DRC-2010-001041 - 0901a0688015a929

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State of Utah
GARY R. HERBERT
Governor
GREG BELL
Lieutenant Governor
t)tL-.;ioit"AiD^ll
Department of
Environmental Quality
Amanda .Smith
Executive Director
DIVISION OF RADIATION CONTROL
Dane L. Finerfrock
Direcloi
MEMORANDUM
TO: Loren Morton, Section Manager
FROM: Dean Henderson, Hydrogeologist
DATE: January 4, 2009
SUBJECT: Drilling Activifies
Nitrate Contamination Investigafion
White Mesa Uranium Mill near Blanding. Utah
Denison Mines (USA) Corp.
On September 29, 2009 Division of Radiation Control (hereafter "DRC") staff Dean Henderson
observed the drilling for borings TWN-12 and TWN-I3 (see boring locafions in Attachment 1) as
part of nitrate contaminafion investigafion at the White Mesa Uranium Mill near Blanding Utah.
Observafions are described below.
FIELD OBSERVATIONS
Site Personnel
The Drilling Company was Bayles Exploration. The drilling crew was Randy Bayles and Hansen
Perkins. The method to drill the borings was accomplished with the use of an air rotary drilling
rig using try cone drill bits. The borings were logged by Mr. Larry Casebolt. Ryan Palmer
represented Denison Mines (USA) Corp. (hereafter "DUSA") in the field and performed the
nitrate testing on the groundwater.
Drilling Activities
The soil overburden at the ground surface above bedrock in these two boring ranged from 5 to 7
feet. The first 10 feet of each boring was drilled with the use of a 12 VA inch OD tri-cone bit.
There after this bit was removed from the boring and a 10 foot secfion of 8" OD schedule 80 PVC
pipe casing was inserted in to the boring. This PVC casing would prevent the soil overburden
from falling or washing down the boring. After the casing was installed the 12 Vi inch OD tri-
cone bit was replaced with a 5 inch OD tri-cone bit and drilling continued until the final boring
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depth was achieved. To aid in the boring cuttings to be air lifted out of the boring, the drillers
would introduce water into the boring. The water was from Recapture Reservoir. DUSA
representative Ryan Palmer stated that the water had been recently tested for nitrate
concentrafions and the results were below 10 mg/L.
Bore Hole Logging
The boring was logged by observing the boring cuttings. Beginning at the ground surface a
sample of the cuttings were taken on 2.5 foot depth intervals and were placed in piles on the
ground (see photograph in Figure 1). From each pile Mr. Casebolt would grab a portion of the
cutfings and wash and placed place them in plastic bags and in a plasfic container (see photograph
in Figure 2) thereafter recording his findings.
Nitrate Testing
Litmus paper with a color code for nitrate concentrations at 0, 10, 25, 50 mg/L was used to test the
groundwater for approximate nitrate concentrafions. If color on the litmus paper showed a nitrate
concentrafion in the groundwater greater than 10 mg/L the boring may be completed as a
monitoring well.
Boring NTW-12 Details
There was approximately 5 to 6 feet of soil overburden before the bedrock of the Dakota
Formation was encountered. To aid in the air lifting of the boring cutfings, at 50 feet the drillers
introduced water into the boring. As stated above the water was from Recapture Reservoir.
DUSA tested this water for nitrate concentrafions and the results were below 10 mg/L. At 60 the
drilling crew indicated that formation water may have been encountered. At 80 feet Mr. Casebolt
deteiTnine that the Burrow Canyon Formation may have been encountered. At 140 feet Mr.
Casebolt determined that the Brushy Basin Member of the Morrison Formafion (hereafter "Brushy
Basin") had been encountered (see photograph in Figure 2). The final boring depth was based on
the depth of the Burrow Canyon Brushy Basin contact. The final boring depth for TWN-12 was
147.5 feet. With the drilling pipe near the bottom of the boring air pressure was applied though
the bottom of the drilling pipe to left the cuttings and formafion water out of the boring. This
process also allowed the driller to esfimate that this boring was producing approximately 10 to 15
gallons of water per minute.
