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3.6.3.2 LCI Wells 

There are seven existing or planned water supply wells and numerous monitor 

wells permitted and bonded by WSEO and WDEQ, respectively, to LCI and its 

affiliates. The existing and planned water supply wells and their completion 

horizons include: 

x In the FG horizon, well LC1W would be used for dust suppression and 

drill water. An additional potable water well (not yet named) is planned 

for the FG also. 

x Well LC28M is completed in the middle HJ horizon and would be used 

for drill water and dust suppression. The M horizon has three drill water 

and dust suppression wells completed in it; they are LC32W, LC229W 

and LC606W. 

x The final on-site well for drill water and dust suppression is LC33W, 

which is completed in the N horizon. 

The existing monitor wells include 27 wells that were used to establish baseline 

conditions in the Permit Area and 63 wells that were used for aquifer testing and 

water quality sampling for MU1. All of these wells are completed in the DE, FG, 

HJ, and KM Horizons. 

Five deep UIC Class I wells are planned for injection of waste water from the 

Plant (Section 2.1.4), and one of the five was installed in the southwest portion of 

the Permit Area to obtain subsurface information to ensure the feasibility of this 

disposal option. The well was completed in the Fort Union Formation. 

3.6.4 Groundwater Quality 

This section summarizes the regional and Permit Area groundwater quality. The 

groundwater quality in the Permit Area is separated on the basis of: site-wide 

characteristics of the ore-bearing and associated aquifers; characteristics within 

MU1 in the ore-bearing and associated aquifers; and characteristics of the deeper 

formations evaluated for the UIC Class I wells. 

3.6.4.1 Regional Groundwater Quality 

Water quality within the Basin ranges from very poor to excellent. Groundwater 

in the near surface, more permeable aquifers is generally of better quality than 

groundwater in deeper and less permeable aquifers. Groundwater with TDS less 

than 3,000 mg/L can generally be found at depths less than 1,500 feet within the 

Tertiary aquifer system, which includes the Battle Spring/Wasatch, Fort Union 

and Lance aquifers (Collentine et al., 1981). 

Water quality within the shallow Tertiary aquifers generally represents sodiumbicarbonate to sodium-sulfate water types. TDS levels within the Wasatch aquifer 

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in the west and south parts of the Basin tend to be high relative to the EPA’s 

Secondary Drinking Water Standard (SDWS) of 500 mg/L, even at shallower 

depth. TDS levels within the Battle Spring/Wasatch aquifers are generally below 

500 mg/L along the northern flank of the Basin (which includes the Permit Area). 

Elevated TDS levels (greater than 3,000 mg/L) are present within the Wasatch 

aquifer along the eastern edge of the Washakie Basin and within the Fort Union 

and Lance aquifers along the east side of the Rock Springs uplift. Elsewhere 

within the Great Divide and Washakie Basins, TDS levels in the Tertiary aquifer 

system are typically between 1,000 and 3,000 mg/L (Collentine et al., 1981). 

Low-TDS waters within the Battle Spring aquifer are predominately sodiumbicarbonate type waters. With increasing salinity, the water type tends to become 

more calcium-sulfate dominated. However, this trend is not exhibited in the 

Wasatch, Fort Union and Lance aquifers within the Great Divide and Washakie 

Basins. The Wasatch and Lance aquifers are characterized by predominately 

sodium-sulfate type waters, particularly near outcrop areas. The Fort Union is 

more variable in composition. 

Water quality within the Battle Spring aquifer is generally good in the northeast 

portion of the Basin, with TDS levels usually less than 1,000 mg/L and frequently 

less than 200 mg/L. The water type of the Battle Spring aquifer is typically 

sodium-bicarbonate to sodium-sulfate. Mason and Miller (2005) reviewed 

eighteen groundwater samples collected from the Battle Spring aquifer and 

observed that those samples represented some of the best overall quality of those 

studied in Sweetwater County. Sulfate levels can be elevated in Tertiary aquifers, 

but are generally low in the shallow aquifers of the Battle Spring Formation. Out 

of 18 samples included in the Mason and Miller (2005) study, only one sample 

exceeded the WDEQ Class I Drinking Water Standard for sulfate of 250 mg/L. 

Most of the samples were also below the WDEQ TDS Class I Drinking Water 

Standard of 500 mg/L. Nitrate, fluoride and arsenic levels were below WDEQ 

and EPA standards for all of the samples. 

