5. Mechanical Rock Breakage Flashcards
Rock Breakage
detaching large masses of harder rock from the parent deposite
What are the 2 types of rock breakage operations?
- Rock penetration
2. Rock fragmentation
Rock Penetration
creating a directed hole by drilling, boring, or channeling to produce free faces for blasting, holes for blasting, openings and dimensional stone
Kerf Cutting
creating a slit or notch made by a saw or cutting torch
When to kerf cut?
- decorative stone
2. coal/soft metallic minerals
When to full face mechanical excavation?
- underground potash/coal/soft non-metallic
2. surface soil, coal, weathered soft rock
What are 6 things to consider in drilling design?
- mining method
- blast hole depth
- hole diameter
- drillability
- hole orientation
- equipment size
What are the 4 components of a drill system?
- drill
- drill rod
- bit
- fluid
What are the 2 mechanical energies of drills?
- Percussive energy
2. Rotary energy
Percussive Energy
delivers rotating hammer blows in different locations (used for hard rock)
Rotary Energy
applies shearing force by rotating (used for soft rock)
What are the 3 types of drilling?
- Percussive
- Down/In the hole
- Top Hammer
Pneumatics
mechanical task is done using gas
Hydraulics
mechanical task is done using fluid
What 5 things affect borehole accuracy?
- poor hole alignment
- imprecise collaring
- geological conditions
- drill used
- using worn out bits
