2013-08-21_REVISION - C1981014 ‎(2)‎

• Permit No: C1981014
• IBM Index Class Name: Revision
• Doc Date: 8/21/2013
• Doc Name: Review ‎(Memo)‎
• From: Mike Boulay
• To: Janet Binns
• Type & Sequence: TR40
• Email Name: JHB
• Email Name: DIH
• Email Name: MPB
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
INTEROFFICE MEMORANDUM
TO: Janet Binns
FROM: Mike Boulay ! 's
DATE: August 21, 2013
COLORADO
D IV IS I ON OF
RECLAMATION
MINING
SAFETY
John W. Hickenlooper
Governor
Mike King
Executive Director
Loretta E. Pineda
Director
SUBJECT: Southfield Mine Permit No. C- 1981 -014
Technical Revision No. 40 (TR -40) - Southfield Monitor Well MW -NW
At your request I have reviewed TR -40 submitted by Energy Fuels Coal, Inc (EFCI). With TR-
40 EFCI is requesting approval to terminate further groundwater monitoring in monitoring well
MW -NW and eliminate MW -NW from the groundwater monitoring program. EFCI contracted
Bishop - Brogden Associates, Inc, (BBA) to review hydrogeologic information concerning the
Southfield Mine and MW -NW and prepare a conceptual model utilizing different scenarios of
how long it would take mine inflow water to reach an identified monitoring point elevation of
5,860.5 feet at the intake or bottom of well MW -NW. BBA concluded that it would take
between 106 to 120 years for the water level in the flooded mine workings to reach the intake at
well MW -NW. The previous estimate of mine inflow of 20 of /year for the Southfield Mine was
used to calculate an estimated time of 285 years for the mine to fill entirely with water. The
BBA report dated July 19, 2013 further revised the estimated time for the mine to flood based on
a more detailed review of available mine inflow data and then applied this to three different
conceptual models that differ based on the hydrogeologic connectivity between different areas of
the mine workings.
BBA concluded that the current monitoring program with MW -23 serving as an up gradient well
and MW -65 as a down gradient well is adequate to determine the effects of mining activities on
the quantity and quality of groundwater in the Southfield Mine area. This is consistent with the
DRMS findings as presented in our detailed memorandum dated June 3, 2013. Based on the
conclusions presented for the North Entry Well (MW -NW) contained in BBA's report EFCI is
requesting that NOV No. CV- 2013 -002 be vacated and that the DRMS approve the removal of
the MW -NW monitoring well from the Southfield Mine groundwater monitoring program.
I was able to reproduce the BBA calculations based on the data presented and generally agree
with their approach. I have two adequacy comments regarding the assumptions used in the
Conceptual Models presented in the report.
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines