Details:

Personal Author:
Stachura, Virgil J. ; Fletcher, Larry R.
Stachura, Virgil J. ; Fletcher, Larry R. Less -
Corporate Authors:
United States. Bureau of Mines.
Description:
"The Bureau of Mines conducted a series of delayed blasting experiments at a West Virginia contour coal mine that resulted in smoother highwalls. The highwalls were smoother owing to reduced overbreak and inherently safer owing to reduced likelihood of rockfall. Reduced overbreak was accomplished by an increase in the highwall hole delays, which changed the effective delay pattern geometry and the direction of burden movement. The blast delays in the highwall holes were 50 to 100 ms longer than the mine's nominal design pattern (flat V, 17-, by 42-ms surface delays, 200-ms in-the- hole delay). The burden movement was effectively changed from a 45 deg angle to 90 deg with respect to the highwall. The results of the blast delay changes were evaluated using terrestrial photogrammetry to generate vertical profiles at regular intervals. This evaluation showed that delay changes produced generally smoother vertical profiles." - NIOSHTIC-2

NIOSH no. 10004258


Subject:
[+]
Blasting.
Coal Mines And Mining -- Safety Measures.

Series:
Report of investigations (United States. Bureau of Mines) ; 8916
Document Type:
Report
Collection(s):
National Institute for Occupational Safety and Health
Main Document Checksum:
[+]
urn:sha256:4d39b84557d0749a16a94ddb0745ad1f498e69179c781495988b7765c10980ed
File Type:

Supporting Files

• No Additional Files

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