Mine Development And Mining Methods - Study Mode
[#191] The recovery of pillars in room and pillar mining is called:
Correct Answer
(B) Retreat mining
Explanation
Solution: Room and Pillar Mining: Room and pillar mining is a mining method where ore is extracted by creating a grid of rooms separated by pillars of ore. These pillars support the overlying rock and prevent cave-ins. After the rooms are mined, the pillars may be subsequently extracted, depending on the stability of the ground and mining goals. This subsequent extraction of the pillars is the key to understanding the question. Retreat Mining: Retreat mining is the correct answer. In retreat mining, the rooms are initially mined leaving the pillars in place. These pillars then provide support for the overlying strata. Once mining in a section is complete, the pillars are systematically removed in a planned retreat, allowing the overlying ground to subside in a controlled manner. This controlled subsidence is important for ground stability and safety. Why other options are incorrect: Primary Stoping: This is a method of underground mining typically used in steeply dipping orebodies, not related to room and pillar techniques. Forward Mining: This involves mining in a continuous advance, typically without leaving pillars for later extraction. It's opposite to retreat mining. Sublevel Mining: This method involves creating a series of horizontal sublevels in an orebody, it does not involve the room and pillar layout and pillar extraction characteristic of this question.
[#192] Which of the following techniques is used to ensure controlled rock fragmentation?
Correct Answer
(B) Blasting pattern design
Explanation
Solution: Blasting pattern design involves planning hole spacing and charge size.The correct answer is: Blasting pattern designControls fragmentation size, safety, and wall stability.Essential for production and development blasts.
[#193] Which mining method generally produces the lowest dilution?
Correct Answer
(B) Cut and fill
Explanation
Solution: Cut and fill mining allows selective extraction and backfilling.The correct answer is: Cut and fillMinimizes mixing of ore and waste.Ideal for narrow, irregular ore bodies.
[#194] The term "shaft station" refers to:
Correct Answer
(C) A level access point from a shaft
Explanation
Solution: Shaft stations are horizontal access points from vertical shafts.The correct answer is: A level access point from a shaftUsed for loading, unloading, and level transitions.Usually reinforced and well-lit for safety.
[#195] What is a common layout pattern for room and pillar mining?
Correct Answer
(A) Checkerboard
Explanation
Solution: Checkerboard patterns are typical in room and pillar layouts.The correct answer is: CheckerboardEnsures structural support and access throughout the mine.Optimizes ore recovery and ventilation.