APPCOR12443

• Permit No: C1996083
• IBM Index Class Name: Application Correspondence
• Doc Date: 5/31/1996
• Doc Name: BOWIE RESOURCES LIMITED BOWIE 2 MINE FN C-96-083 NEW PERMIT APPLICATION
• From: DMG
• To: J E STOVER & ASSOCIATES
• Media Type: D
• Archive: No

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J.E. Stover & Associates -35-
Bowie No. 2 Mine
May 31, 1996
This evaluation applies the general roof fall bulking principles
for determining the limit of chimney collapse propagation. The
Division agrees with this method for areas of uniform overburden
conditions. However, as in the case of general trough subsidence
propagation, chimneying may also be significantly influenced by
the existence of discontinuities, such as faults. Differential
settlement and stopping (chimney) collapse can also be more
pervasive along discrete discontinuities.
91. Therefore, specific accommodation should be made for thin
overburden, near outcrop situations adjacent to known or
mapped faults, such as panels 32 and 35.
2.0 SUBSIDENCE IMPACTS
2.1 LAND USE
Since both the pre-and post-mining land use of the area is
classified as rangeland, considerations such as sustainable
animal units and walking time between water sources, including
stock ponds, become appropriate topics for consideration.
Subsidence impacts which would preclude the "Range Land" use
might therefore constitute material damage and would require
mitigation in the short term and long term.
2.2 SURFACE WATER
The preparer proposes that "surface modifications of the surface
drainage and ponds could be made in cases of any occurrence of
subsidence cracks. "This pragmatic approach would be acceptable
if timely detection and implementation of the appropriate
mitigative techniques can be assured. The applicant should
propose a detailed inspection methodology to detect subsidence
cracking impact to the potentially effected ponds and surface
drainage ways. This should include inspection prior to the
runoff season, during which the major diversion of surface runoff
might occur. Further, in the case of the ponds and their
antecedent ground or surface water sources, inspections should
occur frequently throughout the stock watering season. These
inspections should be completed in areas undermined for an
appropriate period of time following retreat extraction, to
verify negative impact from cracking.
2.3 GROUND WATER
The position of the applicant presented throughout the
application is that no significant water resources exist within
the overburden or on the surface of the permit area. The
Division's experience in the North Fork Valley suggests that many