DRC-2012-001030 - 0901a068802a4b95

DENISO
MINES
DRC-2012-001030
January 20,2^
Denison Mines (USA) Corp.
105017th Street, Suite 950
Denver, CO 80265
USA
Tel: [phone]
Fax:[phone]
www.denisonmines.com
VIA E-MAIL AND FEDEX
Rusty Lundberg, Executive Secretary
Utah Radiation Control Board
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144810
Salt Lake City, UT 84114-4810
Re: Plan and Time Schedule under Utah Ground Water Discharge Permit UGW370004 Part
i.G.4(d)
Dear Mr. Lundberg:
Reference is made to the Plan and Time Schedule Under Part I.G.4(d) for Violations of Part I.G.2 for
Constituents in the First, Second, Third and Fourth Quarters of 2010 and First Quarter of 2011 dated
June 13, 2011 (the "Initial Plan and Schedule") and the Plan and Time Schedule Under Part I.G.4(d) for
Violations of Part I.G.2 for Constituents in the Second Quarter of 2011 dated September 7, 2011 {the
"Q2 2011 Plan and Schedule" and together with the Initial Plan and Schedule the "Plans and
Schedules"), relating to Denison Mines (USA) Corp's ("Denison's") White Mesa Mill (the "Mill" or "site").
During conference calls held on December 5 and December 19, 2011 Utah Division of Radiation
Control ("DRC") staff discussed the proposed Plan and Schedule with Denison personnel, and a
number of changes to the Plan and Schedule were discussed to address DRC's concerns.
This letter summarizes Denison's understanding of the changes to the Plan and Schedule and the
regulatory path forward, that were agreed upon in principal during those conference calls.
1. Assessments Outlined in the Plans and Schedules.
The assessments proposed by Denison and described in Section 4 of the Initial Plan and Schedule and
Section 4 of the Q2 2011 Plan and Schedule, will continue to be performed as proposed and in the
timeframes set out in those Plans and Schedules.
Those assessments are intended to determine if the exceedances in question are due to background
influences or Mill activities. If the exceedances are determined to be due to background influences
then, as contemplated by the Plan and Schedule, it will not be necessary to perform any further
evaluations on the extent and potential dispersion of the contamination or to perform an evaluation of
potential remedial actions, other than as set out in Sections 2, 3, 4 and 5 below. Monitoring will
continue, and if appropriate revised groundwater compliance limits ("GWCLs") will be proposed to
reflect changes in background conditions at the site.
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Letter to Mr. Rusty Lundberg
January 20, 2012
Page 2
2. Statistical Analysis of pH Trends.
As mentioned in Section 3.3 of the Initial Plan and Schedule, Denison noted that it has observed a
decreasing trend in pH in a number of monitoring wells across the Mill site, as initially identified by
Denison in Section 2.5.6 of the Revised Addendum; Background Groundwater Quality Report: New Wells
For Denison Mines (USA) Corp.'s White Mesa Mill Site, San Juan County, Utah, dated April 30, 2008,
prepared by INTERA Inc. (the "New Wells Background Report"), and as observed by Denison in
subsequent sampling results.
Denison will provide to DRC a statistical analysis of pH in all wells at the Mill site, which will confirm the
decreasing trends in pH at the site as a whole, and indicate which monitoring wells have significant
decreasing trends in pH. In performing this statistical analysis, Denison will follow the Groundwater Data
Preparation and Statistical Process Flow for Calculating Groundwater Protection Standards, White Mesa
Mill Site, San Juan County, Utah, included as Figure 17 in the New Wells Background Report. This report
will be submitted to the Executive Secretary within 90 days after execution and delivery of the Stipulated
Consent Agreement referred to in Section 6 below (the "Stipulated Consent Agreement").
3. Analysis of Pyrite at the Site.
Pyrite has been visually detected in drill cuttings from numerous borings installed in the perched water
zone at the site, and oxidation of pyrite has been postulated as one potential mechanism for the
decreasing pH measured in most of the perched wells.