Notable exceptions to the relatively good water quality included waters with 

elevated radionuclides. Uranium and radium-226 (Ra-226) concentrations 

exceeded their respective EPA Maximum Contaminant Levels (MCLs) of 0.03 

mg/L and 5 pCi/L in some samples; radon-222 (Rn-222) concentrations were also 

relatively high in some samples (Mason and Miller, 2005). The presence of high 

levels of uranium in Tertiary sediments and groundwater of the Basin has been 

well documented. The Lost Creek Shroeckingerite deposit located northwest of 

the Permit Area is noted for high uranium levels in groundwater. Uraniumbearing coals are also present in the Basin. Sediments of the Battle Spring 

Formation were derived from the Granite Mountains and contain from 0.0005 to 

0.001 percent uranium (Masursky, 1962). Based on historical exploration results, 

certain areas of the Battle Spring Formation (e.g., Lost Creek) contain much 

higher uranium concentrations. The BLM Battle Spring Draw Well No. 4551 is 

an example of the higher radium and uranium concentrations (Table 3.6-7).

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3.6.4.2 Site Groundwater Quality, Ore-Bearing and Associated 

Aquifers 

Information on the Permit Area groundwater quality is primarily derived from 

reconnaissance studies conducted by Conoco (Hydro-Search, Inc., 1982) and 

more detailed studies by LCI. The historical well locations were generally closer 

to the ore trend (Figure 3.6-4), while the wells installed by LCI include locations 

close to and well away from the ore trend. 

Historical Data 

Conoco installed 12 wells, separated into four groups, to evaluate aquifer 

properties and water quality of the uranium ore-bearing sands and overlying and 

underlying aquifers within the Permit Area. Three of the groups included wells 

completed within the HJ Horizon aquifer and the overlying (LFG) and underlying 

(UKM) aquifers. The fourth group included three wells completed within the HJ 

Horizon aquifer. The location of the wells is shown on Figure 3.6-4. These 12 

wells were installed as part of a joint venture between Conoco and Texasgulf Inc. 

The twelve wells were abandoned as documented in a September 16, 1987 letter 

from Texasgulf Inc. to WSEO.

Ten of the 12 monitor wells installed by Conoco were sampled in August 1982. 

Hydro-Search, Inc. reported that there were no major differences in water quality 

between the HJ Horizon aquifer and the overlying and underlying aquifers (1982). 

The predominant ions were calcium and sulfate. TDS values were all below the 

WDEQ Class I Standard of 500 mg/L, ranging from 200 to 490 mg/L. The pH of 

the waters ranged from 7.1 to 8.5, indicating slightly alkaline conditions. 

Chloride levels were very low, ranging from seven to 18 mg/L. 

Most trace constituents were below the detection limits. Selenium was present in 

two samples at 0.023 mg/L, which was above the WDEQ and EPA drinking water 

standards at that time (0.01 mg/L). The WDEQ Class I Standard and the EPA 

MCL are currently 0.05 mg/L. Ra-226 was detected in all of the samples, with a 

range of 2.5 to 300 pCi/L. Only two samples, one collected from the overlying 

aquifer and one from the underlying aquifer, were below the WDEQ Class I 

Standard and EPA MCL of 5.0 pCi/L for Ra-226 (Figure 3.6-19). Uranium 

levels ranged from below detection (less than 0.005 mg/L) to 0.48 mg/L. Six of 

the ten samples exceeded the current EPA MCL for uranium of 0.03 mg/L 

(Figure 3.6-20).

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Current Data 

LCI has conducted baseline sampling since September 2006. Per WDEQ-LQD 

requirements, at least four quarters of baseline data are required to determine 

variability and if there are any trends in the variability fluctuations (e.g., seasonal 

changes). The baseline sampling locations, which cover all portions of the Permit 

Area and are completed in different Sands, are shown in Figure 3.6-4, and the 

sampling results are summarized in Table 3.6-8. The raw laboratory data are

presented in Attachment D6-4 of Appendix D6, of the WDEQ-LQD Permit to 

Mine (LCI, 2011b).

