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In Situ Horizontal Stress Determinations in the Yampa Coalfield, Northwestern Colorado.

Authors
Bickel-DL; Donato-DA
Source
MISSING :43 pages
Link
NIOSHTIC No.
10006032
Abstract
This report presents a Bureau of Mines study intended to determine if horizontal stress trends exist and if the stresses can be projected for improved mine design in a selected coalfield. The horizontal stresses were determined in three mines in the yampa coalfield and one mine in the adjacent Danforth Hills coalfield of northwestern Colorado. Stresses were determined from stress-relief measurements using a three-component borehole deformation gauge and overcoring techniques developed by the Bureau. A least-squares method of calculating the average rock stress components in the horizontal plane was performed. Physical properties of the rock from the test sites are also included. For the yampa coalfield, the maximum horizontal compressive stress in the floor ranged from 363 to 1,956 psi, and the maximum horizontal compressive stress in the roof ranged from 235 to 875 psi. For the Danforth Hills coalfield, the maximum horizontal compressive stress in the floor ranged from 360 to 1,494 psi, and the maximum horizontal compressive stress in the roof was 1,033 psi. Results indicated a trend of low horizontal stresses in the yampa coalfield that have not impacted ground control conditions in mines less than 1,000 ft deep.
Publication Date
19880101
Document Type
IH; Report of Investigations;
Fiscal Year
1988
NTIS Accession No.
NTIS Price
Identifying No.
RI 9149
NIOSH Division
TCRC;
Source Name
MISSING
State
CO;
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