DRC-2010-004682 - 0901a068801bb9b9

DENISO
MINES
August 23, 2010
VIA E-MAIL AND OVERNIGHT DELIVERY
Mr. Phillip Goble
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144810
Salt Lake City, UT 84114-4820
J5 Received
AU6 2010
Division of
Radiation Control
Denbon Mines (USA) Corp.
1090 17th Street, Suite 950
^\ Denver, CO 80269
Ul USA
Tel: [phone]
Fax: [phone]
www.denisonmines.coin
Re: State of Utah Ground Water Discharge Permit ("GWDP") No. UGW370004
White Mesa Uranium Mill - Installation and Development of MW33 and MW34.
Dear Mr. Goble:
This letter summarizes our phone conversation of August 18, 2010 regarding plans for installation and
development of new monitoring wells MW-33 and MW-34, to be installed in conjunction with construction of
tailings Cell 4B, as required by Denison Mines (USA) Corp's ("Denison's") GWDP.
Well Drilling Schedule
As we discussed, Denison plans to have our drilling contractor begin drilling of MW33 and MW34 on August 31,
2010. It is anticipated that the drilling of each well may take approximately one day.
Well Development Schedule
As we have discussed with UDEQ previously, the hydraulic response of MW33 and MW34 will be used to
determine a potential location for the future MW35. Our hydrogeology consultant, Stewart Smith of Hydro Geo
Chem, Inc., has advised that following installation, the wells should be given a period of several weeks for
stabilization during which time the Mill environmental personnel should collect periodic static water level data.
Once this data indicates that static water level has stabilized, the static water level data will be used to assist in
determining a location and depth for MW35.
Mr. Smith has requested that development of MW33 and MW34 be initiated after water elevation data are
collected and stabilization has been confirmed. Based on Hydro Geo Chem's estimation, well stabilization
could require from a few days to several weeks. To accommodate this requirement, Denison plans to begin
well development activities in approximately late September.
Per the GWDP, Denison is required to provide an as-built report, containing the information specified in Part
I.F.6 a through c, within 45 calendar days of completing installation of MW33 and MW34. Part 1.F.6 does not
include a requirement to include well development confirmation in the as-built report. Denison will provide this
report containing the required information within the required 45 days after these two wells are installed. If well
Letter to Phil Goble on MW33 and 34 Development
August 23, 2010
Page 2
development, as described below, has not been completed in time to be included in the as-built report for these
two wells, Denison will provide a separate confirmation after development is completed, confirming that
development has been performed, identifying the methods employed, and whether successful development was
achieved.
Well Development Discussions to Date
Denison understands from our discussions on July 12 and August 18, 2010, and your letter of June 1, 2010,
that UDEQ requires that Denison
"[use] all commonly available well development techniques on the wells in question, including:
bailing, surging, jetting, and overpumping....Before the DRC can consider approval of any
variance regarding turbidity in monitoring wells, DUSA has to provide convincing evidence that all
monitoring wells at the Mill have been developed properly and all commonly (sic) well
development methods were attempted and exhausted."
UDEQ indicated during our discussion on July 12, that Denison is expected to apply each of the four methods
indicated in the June 1 letter unless EPA or other regulatory guidance directed against its use. Mr. Loren
Morton indicated that the risk of sweeping volatile compounds or changing the redox chemistry of the formation
was not sufficient rationale to dismiss air-based jetting, since air had already been introduced during air rotary
drilling of the wells.
During our discussion on August 18, 2010, you reiterated that Denison was to apply the more aggressive
methods unless regulatory guidance directed otherwise. You also reiterated Mr. Morton's determination that
effects of air introduction were not sufficient reason to reject the use of air jetting.
During our discussion on August 18, 2010, you agreed with Denison's understanding that we would attempt
surging and bailing of the wells first, followed by over-pumping if surging and bailing did not achieve completion.
You added that we should go on to the jetting method if lesser methods were unsuccessful, unless regulatory
guidance provided compelling reasons not to do so. Denison agreed to the approach outlined in the phone call.
Well Development Guidance
Denison has reviewed the following regulatory guidance on well development including documents referenced
in the GWDP and Utah Administrative Code R317-6-6.3(1 )(6):
• ASTM Standard Guide for Development of Ground-water Monitoring Wells in Granular Aquifers, D5521 -
05, Downloaded August 17, 2010 (the "ASTM Development Guide").
• EPA Handbook of Suggested Practices for the Design and Installation of Ground-water Monitoring
Wells, March 1991, EPA/600/4-89/034 (the "1991 Handbook").
• EPA RCRA Ground Water Monitoring Draft Technical Enforcement Guidance Document, November
1992, OSWER-9950.1 (the "TEGD").
• EPA Practical Guide for Groundwater Sampling, November 1985, EPA/600/2-85/104.
• EPA Standard Operation Procedure for Well Development, 1994 (the "EPA SOP").
• EPA Region 8 Standard Operation Procedure for Well Development, 1994 (the "Region 8 SOP").
DENISO
MINES
Letter to Phil Goble on MW33 and 34 Development
August 23, 2010
Page 3
Per the TEGD,
"Well development methods and equipment that alter the chemical composition of the
groundwater should not be used. Development methods that involve adding water (including
water pumped from the well) or other fluids to the well or borehole, or that use air to
accomplish well development, are rarely permissible."
Per the ASTM Development Guide, D5521-05, Section 8.6, air jetting is not recommended for monitor wells,
"Development with air is not recommended for monitoring wells...Blowing air into the well
during the process of air development may cause air to become entrapped in the narrow slots
of some monitoring well screens, the pores of the filter pack or formation materials
immediately adjacent to the borehole. Entrapped air is difficult to remove and it may
significantly reduce formation hydraulic conductivity and effectively reduce the amount of
open area of the well screen...For these reasons, compressed air alone should not be used
to develop monitoring wells."
