Non-pollution damage hazard of underground mining on reservoir ecological environment

Abundant coal resources also exist under rivers and oceans besides lands. Underwater mining has a history of more than 100 years. For a long time, all the technological measures in the mining process are to protect the mine itself, and mining engineers seldom consider the non-pollution damage to the ecological environment caused by mining subsidence. Thus, mining under a medium-sized reservoir is selected as a case study in this paper, the damage hazard of underground mining on a reservoir’s ecological environment is researched based on reservoir area variations from Landsat remote sensing and subsidence basin volume calculations. The results illustrate the subsidence basins by large-scale mining under a reservoir can alter the original topography of the reservoir bottom, which will form new stagnant water basins, and also a large water area will be dried up. The non-pollution damage is difficult to be recovered and even irreversible, especially for small- and medium-sized reservoirs. The subsidence basin volume was 3.04 × 10⁷ m³ until 2018, which was more than the original reservoir capacity. Most of the water would flow into the subsidence basin and cause the reservoir water to dry up. The essence of non-pollution damage hazard is bottom subsidence caused by underwater mining. Therefore, governments should limit mining activities or close the coal mines for protecting the ecological environment of the reservoir.