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Kettlebottoms: Their Relation to Mine Roof and Support.

Authors
Chase-FE; Sames-GP
Source
MISSING :12 pages
Link
NIOSHTIC No.
10003005
Abstract
Kettlebottoms are columnar masses of rock--the preserved casts of ancient tree stumps--embedded in coal mine roof strata (of which they are a part). Because unsupported kettlebottoms can detach from a mine roof without warning, they are a hazard to miners. The primary objectives of this investigation were (1) to better define and describe kettlebottoms and (2) to evaluate kettlebottom support techniques in terms of safety and effectiveness. A telephone survey of mine operators, interviews with Mine Safety and Health Administration (MSHA) personnel, and underground mine visits were conducted in Pennsylvania, West Virginia, and Kentucky. Information gathered during this investigation indicates that the size and frequency of kettlebottoms in mine roof are dependent upon past geologic events and biological processes active during the deposition of roof sediments. To ensure the safety of mine personnel, all undermined kettlebottoms should be supported. The roof should be bolted next to kettlebottoms less than 3 ft in diameter, close enough to allow a portion of a wood or steel header to be extended beneath each kettlebottom for support. Two bolts and a wood plank or steel strap should be employed to support kettlebottoms over 3 ft in diameter.
Publication Date
19830101
Document Type
IH; Report of Investigations
Fiscal Year
1983
NTIS Accession No.
NTIS Price
Identifying No.
RI 8785
NIOSH Division
PRC;
Source Name
MISSING
State
KY; PA; WV;
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