DRC-2011-004770 - 0901a0688022b013

State of Utah
GARY R. HERBERT
Govemor
GREG BELL
Lieutenant Governor
Department of
Environmental Quality
Amanda Smith
Executive Director
DIYISION OF RADIATION CONTROL
Rusty Lundberg
Director
April 28, 2011
CERTIFIED MAIL
(Return Receipt Requested)
Mr. David C Frydenlund
Vice President and General Counsel
Denison Mines (USA) Corp. (DUSA)
1050 Seventeenth St. Suite 950
Denver, Colorado, 80265
Subject: Signed and Executed Revised Tolling Agreement, Relevant to Terms of the January 27, 2009
Stipulated Consent Agreement Docket No. UGW09-03
Dear Mr. Frydenlund:
A copy of the April 28, 2011 Revised Tolling Agreement (Rev. 1) between Denison Mines (USA) Corp.
(DUSA) and the Co-Executive Secretary is enclosed. The Revised Tolling Agreement has been signed by
David C. Frydenlund (DUSA Vice President and Counsel) and Rusty Lundberg (Co-Executive Secretary).
The April 28, 2011 Revised Tolling Agreement will expire June 30, 2011 and replaces the previous
December 15, 2010 Tolling Agreement that expires April 30, 2011.
If you have any questions or concems please contact Phil Goble at [phone] or Loren Morton at
[phone].
UTAH WATER QUALITY BOARD
17
Rusty Lundberg
Co-Executive Secretary
RL:PRG:prg
Enclosure: April 28, 2011 Revised Tolling Agreement
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144850 • Salt Uke City, UT 84114-4850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
Rev. 1
TOLLING AGREEMENT
This Tolling Agreement (Agreement) is made by and between Denison Mines (USA)
Corp. (DUSA) and the Co-Executive Secretary of the Utah Water Quality Board (Co-Executive
Secretary).
WITNESSETH
WHEREAS, DUSA and the Co-Executive Secretary entered into a Stipulated Consent
Agreement Docket No. UGW09-03 dated January 27,2009 (Consent Agreement) related to
nitrate contamination at DUSA's White Mesa Uranium Mill Site, Blanding Utah (Mill);
WHEREAS, pursuant to Item 6. A of the Consent Agreement, DUSA submitted Si Nitrate
Contamination Investigation Report, White Mesa Uranium Mill Site, Blanding Utah, dated
December 30, 2009 (CIR) to the Utah Division of Radiation Control (DRC);
WHEREAS, Item T.C of the Consent Agreement provides as follows:
Ifthe Executive Secretary determines that the CIR has omitted any
information, content requirements, or failed to meet the
performance standards or objectives mandated by Item 6.A, the
Executive Secretary will so advise DUSA by written notice and
DUSA will remedy such omission or failure within 30 calendar
days of receipt of such notice. If DUSA fails to remedy such
omission or failure within such 30 day period, DUSA will pay
stipulated penalties in the amount of $2,000 per calendar day for
every day after such period that the CIR remains incomplete, as
determined by the Executive Secretary;
WHEREAS, by letter dated October 5, 2010 and hand delivered to DUSA on the same
date, the Co-Executive Secretary notified DUSA of his determination that the CIR is incomplete
(October 5, 2010 DRC Notice). As a result ofthis detennination under Item 7.C of the Consent
Agreement, DUSA is to remedy such omissions in the CIR on or before November 4,2010;
WHEREAS, Item 11 of the Consent Agreement provides as follows:
The deadline stipulated in items 7.A - 7.D may be amended by prior
written mutual agreement of the parties. The party requesting the
amendment must write to the other party 14 days before the
stipulated deadline and request an amendment of the deadline. The
other party will either agree to or deny the amendment in writing
within 10 days;
WHEREAS, the October.5,2010 DRC Notice also directed DUSA to take one of the
following actions, in accordance with the Consent Agreement:
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1. perform a number of additional studies suggested by DRC under a revised CIR that
could be submitted to the Co-Executive Secretary for review and approval;
2. opt to request to amend the 30-day deadline for DUSA to submit a revised CIR,
pursuant to Item 11 of the Consent Agreement; or
3. opt to request amendment of the Consent Agreement (under Item 11) to provide a
