Highwall damage control using presplitting with low-density explosives

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:400828

Stachura, V J; Cumerlato, C L ^[1]

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1. Bureau of Mines, Minneapolis, MN (United States)

The US Bureau of Mines is conducting research on blasting methods that reduce highwall overbreak and the associated rockfall hazards. This paper presents the results of tests using a low-density water gel to improve the quality of air-decked presplit blasts at a surface coal mine in New Mexico. The explosive`s specific gravity averaged 0.50 and was bulk loaded using a modified truck which injected the gassing agent. Reductions in overbreak and resulting rockfall were achieved in comparison to a highwall presplit with ANFO. The test sections used 15{degree} angled blast holes and resulted in 1,119 m of air deck presplit highwall using a low-density water gel which was then compared to 894 m of highwall shot with an ANFO air decked presplit design. The total quantity of explosives per hole ranged from 68 to 113 kg and the 27 cm holes were 19- to 33-m deep on 5.5 m centers. Periodic visual examination and photographic surveys of the highwall test areas were used to document the amount of rockfall. In addition, laser profiles of selected sections were conducted to further delineate the damage and highwall contour differences.

• OSTI ID: 400828
• Report Number(s): CONF-950247--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CHEMICAL EXPLOSIVES
EXPLOSIVE FRACTURING
PROCESS CONTROL
RECOMMENDATIONS
ROCK FALLS
SLOPE STABILITY
SURFACE MINING