The Region 8 SOP, Section 3.3, likewise states,
"[JJetting, airlift pumping, and air surging are not recommended for development of monitoring
wells."
Further, Denison's hydrogeology consultant does not wish to risk the introduction of hydrocarbons into the
monitor wells by unintentional injection of compressor oils along with compressed air during development.
Water jetting is also not recommended for monitor wells. The 1991 EPA Handbook, Page 117, states,
"Adding clean water of known quality for flushing and/or jetting should be done only when no
better options are available. A record must be kept of the quantities of water lost to the
formation during the flushing/jetting operation and every attempt must be made to establish
background levels in a manner similar to that described in Barcelona et.al. (1985a) and/or the
United States Environmental Protection Agency (1986)..."
With respect to hydraulic (water) jetting, the 1991 EPA Handbook, Page 120, states,
"The disadvantages of using jetting even in "ideal conditions" are fourfold: 1) the water used
in jetting is agitated, pumped, pressurized, and discharged into the formation; 2) the fine
(e.g., 10-slot, 20-slot) slotted screens of most monitoring well intakes do not permit effective
jetting, and development of the material outside the screen may be negligible or possibly
detrimental; 3) there is minimal development of the interface between the filter pack and the
wall of the borehole....4) water that is injected forcibly replaces natural formation fluids.
These are serious limitations on the usefulness of jetting as a development procedure."
The Region 8 SOP likewise describes the addition of water to a well as "undesirable" due to effects on water
chemistry.
The 1991 EPA Handbook, Page 120 states that the preferred methods for well development are as follows:
DENISO J>i
MINES
Letter to Phil Goble on MW33 and 34 Development
August 23, 2010
Page 4
"after due consideration of the available procedures for well development, it becomes evident
that the four most suitable methods for monitoring well development are: 1) bailing, 2) surge
block surging, 3) pumping/overpumping/backwashing and 4) combinations of these three
methods.
Although Denison still believes that jetting is not suitable for monitoring wells, we are not certain whether UDEQ
considers the information above to be compelling enough evidence to exclude jetting. Therefore, if MW33 or
MW34 cannot achieve stabilization as indicated by a turbidity of 5 NTU or less via surging and bailing, or
overpumping, Denison will proceed with jetting unless you advise us otherwise.
Proposed Well Development Approach
Denison plans to implement the following approach for development of MW33 and MW34:
Initial development of the wells will be by surging and bailing. Mill environmental personnel will measure and
record turbidity to assess whether development by these methods is successful. As we agreed in our phone
discussion, if turbidity measurements of 5 NTU or less indicate that these methods have successfully developed
the well, no further development methods will be attempted.
If turbidity indicates that development has not been successful, we will cease surging and bailing and initiate
development by over-pumping. Mill environmental personnel will measure and record turbidity to assess
whether development by this method is successful. If turbidity measurements indicate that this method has
successfully developed the well, no further development methods will be attempted.
If turbidity measurements indicate that development has not been successful, we will cease over-pumping and
initiate development by air and/or water jetting. Mill environmental personnel will measure and record turbidity
to assess whether development by this method is successful.
If, after application of the above techniques, well development is not successful, Denison will inform UDEQ of
the situation, and proceed with use of the well.
Technical Issues Associated with Jetting
Denison, at this time, proposes to employ air jetting, if well stabilization is not achievable via surging, bailing, or
overpumping, and UDEQ requires jetting. Denison will confirm that the well installer has an appropriate filter on
the compressor discharge used to jet the well(s), to ensure that lubricating oils are not introduced into the
formation during the jetting process.
It should be noted that Denison's hydrogeology consultant, consistent with the EPA guidance cited above, has
indicated that air jetting of monitoring wells can potentially be expected to have the following detrimental effects
on the quality of samples subsequently collected from the jetted well(s):
• Volatile organic compounds (VOCs) are swept from the formation near the well (that is, chloroform will
be unrepresentatively low).
• The oxygenation of the formation near the well will reduce the natural attenuation of residual chloroform
(that was not swept out) and other chlorinated compounds for which the attenuation reactions are
favored by reduced, not oxidized, conditions.
• The oxygenation of the formation near the well will convert more nitrogen bearing compounds from the
ammonia or amino form to the nitrate/nitrate form (that is nitrate levels will be unrepresentatively high).
DENISO
MINES
Letter to Phil Goble on MW33 and 34 Development
August 23, 2010
Page 5
If air jetting should be infeasible, and UDEQ requires that Denison continue development attempts, Denison will
proceed to water jetting. If water jetting is employed, Denison proposes to use the following approach:
• Jetting will employ water from Recapture Reservoir, collected in the Mill's on site water supply tanks.
• Water will be sampled from the Mill's water tank prior to the first use of water for jetting.
• The volume of water introduced during jetting will be measured.
• Consistent with EPA guidance, Denison will attempt to remove 5 times the volume introduced via
bailing or pumping. However, it should be recognized that even in the best of circumstances, the
introduction of water into the well will be expected to change the water chemistry of the formation for
some period thereafter.
It should be noted that, per the US EPA in the 1991 Handbook, Page 117, for some geologic settings:
"[Cjollecting a non-turbid sample may not be possible because there are monitoring wells that
cannot be sufficiently developed by any available technique."
Confirmation
Denison would appreciate receiving confirmation that the above-described approach is acceptable to UDEQ, or
receive timely input from UDEQ with further direction if it is not acceptable, prior to the start of anticipated
drilling activities on August 31, 2010.
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: David C. Frydeniund
Ryan Palmer
Harold R. Roberts
Stewart Smith, Hydro Geo Chem, Inc.
David E. Turk
K. Weinel
DENISO
MINES