schedule for submittal of performance standards and a Corrective Action Plan for the
nitrate contamination for Co-Executive Secretary approval under Item 8 ofthe
Consent Agreement;
WHEREAS, by an email transmitted to the Co-Executive Secretary on October 20, 2010,
and pursuant to Item 11 of the Consent Agreement, DUSA requested an amendment to the
deadline stipulated in item I.C of the Consent Agreement, which required that Denison must
remedy any omissions in, content requirements of, or failure to meet any performance standards
or objectives relating to the CIR mandated by Item 6. A of the Consent Agreement, within 30
calendar days of receipt ofthe October 5, 2010 DRC Notice {i.e., November 4, 2010). Instead,
DUSA requested item 7.C be amended as follows:
a. DUSA representatives will meet with the Co-Executive Secretary and his legal
counsel within two weeks fi-om the date of the email to discuss the legal
responsibilities of DUSA with respect to the nitrate contamination;
b. Once the legal responsibilities of DUSA with respect to the nitrate contamination
have been determined, DUSA will, vithin 30 days after such a detennination is made,
submit to the Co-Executive Secretary for approval a plan and schedule to perform any
further investigations that may be required in order to remedy any such omissions,
content requirements or failures of performance standards, and to submit a revised
CIR; and
c. DUSA will perform such investigations and submit a revised CIR in accordance with
the agreed upon plan and schedule;
WHEREAS, on October 26, 2010, DUSA met with the Co-Executive Secretary, DRC
staff and legal counsel (October 26, 2010 Meeting) to discuss DUSA's legal obligations with
respect to the nitrate contamination. At the meeting, DUSA reported that it was premature to
submit a schedule for submittal of performance standards and a Corrective Action Plan for the
nitrate contamination. In tum, DUSA presented a new theory for a possible source of the nitrate
and chloride contamination beneath the Mill, based on DUSA's review of the scientific literature
(New Theory). Based on this New Theory, DUSA suggested that the nitrate contamination
source is or could be caused by naturally occurring nitrate and chloride salt deposits located in
the vadose zone near or beneath the Mill site area, which have been mobilized by natural and/or
artificial recharge. The parties agreed that this New Theory warrants additional investigation,
along with certain of the other additional studies suggested in the October 5, 2010 DRC Notice;
WHEREAS, as agreed at the October 26,2010 meeting, DUSA submitted via email on
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November 15, 2010, a letter setting out the additional studies to be considered that have been
identified to date, including the additional studies suggested in the October 5, 2010 DRC Notice,
proposed additional studies relating to the New Theory, and any other additional studies that
DUSA believes may be relevant. In the November 15, 2010 letter, DUSA proposed that a
meeting be held on November 30, 2010 between DRC Staff and DUSA technical and regulatory
staff to discuss the foregoing studies and any associated matters, to agree on the studies to be
performed and the manner of performing those studies, and to develop a plan and schedule for
performing such studies and for submittal of a revised CIR;
WHEREAS, the meeting contemplated in DUSA's November 15, 2010 letter was held on
November 30, 2010, among DRC Staff and DUSA technical and regulatory staff At that
meeting, DUSA presented a number of additional studies (herein "Additional Studies") to be
performed by DUSA in order to complete the CIR. The Additional Studies were in addition to
the New Theory. The Co-Executive Secretary and DUSA further agreed that DUSA would
prepare a detailed plan and schedule (the "Plan and Schedule") for perfonning such studies and
for submittal of a revised CIR that meets the requirements of all applicable regulations on or
before February 15, 2011. The February 15, 2011 date for submittal of the Plan and Schedule is
