The influences of mining subsidence on the ecological environment and public infrastructure: a case study at the Haolaigou Iron Ore Mine in Baotou, China

The scope and extent of mine subsidence caused by exploitation of metal ores are usually low. However, in some cases, owing to such factors as special geological conditions in ore body, backward mining technology and unsound management systems, exploitation of metal ores would also lead to a large area of mine subsidence, causing great damages to the mining environment and infrastructure. A serious mine subsidence happened in January 2007 at the Haolaigou Iron Ore Mine has caused a huge collapse pit on the earth's surfaces. This provides a suitable place to study the influence of mine subsidence. Based on former research results, a 3D geological model is constructed using the ROCK MODEL software developed by authors' group. Based on in situ geological conditions, the range of orebody mining and the physical and mechanical parameters of rock and soil mass were determined by inverse analysis. Creep analysis of the collapse pit was also performed. Furthermore, the elastoplastic and creep of the secondary collapse were computed, and the final range of the collapse pit was predicted. Finally, the influences of mining subsidence on the ecological environment and public infrastructure are discussed and control measures were proposed. The results indicate that the collapse pit would not affect the road even if creep is considered; however, the secondary collapse would influence the road. So the collapse pit should be dealt with as soon as possible.