Determination of the Ultimate Underground Mining Depth considering the Effect of Granular Rock and the Range of Surface Caving

Table 1

The stages of excavation and filling.

Mining stage	Excavation number	Filling number	Mining level (m)
First stage	1, 2, 3, 4, 5, 6, 7, 8	1, 2, 3, 4, 5, 6, 7, 8	Surface to 190
Second stage	9, 10	9, 10	190 to 150
Third stage	11	11	150 to 130
Fourth stage	12	12	130 to 110
Fifth stage	13	13	110 to 90
Sixth stage	14	14	90 to 70
Seventh stage	15	15	70 to 50