Question

Which drilling method is most commonly used in underground metal mines?

• A. Auger drilling
• B. Rotary drilling
• C. Percussive drilling
• D. Core drilling

Hint:

Mining applications: \[ \boxed{ \begin{aligned} \text{Percussive drilling} &\rightarrow \text{Underground hard-rock mining} \text{Rotary drilling} &\rightarrow \text{Soft formations and oil wells} \text{Core drilling} &\rightarrow \text{Exploration and sampling} \end{aligned} } \]

Answer 1

The Correct Option is C

Step 1: Recall the common drilling methods. Underground metal mines generally require drilling hard rocks before blasting.

Step 2: Identify the suitable method. Percussive drilling breaks hard rock efficiently by repeated impacts and is therefore the most widely used method in underground metal mining. Hence, \[ \boxed{\text{Percussive drilling}} \] is the correct answer. Therefore, \[ \boxed{(C)} \] is the correct answer.