PERMFILE64512

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 7/24/2007
• Section_Exhibit Name: Exhibit 77 Deer Creek Shaft Plan
• Media Type: D
• Archive: No

MOUNTAIN COAL
~~s~ ~ COMPANYL.L.C.
A Subsidiary ofArch Western Resources, LLC
REGE~~~~
July 16, zoo? JUG ~ ~ ~p010~
~1V M ~to9 a d Sa etY
Mr. Tom Kaldenbach
Colorado Division of Reclaniation, Mining and Safety
1313 Sherman Street, Room 215
Denver, Colorado 80203
West Elk Mine
P O Box 591
5174 Highway 133
Somerset, CO 81434
[phone]
Fax [phone]
Subject: Mountain Coal Company L.L.C.(MCC), West Elk Mine, Permit No. C-80-007;
Technical Revision No. 109, Deer Creek Shaft Adequacy Responses.
Dear Mr. Kaldenbach:
MCC is submitting the attached responses to the Division's adequacy comments received June 25,
2007. The Division's comments are italicized and MCC's responses aze bolded.
1) Please add to the submittal a description of the measures that will be taken to ensure
compliance with Rule 4.07.3(2), which requires sealing aquifers that are penehated in drilled
holes.
MCC has drilled numerous holes and has sunk three shafts in the area without intercepting
or encountering water of sufficient quantity or a group of strata acting as a hydraulic unit
that can store and transmit water in sufficient quantities for beneficial use. MCC has
attached a typical cross-section of the shaft that depicts the concrete lining that would seal an
aquifer or group of strata acting as a hydraulic unit:
2) The proposed closure for eac]z of the two shafts is a concrete and steel cap that will be installed
just below the ground surface. The cap will be covered to the ground surface with material
from the subsoil stockpile. The Division is concerned that a concrete and steel cap which spans
the shaft void will eventually deteriorate and result in a safety hazard. The Division prefers and
requests that the vent and escape shafts be closed by bacl~lling them with drill cuttings (azuJ
purchased backfill, if necessary) from the bottoms of the shafts up to the concrete and steel
caps, and then cover the caps to the ground surface with material from the subsoil stockpile.
With this complete backfilling, total reclamation costs for TR-109 are estimated to be
$169, 291, compared to $130, 015 for partial backf Ilizzg, as you have proposed (please see
enclosed cost estimating worksheets). From these two amounts, $17, 060 will be deducted for
the bond liability associated with the three geotechnical holes orz the shaft site (approved in
MR-338 and which will be replaced by the shafts), resulting in net new liability for TR-109 of
$152,231 for complete backfrlling of the shafts, compared to $112,955 for partial backf fling.
The complete backfilling closure method may also require a small amount of additional