Longwall mining “cutting cantilever beam theory” and 110 mining method in China——The third mining science innovation

With the third innovation in science and technology worldwide, China has also experienced thismarvelous progress. Concerning the longwall mining in China, the ＂masonry beam theory＂ （MBT） wasfirst proposed in the 1960s, illustrating that the transmission and equilibrium method of overburdenpressure using reserved coal pillar in mined-out areas can be realized. This forms the so-called ＂121mining method＂, which lays a solid foundation for development of mining science and technology inChina. The ＂transfer rock beam theory＂ （TRBT） proposed in the 1980s gives a further understanding forthe transmission path of stope overburden pressure and pressure distribution in high-stress areas. In thisregard, the advanced 121 mining method was proposed with smaller coal pillar for excavation design,making significant contributions to improvement of the coal recovery rate in that era. In the 21st century,the traditional mining technologies faced great challenges and, under the theoretical developmentspioneered by Profs. Minggao Qian and Zhenqi Song, the ＂cutting cantilever beam theory＂ （CCBT） wasproposed in 2008. After that the 110 mining method is formulated subsequently, namely one stope face,after the first mining cycle, needs one advanced gateway excavation, while the other one is automaticallyformed during the last mining cycle without coal pillars left in the mining area. This method can beimplemented using the CCBT by incorporating the key technologies, including the directional presplittingroof cutting, constant resistance and large deformation （CRLD） bolt/anchor supporting systemwith negative Poisson＇s ratio （NPR） effect material, and remote real-time monitoring technology. TheCCBT and 110 mining method will provide the theoretical and technical basis for the development ofmining industry in China.

Principles of the roof cut short-arm beam mining method (110 method) and its mining-induced stress distribution

Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)" and ‘‘Transfer Rock Beam Theory(TRBT)". Based on those theories, the conventional mining method(being called the 121 mining method) was established, consisting of excavating two tunnels with a pillar left for mining a working panel. However, with increasing mining depth,engineering geological disasters in the underground caverns have been frequently encountered. In addition, the use of the coal-pillar mining results in a large amount of coal resources unexploited. In order to address the problems above, the ‘‘Roof Cut Short-Arm Beam Theory(RCSBT), being called the 110 mining method)" was proposed by He Manchao in 2008. The 110 mining method features the mining of one coal seam panel, excavating necessarily only one roadway tunnel and leaving no pillars. Realization of the 110 mining method includes the following steps:(1) directional pre-splitting roof cutting,(2) supporting the roof by using high Constant Resistance Large Deformation bolt/cable(CRLD), and(3) blocking gangue by hydraulic props. This paper presents an overview of the principles, techniques and application of the 110 mining method. Special emphasis is placed on the numerical simulation of the geostress distribution found in the mining panel using the 110 method compared to that of the 121 method. In addition, the stress distribution on the ‘‘short beam" left by the roof cutting when performing the 110 method was also investigated using both numerical simulation and theoretical formulation.

采矿未来——智能化5G N00矿井建设思考

目前,国内外普遍采用的传统采煤方法为源自英国的长壁开采121工法体系(开采1个工作面,需要提前掘进2条巷道,留设1个煤柱),该采煤方法存在采掘分离、巷道掘进量大以及易造成工作面采掘失衡等问题;在掘进过程中,采用高强支护对抗矿山压力,易造成冒顶、冲击地压等灾害事故;在开采过程中,留设煤柱不仅浪费宝贵的煤炭资源,而且易造成地表不均匀沉降和生态环境损伤。为了解决上述问题,笔者提出了“切顶短臂梁”理论,利用矿山压力做功与垮落矸石碎胀特性,取消巷道掘进与煤柱留设。研发了配套核心技术与采留一体化装备,形成了无煤柱自成巷N00工法开采体系(开采N个工作面,0巷道掘进,0煤柱留设)。N00工法发展包括5个阶段(1G N00工法~5G N00矿井),利用采留一体化关键技术工艺体系和智能化装备系统,逐步实现“单侧自动成巷,取消采区回采巷道掘进→双侧自动成巷,取消采区准备巷道掘进→简化井底车场,取消大巷掘进→取消矿井通风,将瓦斯灾害变为天然气资源→融合双5G通讯技术,创建远程无人化智慧采矿模式”。同时,笔者还介绍了无煤柱自成巷1G N00工法在陕煤集团陕北矿业柠条塔煤矿的成功应用。