In Table 3.6-8, those analytical results which exceed specific WDEQ or EPA 

criteria are highlighted, and the WDEQ and EPA criteria used for the comparison 

are included in Table 3.6-9. The table shows that the WDEQ TDS Class I 

standard is exceeded at one well in each of the DE, HJ and UKM aquifers, Wells 

LC31M, LC26M, and LC23M, respectively. Twenty-two out of the 25 wells have 

TDS levels below the Class I Standard. Sulfate exceeds the WDEQ Class I 

Standard (250 mg/L) in one DE monitor well (LC31M) and one HJ monitor well 

(LC26M). As with the Conoco monitoring results, chloride values are low with 

all but five samples at 10 mg/L or lower. 

Piper diagrams have been developed to compare groundwater quality between 

individual wells (Figure 3.6-21) and between different aquifers (Figure 3.6-22). 

The individual well comparison plots the average value for each of the wells for 

all of the samples analyzed. The Piper diagram comparing different aquifers 

represents the average water quality for all wells sampled within individual 

aquifers (DE, LFG, HJ and UKM). Groundwater within the shallow Battle 

Springs aquifers beneath the Permit Area is a calcium sulfate to calcium 

bicarbonate type water. There is some variability in water chemistry when the 

wells are compared individually. 

With the exception of four UKM monitor wells (LC17M, LC23M, LC27M, and 

LC28M), one LFG monitor well (MB-5), and one HJ monitor well (MB-6), every 

well exceeded the EPA uranium MCL of 0.03 mg/L in at least one quarter. 

Similarly, with the exception of one DE monitor well (MB-1), one LFG monitor 

well (MB-2), one HJ monitor well (MB-3B), and one UKM monitor well (MB-4), 

every well exceeded the WDEQ Class I Standard and EPA MCL for radium226+228 of 5.0 pCi/L. The distributions of radium and uranium in the DE, FG, 

HJ, and UKM Horizons are shown on Figures 3.6-23 and 3.6-24.

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Table 3.6-9 State and Federal Groundwater Quality Criteria for

Specified Parameters

Parameter 

WQD Class-of-Use Criteria EPA Drinking Water Criteria 

Domestic 

(Class I) 

Agriculture 

(Class II) 

Livestock 

(Class 

III)

MCL 

Treatment 

Action 

Level 

Secondary 

Standard 

Aluminum -- 5.0 5.0 -- -- 0.05 to 0.2 

Ammonia 0.5 -- -- -- -- --

Arsenic 0.05 0.1 0.2 0.010 -- --

Barium 2.0 -- -- 2.0 -- --

Boron 0.75 0.75 5.0 -- -- --

Cadmium 0.005 0.01 0.05 0.005 -- --

Chloride 250.0 100.0 2000.0 -- -- 250.0

Chromium 0.1 0.1 0.05 0.005 -- --

Copper 1.0 0.2 0.5 -- 1.0 --

Fluoride 4.0 -- -- 4.0 -- 2.0

Gross Alpha 

(pCi/L, 

including Ra226, excluding 

Radon and 

Uranium) 

15.0 15.0 15.0 15.0 -- --

Lead 0.015 5.0 0.1 -- 0.015 --

Manganese 0.05 0.2 -- 0.05 -- --

Mercury 0.002 -- 0.00005 0.002 -- --

Nickel -- 0.2 -- -- -- --

Nitrate 10.0 -- -- 10.0 -- --

pH (SU) 6.5 - 8.5 4.5 - 9.0 6.5 - 8.5 -- -- 6.5 - 8.5

Ra-226+Ra228 (pCi/L) 5.0 5.0 5.0 5.0 -- --

Selenium 0.05 0.02 0.05 0.05 -- --

Sulfate 250.0 200.0 3000.0 -- -- 250.0

TDS 500.0 2000.0 5000.0 -- -- 500.0

Uranium -- -- -- 0.03 -- --

Vanadium -- 0.1 0.1 -- -- --

Zinc 5.0 2.0 25.0 -- -- 5.0

All concentrations are in mg/L unless otherwise noted. Dashes indicate no criteria have been established. 

WQD Class-of-Use criteria are from Table I in Chapter 8 (Quality Standards for Wyoming Groundwater) of 

the WQD Rules and Regulations, available at http://deq.state.wy.us/wqd/WQDrules/Chapter_08.pdf, 

accessed on November 3, 2008. 

EPA Drinking Water Criteria are from http://www.epa.gov/safewater/consumer/pdf/mcl.pdf, accessed on 

November 3, 2008. 

