Design method for cadmium and arsenic contamination control during the mining-selecting-backfilling integrated technology

Because of the toxicity and harmfulness of heavy metals including cadmium and arsenic, how to reduce and control the pollution of these heavy metals in coal mining areas has always been a challenging issue. Although earlier studies focused on cadmium and arsenic contamination caused by coal combustion and waste rock piles and their control, there have been few reports of measures for pollution control in the coal mining process. Thus, the pollution in coal and residues cannot be initially controlled from the source. From this viewpoint, this paper first analyzes the possible hazard forms of cadmium and arsenic in coal during regular coal mining. The method and design processes of the mining-selecting-backfilling integrated technology are investigated for the control of arsenic and cadmium pollution during the mining process, and the effectiveness of this method is verified by an engineering example. The research results indicate that the mining-selecting-backfllling integrated technology can completely eliminate heavy metal contamination in coal gangue through avoiding coal gangue accumulation and spontaneous combustion. Meanwhile the contamination risks of heavy metals such as cadmium and arsenic can also be reduced by underground unmined coal resources via reasonably designing the backfllling rate and controlling the development of mining fissures. (C) 2020 Elsevier Ltd. All rights reserved.