Laserfiche WebLink
~~- 1 °~ 7'7~ ~~ ~.. <br />Bird, David <br />Page 1 of 2 <br />From: Bird, David <br />Sent: Monday, Mav 12, 2008 3:08 PM <br />--~_ <br />To: (monica.sowders@cemex.com) <br />Cc: Mount, Carl; Crosby, Erica <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 <br />some constituents. For thallium, the surface water aquatic life criterion is 15 ug/L and for drinking water is 0.5 ug/L. For <br />ground water, 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 <br />criteria for both surface and ground water. This unfortunately renders the analysis useless for comparison to regulatory <br />criteria. (This may have happened before but I am just now noticing it). For future analyses, please instruct your laboratory <br />that detection limits for all analyzed constituents must meet or exceed the regulatory criteria. Method 200.8 may be <br />adequate for thallium. And since we know that there is hydraulic communication between the pit and the ground water, it <br />seems prudent that analyses should be able to detect concentrations at the most stringent of these criteria, which would be <br />the 0.5 ug/L surface water standard. <br />The regulations may be downloaded from: http•//www cdphe state co us/regulations/wgccregs/ <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 <br />capture the 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 />Tel: 303-866-3927 <br />Fax: 303-832-8106 <br />email: david.bird(a,state.co.us <br />www.mining. state. co.us <br />From: Crosby, Erica <br />Sent: Monday, May 05, 2008 2:15 PM <br />To: Mount, Carl; Bird, David <br />Subject: CEMEX Lab Report - L342769 <br />Hi. <br />Below is the CEMEX update on selenium levels. <br />Erica S. Crosby <br />Environmental Protection Specialist <br />Division of Reclamation, Mining & Safety <br />1313 Sherman St. Rm. 215 <br />Denver, CO 80203 <br />303-866-4943 <br />From: Monica Sowders [mailto:monica.sowders@cemex.com] <br />Sent: Monday, May 05, 2008 1:36 PM <br />5/14/2008 <br />