Characteristics and source analysis of erosion sediment in dump of open pit coal mine based on REE tracing

Mine dump is a huge loose cushion landform formed by human disturbance，which has the characteristics of complex material， loose slope and compact platform. In order to reveal the soil erosion law of the dump， the East dump of Heidaigou open pit coal mine in Shengli was selected as the research object，and the indoor model(sec⁃ ond⁃order) of the dump was established.The soil erosion law of different platforms and slopes of the dump model under rainstorm was studied by using the method of artificial rainfall simulation and stability REE tracer technology，and the source of erosion sediment of the dump model was interpreted. The results show that: The runoff and sediment yield curves of the dump model were similar，showing a trend of first increasing and then stable fluctuation with the ex⁃ tension of rainfall time.The total runoff and sediment yield increased with the extension of rainfall time，and there was a good power function relationship between the total runoff Z and sediment yield Y and the rainfall duration X. Under the condition of 90 mm / h heavy rainfall， the contribution rate of sediment yield of the first slope of the dump model was about 90%，which was the main source of erosion sediment.Under the condition of 120 mm / h heavy rainfall，the contribution rate of sediment yield of the first slope of the dump model was about 70%，and that of the first terrace was about 20%，which was the main source of erosion sediment.The first stage platform was an important source of erosion sediment.Under the condition of 150 mm/h heavy rainfall，the contribution rate of sediment yield of the first slope and the first platform fluctuated between 30% and 50%，and the contribution rate of sediment yield of the second slope increased steadily from about 10% in the early stage of rainfall to about 25%.The first platform and slope were the main contribution area of sediment yield， and the second slope was an important contribution area.With the increase of rainfall intensity，the soil erosion of the dump model was stronger，and the contribution rate of sediment yield of the dump high⁃level platform and slope was greater.