2010-09-10_HYDROLOGY - M1977342

• Permit No: M1977342
• IBM Index Class Name: HYDROLOGY
• Doc Date: 9/10/2010
• Doc Name: Follow-up Notice for Overflow of Process Water from Mill Water Supply Pipeline.
• From: Climax Molybdenum
• To: DRMS
• Permit Index Doc Type: Hydrology Report
• Email Name: ACS
• Media Type: D
• Archive: No

® Climax Molybdenum
A Freeport-McMoRan Company
September 9, 2010
COLORADO OPERATIONS
Henderson Mill
P.O. Box 68
Empire, CO 80438
Phone [phone]
Fax [phone]
RECEIVED
SEP 10 2010
Via Email and UPS Tracking #: 1Z 804 847 03 6470 6958 Divislon of Reclamatlan,
Mlning & Safety
Mr. Allen C. Sorenson
Division of Reclamation, Mining and Safety
1313 Sherman St., Rm. 215
Denver, CO 80203
Re: Follow-up Notice for Overflow of Process Water from Mill Water Supply Pipeline, Permit
No. M-1977,342
Dear Mr. Sorenson:
Henderson Mill is providing this written follow-up notice to a phone call made to you on August 15, 2010
pursuant to Rule 8.2.3 of the DRMS Rules and Regulations.
This notice is regarding an overflow of process water from the partially-constructed, replacement mill
process water supply pipeline (PWSP), which occurred on August 15th, 2010 at 2:10am. The PWSP is
an Environmental Protection Facility at the Henderson Mill. An undetermined volume of process water
was observed at the surface of an excavation for the new mill PWSP up gradient of the East Branch
Pump Station, which was still under construction. The water was flowing from the east shoulder of Grand
County Road 3, across the pavement and back onto Henderson Mill property where it entered the upper
end of the tailing impoundment.
(a) After discovering the issue, Henderson employees began investigating where the water
was coming from. Since there are several lines in the vicinity of the leak (process water,
raw water and domestic sewer), several different lines had to be investigated. This was
done by turning off the various pumps at the East Branch Pumphouse to monitor flow
changes at the surface. When it was determined that mill process water was leaking, a
trench was constructed to route water from the excavation into East Branch Reservoir.
The project manager contacted the pipeline contractor to have them mobilize to the site
to begin repair. By 8pm the same day (August 15, 2010), the line had been repaired and
all flows stopped.
(b) Henderson does not believe that the water spilled will adversely impact human health,
property or the environment. This is based on the fact that the process water flowed from
Mill property, across a paved surface, then back onto Mill property and into the tailing
system, where water of this nature is designed to be stored. All overflow water remained
within Henderson's closed process water loop throughout the event.
(c) The operator contact person for this event is:
1. Miguel Hamarat
2. 19302 County Road 3, Parshall, CO 80468