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41
What term describes the vertical distance between levels in underground mines?
Discuss
Answer & Solution
Answer: Option D
Solution:
Vertical interval is the distance between successive levels.The correct answer is: Vertical intervalIt affects haulage cost, ventilation, and stope design.Common values range from 30 to 60 meters depending on method.
42
What does the term "overbreak" refer to in tunnel development?
Discuss
Answer & Solution
Answer: Option B
Solution:
Overbreak is unintentional excavation beyond the tunnel design profile.The correct answer is: Excess rock excavation beyond design limitsIt leads to extra ground support costs and instability.Caused by over-blasting or weak rock zones.
43
Which equipment is commonly used in mechanized mine development?
Discuss
Answer & Solution
Answer: Option C
Solution:
Jumbo drill is a mechanized drilling machine for tunnel and drift development.The correct answer is: Jumbo drillIt ensures precision drilling of blast holes in hard rock.Draglines are for surface mining; dredgers for marine mining.
44
What is the purpose of a refuge chamber in underground mines?
Discuss
Answer & Solution
Answer: Option C
Solution:
Refuge chamber provides temporary shelter during emergencies like fire or gas leaks.The correct answer is: Emergency shelterIt is equipped with air supply, water, and communication devices.Crucial for miner safety in emergency evacuation plans.
45
The term "footwall" in mining refers to:
Discuss
Answer & Solution
Answer: Option C
Solution:
Footwall is the rock mass beneath the ore body or vein.The correct answer is: Bottom surface below ore bodyThe rock above the ore is called the hanging wall.Important in structural analysis and access planning.
46
Which factor is least considered while choosing a shaft location?
Discuss
Answer & Solution
Answer: Option D
Solution:
Ore grade is important for economic feasibility, but not a primary consideration for shaft siting.The correct answer is: Ore gradeFactors like geological stability, groundwater, and access are prioritized to ensure safe and cost-effective development.Ore grade influences mining methods, not necessarily shaft position.
47
What is a crosscut used for in underground mining?
Discuss
Answer & Solution
Answer: Option C
Solution:
Crosscut is a horizontal tunnel driven perpendicular to the main drift.The correct answer is: Accessing veins perpendicular to driftIt provides access to ore zones that are not aligned with the main tunnel.Essential in block caving and vein mining.
48
Which of the following is a horizontal opening used for drainage or access?
Discuss
Answer & Solution
Answer: Option C
Solution:
Adit is a horizontal or nearly horizontal passage driven from the surface.The correct answer is: AditUsed for access, drainage, and ventilation.Shafts are vertical; raises and winzes are internal vertical workings.
49
What is the primary support used in weak underground conditions?
Discuss
Answer & Solution
Answer: Option B
Solution:
Timber sets are commonly used to support weak or fractured rock.The correct answer is: Timber setsComposed of vertical and horizontal wooden beams, they stabilize tunnels and stopes.Especially useful in narrow vein mines and older operations.
50
What is the name of the equipment used to hoist material in vertical shafts?
Discuss
Answer & Solution
Answer: Option B
Solution:
Skip is a shaft hoisting device used for transporting ore and waste.The correct answer is: SkipIt operates on a guide rail and works with hoisting engines.LHDs are for horizontal haulage, and drill jumbos for drilling.