What is the primary purpose of a boxhole in mining?

Solution (By Examveda Team)

Definition of Boxhole:
A boxhole in mining is a short, upward-driven raise or excavation typically created from a lower level toward an upper area in underground mining. It is a narrow and steeply inclined or vertical opening used for specific operational tasks in confined or controlled spaces.

Correct Answer: Option D: Explosive charging
The primary purpose of a boxhole is to serve as a safe and controlled location for loading explosives in blasting operations. Boxholes allow miners to insert and position explosives precisely into the rock mass, which is critical for achieving effective and targeted rock breakage.

Boxholes are strategically placed to ensure that the blast energy is directed in the intended direction, and they provide a degree of protection for personnel by isolating them from direct exposure to the blast area. Their compact and enclosed design also helps in minimizing risks associated with misfires or fly rock in underground environments.

Explanation of Other Options:
Option A: Dewatering
Dewatering involves removing water from the mine using pumps and drainage systems. While water may occasionally drain through a boxhole due to gravity, it is not designed or used primarily for dewatering purposes.

Option B: Horizontal ventilation
Ventilation systems in mines include dedicated airways, raises, and fans that manage airflow across the entire mine. A boxhole, being vertical and small, does not play a role in horizontal ventilation.

Option C: Ore transfer upward
Ore transfer is usually carried out using larger infrastructure such as ore passes, vertical shafts, conveyors, or skips. A boxhole is too small and structurally unsuitable for regular ore transport in an upward direction.

Conclusion:
Thus, the correct answer is Option D: Explosive charging, as boxholes are specifically constructed to support the safe, effective, and controlled placement of explosives in underground mining operations.