Litmus paper used to test nitrate concentrations in the water was color coded for nitrate
concentrafions at 0, 10, 25, 50 mg/L. After the driller had determined that formation water was
being air lifted out of the boring Ryan Palmer exposed the litmus paper to the water. The litmus
paper indicated nitrate concentration very close to 10 mg/L. DUSA felt that they needed a more
accurate nitrate concentration result. Therefore, it was decided to wait and re-test the water the
next day with litmus paper that had tighter nitrate concentrafions (example: 2, 4, 6, 8, 10, 12 etc.
mg/L) before deciding to complete this boring as a well.
Boring TWN-13
There was approximately 5 to 7 feet of soil overburden before the bedrock of the Dakota
Formafion was encountered. To aid in the air lifting of the boring cuttings, at 40 feet the drillers
introduced water into the boring. As with TWM-12. the water was from Recapture Reservoir. At
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50 the drilling crew indicated that formafion water may have been encountered. At 55 feet Mr.
Casebolt determined that the Burrow Canyon Formafion may have been encountered. At 107 feet
Mr. Casebolt determined that the Brushy Basin had been encountered. The final boring depth for
TWN-13 was 110 feet. With the drilling pipe near the bottom of the boring air pressure was
applied though the bottom of the drilling pipe to left the cuttings and water out of the boring. This
process also allowed the driller to esfimate that this boring was producing approximately 7 to 10
gallons of water per minute.
As with water from boring TWN-12, litmus paper used to test nitrate concentrafions in the water.
After the driller had determined that formafion water was being air lifted out of the boring Ryan
Palmer exposed the litmus paper to the water. As with TWN-12, the litmus paper indicated nitrate
concentration very close to 10 mg/L. Again, DUSA felt that they needed a more accurate nitrate
concentrafion result. Therefore, it was decided to wait and re-test the water the next day with
litmus paper that had fighter nitrate concentrafions (example: 2, 4, 6, 8, 10, 12 etc. mg/L) before
deciding to complete this boring as a well.
DRC COMMENTS
Mr. Casebolt provided adequate skills in logging borings TWN-12 and TWN-13. The use of
litmus paper to determine approximate nitrate concentrations in the groundwater to help determine
monitor well placement was reasonable. The air rotary drilling method using tri-cone drilling bits
to the drill borings was adequate.
Figures 1 though 4
Figure 1. Photograph showing boring profile of drill cuttings for TWN-12. Each pile of cuttings
represents approximately 2.5 foot boring depth interval.
Approximate contact between the
Burrow Canyon Formation and the
Brushy Basin Member of the Morrison
Formation.
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Figure 2. Photograph of washed boring cuttings from TWN-12. Above, the contact between the
Burrow Canyon Formation (light green) and the Brushy Basin Member ofthe Morrison Formation
(reddish brown) is identified at approximately 140 feet.
Figure 3. Photograph of saturated boring cuttings at TWN-13.
Figure 4. Photograph ofthe drill rig set up at the location of boring TWN-13.
Attachment 1
Boring Location Map
'(10/1/2009) bean Henderson-2b090910NewWellLocMap3.pdf Page 1
900 450 0 900
i Feet
#
#
4-
Existing TWN Weils
New Wel Ijjcation
Perched Monitoring Well
Peiched Monitoring Well
Installed April 2005
Perched Piezometer
Lei3,e,o,d
Q Well Installed 12-08
O Temporary Perched Monitoring Well
. Temporary Perched Monitoring *" Well Installed Apri! 2005
A Temporary Perched Monitoring ^ Well Installed May 2007
Source(s): Aerial lUtah GIS Portalwebsite;
Wells tWGC, Inc.,May 2008report.
Figure #
Title
Title
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