somewhat later than the original 30 days proposed by DUSA in its October 20, 2010 email to the
Co-Executive Secretary, due to the complexity of certain of the Additional Studies to be
performed. During the November 30, 2010 meeting it was agreed that both the Plan and
Schedule and the revised CIR will be subject to Co-Executive Secretary approval;
WHEREAS, via email correspondence between October 29 and December 13, 2010 the
parties exchanged various drafts of the Tolling Agreement;
WHEREAS, the original Tolling Agreement was signed by both parties on December 15,
2010. The Tolling Agreement documented DUSA's commitment that the detailed plan and
schedule would be submitted for Co-Executive Secretary review and approval on or before
February 15,2011;
WHEREAS, pursuant to the December 15,2010 Tolling Agreement, DUSA submitted a
Work Plan and Schedule for Supplemental Contaminant Investigation Report for White Mesa
Mill Nitrate Investigation (hereafter Work Plan) to the DRC on February 14,2011. In a meeting
the same day, DUSA presented a summary of the proposed Work Plan. The DRC noticed that
some figures shown in the presentation were not included in the February 14, 2011 Work Plan
and requested that they be added. DUSA committed that the Revised Work Plan would be
submitted for Co-Executive Secretary review and approval on or before February 18, 2011.
WHEREAS, pursuant to the DUSA commitment that a Revised Work Plan would be
submitted on or before February 18, 2011, DUSA submitted the Revised Work Plan on February
18,2011. During the February 14,2011 meeting both parties agreed that the DRC comments
would be provided to DUSA on March 21, 2011 instead ofthe previously agreed deadline of
March 15,2010;
WHEREAS, the DRC provided DUSA with its comments regarding the February 18,
2011 Work Plan in a March 21, 2011 URS Memorandum by e-mail on March 21, 2011.
4843-76374791.2
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WHEREAS, a meeting was held with both parties in Salt Lake City, Utah on April 13,
2011 to discuss the DRC comments for the February 18, 2011 Work Plan. A subsequent meeting
was held in Salt Lake City, Utah on April 20, 2011 (hereafter April 20 Meeting). During the
April 20 Meeting, it was agreed by both parties that the Nitrate Investigation field work would be
conducted in five (5) Phases. During the meeting, the DRC and DUSA discussed in detail what
Phase 1 would include and came to a consensus. Phase 1 will include three (3) sub-phases, as
follows:
Phase 1A - Geoprobe investigation of a possible natural nitrate salt reservoir in vadose
zone soils.
Phase IB - Geoprobe investigation of potential nitrate source locations in the Mill site
area.
Phase IC - Geoprobe investigation of other potential nitrate sources.
During the April 20 Meeting, the Co-Executive Secretary and DUSA agreed that DUSA would
prepare and submit a Revised Work Plan for Phase 1A through C on or before May 6,2011, and
would include, but is not limited to the study information items and objectives found in
Attachment 1, below. The DRC committed to give DUSA its comments for the Phase 1 Work
Plan on or before May 12, 2011.
During the April 20 Meeting, it was agreed that as many as four other phases of study / activity
may be required as part of the nitrate investigation. These were briefly discussed in concept; and
it was agreed that the possible remaining phases and activities could include the following:
Phase 2 - Groundwater quality sampling and analysis of existing wells for non-isotopic
analytes, including, but not limited to submittal of a revised Quality Assurance Plan
(hereafter QAP) for all non-isotopic constituents not currently found in the March 22,
2010 DUSA QAP (Rev. 6).
Phase 3 - Deep bedrock core sampling and analysis at possible natural nitrate reservoir
and potential nitrate source locations, with similar objectives as Phase 1 A, B and C,
above.
Phase 4 - Stable isotopic sampling and analysis of groundwater in existing wells, with
details to be defined later, and approved by both parties.
Phase 5 - Isotopic soil sampling and analysis (if needed).
