Design a drilling, charging, and timing round for a tunnel with the following dimensions:
Height – 3.5m and width – 4.0m in a competent dolerite. The proposed hole diameter is 48mm. Drill length is 3.2 using a mechanised drill. Select emulsion explosives with an in-hole density of 1.15g/cc. Calculate the drilling and blasting cost per m3 and per metre advance for the design. Assume a drilling cost of R45.50 per metre, and the initiation system cost per hole is R65.00. The average advance per blast is 2.9m. Emulsion cost is R17.50 per kilogram delivered in the hole. The tamping cartridges are 200mm in length and 42mm diameter, costing R0.95 per cartridge. The overbreak is 150mm on the side walls and hanging wall. Do you agree with the advance?
Clearly show all the assumptions you are making. Please do not use a software program for the design.