Collaborative governance model for spoil disposal and gully infill land creation near open-pit coal mines

Large scale open-pit mining activities have had a significant impact on the topography, geomorphology, and ecological environment of the loess gully region. In order to alleviate the common problems of insufficient internal drainage space in open-pit mines, such as excessive slope angles, over elevation soil discharge, limited production capacity, as well as soil erosion and difficult treatment and utilization of fragmented gully land in the natural gully area around the coal mine, this paper proposes a collaborative mining and treatment technology model for ditch filling and land reclamation in the vicinity of open-pit mines. The principle is based on the analysis of technical, economic and environmental benefits. The suitable stripped rock and soil materials that were originally intended to be dumped in the dumping site are backfilled to adjacent gullies outside the mining area that are suitable for treatment, and finally covered with soil and vegetation construction, in order to save dumping space and reuse land in the gully area. The main technical steps include: extracting the location of the gully to be treated based on the algorithm of constructing concentric rectangular windows inside and outside, optimizing the earthwork allocation path of the waste dump based on the “source sink” theory, backfilling the gully area based on the reshaping of the near natural landform, screening the waste materials and reconstructing the soil layer profile of the gully backfilling, greening and land reuse of the covering soil, and evaluating the ecological effects of collaborative mining and treatment. This article takes a certain open-pit coal mine in Zhungeer Banner, Inner Mongolia as an example to conduct research. The results show that the total area of natural gullies around the open-pit mine treated by this model is 2.588 × 105 m², reducing the amount of earthwork discharge in the mining area by about 1.536 × 107 m³; By combining the CLiDE geomorphic evolution and soil erosion assessment model, we simulated and evaluated a 66.53% reduction in regional soil erosion after collaborative treatment of surrounding gullies over a 30-year period. At the same time, the landscape after collaborative treatment showed a relatively stable evolution trend, and a large amount of available land was added, achieving the goal of “one soil, two uses”. To ensure the promotion of this technological model, corresponding policy support and strict process supervision are also needed to ensure that the model generates maximum comprehensive benefits and avoids causing new land occupation and ecological environment problems.