The attached January 20, 2012 letter report, by Hydro Geo Chem, Inc. (the "Hydro Geo Chem Report")
describes Denison's proposed method for selecting samples of existing core and drill cuttings for
evaluation. The intent is to obtain a sufficient number of such core or drill cuttings samples to verify the
accuracy of the well logs, rather than to attempt to find a core or drill cutting sample for each monitoring
well in question.
Verification of the presence of pyrite will be accomplished using visual and analytical methods. Visual
verification will rely on examination of samples by an experienced geologist or mineralogist other than the
geologist(s) who originally logged the borings. Analytical verification will rely on laboratory analysis of
selected samples for pyrite or sulfides. The locations of borings from which samples are to be submitted
for either visual or laboratory identification of pyrite are provided in Figure 2 of the attached Hydro Geo
Chem Report. The sample set provides site-wide coverage.
A report will be prepared that summarizes the sample selection and submission process, the visual and
analytical methods employed, and the visual and analytical results. The report will include an
assessment of the results with regard to the potential for pyrite oxidation to affect pH at site perched
monitoring wells. This report will be submitted to the Executive Secretary within 120 days after execution
and delivery of the Stipulated Consent Agreement.
The approach proposed by Denison herein for the analysis of pyrite is subject to Executive Secretary
approval. Any required changes to the proposed approach will be agreed upon by the Executive
Secretary and Denison and incorporated into the Stipulated Consent Agreement.
4. Wildlife Ponds.
DRC and Denison acknowledge that recharging the existing wildlife ponds at the site may also be adding
oxygen to the groundwater, which, on the assumption that sufficient pyrite exists in the formation, nriay
also be leading to the decreasing trends in pH at the site, and to exceedances of certain metals in wells
possibly as a result of decreases in pH.
DENISO
MINES
Letter to Mr. Rusty Lundberg
January 20, 2012
Page 3
The Mill has therefore agreed to stop recharging both upper wildlife ponds immediately. No actions to
prevent natural accumulation of water will be taken. However, the ponds are not designed to gather
precipitation from the local drainages, so the net evaporation rate should ensure that the ponds do not
accumulate any significant precipitation. Recharge at the two upper wildlife ponds would not resume
without approval of the Executive Secretary.
The Mill will continue to recharge the lower wildlife pond ("Butch's Bayou").
DRC and Denison acknowledge that stopping the recharge of the two upper wildlife ponds is expected to
affect the perched water quality and water levels over time, which could result in the need to reset
GWCLs at the site.
5. Regulatory Actions
As a result of the foregoing assessments and actions:
a) a new core hole for the analysis of pyrite will not be required adjacent to each monitoring well in
question;
b) an isotopic analysis will not be required, unless the characterization activities described in Section 1
above indicate tailings cell leakage; and
c) Assuming that the characterization activities described in Section 1 above do not indicate tailings cell
leakage;
(i) DRC will not pursue any enforcement action or require any remedial activities associated with the
current dual exceedances or decreasing pH trends, other than as set out in the Plans and
Schedules and in this letter;
(ii) DRC will work with Denison to reset GWCLs to properly reflect the decreasing pH trends;
(iii) DRC will work with Denison to reset GWCLs to properly reflect increasing trends in constituents;
(iv) Denison will continue to monitor out-of-compliance constituents on an accelerated basis, until
such time as the respective GWCLs are reset; and
(v) DRC will work with Denison to reset GWCLs in the future to reflect any changes to groundwater
caused by stopping the recharge to groundwater from the two upper wildlife ponds.
6. Stipulated Consent Agreement.
DRC and Denison will enter into a Stipulated Consent Agreement to reflect the foregoing.
Please contact the undersigned if you have any questions or require any further information.
Yours very truly,
DENISON^INES^SA) CORP.
cc:
denlund
, Regulatory Affairs and Counsel
Ron F. Hochstein
Harold R. Roberts
Jo Ann S. Tischler
David E. Turk
Stewart J. Smith, Hydro Geo Chem, Inc.