During the April 20 meeting, the Co-Executive Secretary and DUSA agreed that DUSA would
prepare and submit a Revised Phase 2 through 5 Work Plan and Completion Schedule for Co-
Executive Secretary review and approval on or before June 3,2011. DUSA also committed to
provide, as part of the Revised Phase 2 through 5 Work Plan, an initial Conceptual Site Model
(hereafter CSM) to guide the Nitrate Investigation. Both parties agreed that the initial CSM
could be subject to revision as Phases 2 through 5 of the investigation proceeded forward. It was
also agreed by both parties, during the April 20 meeting, that the Automatic Termination Date
4843-76374791.2
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for the Tolling Agreement would then be extended to June 30, 2011.
WHEREAS, in lieu of proceeding further under Item 11 of tiie Consent Agreement, and
amending any deadlines pursuant to Item T.C, or pursuing dispute resolution under Item 13 of
that agreement, the parties desire to give themselves time for:
a. DUSA to prepare and submit the Revised Work Plan for Phase 1 and Revised Phase 2
tiirough 5 Work Plan, which will also include an initial CSM of tiie Potential Nitrate
Sources; and
b. the Co-Executive Secretary to review and approve the Revised Work Plan for Phase 1
and the Revised Phase 2 through 5 Work Plan, with any modifications deemed
necessary by the Co-Executive Secretary; and
c. the Co-Executive Secretary and DUSA to agree on a revised or replacement Consent
Agreement that incorporates the deliverables and timelines set out in the approved
Revised Phase 2 through 5 Work Plan; and
WHEREAS, the parties acknowledge that the covenants and forbearance under this
Agreement constitute adequate and sufficient consideration.
NOW, THEREFORE, in consideration of the promises contained herein, the parties to
this Agreement do hereby stipulate, covenant, and agree as follows:
1. Calculation of any time period or monetary penalty by the Co-Executive Secretary under
Item T.C of the Consent Agreement shall:
a. Not include the period from January 4, 2010 (submittal of the CIR to DRC) tiirough
October 5, 2010 (delivery of the DRC Notice to DUSA);
b. Not include tiie period fi-om October 5 to October 20, 2010 (whereby DUSA
requested amendment of the Consent Agreement pursuant to Item 11);
c. Not include the period from October 20, 2010, through the effective date of this
Tolling Agreement; and
d. Include the earlier of either: (i) the Effective Date of Termination of this Agreement
as defined in paragraph 6, or (ii) the Automatic Termination Date as defined in
paragraph 6, below.
Commencing January 4, 2010 and ending on the date specified in subparagraph I.d, above,
inclusive, is herein referred to as the "Tolling Period".
Stipulated Penalties have not begun to accrue imder Item T.C of the Consent Agreement, and
shall not accrue during the Tolling Period.
4843-76374791.2
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2. Revised Phase 1 Work Plan - on or before May 6,2011, DUSA shall complete and
submit for Co-Executive Secretary review and approval a Revised Phase 1 (A through C) Work
Plan including, but not limited to the infonnation items and objectives found in Attachment 1,
below.
3. The Co-Executive Secretary shall provide his initial comments on the Phasei (A through
C) Work Plan and Schedule on or before May 12, 2011, and DUSA and the Co-Executive
Secretary will cooperate to finalize the Revised Phase 1 Work Plan as expeditiously thereafter as
reasonably practicable to allow DUSA to begin fieldwork for Phase 1 as soon as possible. DUSA
shall provide at least a 14 calendar day written notice to allow the Co-Executive Secretary to
observe all field activities.
