Theory and technical system of coal ecological open-pit mining and its application

Large-scale open-pit coal mining will cause ecological problems such as land excavation and occupation, groundwater drainage, soil erosion, vegetation destruction, air pollution, and regional landscape damage. The selection of existing open-pit coal mine ecological restoration technologies is relatively limited, and there is a lack of systematic research on ecological total factors. In this paper, the concept of “damage reduction mining and systematic restoration” was proposed, and the connotation and technical approach of ecological mining of open-pit coal mine were expounded. The key scientific issues and basic theoretical framework of ecological mining of open-pit coal were proposed. Then the whole life cycle ecological impairment mining technology and the coordination system restoration technology of ecological elements (water, soil, vegetation, landscape) of “pre-harvest ecological design-mining during mining loss-postharvest ecological restoration”were developed. At last, the theory and technical system of open-pit coal mine ecological mining was established, and a generalizable and replicable open-pit mine ecological mining mode was formed. The results show that in the semi-arid area, the ecological restoration technology has significant effects. The area of land excavation and occupation loss is reduced by 60 003 m2 every year, the ecological restoration period of the dump site is advanced by more than one year, and the vegetation coverage rate increases by 41.78% compared with the background value in the semi-arid area of the Shengli open-pit mine demonstration area. A surface reservoir with a water storage capacity of 400 000 cubic meters has been built, and the seasonal and graded utilization of mine water has been realized. In the extremely cold area of Baorixiler, the area occupied by land excavation is reduced by 106 672 m2 per year, the number of new species has increased from 14 to 21, the soil moisture content has increased by 10%, the annual soil erosion rate has decreased by 59.6%, and the vegetation coverage rate has increased by 37.96% compared with the background value in the demonstration area of the Baorixiler open-pit mine. An open-pit coal mine underground reservoir with a water storage capacity of 1.22 million square meters has been built, realizing the “winter storage and summer use” of mine water. © 2024 China Coal Society. All rights reserved.