Mining Methods

Question 1

Sub-level stoping

Answer 1

• Extraction of large massive or tabular steeply dipping orebodies
• Ore is extracted by longhole drilling from sublevels. The blasted ore fall to the bottom of the stopes where it is loaded at the haulage levels
• Main haulage drive is at the bottom of the stoping level
• Ring or fan filling is the main form of rock breakage
• Stability is maintained typically by pillars and backfill
• Top down or bottom up using upholes or down hole drilling
• Multiple stopes and drawpoints for extraction
• Haulage drifts is in the wall along the FW/HW outside the mining area
• Low to moderate costs, non-entry production, high

Question 2

Open stoping

Answer 2

• Naturally supported mining method
• Tabular in lenticular orebody shape
• Up to 2400m depth
• Dip > 50
• Bulk mining method
• Competent footwall
• Grade should be moderate to high
• Use of pillars for support to aid with mining sequence
• Objective is 100% recovery

Question 3

Overhand cut and fill

Answer 3

• Cut and fill is a mining method in which a single excavation is possible
• Overhand cut starts at the bottom that cuts a horizontal slice of 1.8m-4.6m
• Advancing from an access point
• Ore fall and rests on the backfill placed during last cycle. Advancing upwards
• Back needs little support
• Roof is less stable therefore have to use rockbolts

Question 4

Bench and Fill Open Stope

Answer 4

• Uphole/downdip method
• Flexible, low grade/sub-economic zones can be left
• High recovery, low dilution
• Pillars need to be left in the orebody to maintain integrity
• Operator exposed during drilling and charging

Question 5

Underhand cut and fill

Answer 5

• Direction of stope advances downwards
• Cement is used to provide the roof or back
• Weak narrow vein orebodies
• Require cemented backfill

Question 6

Mechanised cut and fill

Answer 6

• Selective mining method for highgrade irregular deposits
• Used for pillar recovery as well as primary stoping
• High cost of labour and materials
• Fill is required