4. Revised Phase 2 through 5 - on or before June 3, 2011, DUSA shall complete and submit
for Co-Executive Secretary review and approval a Revised Phase 2 through 5 Work Plan and
Schedule, which will include, but is not limited to:
a) Detailed description of the activities, equipment, procedures, performance
objectives, and decision criteria involved in each Phase.
b) An initial CSM of tiie facility (Revision 0), that DUSA will use as a guide to plan
/ conduct the Nitrate Investigation.
c) A logic diagram for each Phase to identify all studies and decision processes that
may be required to meet all applicable regulatory requirements including the performance
objectives of the Consent Agreement, Item 6(A)(vi).
d) Deadlines for commencement and completion of all field and laboratory work for
each Phase, and final CIR report preparation,
e) Deadline for submittal of a final revised CIR for Co-Executive Secretary review
and approval.
5. After review and approval of the Revised Phase 2 through 5 Work Plan and Schedule,
DUSA and the Co-Executive Secretary shall cooperate to negotiate and finalize and execute a
revised or replacement Consent Agreement that incorporates the Plan and Schedule, as soon as
reasonably practicable. The revised or replacement Consent Agreement will contain a provision
to the effect that DUSA will pay to DRC the reasonable fees payable by DRC to the URS
Corporation for consulting services to be rendered by the URS Corporation in support of its
review of 1) tiie February 18,2011 Work Plan and Schedule, 2) tiie Revised Phase 1 (A through
C) Work Plan and Schedule, 3) the Revised Phase 2 Work Plan and Schedule, and 4) the revised
CIR on behalf of DRC, based on an estimate or estimates of such services approved by DUSA.
6. This Agreement shall terminate on the earlier of: (a) June 30, 2011 ("Automatic
Tennination Date") unless extended by prior written agreement executed by the parties; and (b)
the date of execution and delivery of the revised or replacement Consent Agreement
contemplated by paragraph 5 above. Prior to the Automatic Termination Date, any party may
terminate this Agreement for any reason and without cause by sending a written temiination
notice to the other party ("Termination Notice"). Such Termination Notice shall be sent to the
other party by certified mail or registered mail, retum receipt requested, using the addresses
4843-76374791.2
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indicated below. Termination shall not be effective until five (5) days after the date the
Termination Notice is received by the otiier party (the "Effective Date of Termination"), as
indicated by the retum receipts. The Tolling Period shall extend only to the earlier date of: (a)
the Effective Date of Termination, or (b) the Automatic Termination Date.
T. The undersigned representatives of the parties certify that they are authorized to enter
into the terms and conditions of this Agreement, and to execute for and bind tiie party whom he
represents.
The addresses and persons to whom notice is to be given are as follows:
If to DUSA:
David C. Frydenlund
Vice President and Counsel
Denison Mines (USA) Corp.
1050 IT*''Street, Suite 950
Denver, CO 80265
If to the Co-Executive Secretary:
Rusty Lundberg
Co-Executive Secretary
Utah Water Quality Board
195 North 1950 West
Salt Lake City, Utah 84116
With a copy to:
Assistant Attomey General Denise Chancellor,
Office of Attomey General
160 East 300 South, 5* Floor
P.O. Box 1408T3
Salt Lake City, Utah 84114-08T3
8. Subject to all other terms of this Agreement, the parties reserve all existing rights,
privileges, defenses and contentions which exist as against each other, and enter into this
Agreement without prejudice to or waiver of those rights, privileges, defenses, or contentions.
9. This Agreement may not be modified except in writing and signed by the parties to this
Agreement.
10. This Agreement shall continue in fiill force and effect until the earlier of the Effective
Date of Termination or the Automatic Termination Date, as defined in paragraph 6 ofthis
Agreement.
.11. The parties acknowledge that they have had the opportunity to consult with counsel, and
have consulted with counsel, prior to executing this Agreement.
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12. This Agreement was initially executed and delivered on December 15,2010^ which is the
Effective Date of this Agreement. This Agreement was revised on April 28,2011, and tiie
revised Agreement is referred to as Rev 1 of the Agreement.
