GENERAL45906

• Permit No: M1977342
• IBM Index Class Name: General Documents
• Doc Date: 5/8/2007
• Doc Name: Wind Event Creating Tailing Dust Release
• From: Climax Molybdenum Company
• To: DRMS
• Media Type: D
• Archive: No

Permit #: M1977342 Confidential?: NO
Doc. Type: Upset condition report
From: Climax Molybdenum Company To: DBMS
Doc. Name: Wind event creating tailing dust release
Doc. Date: 5-8-2007
Specialist: ACS
ClimaxMolybdenum
A Phelps Dodge Company
May 3, 2007
Mr. R.K Hancock III, P.E.
Construction Permit Unit Supervisor
Stationary Sources Program
APCD-SSP-61
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530
%OLORADO OPERATIONS
Henderson Mine
P.O. Box 68
Empire, CO 80438
Phone [phone]
Fax [phone]
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Re: Wind Event of May 2, 2007, Henderson Mill, Permit No. 2GR0546
Dear Mr. Hancock:
On behalf of the Climax Molybdenum Company (Climax), this letter is written as a
courtesy notification of a high wind event that occurred at the Henderson Mill site in
Grand County on May 2, 2007. During the wind event, Henderson personnel observed
dust emissions from the Henderson Mill tailing facility for several hours during the
afternoon. While I am unable to provide specifics relative to the intensity of the winds or
visible emissions levels, I wanted to advise you of our current dust control efforts and to
express our commitment toward the mitigation of dust from the tailing area.
The complexity and location of our tailing facility has occasionally presented challenges
to the application of dust control palliatives as snowmelt occurs and where access by
application equipment is limited. Henderson applies an emulsified petroleum product on
the tailing facility in spring months following snowmelt to tackify the tailing sands. This
effective method of dust control is followed by tailing delivery control that maintains a
wetted beach over the exposed beach area.
Snow cover remained on the ponds through fast week following the rain/snow that fell in
Denver and central Colorado on April 24, 2007. Henderson initiated the application of
dust control on Monday, April 30, 2007 using two agricultural spreaders and a low
ground pressure tracked vehicle that is capable of accessing softer beach areas. As of
this morning, an additional spreader is being put into service. Irrigation pipe is also
being laid to apply water over a broad area on the south end of the pond. Climax has
shut down the barge pumps that deliver water to the Mill water storage facility that will
allow for the pond to rise and cover more beach area.
Henderson has also investigated the addition of a native bacterial culture to the tailing
stream that has proven effective at other sites in producing a biological crust that binds