Laserfiche WebLink
VP ARCADIS <br /> ARCADIS <br /> 1687 Cole Blvd. <br /> Suite 200 <br /> Lakewood <br /> Colorado 80401 <br /> Mr. Timothy A. Cazier, P.E. Tel303,231.9115 <br /> Environmental Protection Specialist Fax 303.231.9571 <br /> Colorado Division of Mining Reclamation and Safety www.arcadis-us.com <br /> Department of Natural Resources <br /> 1313 Sherman Street, Room 215 <br /> Denver, Colorado 80203 <br /> Environment <br /> Subject: <br /> Holcim (US)Inc. Portland, Colorado <br /> Proposal to Remove Sodium as a Groundwater Quality Parameter <br /> DRMS Permit No. M-1977-344,Technical Revision No. 6 Date: <br /> August 4, 2014 <br /> Dear Mr. Cazier: <br /> Contact: <br /> ARCADIS has prepared this letter on behalf of Holcim (US) Inc. (Holcim) to propose Chris Peters <br /> that sodium be removed as groundwater quality indicator parameter for the <br /> groundwater monitoring program from the above referenced Phone: <br /> 9 9 P 9 permit. We have <br /> provided Site and literature data to show that sodium concentrations are not a useful 517.324.5052 <br /> indicator of groundwater impacts from leaching of cement kiln dust(CKD),which has Email: <br /> been disposed at the Holcim Portland Quarry landfill (Figure 1)throughout the life of chris.peters@arcadis- <br /> the permit. us.com <br /> The requirement for using sodium as an indicator parameter in groundwater oeref <br /> monitoring is based on Division of Mining Reclamation and Safety (DRMS) letters B0025510 <br /> from February 24, 2009 and November 27, 2012 to Holcim, setting the numeric <br /> protection limits (NPLs) for monitoring wells MW-7 and MW-13, respectively. These <br /> letters are included in Attachment 1 to this letter. <br /> Sodium concentrations in monitoring well MW-7 have increased over time as shown <br /> on Table 1 and Figure 2, and continue to exceed the sodium NPL for that well. <br /> Based on the latest sampling event (March 2014), the sodium concentrations <br /> exceeds the NPL by approximately 12% (253 vs. 226 mg/L). We believe that the <br /> increases in sodium concentration are unrelated to releases from the CKD landfill, as <br /> discussed below. <br /> On-Site Data <br /> Monitoring well MW-7 was installed in 1998 and has been sampled periodically since <br /> that time. As shown on Table 1 and illustrated on Figure 2, there is a strong <br /> correlation between groundwater elevation (represented as depth to water) and <br /> sodium concentration. Depth to water (DTW) in MW-7 has increased since 1998. <br /> Imagine the result <br />