1. Two surface mines are considering the use of a conveyor in conjunction with their current fleetof trucks and shovels.
The mines are;
i. a strip mine operation in which coal is transported out of the strip from a depth of 37m to a coal plant on the surface, at a rate of 1.2 million tons per month.
ii. an open-pit operation in which coal and waste are transported from a depth of 300m to either a waste dump or a processing plant on the surface, at a rate of 1.22 million
tons per month (ore) at a stripping ratio of 3:1.
Give advice with proper explanation and justification to the mines concerning the practicality and utility of using a conveyor to either replace or supplement the existing systems with proper justification (20 marks).
Give advice with proper explanation and justification to the mines as to what extra additional equipment they may need if they were to combine existing and new conveyor systems with proper justification (20 marks).
2. A new coal mining operation is to be worked employing surface mining using blasting to clear an overburden of Shale using 200mm holes and 12m benches. Dry rock conditions are anticipated and the decision is to use bulk ANFO with emulsion cartridges as a primer. The density of compacted ANFO = 0.80 g/cm3 and the PF is expected not less than 0.60 kg/m3
You are required to do the blast design to facilitate the production request of stripping 3,000,000 m3 overburden annually, including the followings:
(1) Drilling and blasting schedule and production;
(2) Blasthole drilling pattern;
(3) Details of blasthole parameters, e.g. burden and spacing, subdrill and inclination;
(4) Details of blast control techniques employed;
(5) Blast circuit/initiation pattern.
Please include a design drawing whenever appropriate for each of the designs (25 marks).
3. A coal strip mining is designed to use dragline operation as illustrated below. The swell of the spoil is 1.25 to 1.30. You are required to design the effective radius Re and select a dragline that is suitable to the mine. Ho = 16 m, Hc = 4.5 m, pit width = 40 m, φo = φc = 70°,θ = 40° (20 marks)
4. Illustrate with suitable cross-section sketches showing ore and waste components, and how the overall stripping ratio can be;
a. Constant (5 marks)
b. Increasing (5 marks)
c. Decreasing over the life of an open-pit mine (5 marks).
Here, ore and waste quantity should remain the same in all three above-mentioned condition