煤矸石-粉煤灰用作井下充填材料实验研究

黄金矿山由于尾矿氰化物含量较高无法用于井下采空区充填,但随着井下采空区逐渐扩大,亟需充填材料用于回填,实验研究利用煤矸石-粉煤灰用作骨料与水泥混合充填至采空区。岩质煤矸石的普氏硬度为2.74,易于破碎加工。电厂干排粉煤灰,测得细度为18.6%,颗粒较细。将煤矸石破碎至20mm以下用作粗骨料,粉煤灰为细骨料,当煤矸石-粉煤灰比为7:3时,混合骨料级配与Fuller理论曲线接近,级配良好。以水泥为胶凝材料配制1:7、1:9两种灰砂比的充填材料,混合料浆浓度为83%时,均能满足采空区管道高浓度输送的流动度要求。测定不同养护龄期下充填材料的单轴抗压强度,两种灰砂比材料在浓度为83%、82%下,28d的强度均超过4MPa,最高可达6.03MPa,可满足采空区顶底部或中心部位的充填强度要求。

Experimental Study on Coal Gangue-Fly Ash as Underground Filling Material

Due to the high content of Cyanide in gold tailings, which can not be used to fill the underground goaf, However,as the underground mines are gradually expanding, it is urgent to use filling materials for backfilling. Experimental research uses coal gangue-fly ash as aggregate and cement mixture to fill the goaf. The Protodikonov hardness coefficient of rock gangue is 2.74, which is easy to be broken and processed.The fineness of the dry discharge of fly ash from Fuxin Power Plant is 18.6% and the particles are fine. The coal gangue is crushed to less than 20mm for coarse aggregate, and the fly ash is fine aggregate. When the ratio of coal gangue and fly ash is 7:3, the mixed aggregate gradation is close to the Fuller theoretical curve, and the gradation is good. Filling materials with two cement-sand ratio of 1:7 and 1:9 are prepared with cement as the cementitious material. When the concentration of the mixed slurry is 83%, it can meet the fluidity requirements of high-concentration transportation of the goaf pipeline. The uniaxial compressive strength of the filling materials at different curing ages is measured. At the concentrations of 83% and 82%, the strength of the two lime-sand ratio materials exceeds 4MPa at 28 days, and the maximum strength was 6.03Mpa, which can meet the filling strength requirements of the top and bottom or central parts of the goaf.