2011-03-07_HYDROLOGY - M1977348

• Permit No: M1977348
• IBM Index Class Name: HYDROLOGY
• Doc Date: 3/7/2011
• Doc Name: Summary of the March 1, 2011 Conference Call
• From: Golder Associates
• To: DRMS
• Permit Index Doc Type: Hydrology Report
• Email Name: ECS
• Media Type: D
• Archive: No

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Golder
Associates
March 4, 2011
Mr Eric Scott
Colorado Division of Reclamation Mining and Safety
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
RECEIVED
AKAR 07 2011
. ?, Division of PAISMAW- A
7'? Mining dt Sef*
Project No.: 103-81640
RE: SUMMARY OF THE MARCH 1 2011 C NCE CALL IN REFERENCE TO THE
ARY 24, 2011 LETTER FROM DRMS FOR THE BOETTCHER LIMESTONE QUARRY,
LA PORTE, COLORADO
Dear Mr. Scott:
On March 1, 2011, Golder Associates, Inc (Golder) hosted a conference call with the Colorado
Division of Reclamation Mining and Safety (DRMS) and Holcim (US) Inc. (Holcim). The purpose of
the conference call was to discuss the DRMS letter to Holcim dated January 24, 2011, which
reviewed the results of the September 2010 groundwater monitoring event at the Boettcher
Limestone Quarry.
In the DRMS letter, additional groundwater sampling was requested for the site to confirm the
September 2010 results. The specific request was for monthly sampling of the four existing on-site
groundwater wells to determine aquifer conditions during the 2011 calendar year. Additionally, the
DRMS letter requested further characterization of the aquifer and current uses of groundwater in the
area. The focus of the March 1" conference call was to discuss the requested monthly sampling.
The three main discussion topics of the sampling included: 1) the sampling frequency; 2) the
constituent list; and 3) the sampling locations. A summary of each is presented below.
¦ Sampling Frequency: Holcim and Golder proposed to DRMS that the additional
sampling be conducted quarterly instead of monthly. This proposal was made because
Holcim and Golder believe monthly sampling would not yield samples that are
representative of groundwater conditions due to the low permeability of the geologic
materials in which the wells are completed, and because the monthly sampling frequency
would allow limited time to receive and review laboratory results before the start of the
next sampling event. The DRMS agreed with this proposal and approved the alternative
quarterly sampling frequency, with the condition that sampling may need to be conducted
for more than one year depending on the analytical results. With this approval, Holcim
and Golder propose that the first quarter monitoring event for 2011 be conducted in
March. The proposed monitoring schedule for 2011 and, if necessary, 2012 is presented
in Table 1.
¦ Constituent List: Holcim and Golder discussed with DRMS whether there was any value
in limiting the groundwater sampling constituent list to include only the constituents of
concern called out in the January 24, 2011 letter, with the possible addition of a few other
constituents from the Sampling and Analysis Plan (SAP) that DRMS may be concerned
about. DRMS did not approve this request, but stated that the quarterly sampling should
include the full constituent list from the SAP to provide a more comprehensive
understanding of the groundwater chemistry. However, DRMS indicated they would be
open to revisiting a limited constituent list in the future depending on the results of the
sampling conducted in 2011. The SAP constituent list is presented as Table 2.
!:\10\81640\0100\summarymarchl 2011confcall fnl-04mar11\summarymar1 2011confcall_fnl-04mar11.docx
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