2011-09-23_REVISION - M1977208

• Permit No: M1977208
• IBM Index Class Name: REVISION
• Doc Date: 9/23/2011
• Doc Name: Adequacy Review
• From: DRMS
• To: CEMEX, Inc.
• Type & Sequence: TR11
• Email Name: MAC
• Email Name: TAK
• Media Type: D
• Archive: No

pH
Chloride
Sulfate
Dissolved Solids
Selenium
Thallium
6.5 -8.5
250 mg /1
250 mg /1
400 mg/1 or 1.25
times the
background level
0.02 mg /1
0.002 mg /1
Letter to Ms. Arthur 2 September 23, 2011
TR -11 Adequacy Review File No. M- 1977 -208
Technical Revision — 01, approved on January 31, 2000, authorized the Operator to use C -Pit
as a CKD disposal site. Following the approval of TR -01, the Operator submitted the
analytical results from five quarters of baseline data. The Division reviewed the data and set
the numeric protection limits (NPL's) for the analyte suite. The NPL's were based on the
most restrictive water quality standards. The Division reviewed the permit file and found that
the analytical results of the groundwater sampling have been consistently compared to the
lower of either agriculture or drinking water standards. Under Technical Revision — 08,
approved on May 9, 2007, the Operator conducted an investigation to determine the source of
water entering C -Pit. Once it had been determined where the water was originating, the
Operator was to establish a sampling point up- gradient of C -Pit in order to determine
baseline conditions. The Operator reported under Technical Revision — 09, that the
groundwater elevation data collected in the C -Pit area were not adequate to construct a
surface contour map. As a result, a sampling point up- gradient of C -Pit was never
established. In absence of baseline data, the Division will continue to apply the lower of
either agriculture or drinking water standards to the CEM -005 compliance well. The
following table lists the numeric standards to be applied to CEM -005.
4. The Operator has requested the removal of streamers around the C -Pit. The Division
approved the removal of the net or "other surface water cover" and removal of the condition
of daily monitoring for wildlife under Technical Revision — 10. Therefore, the Operator may
remove any streamers around the C -Pit.
5. The Operator has proposed reducing the frequency of sampling from quarterly to semi-
annually for C -Pit and CEM -004 if the numeric standards have not been exceeded during the
first four quarters of sampling. The Division will allow sampling to be reduced to semi-
annually if the numeric standards have not been exceeded during the first four quarters of
sampling. However, if the numeric standards are exceeded during a semi - annual sampling
event, then the Operator will be required to resume quarterly sampling. Sampling will
continue on a quarterly basis until four quarters are shown to not exceed numeric standards,
at which time the Operator may resume semi - annual sampling.
6. The Operator has proposed eliminating monitoring location CEM -001 from the water
sampling program based on the low hydraulic conductivity in the bedrock surrounding the C-
Pit. The method by which the hydraulic conductivity was determined is a non - conventional
method; a slug test would need to be performed to verify the results of the Operator's
hydraulic conductivity test. The Division believes there is value to the continued sampling of
CEM -001, which is the only monitoring location between C -Pit and the compliance point.
The Operator has stated there is no value to continue sampling CEM -001 since the sampling
of C -Pit will provide information on how the water exposed to CKD is changing over time.
Sampling CEM -001 can provide information on how the chemical composition of the water