Identify the WRONG statement:
Break-even stripping ratio
Show Hint
- takes into account the maximum pit slope that is safe
- helps in determining the volume of the overburden
- presents the maximum possible mine size that is economical
- takes into account the life of the mine
The Correct Option is A
Solution and Explanation
BESR depends on ore value, cost of removing overburden, mining cost, and safe pit slope design. It does not depend on mine life. Step 2: Check each option.
(A) Correct — Safe pit slope affects the volume of overburden, hence affects BESR.
(B) Correct — BESR helps determine the volume of overburden that can be economically removed.
(C) Correct — BESR provides a limit to the mine size that remains profitable.
(D) Wrong — Mine life affects planning and investment but is not part of BESR calculation. Thus, the incorrect (wrong) statement is (D).
Final Answer: (D)
Top Questions on Stress Measurement Techniques
In a bord and pillar panel, a square pillar of size 35 m \( \times \) 35 m (centre to centre) is extracted to form four equal square-shaped stooks as shown. The width of each gallery and crosscut is 5 m. The height of the working seam is 3 m. The reduction in safety factor after pillar splitting by using Bieniawski’s pillar strength formula, in %, is _______ (rounded off to 2 decimal places).
Bieniawski's pillar strength formula is given by \( S_p = S_1 \left( 0.64 + 0.36 \frac{w}{h} \right) \), where \( S_1 \) is the strength of a 0.9 m\(^3\) coal block, \( w \) is the pillar width, and \( h \) is the mining height.- GATE MN - 2025
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In a bord and pillar panel, a square pillar of size 35 m \( \times \) 35 m (centre to centre) is extracted to form four equal square-shaped stooks as shown. The width of each gallery and crosscut is 5 m. The height of the working seam is 3 m. The reduction in safety factor after pillar splitting by using Bieniawski’s pillar strength formula, in %, is _______ (rounded off to 2 decimal places).
Bieniawski's pillar strength formula is given by \( S_p = S_1 \left( 0.64 + 0.36 \frac{w}{h} \right) \), where \( S_1 \) is the strength of a 0.9 m\(^3\) coal block, \( w \) is the pillar width, and \( h \) is the mining height.
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