Daniel W. Erskine, INTERA Inc.
DENISO
MINES
HYDRO GEO CHEM, INC.
Environmental Science & Technology
January 20, 2012
David Frydenlund, Esq.
Vice President, Regulatory Affairs, Counsel, and Corporate Secretary
Denison Mines (USA) Corporation
1050 17th Street, Suite 950
Denver, Colorado 80265
Re: Analysis of Pyrite in Existing Perched Zone Drill Cuttings Samples Stored at the White
Mesa Uranium Mill Near Blanding, Utah
Dear Mr. Frydenlund,
This letter provides a plan to verify the presence of and analyze for pyrite in existing perched zone
drill cuttings samples stored at the White Mesa Uranium Mill (the Mill or the site) near Blanding,
Utah. A decline in pH has been observed to be occurring in nearly all wells at the site, including
wells located upgradient, cross-gradient, and downgradient of the mill site and tailings cells. This
sitewide phenomenon may have any number of causes; however, the widespread nature of the
declining pH indicates that, whether recent or longer-term, it results from a natural phenomenon
unrelated to Mill operations. One of the potential causes (although not necessarily the only or
primary cause) is the oxidation of pyrite (or other sulfides) noted in borings across the entire site
including borings located upgradient, cross-gradient, and downgradient of the millsite and tailings
cells.
The purpose of this plan is to verify the presence of pyrite as one of the possible causes of the
decrease in pH. The data quality objectives are as follows.
1. To verify the existence of pyrite reported in existing boring logs from a sample of site
borings. The sample will include borings located across the entire site (upgradient, cross-
gradient, and downgradient of the millsite and tailings cells).
2. To verify the existence of pyrite in a sample of the MW-series wells which have exhibited
dual exceedances.
51 West Wetmore, Suite 101 Tucson, Arizona 85705-1678 520.293.1500 520.293.1550-Fax [phone]-Toll Free
David Frydenlund, Esq.
January 20, 2012
Page 2
The observation of pyrite at levels sufficient to be detected by the naked eye, in as many perched
zone boring locations throughout the site as have been documented in the existing boring logs, is
sufficient evidence to conclude that pyrite can be considered ubiquitous throughout the perched zone.
Verification of the pyrite noted in existing drill cuttings samples from a subset of borings installed
across the entire site is sufficient to demonstrate that pyrite is present site-wide and that oxidation of
pyrite (or other sulfides) is one plausible mechanism for the decreasing pH. Pyrite has been noted in
most borings at the site having detailed lithologic logs which includes borings installed across the
entire site. Although pyrite has not been noted in every boring at the site having a detailed lithologic
log it has been noted in sufficient borings for pyrite oxidation to be considered a plausible
mechanism for decreasing pH. The lack of visually detectable pyrite in the lithologic log of any
specific boring does not indicate pyrite is not present in or near that boring.
Background
The White Mesa site contains a total of 97 perched monitoring wells, temporary perched monitoring
wells, and piezometers (Figure 1) that are screened in a relatively shallow perched water zone hosted
primarily by the Burro Canyon Formation. Where saturated thicknesses are greater, the perched
water rises into the overlying Dakota Sandstone. The 29 MW-series perched monitoring wells are
located upgradient, cross-gradient, downgradient, and within the area of the tailings cells at the site
and are designed primarily for early detection of any potential seepage from the tailings cells. The
TW4-series monitoring wells are located upgradient and cross-gradient of the tailings cells; the
TWN-series wells are located primarily upgradient of the tailings cells; and the DR-series
piezometers (monitored only for depth to water) are located primarily downgradient of the tailings
cells.
