REV15049

• Permit No: M1977215
• IBM Index Class Name: Revision
• Doc Date: 3/19/2002
• Doc Name: Adequacy of Plan to Close 9360 Adit
• From: DMG
• To: Homestake Mining Company
• Type & Sequence: TR10
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Na[ural Resources
t313 Sherman st, Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
March 19, 2002
Bill Owens
Governor
Greg E. Walther
Alan COX ~ Execmive Director
Homestake Mining Co. ~ Michael B. long
P.O. Box 98 Division Director
Grants, NM /
/ 1/
Re: Bulldog Mine, Permit M-1977-215, Technical Revision TR-10, Adequacy of Plan to Close 9360 Adit,
/Approval of Technical Revision TR-10.
Dear Mr. Cox,
I have reviewed the materials you submitted for the above-named revision, as well as consulted with several of the
Division's staff in regard to these materials. I am approving the technical revision, with no changes to the content
of your submittal. I would like to emphasize a few important items pertinent to the revision, below.
1. The stainless steel pipes must be plugged, and it will be by use of the acid-resistant, non-shrink cement grout as
set forth in the revision.
2. The pipes will be capped again after the plugging. It might be useful to remove the pressure gauge, valves or
other fittings during the plugging, if they are believed to be too "fragile" to withstand the impacts from the
pneumatic backfilling. All removed•fittings should be replaced with caps to ensure along-term seal on the piping.
3. It was stated that certain timbers might be selectively cut during the backfilling, to accomplish some settling of
earth on the top of the backfill mass in the adit. This would seem to allow for such settling, but the Division does
not believe it would be absolutely necessary. The operator or contractor should exercise caution if performing such
activity during the placement of the backfill.
4. The mine pool behind the adit hydraulic bulkhead was inoculated with tracer dye. No tracer dye was detected
during the two years of monitoring, which this office feels was a sufficient time. Therefore, the piping in the
bulkhead may be permanently sealed by plugging and made inaccessible by backftlling. However, as part of the
agreement of Technical Revision TR-07, the operator must place charcoal tracer packets in all of the monitoring
locations still extant, to be retrieved at a time chosen by the Division. Please ensure that such placement is
completed. If this requirement is to be modified or removed, the operator must provide the necessary rationale.
5. Final surface grading might have to include a minor upslope diversion above the portal to decrease the amount
of erosion during the initial period after closure. This is a small detail to be decided at the time of performing the
earthwork.
DENVER DIVISION OF
~~~~C~ MINERAL S
GEOLOGY
REC LA MA710N
MINING•SAFETY
6, The replacement of growth medium and seeding should be carried out promptly after backfilling, as long as it is
in accordance with proper soil moisture and season of planting, as stated in the approved reclamation plan.