2010-07-30_REVISION - M1977342

• Permit No: M1977342
• IBM Index Class Name: REVISION
• Doc Date: 7/30/2010
• Doc Name: Lime Slaker Construction Request
• From: Climax Molybdenum
• To: DRMS
• Type & Sequence: TR4
• Email Name: ACS
• Media Type: D
• Archive: No

-,Climax
F-r-
Molybdenum
A Freeport-McMoRan Company
i/July 30, 2010
Via Email and UPS Tracking #: 1Z 804 847 03 6594 5402
Mr. Allen C. Sorenson
Division of Reclamation Mining and Safety
1313 Sherman St., Rm. 215
Denver, CO 80203
Re: Permit M-197742, TR-04, Lime Slaker Construction Request
Dear Mr. Sorenson:
COLORADO OPERATIONS
Henderson Mill
P.O. Box 68
Empire, CO 80438
Phone [phone]
Fax [phone]
Climax Molybdenum Company (CMC) is currently planning a project to construct a lime slaker at the
Henderson Mil in order to neutralize the tailing slurry. The slaker will be located on southwest side of the
Mill building and slaked lime will be gravity fed directly into the existing tailing discharge line.
When Henderson operations began in 1976, slaked lime was used as a control agent in the flotation
process. Eventually soda ash replaced the lime, but still as a process control agent. Over the years as
the flotation process evolved, it was determined these reagents were no longer required. In 2005, their
use was discontinued. The original detention type lime slaker, prone to continuous maintenance issues,
was partially dismantled.
A benefit of using these agents to control pH in the flotation process was that they also controlled pH of
the entire process water system. Discontinuing use of these agents has led to acidification of the mill
process water over the last couple of years, which results in corrosion to metal piping in the mill process
components.
The proposed lime slaker includes a complete system to receive, store and prepare lime slurry. The
design process rate is 4,000 lb/hr of dry quicklime with a minimum of 90% CaO content. Quicklime is
pneumatically conveyed from differential pressure bulk trucks to the lime storage silo with a capacity of
approximately 125 tons. The unloading area is sloped to a drain that flows to the tailing discharge line.
Quick Lime will be discharged from the storage silo via a bin activator and rotary valve. The rotary valve
will feed a volumetric feeder which meters lime into a slurry slaker. The slaker building is constructed with
a 2 foot high foundation wall and drains that will direct any overflow to the tailing discharge line.
The slurry will flow from the slaker by gravity discharge into an inclined chute/pipe for delivery to the
tailing discharge line. Controls and instrumentation will monitor and control the system.
The proposed lime slaker will constitute a new Environmental Protection Facility (EPF) per Mineral Rules
and Regulations of the Colorado Mined Land Reclamation Board for Hard Rock, Metal and Designated
Mining Operations (Rules), and will be managed in accordance with the Henderson Mine and Mill
Environmental Protection Plan submitted as Technical Revision #4 (TR-04) to Permit M-1977-342.