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A summary of the water quality for each of the four hydrostratigraphic units of 

interest (DE, LFG, HJ and UKM) is presented below. All metal concentrations 

are reported as dissolved. 

DE Sand 

Six wells completed in the DE Sand were included in the baseline sampling 

program (LC29M, LC30M, LC31M, MB-1, MB-7, and MB-10). Both MB-7 and 

MB-10 had insufficient water to sample and therefore were not included in the 

analyses. Sample results from the existing baseline monitor wells are included in 

Table 3.6-9.

Results of the baseline sampling indicate that three of the DE monitor wells 

(LC29M, LC30M, and MB-1) are calcium bicarbonate water, whereas well 

LC31M is a calcium sulfate type. Both sulfate and TDS levels in LC31M exceed 

the WDEQ Class I Standards (250 mg/L and 500 mg/L, respectively). Chloride 

levels in all four wells are low (12 mg/L or less). 

Manganese exceeded the WDEQ Class I Standard (0.05 mg/L) in seven of the 16 

samples collected from DE monitor wells. The average detectable manganese 

value was 0.10 mg/L for the DE monitor wells. The average selenium 

concentration at well LC31M was 0.172 mg/L, exceeding the WDEQ Class I 

Standard of 0.05 mg/L. 

Iron exceeded the WDEQ Class I Standard (0.3 mg/L) in two of the four samples 

from LC29M and one of the four samples from MB-1. The average values for the 

four samples from LC29M and MB-1 were below the standard. Similarly, the 

average ammonia concentration was below the WDEQ Class I Standard (0.5 

mg/L) at well LC29M, although two of the four samples exceeded the standard. 

Uranium levels exceeded the EPA MCL in every sample collected from the DE 

monitor wells except one MB-1 sample collected in August 2009. The average 

uranium concentration for the 16 samples collected was 0.577 mg/L. Ra-226 

exceeded the EPA Radium 226+228 MCL of 5.0 pCi/L in two samples. 

Combined radium 226+228 exceeded the standard in four of the samples. 

However, the average radium 226+228 activity for each of the DE monitor wells 

was below the WDEQ Class I Standard. 

LFG Sand 

Seven wells completed in the LFG Sand were included in the baseline sampling 

program (LC15M, LC18M, LC21M, LC25M, MB-2, MB-5, and MB-8). Sample 

results from the existing baseline monitor wells are included in Table 3.6-9.

Results of the baseline sampling indicate that the LFG monitor wells are calciumbicarbonate to calcium-sulfate water. TDS and sulfate levels are below the 

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WDEQ Class I Standards (500 mg/L and 250 mg/L, respectively) and chloride 

levels in all seven wells are low (10 mg/L or less). 

Manganese and selenium were below the respective WDEQ Class I Standards in 

all the LFG samples. Iron exceeded the WDEQ Class I Standard in three out of 

four samples at LC18M, one out of four samples at LC25M, and in one sample at 

MB-8 for total iron. 

Uranium levels exceeded the EPA MCL in every sample collected from the LFG 

monitor wells except for samples taken at MB-5. The average uranium 

concentration for the LFG samples was 0.289 mg/L. Radium levels were widely 

distributed. At least one sample from all LFG wells exceeded the WDEQ Class I 

Standard for radium 226+228 except for MB-2. 

HJ Horizon 

Seven wells completed in the HJ Horizon were included in the baseline sampling 

program (LC16M, LC19M, LC22M, LC26M, MB-3B, MB-6, and MB-9). 

Sample results from the existing baseline monitor wells are included in Table 

3.6-9.

Results of the baseline sampling indicate that the HJ monitor wells are calciumbicarbonate to calcium-sulfate water. Both sulfate and TDS levels in LC26M 

exceed the WDEQ Class I Standards (250 mg/L and 500 mg/L, respectively). 

Chloride levels in all four wells are low (11 mg/L or less). 

Manganese and selenium were below the respective WDEQ Class I Standards in 

all the HJ samples. 

Uranium levels exceeded the EPA MCL in every sample collected from the 

LC16M, LC19M, LC22M, LC26M, and MB-3B monitor wells. Only one sample 

from MB-9 and no samples from MB-6 exceeded the EPA MCL. The average 

uranium concentration for the HJ samples was 0.160 mg/L. 

