Large Opencast Mine Dump Erosion Characteristics Of Soil And Water Safety Evaluation

The stockpile of opencast coal mine is a kind of huge artificial loose dump, which has the problems of serious soil erosion and instability. This research object is the biology water protecting measures of the AnTaiBao Surface Opencast Coal Mine (ATB) south stackpile within loess area, including 4 aspects as below:(1) The form and distribution characteristics of erosion in original and newly-constructed lands of the ATB south stackpile. The original water erosion modulus is 3700⁴400t/km²a in the south stackpile. On newly-constructed lands there are not only splash erosion, surface erosion. gully erosion, which is universal on original lands, but also the special forms, for example, hole erosion gravel erosion debris slide and debris flow, which is unusual in loess area,(2) Based on a long-term fixed point experiments in proving ground of the south stackpile, the soil erosion factors have been researched quantitatively, the runoff and erosion affected factors have been made sure and the experiential models of producing water and soil have been taken in newly-constructed stage, early stage and later stage of reclamation. (1)In newly-constructed stage and early stage of reclamation, the most important factor of runoff is 30min rainfall intensity. In later stage of reclamation, the most important one is 45min rainfall intensity. And the runoff capacity is the most important influence factor to soil erosion always; (2)On the certain degree, loosening surface has an active function to infiltration condition but not to conserve soil;(3)The most runoff is formed on platform of stackpile and the soil erosion often happens in the slope;(4)Stone-soiled dumps have an advantage over soil at respect of erosion resistance so that soil is not adapt in covering slope;(5)Grass has a better role in conservation of water and soil than arbor in early stage of reclamation;(6)Arbor-arboret-hemp mix is the best model for conservation. Hemp is the worst one with its degeneration in later stage of reclamation.(3) Soil erosion assessing systems and evaluating water-soil safety models have been first raised in the stackpile of large opencast mine within loess area. 8 disaster factors of soil erosion have been defined: surface material, landform and slope gradient, cover-degree, topographic, 30min rainfall intensity, engineering measure grade of conservation of water-soil, irregular subsidence and volume weight. In newly-constructed stage, early stage and later stage of reclamation, the degree of erosion and the space-time characteristics of influence factors have been analyzed and compared by the evaluation index and model.(4) Water-soil curing and using techniques of large opencast coal mine within loess area in our country have been divided into three types: water-soil safety techniques, water-soil conservation and water-soil recycling use techniques. And the direction of the techniques of water-soil recycling use has been raised.