Extraction of sand from the complex matrix of coal mining dump waste: A sustainable approach in Indian context

Dump waste generated by open cast coal mining industry is a significant global source of environmental pollution, land degradation and possesses threats to the environmental sustainability. After conducting pilot study, experimental investigations were conducted to study the reuse of waste rocks coming from mining as fine aggregates as a possible replacement of river sand. Physical, chemical and mechanical tests have been carried out in order to analyze in detail the interaction whether extracted sand is suitable in construction sector or not. The present study focuses on utilizing the overburden of the Sasti open cast coal mine of Western Coal Limited in the Chandrapur District of Maharashtra state, India for extraction of sand. Extracted sand contains minerals mainly quartz, alumina, and satisfies the prescribed permissible limit as per the Indian coal provisions for its use in construction work and observed to be equivalent to river sand. The compressive strength obtained with extracted OB sand after 28 days of curing was 29.294 MPa as compared to 33.153 MPa for the river sand for M25 grade of concrete. The focus of the study is on the reclaimed sand and its possible usages and not on the other components like clay of dump waste.