Quantitative evaluation and reuse path of underground space resources in closed mines

With the long-term mining of coal resources，more and more coal mines are facing closure or have been closed. In the long-term exploitation of these mines，a large amount of underground space has been formed，and the traditional well sealing measures will cause a huge waste of underground space resources. Under the background of increasing number of closed mines and green development at home and abroad，the use of mathematical models to quantitatively evaluate the underground space resources of closed mines and the ways to reuse these resources are not only important issues in the field of energy and environment，but also hot spots of social concern. It is also the urgent need of mining enterprises to solve the development dilemma. The contents of this article consists of three main parts：① Dividing the types of underground space resources in closed mines，and proposing the methods for calculating the space of different types of roadways and working face goafs，and estimating residual coal resources. ② The transformation and utilization modes of mines in the world were analyzed. Based on the ecological benefit，economic benefit and social benefit，the evaluation index system of comprehensive benefit of mine transformation was built. The analytic hierarchy process was used to evaluate comprehensive benefit of different transformation scheme in the underground space of closed mines. On the basis，the optimal transformation path was obtained through comparative analysis. ③ Taking a mine in Weihe River Basin of China as an example，the underground space of the mine was 1.18×105 m3，the total residual resources were 56 million tons. The underground transformation mode in descending order of benefit were underground mine museums，underground resorts，and underground material storages. According to the characteristics of resources and the hierarchical structure model，the optimal transformation and utilization scheme of the mine was aboveground mine park + underground mine museum based on the comprehensive space resources of the closed mine. This paper mainly gives the division standard of underground space resources of closed mines，and puts forward the quantitative evaluation method of closed mine resources. It provides a new idea of transformation and sustainable development for mining enterprises，and also provides theoretical reference and practical examples for the transformation and utilization of closed/abandoned mines，which is of great significance for the implementation of the “carbon peaking and carbon neutrality” strategic goals in China.