大柳塔煤矿活鸡兔井1-2煤复合区煤层埋深76~106m，厚度10m左右。由于当时国内外装备制造业水平受限的原因，从2001年3月至2006年5月，神东公司对该盘区煤层配套5.0液压支架采用综合机械化采煤法进行了回采，采高4.5~5m，剩余的5m厚的煤层保留在上分层的采空区下，剩余煤炭资源超过3000万吨未回收，经重新设计可以布置回采工作面9个。 本文以1-2下202工作面采煤工程为例，对采用综合机械化一次采全高采煤法和综采放顶煤采煤法工艺进行了对比研究，合理确定了采空区下资源回收最佳采煤方法；采用理论分析，数值计算模拟及相似材料模拟等方法验证了选择采用放顶煤开采的科学合理性。坚硬顶煤在上分层开采底板破坏以及本工作面支架反复支撑作用下，顶煤冒放性较好。工程实践表明，工作面矿压显现不明显，周期来压步距为4.8~14.9m，平均为8.1m；来压时支架载荷为9153~10026kN，平均为9434kN，设计配套的液压支架能满足现场矿压显现需要。 针对此工作面在极近距离采空区下掘进及回采作业存在的安全风险，还研究制定了安全开采的保障措施，建立起来一整套从采煤方法的确定—合理性验证—巷道安全掘进支护方案—安全开采措施的系统性技术体系，为后续工作面的开采提供了依据。该工作面的高效安全回采也为国内外类似条件煤矿资源的回收提供了良好的借鉴，它为国家煤炭不可再生资源的可持续发展做出了贡献。

The coal seam of the 1-2 coal complex in the HuoJitu of DaLiuta coal mine is 76~106m deep and the thickness is about 10m. Due to the limited level of equipment manufacturing industry at home and abroad at that time, from March 2001 to May 2006, Shendong Company adopted the comprehensive mechanized mining method to extract 5.0 hydraulic support for the coal seam in the panel, the mining height was 4.5~5 m, the remaining 5 m thick coal seam was retained under the goaf of the upper layered, and the remaining coal resources exceeded 30 million tons were not recovered, after redesign, the mining work could be arranged 9 faces. Taking the mining engineering of 202 working face of 1-2 lower seam as an example, this paper makes a comparative study on the technology of fully mechanized mining overall height in one times and fully mechanized top-coal caving mining, and reasonably determines the optimum mining method for resource recovery under goaf. By means of theoretical analysis, numerical simulation and similar material simulation test, the scientific and rationality of top-coal caving mining method has been verified. The caving performance of top coal is better under the action of floor failure in upper layer mining process and repeated support of hydraulic support in this working face. Engineering practice shows that the mine pressure appearance of working face is not obvious, the periodic weighting step is 4.8-14.9 m, with an average of 8.1 m, and the support load is 9153-10026 kN, with an average of 9434 kN. The design of matching hydraulic support can meet the needs of field mine pressure appearance. In view of the safety risks of the excavation and mining operations under the condition of extremely short-range goaf, the safeguard measures for safe mining are also studied and formulated, and a set of systematic technical system is established from the determination of mining methods-rationality verification-roadway safe driving support scheme-safe mining measures, which provides a basis for the subsequent mining of the working face. The efficient and safe mining of this working face also provides a good reference for the recovery of coal resources under similar conditions at home and abroad. It contributes to the sustainable development of non-renewable coal resources in our country.