The pH in most of the MW-series, TW4-series, and TWN-series wells has demonstrated a decreasing
trend over time. This trend is present in upgradient, cross-gradient, and downgradient wells in
addition to many of the wells located within the area of the tailings cells. It is not certain whether this
sitewide phenomenon is a recent or longer term phenomenon. The widespread distribution of wells
showing this trend, and the presence of the trend thousands of feet upgradient of Mill operations,
indicate that the trend is a natural phenomena unrelated to site operations, and affects either the
entire perched zone monitored by the wells or at least affects the perched zone in the immediate
vicinity of each impacted well. MW-series wells currently under accelerated monitoring for pH
include MW-3, MW-3A, MW-12, MW-14, MW-18, MW-19, MW-23, MW-24, MW-25, MW-26,
MW-27, MW-28, MW-29, MW-30, MW-31, and MW-32. As discussed below, logs detailed enough
to establish the presence of pyrite only exist for a portion of the MW-series wells.
Burro Canvon Formation and Overlving Materials
The Burro Canyon Formation is composed primarily of sandstone and conglomeratic sandstone, with
interbedded siltstone, claystone, and shale. The Burro Canyon is underlain by the Brushy Basin
Member of the Morrison Formation, a bentonitic shale that essentially forms the base of the perched
water zone. The permeability of the Burro Canyon is generally low, with a geometric average on the
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David Frydenlund, Esq.
January 20, 2012
Page 3
order of 10"^ centimeters per second (cm/s), but with a range of approximately 10'^ cm/s to 10'^ cm/s.
The Burro Canyon Formation and Dakota Sandstone are overlain either by aeolian sands or by
Mancos Shale with a thickness of as much as 20 to 30 feet in the area immediately upgradient
(northeast) and cross-gradient (east) of the tailings cells. Drilling reveals that the unsaturated zone
typically has low moisture, especially the unsaturated portions of the Dakota and Burro Canyon.
Lithologic logs reveal that iron oxides and pyrite are common within the Burro Canyon and
overlying Dakota. Many of the logs indicate the presence of carbonaceous fragments consistent with
reduced conditions and the presence of pyrite. The iron oxides present in many of the borings may
result from oxidization of pyrite or other sulfides.
Table 1 indicates the presence of visible pyrite, iron oxides, and carbonaceous material from borings
at the site for which detailed logs are available. Logs for many of the older wells at the site (MW-1
through MW-15) are not detailed enough to contain this information. Logs for wells MW-T 6 through
MW-22 are moderately detailed. Logs for wells MW-3 A, MW-23 through MW-37, temporary wells
(TW4-series and TWN-series wells), and piezometers (PIEZ-series and DR-series) contain the most
detail. Logs for temporary wells and piezometers are included because many of these wells are in the
vicinity of MW-series wells lacking detailed logs (for example, upgradient well MW-1) and they
demonstrate the site-wide occurrence of pyrite.
Potential Mechanisms for Decreasing pH
As discussed above, the decreasing pH is a site-wide trend and occurs in wells that are upgradient,
cross-gradient, and downgradient of the millsite and tailings cells. The occurrence ofthe trend over
the entire site indicates that the trend is not the result of site operations. Otherwise the decreases in
pH would occur primarily within the area of the millsite and tailings cells.
One potential mechanism for the decreasing pH measured in perched zone wells involves oxidation
of pyrite. Pyrite oxidizes in the presence of oxygen according to the following equation, producing
hydrogen ions and sulfate in the process:
2FeS2 + 702+2H20 = 2Fe^^ + 4S04^+4H^ (I)
This is the same mechanism that results in acidic drainage from mine tailings or waste rock piles
containing pyrite. Oxygen transported into the piles reacts with the pyrite (in the presence ofwater)
releasing acid and sulfate.
The widespread occurrence of visible pyrite in the Burro Canyon Formation (upgradient, cross-
gradient, and downgradient of the millsite and tailings cells) makes this mechanism plausible.
Sources of oxygen include 1) diffusion through the vadose zone aided by the generally dry condition
of the vadose zone and barometric pumping 2) transport of oxygen from the surface directly to the
formation via perched monitoring well casings, and 3) infiltration of water containing dissolved
oxygen. Significant sources of infiltrating water containing oxygen include the wildlife ponds.