Uv^lsXy Date: ^/ZfejZg^U
Rusty Lundbi
Co-Executive Secretary
UTAH WATER OJ^ALITY BOARD
DsvidMf ^rydinlund, Esq.
Vice President and Counsel
Date:
4843-7637479L2
Attachment 1
Two meetings were held in Salt Lake City, Utah on April 13 and 20,2011 witii tiie DRC,
DUSA, INTERA, and URS personnel to discuss tiie March 21, 2011 DRC conmients for
tiie February 18,2011 DUSA Work Plan for tiie Nitrate Investigation. As the result of
these two meetings, it was agreed by botii parties, that the Nitrate Investigation field work
could be conducted in five (5) Phases. During the April 20, 2011 meeting, the DRC and
DUSA discussed in detail what Phase 1 would include and came to a consensus, as
follows:
PHASE lA - Geoprobe Investigation in Undisturbed Locations
Part 1 - Geoprobe Investigation to Determine Background Nitrate, Chloride and
Ammonia Soil Concentrations in Areas Unimpacted by Human Activities
("undisturbed locations "):
1. A Geoprobe boring (Boring #1) will be conducted down to bedrock refijsal at
each of the 20 undisturbed geoprobe boring locations (per Figure 20 ofthe
February 18, 2011 DUSA Work Plan and Schedule). Three (3) samples will be
collected from each geoprobe core location. Soil core samples will be collected
from the bottom 1-foot of each of the following intervals: first 1/3, second 1/3,
and third 1/3 of the total penetrated depth at each location. Each soil core
sample will be sent to the analytical laboratory for analysis of nitrate (as N),
chloride, and ammonia nitrogen (as N). Soil analysis will be conducted by an
environmental laboratory currently certified by the State of Utah, using EPA
approved sample and analysis methods. The Nitrate Extraction and Field Test
Procedure, as described in Appendix A of the Febmary 18, 2011 DUSA Work
Plan (hereafter Nitrate Field Test) will not be used. Background concentrations
for each of the above analytes will be based on the 95% Upper Confidence
Limit (UCL) of tiie 60 samples collected and analyzed. Said UCL will be
determined using commonly accepted descriptive statistical methods and will be
subject to DRC approval. After DRC approval, said site soil "background"
concentration will be used for comparative and determinative purposes in
PHASES IB and IC of tiie Geoprobe Investigation of Potential Nitrate Source
Locations described below.
Part 2 - Geoprobe Investigation of a Possible Natural Nitrate Salt Reservoir:
1. A duphcate geoprobe boring (Boring #2) will be installed in close proximity
(within 5 horizontal feet) to each of the geoprobe borings (Boring #1) from
Phase 1 A, Part 1, above). Each of these duplicate geoprobe borings (Borings
#2) will be driven down to bedrock refiisal at each ofthe 20 undisturbed
locations, mentioned in Phase lA, Part 1, above.
A sample from within the 0 to 0.5 foot interval below ground surface (BGS)
will be collected in each of these 20 geoprobe boring locations. These surface
soil samples will be analyzed using the Nitrate Field Test, described above and,
if nitrate concentrations are detectable, will be sent to an approved analytical
laboratory for analysis. The sample taken in this manner for each geoprobe
location will serve as baseline for that borehole for the purposes of determining
whether or not a nitrate or chloride reservoir is indicated at that location.
Soil core samples will be collected at each geoprobe location to:
a) ensure a minimum core recovery of 95%, or as otherwise approved in
advance by the Co-Executive Secretary,
b) provide discrete and individual 1 -foot depth samples,
c) be placed into a sealable plastic bag that is labeled in accordance with
EPA approved field methods. This sealed bag will be retained for the
purpose of fiirther laboratory analysis at DUSA's discretion, and
d) Each discrete 1 -foot soil sample will be thoroughly mixed and
homogenized within the plastic bag before any field or laboratory analysis.
Said soil samples will then be considered representative ofthe individual 1-
foot core interval.
