Feasibility of Injecting Pretreated Mine Water into a Deep Ordovician Aquifer in the Lilou Coal Mine, China

The groundwater quality in the Lilou Coal Mine in Shandong Province can be divided into “three zones” based on the range of mining-induced fractures. Considering the observed Ordovician aquifer water level decline rate of 2.6 m/year, we propose that the saline mine water contained in Zones II and III can be injected into the well-developed underling karst Ordovician aquifer in Zone I. A water quality comparison of 27 factors demonstrated that only the Na+ concentration in the mine water exceeded that in the Ordovician aquifer water. The Ordovician aquifer has an average karst development thickness of 140 m, and the karst fracture rate ranges from 6 to 14