REV09342

• Permit No: C1981033
• IBM Index Class Name: Revision
• Doc Date: 1/11/1994
• Doc Name: C-81-033 BEAR COAL CO PERMIT REVISION
• From: DMG
• To: STEVE SHUEY
• Type & Sequence: PR1
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
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Department of Natural Resources ~
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1313 Sherman Sr., Room 215
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Denver, CO 80203 '
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Phone: [phone] reps
FAX: [phone]
Roy ROmer
Governor
To: Steve Shuey, Environmental Protection Specialist Michael B. Long

From: Bruce Stover, Technical Support Division Direciar
Date: January 11, 1994
Re: C-81-033, Bear Coal Co. Permit Revision
I have reviewed the revised B-Seam mining and subsidence monitoring plan for the Bear Coal
Company No. 3 Mine. The revised plan involves mining additional panels west of the First
North Mains, north of Lone Pine Gulch. Concerns as related to subsidence are: 1) the potential
for inducing slope failures in the extensive landslide complexes which characterize the area, and
2), potential adverse effects on Lone Pine Gulch and springs G26A and CR12.
Two identified landslides are located above the new mining area. A 200 foot barrier pillar and
minimum 110 foot overburden limit have been incorporated to minimize subsidence near the
out crop areas in the vicinity of these land slides. Based on this plan, the fact that mining has
already occurred under several other adjacent slides without incident, and that subsidence
effects on the unconsolidated surficial deposits are subordinate to driving factors such as
precipitation influenced increases to soil moisture, underground mining in accordance with the
revised plan should not significantly affect land slide stability.
Panel 24 is proposed to be mined in close proximity to Lone Pine Gulch at the south west
corner of Section 17 (underground workings will be within 170 feet of the gulch floor, at a depth
of 120 feet). The revised mine plan proposes to minimize subsidence affects to the gulch and
springs by limiting extraction to 50% in this panel and part of the Third West Mains in the area
of the springs. I believe this approach will protect these renewable resources, however, I
recommend that the springs and area above panel 24 be monumented and monitored for
potential subsidence to verify this. If there are ever undesirable effects on the springs or gulch,
it wouid be difficult to rule out subsidence as a cause if there is no subsidence data available
for this area. Two additional subsidence monuments, one along the gulch near the springs, and
one above panel 24, should be enough to incorporate this area into the subsidence monitoring
plan.
In summary, I believe the revised mine plan will minimize surface subsidence to an acceptable
level, and that subsidence will be on the order of the predicted and obseFVed values for the
existing mined areas. If you have any questions, give me a call.
xc: Jim Pendleton