Research on the "Five-in-One" Ecological Restoration Technology and Benefits of Karst Mines in the Lijiang River Basin — A Case Study of Pengxin Quarry

Abstract: The ecological degradation caused by historical mining sites in the karst region of the Li River Basin poses a severe and persistent threat to regional ecological security. This study targeted the Pengxin Quarry, a typical open-pit karst mine in the basin, with the aim of establishing a systematic ecological restoration technology system to achieve multi-dimensional synergistic rehabilitation of landform, soil, vegetation, hydrology, and maintenance mechanisms. Based on ecosystem succession theory and on-site ecological diagnosis, an innovative integrated restoration model termed “landform reshaping–soil improvement–vegetation restoration–water and soil conservation–long-term maintenance” was proposed and implemented. Engineering practices and long-term monitoring were carried out over a damaged area of 5.17 hm². The results demonstrated that the restoration project successfully established new land uses: 9.28 mu of paddy field, 24.51 mu of dry farmland, 9.83 mu of forest land, and 7.00 mu of grassland. Vegetation coverage increased significantly from less than 15% before restoration to over 85%. Soil and water loss was reduced by more than 90%. Concurrently, water conservation capacity and landscape connectivity were markedly improved, and farmland quality was effectively enhanced, achieving synergistic gains in ecological recovery, social benefits, and economic value. This study verifies the applicability of the “five-in-one” restoration model in karst mining areas and forms a closed-loop management pathway of “technology integration–process monitoring–long-term management.” It provides a systematic technical reference and a replicable practical paradigm for the ecological restoration of similar mines in karst regions of southern China.