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Hillseam Geology and Roof Instability Near Outcrop in Eastern Kentucky Drift Mines.

Authors
Sames-GP; Moebs-NN
Source
MISSING :32 pages
Link
NIOSHTIC No.
10007248
Abstract
This U.S. Bureau of Mines study was conducted in eastern Kentucky drift mines as part of an ongoing research program to characterize the outcrop barrier zone. "Hillseams" were identified as the dominant geologic cause of roof instability unique to the outcrop barrier zone, with many roof fall injuries and fatalities attributed to them. Hillseam is the eastern Kentucky miners term for weather- enlarged tension joints that occur in shallow mine overburden where surface slopes are steep. Hillseams are most conspicuous within 200 ft laterally of a coalbed outcrop and under 300 ft or less of overburden. Hillseams form by stress relief, and therefore tend to parallel topographic contours and ridges. They can intersect at various angles, especially under the nose of a ridge, and create massive blocks or wedges of roof prone to failure. Examples of hillseams are described in both outcrop and coal mine roof to establish their geologic character and contribution to roof failure.
Publication Date
19890101
Document Type
IH; Report of Investigations;
Fiscal Year
1989
NTIS Accession No.
NTIS Price
Identifying No.
RI 9267
NIOSH Division
PRC;
Source Name
MISSING
State
KY;
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