RAISES

RAISES

1. ·         A connection from lower level to upper level
2. ·         Upward drivage made from lower level to upper level
3. ·         It may be either vertical connection between levels or slope /inclined connection
4. ·         Making raise is more economical than making winze
5. ·         In good ground no supports are required
6. ·         Steep dips timber hitched on sides for making plat forms for access of persons and for laying track
7. ·         Generally stoping is started on each side of raise – winze connection
8. ·         Raise – winzing carried away by the same time to complete the excavation as soon as possible

                          

PURPOSE OF RAISES

1. ·         Used for sampling
2. ·         Acess
3. ·         Ventilation
4. ·         For inspection
5. ·         Easy extraction
6. ·         More production
7. ·         Used as intake/return airways
8. ·         Haulage road ways
9. ·         Travelling ways
10. ·         Supply of material
11. ·         Carry water pipe lines
12. ·         Carry electric cables

MERITS OF RAISES

1. ·         Fewer holes are required for blasting
2. ·         Gravity assist for breaking
3. ·         Water does not accumulate
4. ·         Rate of advancement of face is faster
5. ·         Face is readily available for blasting
6. ·         Inspection of face is easy
7. ·         Mis fires are easily detected
8. ·         More efficiency of blasting
9. ·         No pumps are required
10. ·         Face will be cleaner
11. ·         Easy driving
12. ·         Easy loading
13. ·         Good ventilation

DE-MERITS OF RAISES

1. ·         Drilling is difficult
2. ·         Skidding of men in steep raises occurs
3. ·         Need ladders or platforms in steep raises to climb upon
4. ·         Hazardous of rock falling is hazardous