Introduction To Mining Engineering - Study Mode

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[#26] The sale value of chromite ore from an open pit mine is Rs. 6500 per tonne. Cost of mining, excluding stripping cost, is Rs. 2450 per tonne. If the cost of stripping is Rs. 1150 per m 3 , the breakeven stripping ratio in m 3 /tonne is

(A) 2.18

(B) 3.52

(C) 3.65

(D) 4.25

Correct Answer

(B) 3.52

[#27] From a hard rock open pit mine, the following data available Burden : 3 m Spacing : 4 m Bench height : 12 m Sub-drilling : 1 m Collar stemming : 4 m Diameter of hole : 150 mm Density of rock : 2500 kg/m 3 Density of explosive : 800 kg/m 3 The powder factor in kg/t is

(A) 0.314

(B) 0.353

(C) 2.833

(D) 3.183

Correct Answer

(C) 2.833

[#28] As per the Indian Electricity Rules 1956. the maximum permissible length of a flexible cable used with an electric rope shovel in m is

(A) 100

(B) 200

(C) 300

(D) 500

Correct Answer

(C) 300

[#29] The slope angle for hard and compact ground should not be more than

(A) 10°

(B) 30°

(C) 50°

(D) 70°

Correct Answer

(D) 70°

[#30] The opening cut in open cast mining is known as

(A) berm

(B) box cut

(C) trench

(D) drift

Correct Answer

(B) box cut