Oxygen transport in the vicinity of perched wells will be enhanced by fluctuations in the perched
water table caused by routine purging and sampling, the recent redevelopment effort, and changes in
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David Frydenlund, Esq.
January 20, 2012
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pumping. Changes in purging and sampling methodology and frequency are also expected to impact
oxygen transport to perched water.
A low rate of pyrite oxidation is likely taking place over the entire site due to diffusion of oxygen
through the vadose zone and via oxygen dissolved in recharge. However, the rates are likely much
larger in the vicinity of the perched zone wells where the well casings are a direct conduit for oxygen
transport to the groundwater. With each well easing acting as a constant source of oxygen direcdy to
groundwater, gradually expanding volumes of the perched zone near each well are expected to be
impacted over time as oxygen spreads out, more pyrite is oxidized, and any neutralization capacity in
the formation is consumed.
Rationale
As discussed above, pyrite has been noted in most borings at the site having detailed lithologic logs.
Pyrite has been noted in borings located upgradient, downgradient, and cross-gradient ofthe millsite
and tailings cells. The site-wide occurrence of pyrite makes pyrite oxidation a potential mechanism
for the site-wide decreasing trend in pH. Although pyrite has been noted in most of the detailed
lithologic logs for the site, the DRC has requested verification of pyrite occurrence before
considering oxidation of pyrite as a potential mechanism for decreasing pH.
Drill cuttings and core samples from the installation of numerous perched monitoring wells and
borings have been collected, labeled as to the borehole name/number and depth interval, and stored
on-site. Pyrite present in these existing samples is expected to have undergone small to negligible
degradation since collection. Use of existing samples in the verification process is therefore
considered acceptable.
Pyrite has been detected visually in drill cuttings from the site since at least 1999. Visual detection of
pyrite in a particular sample suggests that the volumetric content of pyrite in the sample is at least
0.1 %. Notations in the logs indicate volumetric pyrite contents may be as high as a three percent in
some intervals. Visual re-examination by an experienced geologist or mineralogist of drill cuttings
samples previously identified as having pyrite is considered sufficient to verify the presence of
pyrite. As an additional measure, laboratory analysis of pyrite is also proposed as discussed below.
The presence of visually detectable pyrite in a sample would increase the sulfur and iron contents of
that sample and yield total iron and sulfur concentrations that are expected to be noticeably higher
than samples without visually detectable pyrite, assuming all other conditions equal. Analysis of total
iron and sulfur would likely identify samples with pyrite. However, gypsum has also been identified
in drill cuttings from the site and gypsum would contribute to the total sulfur analytical result.
Furthermore, high iron content could result from high concentrations of iron oxide minerals which
may or may not be indicative of oxidized pyrite. Therefore, analysis of samples for total iron and
sulfur would likely yield results that are ambiguous with respect to pyrite content.
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David Frydenlund, Esq.
January 20, 2012
Pages
Using a method specific to pyrite is expected to yield more conclusive results. Scanning electron
microscopy coupled with energy dispersive x-ray analysis is one method capable of detecting pyrite.
Other potential methodologies capable of detecting total sulfides will also be considered.
Plan to Verify Pyrite In Drill Cuttings
Verification of the presence of pyrite will be accomplished using visual and analytical methods.
Visual verification will rely on examination of samples by an experienced geologist or mineralogist
other than the geologist(s) who originally logged the borings. Analytical verification will rely on
laboratory analysis of selected samples for pyrite or sulfides. The locations of borings from which
samples are to be submitted for either visual or laboratory identification of pyrite are provided in
Figure 2. The sample set provides site-wide coverage.
Since 1999 drill cuttings samples were typically collected at 2 V2 foot depth intervals and stored in
zip-seal bags labeled with the boring identification (ID) and the depth interval. Smaller samples of
the drill cuttings were typically washed and stored in plastic cuttings boxes labeled with the borehole
ID and having each sample compartment labeled with the depth interval. When collected, core
samples were logged continuously except for intervals where core recovery was not possible. Core
was stored in cardboard core boxes labeled with the borehole ID and depth interval represented in
each box.
