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~'(- lGC7 7- zog- <br />Bird, David <br />Page 1 of 3 <br />From: Monica Sowders [monica.sowders@cemex.com] <br />Sent: Tuesday, May 13, 2008 8:50 AM <br />To: Bird, David <br />Cc: Mount, Carl; Crosby, Erica <br />Subject: Re: CEMEX Lab Report - L342769 <br />We can make the change on the next analysis. In fact, I cannot explain why the detection limit has changed; in the past (es recent as March) it <br />was .001mg/L. <br />Also, in the past, the Division had determined we were under the agricultural standards, and not the drinking water standards. The <br />groundwater we are dealing with is a perched isolated area, not connected to the drinking water formations. I spent some considerable time <br />going back through the files about a year ago, understanding how the standards specific to C-Pit were established. Since DRMS has primacy <br />on groundwater in mining situations, the CDPHE regulations were never referenced or compared to - it was a comparison to background. It <br />may be beneficial to have the review sometime prior to Carl's retirement. The comparison was to the Zug/L standard, with the notations that <br />some exceedance of that level was tolerable, is in prior reviews by the Divsion, which is why I was referencing that standard. <br />Monica Sowders <br />Environmental Manager <br />Lyons Cement Plant <br />5134 Ute Hwy Box 529 <br />Lyons CO 80540 <br />(303) 823-2115 <br />Fax (303) 823-2199 <br />"Bird, David" <David.Bird~state.co.us> To <br />Monica Sowders/US/Cemex@CEMEX <br />05/12/2008 03:06 PM ~ "Mount, Carl" <Carl.Mount@state.co.us>, "Crosby, Erica" <Erica.Crosby@state.co.us> <br />Subject CEMEX Lab Report - L342769 <br />Monica <br />As you may be aware, CDPHE has different regulatory criteria for ground water (Reg 41) versus surface water (Reg 31) for some <br />constituents. For thallium, the surface water aquatic life criterion is 15 ug/L and for drinking water is 0.5 ug/L. For ground water, <br />the thallium standard is 2 ug/L. <br />I notice that the detection limit for thallium in your most recent report is 5 ug/L, which is higher than the drinking water criteria for <br />both surface and ground water. This unfortunately renders the analysis useless for comparison to regulatory criteria. (This may <br />have happened before but I am just now noticing it). For future analyses, please instruct your laboratory that detection limits for <br />all analyzed constituents must meet or exceed the regulatory criteria. Method 200.8 may be adequate for thallium. And since we <br />know tfiat`there is hydraulic communication between the pit and the ground water, it seems prudent that analyses should be able to <br />detect concentrations at the most stringent of these criteria, which would be the 0.5 ug/L surface water standard. <br />The regulations may be downloaded from: httD•//www cdRhe state.co.us/regulations/waccrees/ <br />This does not necessarily imply that the Division will expect you to comply with the surface water standard if the particular <br />surface water body is not and will not be used as a drinking water source, but we want the detection limits to be able to capture the <br />data. <br />Regards, <br />David Bird <br />Division of Reclamation, Mining & Safety <br />Department of Natural Resources <br />1313 Sherman Street, Rm 215 <br />Denver, CO 80203 <br />5/ 14/2008 <br />