State reasons for the popularity of decline mining in

Question

Question 1.

Calculate the direct unit cost of a 4.5 x 4.5 m drill and blast development in sandstone given the following:

Rock S.G 2.6

Labour cost $400/shift including on costs

Productivity 1.4m/shift

Rock bolts and mesh $25 per m² supported

Depth drilled per round 3.6 m

Depth pulled per round 3.6 m

Overbreak 10%

Overall explosives cost average $2.40/kg

Materials cost excluding explosives and ground support $150/m

Jumbo drilling at $3.50/m drilled

Mucking and tramming $3.40/tonne

Detail any other required assumptions.

Question 2.

State reasons for the popularity of decline mining in modern operations. What factors need to be taken into account in deciding the cut off depth beyond which shaft operations should be used instead of decline access.

Question 3.

Compare critically the cycle of operations in drill and blast and mechanical mining operations.

Question 4.

Describe and compare the ventilation systems used in single entry development operations.

Question 5.

For two of the following mining methods describe the development needs and sequencing required within a production area:

• Rubber tyred block caving
• Sub level open stoping
• Vertical crater retreat mining
• Sub level caving
• Longwall coal mining (retreat or advance)
• Room and pillar