REV97384

• Permit No: C1981018
• IBM Index Class Name: Revision
• Doc Date: 10/29/1997
• Doc Name: DESERADO MINE C-81-018 TR 42
• From: DMG
• To: DAN MATHEWS
• Type & Sequence: TR42
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Deparimenl of Nuluml Resources
1313 Sherman St.. Room 21 5
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
DATE: October 29, 1997/
TO: Dau Mathews r
FROM: Susan Burgmaier
RE: Deserado Mine (C-81-018)
Technical Revision No. 42
~~
DEPARTMENT OF
NATURAL
RESOURCES
Roy Romer
Governor
lames S Lochhead
Executive Director
Michael B. Long
Division Dueaor
I have reviewed the information submitted by Blue Mountain Energy (BME) in response to my adequacy
concerns with TR-42. I have the following comments for BME. The sequence of my comments is
consistent with your October 15, 1996 letter.
BME's response addressed the Division's concems, but Cross Section B-B', shown on Map 150,
is not consistent with the plan view shown. Please revise the cross section.
2. The SEDCAD+modeling provided by BME does not appear to be consistent with the drainage
patterns shown on Map 150. The working map provided indicates that some areas are routed
uphill. The designs for the ponds aze based on two watershed areas per pile, which is inconsistent
with the configuration used to design the ditches and with what would be happening on the
ground. Please revise the designs to accurately reflect proposed ground conditions.
BME indicates that the SEDCAD+ runs include a trickle tube to simulate the ponds being
pumped as soon as practicable after a storm event. BME indicates the runoff pumped from the
ponds would be used for dust suppression. DMG cannot approve the ponds as designed. If the
azea received heavy rainfall on a weekend or at a time of mine shutdown when mine personnel
aze not available to manually pump the pond, it is quite possible that the water level in the pond
could rise to the top of the riser. Also, during wet seasons, if the mine roads are already saturated,
BME would not likely be able to use the water for dust suppression since [here would already be
too much water on the roads. The ponds must be designed so that, in the event that water is up
to the level of the riser top, a ] 0-year, 24-hour precipitation event could be discharged through
the riser while meeting effluent standards. The SEDCAD+ modeling needs to be revised using
this assumption.
4-6 BME's responses were adequate to address the Division's concems.
Items 7-11 were your concems. I looked at their response to Item 8, and the revisions to Map 150 show
all disturbed area runoffreportingto ponds RP-2-3 and RP-4. Should you or the operator have questions
or need more information, let me know.
SLB1102997 WP\V