UKM Sand 

Seven wells completed in the UKM Sand were included in the baseline sampling 

program (LC17M, LC20M, LC23M, LC24M, LC27M, LC28M, and MB-4). Two 

of the wells were originally thought to be completed in the HJ Horizon (LC27M 

and LC28M) but were later reinterpreted as UKM completions. Sample results 

from the existing baseline monitor wells are included in Table 3.6-9.

Results of the baseline sampling indicate that the UKM monitor wells are 

calcium-bicarbonate to calcium-sulfate water. TDS and sulfate levels are below 

the WDEQ Class I Standards (500 mg/L and 250 mg/L, respectively) in all but 

one sample and chloride levels in all seven wells are low (32 mg/L or less). 

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Manganese and selenium were below the respective WDEQ Class I Standards in 

all the UKM samples. 

Uranium levels exceeded the EPA MCL in some samples collected at LC20M, 

LC24M, and MB-4. LC17M, LC23M, LC27M, and LC28M did not have any 

samples that exceeded the uranium EPA MCL. The average uranium 

concentration for the UKM samples was 0.028 mg/L. 

Average radium 226+228 levels exceeded the WDEQ Class I Standard in at least 

one sample for each of the UKM monitor wells except MB-4. 

3.6.4.3 MU1 Groundwater Quality, Ore-Bearing and Associated 

Aquifers 

LCI conducted pre-operational sampling in MU1 in 2009 and 2010. The monitor 

well locations include the monitor well ring and locations within the pattern area 

(Section 2.1.3.2). During Mine Unit Production, these wells are used to monitor 

for excursions, i.e., conditions that indicate the production and injection is out of 

balance, and during Mine Unit Restoration, these wells are used to monitor 

restoration success. The monitor ring wells are completed in the same sand as the 

ore zone, and the wells within the pattern area are completed in overlying and 

underlying aquifers. The locations of the monitor wells are shown on Figure 

3.6-5.

Per WDEQ-LQD requirements, at least four samples were collected, with at least 

two weeks between each sampling. The sampling results and associated 

calculation of Upper Control Limits are included in Attachments MU1 4-1 and 4-

2 of the WDEQ-LQD MU1 documents (LCI, 2011b), and the results are analyzed 

in detail in Section 4.2.2 of the WDEQ-LQD MU1 documents (LCI, 2011b).

None of the results indicate that conditions in MU1 are different than what would 

be anticipated from the site-wide baseline sampling. 

3.6.4.4 Site Groundwater Quality, Deeper Formations Evaluated 

for UIC Class I Wells 

Information on the water quality in the deeper formations that were evaluated for 

UIC Class I wells was obtained by a variety of methods, including sampling and 

evaluation of geophysical logs. In addition, the Wyoming Oil and Gas 

Conservation Commission website and USGS Produced Waters Database were 

reviewed for pertinent information. The results are summarized below and are 

described in more detail in the WDEQ-WQD application for the UIC Class I 

wells, which is included as Attachment ADJ-2 to the WDEQ-LQD Permit to 

Mine (LCI, 2011b).

In the target formation, the Fort Union Formation, samples were collected at 

multiple intervals in the test well, which is the deep well in the southwest corner 

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of the Permit Area (Figure 1.2-2). The samples were collected by cased-hole 

formation sampling at discrete intervals within the Fort Union Formation, and 

after casing perforation, samples of water produced from the well were collected, 

which are representative of the composite fluid from the perforated intervals. The 

sample results indicated an average TDS concentration just under 14,000 mg/L; 

concentrations of several inorganic parameters (mercury, manganese, barium, 

lead, arsenic, and iron) exceeded groundwater quality standards; and gross alpha 

and radium-226+228 concentrations exceeded groundwater quality standards. 

Volatile organic compounds were also detected, which was not unexpected as 

there is hydrocarbon production from this formation elsewhere in the Basin. 

Information from the databases was limited in the vicinity of the Permit Area. 

Most of the data were from distant parts of the Basin, e.g., from areas proximate 

to oil and gas production or from the Basin margins, representing a wide range of 

formation depths and hydrogeologic conditions. Therefore, the water quality in 

the deeper formations was estimated using data from geophysical logs from two 

wells within about four miles of the Permit Area. These estimates are included in 

Table 3.6-10.

Table 3.6-10 Summary of Stratigraphy and Water Quality 

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