Opencast Mining - Study Mode

[#76] The effective position of box cut for a deposit whose OB ratio: ore is least should be
Correct Answer

(B) At the middle of boundary

[#77] Air consumption by down the hole hammer drills at . . . . . . . .
Correct Answer

(A) 7 kgf/cm 2 is 5.5m 3 /min

[#78] Cut off grade is
Correct Answer

(D) The grade of ore below which mining is uneconomical

Explanation

Solution: Option A: The grade of ore ultimately fed to the beneficiation plant This option is incorrect. While the cut-off grade can influence the grade of ore fed to the beneficiation plant, it specifically refers to the economic threshold below which mining is not profitable. Option B: Always the same average grade This option is incorrect. The cut-off grade is not always the same as the average grade. It is determined by economic factors and can vary depending on market conditions, costs, and other variables. Option C: The grade of ore through net the ore body This option is incorrect. The grade of ore through the ore body refers to the overall distribution of mineral content, but the cut-off grade specifically refers to the minimum grade at which mining becomes economically viable. Option D: The grade of ore below which mining is uneconomical This option is correct. The cut-off grade is the grade of ore below which mining operations are not economically feasible. It is a critical factor in determining whether a deposit can be profitably mined. Conclusion: The cut-off grade is the grade of ore below which mining is uneconomical, making Option D: The grade of ore below which mining is uneconomical the correct answer.

[#79] The conditions suitable for internal dump are
Correct Answer

(A) Horizontal deposits

[#80] The best principle for predicting of dump failure at the begining stage.
Correct Answer

(B) Rate of displacement point under consideration