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

Table 7

Secondary stripping amount and the cost with 1160 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	8.86	12	106.31
2016	12.88	12	154.51
2017	12.13	12	145.54
Total	33.86	12	406.36