中国煤炭学会

会员登录 会员注册
西部生态脆弱矿区保水采煤研究与实践
发布时间: 2016年11月1日
来源: 中国煤炭学会

  范立民1,马雄德2,3,冀瑞君4

  (1陕西省地质环境监测总站,陕西西安 710054;2长安大学环境科学与工程学院,陕西西安 710054;3长安大学旱区地下水文与生态效应教育部重点实验室,陕西西安 710054;4中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京)

  目的  我国西部(榆神矿区、神东矿区等)广泛分布着富水性较强的萨拉乌苏组含水层,补给通畅、储水条件良好,具有重要的生态价值和供水意义,在垂向上,水在上煤在下,煤层埋藏较浅,萨拉乌苏组含水层易受采煤影响,需要在开采中加以保护,即保水开采(保水采煤)。经过多年研究和探索,保水开采在基础理论研究、工程实践等领域取得了大量成果,本文就保水采煤研究的最新进展做一系统总结。

  方法在简要综述保水采煤理论形成和发展的基础上,系统总结了保水采煤技术在基础研究和工程实践不同阶段的研究进展。重点论述了水文地质工程地质条件探测及合理分区预测的理论与方法,进而介绍了含水层结构保护的工程实践方法,其中顶板含水层结构保护的方法包括充填开采、窄条带开采、分层(限高)开采、短壁机械化开采、长壁机械化快速推进开采等;底板含水层结构保护主要以注浆改造和加固煤层底板为主。另外地下水转移储存作为水煤共采技术同样提高了水资源利用率。

  结果(1)通过地质水文地质勘探查明了本区地下水和煤层赋存特征,划分了煤层覆岩结构类型和保水采煤地质条件分区,编制了基于保水采煤的采煤方法规划图,指明沙-土-基型和烧变岩型覆岩条件下有保水采煤的可行性和必要性。(2)以风积沙为骨料的膏体充填材料在本区有得天独厚的物源优势,并能极大地控制地面下沉,但成本较高;窄条带采煤方法适用于面积小且不规则的矿区,但煤炭回采率低,回收留滞的“条带煤”仍具有较高的技术难度;限高(分层)开采对于煤层厚度大于10m矿区较为适宜,但上分层开采后,下分层何时回采、回采对含水层结构的影响仍在研究阶段;短壁机械化开采适合于不规则区域及残煤区回收煤柱等;长壁机械化快速推进开采方法是限高开采或局部充填开采方法的衍生,开采中需要提高工作面推进速率;煤层底板承压水防治中物探结合注浆工程改造加固底板在渭北地区部分矿井开采中发挥了重要作用。地下水转移储存技术使矿井水得到了充分利用,但地下水库建设过程中应控制合理的生态水位埋深,以免对植被发育、地下水循环途径造成影响。

  结论综述了保水采煤从理论研究向工程实践发展的历程,开展了保水采煤地质基础研究,划分了煤层覆岩结构类型和保水采煤地质条件分区,提出了生态水位保护采煤理念,编制了基于保水采煤的采煤方法规划图,并推广应用。部分煤矿开展了保水采煤工程实践,实现了高强度采煤条件下煤层顶板含水层、底板岩溶水含水层的保护,促进了矿区地质环境保护。未来,开发低成本、适用性广的保水采煤方法是煤炭科技界面临的新课题。

  Progress in Engineering Practice of Water-preserved Coal Mining in Western Eco-environment Frangible Area

  FAN Li-min1,2,MA Xiong-de3,JI Rui-jun4

  (1. Shaanxi Geological Survey, Xi’an, Shaanxi, 710065,China;2.Shaanxi Institute of Geo-Environment Monitoring, Xian  710054,China;3. College of environmental science and engineering, Chang'an University Xian  710054,China;4.State Key Laboratory of Coal Resource & Safety Mining,China University of Mining & Technology,Beijing 100083,China)

  There widely distributed aquifer in Sala Wusu group with better water yielded property, favorable recharge channel and superior water storage condition in the western China, it has very important ecological value and water supply capacity. The aquifer in Sala Wusu group,located above coal seam, is very easy to be damaged  during mining because the coal seam buried shallowly, therefore, the aquifer should be protected during mining, namely water Cpreserved mining(water Cpreserved coal mining). After years of study and exploration, water Cpreserved mining achieved abundant results in both basic theoretical research and engineering practices. The latest developments of water-preserved mining study are summarized systematically in this paper.

  On the basis of brief summary formation and development of water-preserved mining, the paper summarized systematically the research progress in different stages of basic research and engineering practices. The hydrogeology and engineering geology conditions detection and its divide method were firstly discussed, and then the engineering practical method of aquifer structure protection was introduced. The methods of protecting the roof aquifer structure include backfilling mining, narrow strip-partial mining, thickness limited mining, short-wall mechanized mining, long-wall mechanized fast excavation and so on. reinforced bottom plate by grouting is an effective way to protect Karst confined water. Moreover, the transfer and storage of groundwater as the technology of exploiting water and coal together, enhances the water use efficiency similarly.

  By means of geological and hydrogeological exploration, the storage features of groundwater and of coal were found out, the spatial structure and geological condition of coal bed roof were divided, the map of mining method based on water preserved-coal mining was designed. Aeolian sand paste filling mining method, which has provenance superiority in the area, can control the ground subsidence greatly, but its cost is very high. Narrow strip mining method is fitted small and irregularity mining area, but it has low coal recovery rate and higher technical difficulty in recycling “strip coal”; Thickness limited mining method is suitable for where coal thickness is more than 10m, however the excavation time of lower slicing and its impact on aquifer structure is of  still in research phase. The short-wall mechanized mining is derived from thickness limited mining method or partial backfilling mining method, it is suited to irregularity mining area and recovering coal pillar in residual-coal area, and the workface advance rate must be picked up. Floor reinforcement by geophysical prospecting combined with slip casting has played important role in pressurized water control in some mine north Weihe River. The groundwater transfer storage technology made full use of mine water, but vegetation grows and groundwater circulation might be disrupted if the groundwater depth reduced greatly during underground water reservoir establishing .

  The paper summarized the development course of water preserved-coal mining with from theory research to the engineering practice, studied geological basis of coal mining with water protection, established the structure type of coal bed roof and divided the coal mining area into different partitions to protect aquifer, brought in the concept of coal mining with water protect aquifer, and specified the mining methods in different regions to protect groundwater, then has carried on the popularization and application. Some coal mines carried out engineering practice about coal mining with water protection, and realized the protection of coal bed roof aquifer and Karst floor aquifer during high intensity mining. In the future, the study of a low-cost and widely applicability coal mining with water protection methods is a new task faced by the coal technology.