Visual verification will rely on examination of drill cuttings samples from selected depth intervals
where pyrite was noted in the drilling logs. Samples submitted for visual verification will consist of
zip sealed bags of cuttings from the desired borings and depth intervals, and plastic cuttings storage
boxes containing material from the desired borings and depth intervals. These samples will be
submitted to an experienced geologist or mineralogist for verification of 1) the presence of, 2)
estimated abundance of, and 3) the estimated grain sizes of pyrite (or other visible sulfides) in each
sample. Visual examination will include microscopic examination to ensure that any fine-grained
pyrite not visible to the naked eye will be detected. Samples to be submitted for visual verification
are provided in Table 2. Samples listed in Table 2 were collected from borings installed since 2002
that were upgradient, cross-gradient, and downgradient of the tailings cells (Figure 2). Borings listed
in Table 2 include TWN-19 (the most upgradient boring at the site) and DR-25 (the most
downgradient boring at the site) as well as all of the MW-series wells under accelerated monitoring
for declining pH for which lithologic logs indicate the presence of pyrite. Since the occurrence of
declining pH is site-wide and pyrite is ubiquitous, the presence or absence of pyrite in any particular
well is not conclusive.
Analytical verification will rely on laboratory analysis for pyrite via scanning electron microscopy
coupled with energy dispersive x-ray analysis or another method that is capable of quantifying
sulfides. Samples submitted for laboratory analysis will consist of zip sealed bags of cuttings from
the desired borings and depth intervals and subsamples of core from the desired borings and depth
intervals. Samples to be submitted for laboratory analysis are provided in Table 3.
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David Frydenlund, Esq.
January 20, 2012
Page 6
Cuttings samples submitted for either visual or laboratory analysis will consist of the entire bagged
cuttings sample. Subsamples from the existing bagged samples will not be submitted because ofthe
likelihood that subsamples may not be representative due to pyrite having settled out in the original
sample bags. If the original sample bag has deteriorated, the entire original bag will be placed inside
a new labeled bag and submitted for analysis. The laboratory will be instructed to return unused
sample material to the site within the original bags.
Core samples submitted for either visual or laboratory analysis will consist of subsamples ofthe core
from the desired depth interval and placed in labeled zip-sealed bags. The laboratory will be
instructed to retum unused sample material to the site within the original bags.
Reporting
A report will be prepared that summarizes the sample selection and submission process, the visual
and analytical methods employed, and the visual and analytical results. The report will include an
assessment of the results with regard to the potential for pyrite oxidation to affect pH at site perched
monitoring wells.
Please feel free to contact me if you have any questions.
Sincerely,
>tewart J. Smith
Vice President
Attachments: Tables 1-3
Figures 1-2
