永冻覆岩层下综采工作面坚硬顶板弱化处理技术

Weakening treatment technology of hard roof above fully-mechanized coal mining face under permafrost overlying strata

针对卡洼掌煤矿工作面上覆岩层为永冻岩层,为了保证在该条件下坚硬顶板综采工作面安全生产,在开切眼内向顶板钻孔进行工作面断顶爆破,同时在工作面运输巷和回风巷向顶板布置扇形钻孔进行拉槽截断爆破,在永冻覆岩层下实施了工作面顶板爆破预裂弱化试验,并通过综采工作面安装的KJ27在线监测系统,对顶板弱化处理后的采场矿山压力显现进行监测。监测结果表明:采场顶板初次来压和周期来压步距分别为19、15 m,周期来压步距较顶板弱化前降低50%,避免了工作面大面积悬顶的威胁,防止工作面顶板事故的发生。

Based on the overburden strata in Kawazhang Mine as the permafrost overburden strata,in order to ensure a safety mining of the fully-mechanized coal mining face under the hard roof,roof borehole drillings within the open-off cut were applied to the roof breaking blasting in the coal mining face. Meanwhile,a fan-shaped borehole pattern was made in the roof of the transportation gateway and the air returning gateway of the coal mining face for the cutting and breaking blasting. Under the permafrost overburden strata,a roof blasting pre-fracturing weakening test was conducted in the coal mining face. KJ27 online monitoring and measuring system installed in the fully-mechanized coal mining face was applied to the monitoring and measuring of the mine pressure behavior after the roof weakening treatment conducted. The monitoring and measuring results showed that the initial roof weighting and the periodical roof weighting step distance of the coal mining face was 19 meters and 15 meters individually,the periodical roof weighting step distance was reduced by 50% in comparison with the roof weakening not conducted. Thus,the danger of the large area suspended roof above the coal mining face could be avoided and the roof accident occurred in the coal mining face could be prevented.