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Main Access Protection in Underground Mines

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Main Access Protection in Underground Mines

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Questions and Answers

What is the primary reason for siting a shaft away from the orebody?

To minimize the risk of shaft damage due to mining-induced stresses (correct)

To ensure easier access to the deposit during the initial mining phase

To allow for concurrent mining and shaft sinking operations

To reduce the transportation costs for men, materials, and rock over the mine's life

What is the potential issue with leaving a shaft pillar?

It can become uneconomic, especially at great depths (correct)

It may require concurrent mining and shaft sinking operations

It can lead to long transport distances for personnel and materials

It may become unstable due to increased mining depths

According to Wilson and More O'Ferrall (1970), at what point does shaft damage begin?

When the field stress equals the UCS of the surrounding rock

When the field stress exceeds half of the UCS of the surrounding rock

When the field stress exceeds two-thirds of the UCS of the surrounding rock

When the field stress exceeds a quarter of the UCS of the surrounding rock (correct)

Based on Salamon's (1974) conclusion, at what point is it impractical to keep excavations open?

When the field stress becomes two-thirds of the UCS of the surrounding rock Signup and view all the answers

Which of the following is NOT mentioned as a method to protect a shaft from subsequent damaging effects induced by mining in a tabular orebody?

Reinforce the shaft with additional support structures Signup and view all the answers

What is the exception where the hangingwall is considered more competent than the footwall strata?

When the footwall strata is potentially unstable Signup and view all the answers

What is the main criterion to consider for deep shaft pillar design, according to the text?

Vertical strain, vertical tilt, and vertical stress Signup and view all the answers

According to Wilson and More O'Ferrall (1970), at what point does damage to the shaft become extensive and remedial actions very costly?

When the field stress increases to about half the UCS Signup and view all the answers

What is the potential issue with leaving a shaft pillar, according to the text?

It can become uneconomic, especially at great depth Signup and view all the answers

Which of the following statements is true, based on the information provided in the text?

There is no clear preference among the methods mentioned for shaft protection in tabular orebodies Signup and view all the answers