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ATTACHMENTS
TABLES
1 Tabulation of Presence of Pyrite, Iron Oxide, and Carbonaceous Fragments in Drill Logs
2 Samples to be Submitted for Visual Examination of Pyrite
3 Samples to be Submitted for Laboratory Analysis of Pyrite
FIGURES
1 White Mesa Site Plan Showing Locations of Perched Wells, Piezometers, and Borings
2 White Mesa Site Plan Showing Locations of Samples to be Verified for Pyrite
TABLE 1
Tabulation of Presence of
Pyrite, Iron Oxide, and Carbonaceous Fragments In Drill Logs
Well Pyrite C Fragments Iron Oxide
MW-3A X
MW-16 X
MW-17 X
MW-18 X
MW-19 X
MW-20 X
MW-21 X X
MW-22 X
MW-23 X
MW-24 X
MW-25 X X
MW-26 X X
MW^27 X X
MW-28 X
MW-29 X
MW-30 X X
MW-31 X X
MW-32 X X
MW-33 X
MW-34 X X X
MW-35 X X X
MW-36 X X
MW-37 X X
Piez-2 X
Piez-4 X X
Piez-5 X X
DR-2 X X
DR-5 X X
DR-6 X X
DR-7 X
DR-8 X
DR-9 X X
DR-10 X
DR-11 X X
DR-12 X X
DR-13 X
DR-14 X X
DR-15 X X
DR-16 X X
DR-17
DR-18 X X
DR-19 X
DR-20 X X
DR-21 X
DR-22
DR-23 X X
DR-24 X X
DR-25 X X
TW4-1 X
TW4-2 X X
TW4-3 X X X
TW4-4
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PyriteTable.xls: Table 1 Page 1 of 2 1/20/2012
TABLE 1
Tabulation of Presence of
Pyrite, Iron Oxide, and Carbonaceous Fragments in Drill Logs
Well Pyrite 0 Fragments Iron Oxide
TW4-5 X X
TW4-6 X X X
TW4-7 X X X
TW4-8 X
TW4-9 X X X
TW4-10 X X
TW4-11 X
TW4-12 X X X
TW4-13 X X X
TW4-14 X
TW4-15 X X
TW4-16 X X
TW4-17 X X
TW4-18 X X
TW4-19 X
TW4-20 X
TW4-21 X X
TW4-22 X
TW4-23 X X X
TW4-24 X
TW4-25 X X
TW4-26 X
TWN-1 X
TWN-2 X X
TWN-3 X X
TWN-4 X
TWN-5 X X
TWN-6 X X
TWN-7 X
TWN-8 X X
TWN-9 X
TWN-10 X
TWN-11 X X
TWN-12 X X
TWN-13 X X
TWN-14 X X
TWN-15 X X
TWN-16 X X
TWN-17 X
TWN-18 X X
TWN-19 X X
Note:
C Fragments = particles of carbonaceous material (plant remains, etc)
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PyriteTable.xls: Table 1 Page 2 of 2 1/20/2012
TABLE 2
Samples to be Submitted for Visual Examination of Pyrite
Well Pyrite Noted Cuttings Core Depth Interval
MW-25 X X 65 - 67.5
MW-26 (TW4-15) X X 90 - 92.5
MW-26 (TW4-15) X X 97.5-100
MW-27 X X 80 - 82.5
MW-30 X X 65 - 67.5
MW-31 X X 95 - 97.5
MW-32(TW4-17) X X 105- 107.5
MW-34 X X 67.5 - 70
MW-37 X X 110-112.5
TW4-22 X X 102.5 - 105
TWN-5 X X 110-112.5
TWN-5 X X 142.5-145
TWN-8 X X 85 - 87.5
TWN-8 X X 117.5-120
TWN-16 X X 87.5 - 90
TWN-19 X X 80 - 82.5
TWN-19 X X 90 - 92.5
DR-9 X X 105- 107.5
DR-12 X X 85 - 87.5
DR-16 X X 97.5-100
DR-25 X X 75-77.5
H:\718000\pHdecrease\PyriteTable.xls: Table 2 1/20/2012
TABLE 3
Samples to be Submitted for Laboratory Analysis of Pyrite
Well Pyrite Noted Cuttings Core Depth Interval
MW-26 (TW4-15) X X 92.5 - 95
MW-26 {TW4-15) X X 95 - 97.5
MW-32 (TW4-17) X X 102.5-105
MW-36 X X 112.5 -115
MW-37 X X 112.5-115
TW4-22 X X X 90 - 92.5
TWN-5 X X 112.5-115
TWN-8 X X 87.5-90
TWN-19 X X 82.5 -85
DR-9 X X 102.5-105
DR-12 X X 87.5-90
DR-14 X X 45 - 47.5
H :\718000\pHdecrease\PyriteTable.xls: Table 3 1/20/2012
MW-5
PlEZ-1
9
DR-5
EXPLANATION
location of sample to be
verified for pyrite
perched monitoring well
perched piezometer
perched piezometer installed
May/June, 2011
X abandoned perched well or boring
HYDRO
GEO
CHEM, INC.
WHITE MESA SITE PLAN
SHOWING LOCATIONS OF SAMPLES TO BE
VERIFED FOR PYRITE
DATE REFERENCE
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