19-S2 308 30 156 Final Hole Location Position Hydrology 115m to 4# water yield 8[m.sup.3]/h at 60m 90m to 4# goaf
water yield 30[m.sup.3]/h from final hole No.18 95m to 4# goaf
water yield 35[m.sup.3]/h from drilling final hole field of 99m to 4# goaf
none No.80101 Floor of 8# none return airway scam Floor of 8# none scam Floor of 8# none scam 4# scam water yield 3[m.sup.3]/h.
(3) The degree of pollution risk to the groundwater environment when using the weathered coal gangue as a filling for the goaf
area is obviously higher than that when using the fresh gangue.
Backfill mining is to fill the filling materials into goaf
of working face in order to control overburden strata caving and surface subsidence in goaf
In zone B, bedrock that was deformed after bedrock stratification in zone A, fully transfers its weight into the goaf
, and stratification occurs in the next "packet" of the roof bedrock.
It is a way to place the gob side roof of the roadway with manpower and shorten the spacing in between the goaf
roadway, thereby solving the problems of methane accumulation in the upper corner, air leak on the work face, and great pressure in the supporting roadway.
C20CK0 in Table 3 is set according to the requirements (i.e., fresh filling body is transported mine goaf
by self-flow and UCS of 3.0 MPa at curing 3 days) of filling body adopted in a mine in China, so the slump of slurry is set 260 mm.
One of the most important problems occurring during ventilation of longwall headings in hard coal mining is an air migration of air through the goaf
with caving of these headings [1-3].
In general, the tensile strength of the surrounding rock is larger than the ore rock, which is more conducive to the stability of the mine goaf
The strata near the fault rotate to the goaf
because of the effect of the fault and its dip angle.
filled with water is the common source of water inrush in the roadway.