REP04837

• Permit No: M1977342
• IBM Index Class Name: Report
• Doc Date: 9/28/2001
• Doc Name: CRUSHER CLOSURE CAP PLANS & SPECIFICATIONS RN 1 HENDERSON MILL PN M-77-342
• From: CLIMAX MOLYBDENUM CO
• To: DMG
• Media Type: D
• Archive: No

III IIIIIIIIIIIIIIII
© CLIMAX MOLYBDENUM COMPAN , 999
4 Subs~disry pl Phelps Dptlge Cprporehon
September 24, 2001
RECEIVED
Mr. Allen Sorenson
Environmental Protection Specialist SEP 2 9 2001
Colorado Division of Minerals and Geology
1313 Sherman Street, Room 215 Division of Minerals and Geglogy
Denver, Colorado 80203

FIEIIIDERSON OPERATIONS
19302 County Road 3
Parshall, Colorado 80468
[phone]
Fax [phone]-DD39
RE: Crusher Closure Cap Plans and Specifications-Revision #1, Henderson Mill, Pel~rtit
No. M-77-342
Dear Mr. Sorenson:
This letter is being provided to the Division of Minerals and Geology (Division) as required
per our earlier discussions regarding changes to the final closure and reclamation plans
(previously submitted to the Division) for the abandoned crusher.
Final closure of the crusher continues as planned. Demolition is continuing following the
final inspection of the building that was completed by the Division on September 13, 2001.
The crusher should be completely demolished by mid-October. Backfilling will proceed
when possible based on weather and equipment availability. Changes to the previously
submitted and approved closure plans have occurred with the work scheduled to be
completed on the smaller floor penetrations. The drawings stated that Climax Molybdenum
Company (Climax) would seal the concrete associated with these opening with the
approved epoxy that is required for all steel. Climax has decided not to do this fir two
reasons. First, the manufacturer states that the concrete must cure for a minimum of 28
days before applying the epoxy. This time period would eliminate any chance of
completing this portion of [he project before the onset of winter. Secondly, the cost to
complete this task proved to be very prohibitive for a minimal gain in overall project
effectiveness.
The Division also asked Climax to propose a schedule for the completion of concrete test
cylinders during [he pouring of the crusher closure caps. Climax proposes to follow the
Building Code Requirements for Reinforced Concrete (ACI 318). This specification states
that strength tests for each class of concrete placed each day should be taken not less than
once per day, nor less than once for each 150 cubic yards of concrete, nor less than once for
each 5,000 square feet of surface area for slabs and walls. The average strength of two
cylinders is required for each test. A copy of this specification is attached for the Division's
records. Also, the test cylinders will be cured on-site, near the pour location, as required by
[he Division.
Finally, with my signature below, I, Erich Bower, Environmental Engineer for the Climax
Molybdenum Company, certify that all remaining wood has been removed from the cnlsher
building. During its £nal inspection on September 13'", [he Division requested that all