Research on the pit lake water in an abandoned oil shale goaf

The Jintang oil shale mine, an opencast mine in Maoming, Guangdong Province, has been abandoned for about 20 years after half a century of ore exploration without a reclamation or remediation plan. This article aims at elucidating the revealed and potential environmental risks associated with the pit lake by quantifying pollution in the stagnated water in the goaf. The water in the abandoned goaf had an acidic pH equal to 3.40, whereas concentrations of dissovled iron reached 1.54 mg/L, and 0.00756 mg/L for total cadmium. All these data exceeded the standard scope respectively showed that the natural environment was contaminated by the abandoned oil shale mine. The reason for low pH and overdose of heavy metals were analyzed.These findings urge for an immediate remediation action of the afflicted area. Meanwhile, attentions should be taken to study the mechanism of trace element released from oil shale and the theory of element geochemical migration in order to prevent the accumulation of hazardous trace elements associated with the abolished oil shale mining pits, which was critical to managing the disposal of the abandoned oil shale mine.