The efficiencies of cast blasting in wide pits
Blasting activities in all four pits at Thunder Basin Coal`s Black Thunder Mine are focused on cast blasting. With widths varying from 190 feet to 265 feet and bench heights varying from 90 feet to 175 feet, casting efficiencies vary with different geometry`s. For example, the percent cast to final in the 200 foot pit is on the average higher than the 270 foot pit. The powder factors are somewhat higher in the narrower pits, thus increasing the cost of blasting. This leads to a very detailed look at the actual benefit of cast blasting and the associated cost of these benefits. The simple solution would be to reduce the width of the pits, thereby increasing the percent cast to final. However, the lower rehandle and low coal loss associated with wide pits would be fortified. Upon further review it becomes obvious that the wider pits could not be compared to the narrow pits with the cast to final percent indices. The focus should be shifted to cubic yards cast to final per lineal foot of pit. This will allow for more accurate measures of the casting efficiency of the shot. When comparing the pits with these indices their performances were much closer than the percent cast to final indices. The powder factors being higher in the narrow pits drove up the cost per cubic yard cast to final. Therefore, even though the percent cast to final was higher, the cost per cubic yard was also higher.
- OSTI ID:
- 400827
- Report Number(s):
- CONF-950247-; TRN: IM9650%%233
- Resource Relation:
- Conference: 21. annual conference on explosives and blasting techniques, Nashville, TN (United States), 5-9 Feb 1995; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the twenty-first annual conference on explosives and blasting technique. Volume 2; PB: 345 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Contamination versus recovery rate in multi-seam lignite mining
Strippable coal reserves of Wyoming. Location, tonnage, and characteristics of coal and overburden