Thereafter, an aliquot of each discrete 1-foot soil sample will be taken from the
bag and analyzed using the Nitrate Field Test described in Appendix A of the
February 18, 2011 DUSA Work Plan and Schedule.
Elevated soil samples, i.e. those found with Nitrate Field Test results that are
twice the baseline concentration, as determined by field analysis ofthe 0-0.5-
foot BGS sample described above (Phase 1 A, Part 2, Item 1) or as determined
by field judgment to be elevated will be sent to the approved analytical
laboratory for nitrate (as N) soil analysis. The Nitrate Field Test results from
Boring #2 at each location will be used as a tool by DUSA to examine the
possibility of a natural nitrate salt deposit in vadose zone soils at the White
Mesa Mill site using the 1 -foot sample intervals.
PHASE IB - Geoprobe Investigation of Potential Nitrate Source Locations:
1. Multiple geoprobe borings will be driven down to bedrock refusal at 16 of the
potential on-site Nitrate Sources, shovm on the DUSA handout provided in the
April 20,2011 meeting. Of these 16 potential sources, 8 are considered by DUSA
as High Priority Locations and will be investigated with four (4) geoprobe borings
at each source in a north-east-west-south relative orientation. For the remaining 8
potential sources, DUSA considers them to be Low Priority Locations and will
each receive (2) geoprobe borings. Soil core samples will be collected from each
geoprobe location to ensure a minimum core recovery of 95%, or as otherwise
approved in advance by the Co-Executive Secretary. The location of these
borings will be based on best professional judgement, considering the most likely
water / waste / wastewater discharge direction.
For all of these Phase IB locations, three (3) core samples from each boring will
be collected from the bottom 1-foot of each of the following intervals: first 1/3,
second 1/3, and third 1/3 ,based on the total deptii of penetration at each site. At a
minimum, all 144 samples (from the 48 total Phase IB geoprobe borings) shall be
sent to the approved analytical laboratory for soil analysis. Each laboratory result
will be compared to the statistically derived "site background" concentration as
determined in the Phase 1 A, Part 1, Item 1 described above, to determine if the
source could have contributed significant nitrogen and/or chloride mass to cause,
in part or in whole, groundwater concentrations found in nearby DUSA wells.
The Co-Executive Secretary reserves the right to collect soil samples for
laboratory analysis, at DRC cost, from any 1-foot core interval, ofany boring.
Geoprobing in the area of active leach fields may be conducted in a separate
campaign, with a different field crew if determined necessary by DUSA in order
to address potential health and safety issues.
PHASE IC - Geoprobe Investigation of Other Potential Nitrate Sources:
1. At DUSA discretion, single geoprobe borings may be performed down to refiisal
at each of the Other Potential Nitrate Sources found in a DUSA Figure titied:
"Potential Geoprobe Boring Location - Supplemental Contaminant Investigation,"
submitted during the April 20, 2011 meeting, and at other locations that may be
determined by DUSA. Said figure showed seven (T) additional geoprobe
locations that DUSA wanted to investigate. At each geoprobe location, DUSA
may choose to collect three (3) discrete 1-foot core samples from the bottom 1-
foot of each of the following intervals: the first 1/3, second 1/3, and third 1/3
depth, based on the total depth of penetration at each site. DUSA may use the
Nitrate Field Test to determine whether or not nitrate concentrations are
detectable and whether or not a sample will be sent to the approved analytical
laboratory for analysis. For any boring where soil core samples will be sent for
laboratory analysis, DUSA will ensure a mimmum core recovery of 95%, or as
otherwise approved in advance by the Co-Executive Secretary. Any such soil
laboratory results may then be compared to the "site backgroimd" soil
concentrations as determined in the PHASE lA, Part 1, Item 1 described above.
Any interpretation of the influence or contribution of these "other" potential
nitrate sources to the nitrate groundwater contamination under investigation at the
White Mesa facility will be subject to DRC review and approval.