The influence of oil shale in situ mining on groundwater environment: A water-rock interaction study

Oil shale samples were obtained from Nong'an oil shale ore-bearing area which was located in the southeastern uplift of Songliao basin, China. The XRD test for oil shale identified the minerals in it and a series of water-rock interaction experiment between oil shale-water and oil shale ash-water were carried out to the study the release of organic matter from groundwater during oil shale in-situ exploitation. The content of phenol, BTEX, TOC and TPH in oil shale and oil shale ash aqueous solution were determined. The phenol and TOC in oil shale aqueous solution were higher than that of oil shale ash aqueous solution, conversely, more BTEX and TPH were existed in oil shale ash aqueous solution. The reaction temperature had significant influence on phenol, TOC and TPH in oil shale aqueous solution, which was not obvious in oil shale ash aqueous solution. Besides, the TOC average content in oil shale aqueous solution gradually increased along with the reaction time. The results show that not only oil shale in situ mining process make groundwater organic pollution aggravate but also continuous pollution of groundwater caused by the residual oil shale ash still exist.