Geology of Bhotang Sulphide Deposit, Rangpo, Sikkim

The Bhotang sulphide deposit, situated near the border town of Rangpo, Sikkim was explored in detail during 1957-59. The copper-lead-zinc lode is exposed in a hill scarp over a strike length of about 400 m. with a strike of N 50°E and a dip of 65°SE. The lode is folded into a sinistral drag fold plunging ENE and is faulted along the anti-clinal axis. The ore body shows pronounced zoning along strike and across the Width. It has a strong pitch of about 50° towards south. The pitch and zoning of the ore body and the faults in the area have a significant bearing on the planning of development and exploitation of the deposit.

The ore body has been proved over a vertical extent of 275 m and a strike length of 200 m in the lower levels; and because of erosion in upper horizons, the strike length is gradually reduced to 90 m. The ore body has an average width of 5 m. The drives in different mine development levels indicate a width of about 1.5 m with a total copper-lead-zinc content of 4.90%.