Research on Inpit Dumping Height during Tracing Mining Period between Two Adjacent Surface Coal Mines

Table 5

Secondary stripping amount and the cost with 1130 elevation dumped of Heidaigou surface coal mine.

Year	Secondary stripping tonnage (m^3 × 10^6)	Stripping unit price (yuan)	Secondary striping cost (million yuan)
2015	2.23	12	26.71
2016	6.98	12	83.73
2017	6.53	12	78.31
Total	15.73	12	188.76