2008-02-06_PERMIT FILE - M2007044 ‎(2)‎

• Permit No: M2007044
• IBM Index Class Name: PERMIT FILE
• Doc Date: 2/6/2008
• Doc Name: Initial reclamation liability estimate
• From: DRMS
• To: Energy Fuels Resources
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1:313 Sherman St., Room 215
Deriver, Colorado 80203
Phone: -'3031 866-3567
FAX: [phone]
DATE: November 14, 2007
TO: Russ Means
FROM: Allen. Sorenson y
COLORADO
1)IV1SI Ofd Of
RECLAMATION
MINING
SAFETY
Hill River, jr.
Governor
Harris D. Sherman
Executive Director
Ronald W, Cattany
Division Dirertor
Natural Resource Trustee
RE: Cost Estimate for Water Impounding Concrete Bulkheads, Energy Fuels Resources
Corporation, Whirlwind !Mine, File No. M-2007-044
The Division of Reclamation, Mining, and Safety (DRMS) engineering staff have completed a review of the
underground water impounding bulkhead information provided in the Whirlwind Mine permit application
as supplemented by the Bulkhead Locations plan provided by Lewicki and Associates and dated October
27, 2007. The Applicant proposes a main bulkhead 148 feet in elevation below the decline portal where the
decline dimensions are 12' x 9' and there is approximately 470 feet of ground cover. A secondary bulkhead
is proposed for a location 134 feet in elevation below the decline portal. Lewicki and Associates has
recently communicated to the DRMS that the upper bulkhead is no longer deemed necessary since the
Bureau of Land Management is requiring the decline portal to be backfilled. However, the DRMS will
require that an upper water impounding bulkhead be bonded as a contingency as discussed in the memo
dated November 6, 2007 (Allen Sorenson to Russ Means). The same memo describes the need to bond for
a contingency bulkhead in the Packrat Mine workings. For the purpose of estimating a cost, DRMS will
assume conservatively that the Packrat Mine bulkhead would be installed 268 feet in elevation below the
decline portal where the adit dimensions are 12' x 9' and at a location where there is sufficient ground cover
to prevent h.ydrofraci.ng of the formation around the bulkhead. It is indicated in the application that precise
location selection and detailed designs for the bulkheads is premature at this time; DRMS concurs. It is
necessary to preliminarily consider design basis for the bulkheads in order to estimate costs, and this memo
provides an analysis of the type of bulkheads that will be necessary in order to develop costing information
and estimate the amount of bulkhead bond to be required.
Ei:narson.and Abel (1990) present a step-by-step procedure for design of underground water impounding
bulkheads. Conservatism in design of the bulkheads is necessary because of the safety and envi.ronnlental
implications of a bulkhead failure, the long life required for the bulkheads, and. the ultimate inaccessibility
of the bulkheads. The A merican Concrete Institute's ".Building Code Requirements for Reinforced
Concrete (ACI 31.8.89)" is used because the bulkheads are analogous to reinforced deep-beam concrete
structures and. because of the inherent conservatism o the code. The analysis presented in. this memo
generally follows the Einarson. and Abel template.
The maximum hydraulic head and pressure at the proposed main bulkhead are as follows:
II =1.48 feet
Y"fYrr: 1.48 x 62.4
t 44in' ! f ' 144
Office of Office of
Mined Land Rec.larnation Denver + (;rand iunclion • Durango Ac',ive and Inactive .'dines