10. Underground Production Drilling

Question 1

Characteristics of short hole drilling

Answer 1

less than 5m long

hole diameter 1.25-2.5”

Question 2

When to use short hole drilling?

Answer 2

shrinkage, cut and fill, room and pillar (where ground conditions do not allow larger openings)

Question 3

Characteristics of long hole drilling

Answer 3

Height 10-100m
Width 2-50m
Depth 10-200m
hole diameter 2.5-4.5”

Question 4

When to use long hole drilling?

Answer 4

irregular shapes and dips

Question 5

Drill Hole Rings

Answer 5

holes are drilling from a central location and radiate outwards

Question 6

Boretrack

Answer 6

device that measures drill hole deviation

Question 7

What are 6 issues of inaccurate drill holes?

Answer 7

1. excessive blast damage
2. sympathetic detonations
3. insufficient detonations
4. poor fragmentation
5. damage to stope walls
6. poor recovery

Question 8

What are 3 benefits of drill hole surveys?

Answer 8

1. identify drilling problems
2. allows for the blast design to be modified before any fuck ups
3. improves future drilling accuracy