Study On The Distributing Characteristics Of Karst Collapse Pillars In Yangquan Mining Area And Its Relationship With Folds, Faults And Seismicity

Mostly, karst collapse pillars can hardly conduct water due to compactionand cementation of the sedimentary in geological time. Yet the compacted bodyof the pillar which is unable to conduct water may convert into “incompacted”ones for tectonic activities and mining activities after, which is called thereactivation of karst collapse pillar. And once a single karst collapse pillarinduced water inrush happens, the entire mine will suffer the risk of beingflooded, which leads to significant casualties and property losses. Thus thecapability to conduct water of karst collapse pillar directly affect the safety ofmining production.15#coal seam, which is the oldest major minable coal seam in YangquanMining Area, pertains to the lower Taiyuan Formation. Vertically,15#coal seamis the nearest seam to Majiagou Formation of middle Ordovician, which is themain karst aquifer regionally. The water inflow of this aquifer is strong, thehydraulic pressure is high and the aquifer is connected to the karst collapsepillars, which means once the pillars are able to conduct water, then theexposion of them may lead to catastrophic water inrush. Thus, based on the understanding of the spatial distribution of folds, faultsand karst collapse pillars in15#coal seam that is determined by the exposion ofworking face, by geophysical prospecting, and by geological survey on surfacein Yangquan mining area, statistic analysis of folds, faults and pillars isconducted firstly, while the morphological characteristics of folds are classified.On basis of this, the relation of karst collapse pillar distribution to folds andfaults is studied and the results show that pillars mainly gather along anticlinalaxis, around the turning of folds, and around the intersection of folds or itsbranching node, while pillar distribution seems to be independent of faults.Further more, the spatial distribution of b-value in Yangquan mining area iscalculated in separate time segments using ZMAP6.0based on the earthquakecatalog of Shanxi province from Jan,1970to March,2014. Combined with theOrdovician groundwater level data, the region of probable karst collapse pillarreactivation-induced water-conducting is analysed.