DRC-2012-002049 - 0901a068803141f4

State of Utah
GARY R. HERBERT
Govtmor
OREO BELL
iUratenanf Govcmor
Department of
Environmental Quality
Amanda Smith
Extcuthe Director
BradTJolnson
Deputy Director
DRC-2012-002049
August 20,2012
Scott Clow
Ute Mountain Ute Tribe
Environmental Programs Department
POBox44g
Towaoc, Colorado 81334-0448
Dear Mr. Clow:
On May 24,2012, the Utah Department of Environmental Quality (UDEQ) received a letter and
attached photo inquiring about the emissions fiom White Mesa uranium n^ in San Juan County,
Utah, Our department has investigated this incident and this letter summarizes those findings.
UDEQ contacted Denison Mines, the operator of the White Mesa Mill on June 14,2012, to begin
the investigaton. On June 27,2012, UDEQ received a response from Denison Mines regarding
this event Denison Mmes had no record of an upset on March 12,2012, but did have a record of
an ev^t on March 25,2012, that met the description of your letter. The company reported that
this event occurred during operations involving an alternate feed material. A process upset
resulted fmsn an imbalance between the rate of introduction of feed into the leach circuit, and the
water addition and acid levels used to leach the specific batch in process which resulted in
emissions of Nitrogen Oxides (NOx) Carbon Monoxide (CO) and steam. Denison Mines stated
that the process upset was addressed within minutes by adding water to the leach tank* Emission
testing by Denison Mines indicated that the gases had **dissipated to non-detectable levels outside
the Mill building within minutes after the correction was made.'* The company also stated that
this type of upset is rare and they would not expect a recurrence in the future.
The Division of Radiation Control (DRC) has reviewed the circumstances surrounding the process
upset event at the White Mesa Mill on March 25,2012. The DRC inquired as to what radiological
conditions existed at the time of the event In a letter dated July 16,2012, the Mill showed that
there was no increase in radiological activity detected relating to their routine monitors. Due to the
MilPs inability to supply the DRC with specific radiologica] information from the event, the DRC
has issued a Notice of Enforcement Discretion (NOED) to ensure that specific monitoring be
conducted during any similar future event. However, in light of die available data presented and
process knowledge of the systems involved, the DRC is confident that any radiological release
firom the event would have been minimal and would not have posed a hazard to the public or the
environment
19$ North 1950 Wot • Sah Lake City, UT
Mailing Addiess PO Box 144910-Sah Lake City. UT 84114-4810
Tdephone (801) 536^2 • Fax (80M36-0061 "TOD (801) S36-4414
www tltf.vHii,ge9
Ftiotcd OB 10096 ncycisd pipw
Page 2
The Division of Air (Quality (DAQ) has also reviewed the circumstances surroimding the process
upset event at the White Mesa Mill on March 25,2012. The White Mesa Mill operates under an
Approval Order (AO) from the (DA(^ which limits visible emissions from this stack to 15%
opacity. Opacity observations are required to be conducted in accordance with a federal reference
method that requires 24 visible emission observations to be taken over a six minute period. The
average of these readings is used to determine compliance with the opacity limit in the AO. The
photo attached to your letter certainly shows visible emissions in excess of 15% opacity, however,
the DAQ does not have enough data fit>m this event to determine a six minute average. Due to the
nature and duration of the event, no requirement for reporting was triggered.
Thank you for your letter and providing the photognq^h. We appreciate the information and for
the opportunity to investigate and provide a response to your concems. If you have any additional
questions for die DRC, please contact Kevin Carney at 801-536-0084 or kcamev@»^t?^ pn^. If
you have any additional questions for the DAQ, please contact Sarah Malluche at 801-563-4046
or [e-mail].
Amanda Smith
Executive Director