DRC-2011-002069 - 0901a06880206ad7

DEIMISON
INiS
DRC-2011-002069 Dehlson Mines (USA) Corp.
1050 17th Street, Suite 950
Denver, CO 80265
USA
Tel: [phone]
Fax : [phone]
www.denisonmines.com
February 22, 2011
VIA E-MAIL AND OVERNIGHT DELIVERY
Rusty Lundberg, Co-Executive Secretary
Utah Water Quality Board
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144810
Salt Lake City, UT 84114-4820
Re: White Mesa Uranium Mill - Notice of Violation and Corrective Action Order
UDEQ Docket No. UGQ-20-01
Notice Pursuant to the Chloroform Pumping Well Operations and Maintenance Plan
Dear Mr. Lundberg:
Pursuant to the White Mesa Mill's (the "Mill's") Chloroform Pumping System Operations and Maintenance Plan
("Chloroform O&M Plan") Denison Mines (USA) Corp. ("Denison"), as operator of the Mill, is providing written
notice to the Utah Department of Environmental Quality ("UDEQ") of a temporary outage in one chloroform
capture pump, as described in more detail below.
The Mill's Chloroform Pumping O&M Plan states that Denison will notify UDEQ of system failures that cannot
be made operational within 24 hours of discovery. It was determined on Thursday, February 18, 2011 that a
pump failure had occurred which would require more than 24 hours to be repaired and operational. Initial notice
of this outage was given by telephone to Mr. David Rupp of the Utah Department of Environmental Quality at
approximately 5:10 pm on Wednesday February 18, 2010 (within 24 hours of the discovery).
1. Description of the Pumping System Failure
a) The Mill's Chloroform O&M Plan, submitted on October 25, 2010 and currently under review by
UDEQ, states that Denison will notify UDEQ of system failures that cannot be "repaired and fully
made operational within 24 hours of discovery."
b) During the weekly chloroform pumping well inspection performed Monday February 14, 2011, TW4-
20 appeared to have stopped pumping. During a follow-up monitoring and maintenance check
performed on February 15, the pump was again operational and running at a low flow rate.
c) During an additional inspection on Wednesday February 16, 2011 Mill environmental personnel
decided that, although the pump was still operating, the slow flow rate indicated potential for
pluggage. The pump was replaced with a new pump the same day. Mill electrical maintenance staff
N:\Notices\Chloroform well pump notice 2.22.11\02.22.11 Notice to RLundberg TW4-20.docx
Letter to Mr. Rusty Lundberg
February 22, 2011
Page 2
instructed the environmental staff that the sealant and wrap on the new electrical splicing on the new
pump should be allowed to set until the following morning, before the pump could be turned back on.
d) During a follow-up inspection on Thursday, February 17, 2011, the new replacement pump was
observed to run for only a few seconds before shutting down.
2. Root Cause
The root cause analysis is as follows
a) The high pumping rate in TW4-20 appears to have mobilized and drawn in dissolved iron into the
capture zone of TW4-20. Inspection of material recovered during surging and bailing also showed the
presence of a fine sandy material indicative of hydraulic stress on the formation. A similar
phenomenon has been observed in the past at other chloroform pumping wells (e.g. TW4-19).
b) Due to the oxidizing conditions in the well, formerly soluble iron was oxidized and precipitated inside
the well screen, well sump and pumping equipment.
3. Period of Time the System Was Not in Operation
The system was not in operation from February 17 through February 21, 2011 or approximately 5 days.
4. Date by Which the Pumping System Will be repaired an Operational
The well was repaired and put back into operation by 3:00pm on Monday February 21, 2011, as described
below.
5. steps Taken to Repair and Have the System Full Operational
Upon observing that the new pump was not performing properly on February 17, 2011, the Mill environmental
personnel removed and inspected the pump and discharge hose, noting that the hose as well as the new pump
were now plugged with fines. The Mill environmental personnel then took the following actions:
a) The Mill's Environmental Manager was notified immediately;
b) Mill environmental personnel cleaned and replaced the pump and removed the plugged hose the
same day;
c) A sample of the fine material plugging the pump and hose was sent to the Mill's on-site laboratory;
d) The plugged hose was replaced with a newer larger diameter discharge hose;
e) Local and out-of-state suppliers were contacted to provide a fitting to connect the pump to the new
discharge hose. It was determined during the afternoon of February 17, 2011 that no supplier within
driving distance in Utah or Colorado could provide the needed fitting, and Mill Maintenance
immediately ordered the part for expedited shipment from a non-local supplier;
DENISO
MINES
Letter to Mr. Rusty Lundberg
February 22, 2011
Page 3
0 Verbal notification was given to the Executive Secretary at approximately 5:10pm on February 17,
2011, within 24 hours of discovery. The verbal notification was followed by this written notification
within five days of discovery;
g) Subsequent to the verbal notice, both the Mill laboratory and the Mill's hydrogeological consultant,
Hydro Geo Chem, confirmed that the pluggage material appeared to be naturally-occurring
precipitated iron fines from the perched zone, which could potentially be removed by cleaning and re-
developing the well; and
h) The Mill's well drilling and service contractor re-developed TW4-20 by surging and bailing on Monday
February 21, 2011.
6. Steps Taken to Prevent a Reoccurrence of System Failure
The Mill determined that to maintain more dependable operation of the pump, accumulated iron deposits within
well TW4-20 should be removed before reinstalling and restarting the pumping system. The iron has already
been removed from all components of the pumping system, and the well screen and suhip have been cleaned
by surging and bailing. The Mill has additionally installed a larger diahieter discharge hose to minimize the
likelihood of hose pluggage.
Please contact the undersigned if you have any questions or require any further information.
Yours very truly,
DENISON MINES (USA) CORP.
Jo Ann Tischler
Director, Compliance and Permitting
cc: Rich Bartlett
David C. Frydenlund
Harold R. Roberts
David E. Turk
Central files
DENISON
MINES