Mine Development and Mining Methods MCQs Questions & Answers

11.
Which method is most suitable for highly fractured ore bodies?

A. Sublevel Caving

B. Shrinkage Stoping

C. Cut and Fill

D. Room and Pillar

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Answer & Solution

Answer: Option A

Solution:

Definition:
Highly fractured ore bodies are ore deposits characterized by extensive fracturing and jointing, resulting in weak rock mass and potential instability.

Correct Answer: Sublevel Caving (A)
Sublevel caving is a method particularly well-suited for large, steeply dipping, and highly fractured ore bodies. This is because the method relies on the inherent instability of the fractured rock. The ore is extracted from sublevels, and the overlying ore is allowed to cave progressively. The fracturing facilitates this caving process, making it relatively easy to break down the ore and allowing for efficient extraction. The broken ore is drawn from the drawpoints at the bottom of the stopes.

Why other options are less suitable:
Shrinkage Stoping (B): While shrinkage stoping can handle some fracturing, it's less effective in highly fractured ground because the broken ore's self-supporting nature becomes unreliable in extremely fragmented conditions. Maintaining the stope walls becomes significantly more difficult, leading to instability and safety concerns.

Cut and Fill (C): Cut and fill requires relatively stable walls for effective operation. Highly fractured ore bodies lack this stability. The fill material would be lost into the fractures, rendering the method inefficient and potentially hazardous.

Room and Pillar (D): Room and pillar is suitable for relatively strong, less fractured ore bodies where pillars are left in place to support the roof. In highly fractured ore bodies, maintaining the integrity of the pillars would be challenging, leading to potential roof collapses and operational difficulties. The pillars would be weakened by the fracturing, rendering them ineffective for support.

12.
What is the purpose of grouting in mine development?

A. Ore extraction

B. Reduce water inflow

C. Explosive charging

D. Increase ventilation

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Answer & Solution

Answer: Option B

Solution:

Definition of Grouting:
Grouting is a technique used in mining and civil engineering to inject a fluid material—typically cement-based, chemical, or resin grout—into rock or soil to fill cracks, fissures, or voids. Once the material sets, it strengthens the ground and helps seal off pathways for water or gas infiltration.

Correct Answer: Option B: Reduce water inflow
The correct answer is Option B: Reduce water inflow because the main function of grouting in mine development is to seal water-bearing fractures and reduce or completely block the inflow of groundwater into the underground workings. This is crucial for maintaining safe, dry, and stable conditions during tunneling, shaft sinking, or excavation.

By controlling water ingress, grouting prevents potential flooding, minimizes the need for continuous pumping, and reduces the risk of ground instability caused by water pressure. It also makes drilling and blasting operations more effective and safer in saturated zones.

Grouting is often done ahead of development headings in advance of expected water-bearing zones or during shaft sinking in wet ground. The process enhances the structural integrity of the surrounding rock mass and ensures that construction can proceed efficiently and safely.

Explanation of Other Options:
Option A: Ore extraction
Ore extraction involves drilling, blasting, and transporting broken ore, not sealing fractures or water channels.

Option C: Explosive charging
Explosive charging is related to blasting operations and has no direct connection with the grouting process.

Option D: Increase ventilation
Ventilation is improved through the construction of airways and installation of fans—not by injecting grout into the rock.

Conclusion:
Therefore, the correct answer is Option B: Reduce water inflow, as grouting is primarily employed in mine development to control groundwater and improve ground stability by sealing water pathways.

13.
Which mining method is most applicable for strong ore and weak surrounding rock?

A. Cut and Fill

B. Block Caving

C. Shrinkage Stoping

D. Sublevel Caving

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14.
A drift in underground mining is:

A. A vertical shaft

B. An inclined ramp

C. A horizontal tunnel

D. A backfilled stope

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15.
Which of the following factors does NOT influence the choice of mining method?

A. Ore body geometry

B. Rock mechanics

C. Market price of ore

D. Color of ore

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Answer & Solution

Answer: Option D

Solution:

Ore body geometry refers to the shape, size, and orientation of the ore deposit within the earth.
Rock mechanics describes the physical and mechanical properties of the rocks surrounding and containing the ore body, including strength, stress, and fracturing.

Market price of ore is the economic value of the extracted ore, influencing the profitability of different mining methods.

The choice of mining method is a crucial decision in mining engineering, heavily influenced by various geological and economic factors.

Option A, Ore body geometry, significantly influences the choice of mining method. Different geometries (e.g., tabular, massive, disseminated) necessitate different approaches to extraction. A steeply dipping vein might require underground methods, while a flat-lying deposit may lend itself to surface mining.

Option B, Rock mechanics, are equally critical. The strength and stability of the surrounding rock determine whether open-pit or underground methods are feasible and safe. Weak rocks might necessitate support systems that alter the chosen method.

Option C, Market price of ore, is a major economic driver. If the ore price is high, more expensive and complex methods might be justified to extract all of the ore, even from challenging geometries or rock conditions. Conversely, a low ore price may necessitate simpler, less costly methods, focusing on higher-grade ore.

Option D, Color of ore, is irrelevant to the choice of mining method. The color of the ore has no bearing on the feasibility, safety, or economics of extraction. The physical properties and geological context of the deposit are far more significant.

Therefore, the correct answer is D: Color of ore because the color is an aesthetic property that has no impact on the engineering decisions related to mining methods.

16.
Which excavation is driven upward from one level to another in a mine?

A. Raise

B. Drift

C. Shaft

D. Crosscut

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17.
Which mining method is typically used in thick, steeply dipping ore bodies with competent rock?

A. Room and Pillar

B. Shrinkage Stoping

C. Longwall Mining

D. Cut and Fill

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18.
A ramp in underground mining serves the same function as a:

A. Shaft

B. Raise

C. Decline

D. Drift

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19.
The term "back" in underground mining refers to:

A. The footwall of the stope

B. The sidewall of the tunnel

C. The roof of an excavation

D. The pillar between rooms

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20.
Which of the following methods involves artificially collapsing ore to extract it?

A. Sublevel Stoping

B. Cut and Fill

C. Block Caving

D. Shrinkage Stoping

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Mine Development and Mining Methods MCQs Questions & Answers | Mining Engineering

11. Which method is most suitable for highly fractured ore bodies?

Answer & Solution

12. What is the purpose of grouting in mine development?

Answer & Solution

13. Which mining method is most applicable for strong ore and weak surrounding rock?

Answer & Solution

14. A drift in underground mining is:

Answer & Solution

15. Which of the following factors does NOT influence the choice of mining method?

Answer & Solution

16. Which excavation is driven upward from one level to another in a mine?

Answer & Solution

17. Which mining method is typically used in thick, steeply dipping ore bodies with competent rock?

Answer & Solution

18. A ramp in underground mining serves the same function as a:

Answer & Solution

19. The term "back" in underground mining refers to:

Answer & Solution

20. Which of the following methods involves artificially collapsing ore to extract it?

Answer & Solution

Read More Section(Mine Development and Mining Methods)

11.
Which method is most suitable for highly fractured ore bodies?

12.
What is the purpose of grouting in mine development?

13.
Which mining method is most applicable for strong ore and weak surrounding rock?

14.
A drift in underground mining is:

15.
Which of the following factors does NOT influence the choice of mining method?

16.
Which excavation is driven upward from one level to another in a mine?

17.
Which mining method is typically used in thick, steeply dipping ore bodies with competent rock?

18.
A ramp in underground mining serves the same function as a:

19.
The term "back" in underground mining refers to:

20.
Which of the following methods involves artificially collapsing ore to extract it?