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DRMS CEMEX M1977-208 Quarterly Report <br />January 14, 2009 <br />Page 4 <br />specific background source is established. DRMS indicated that some migration without <br />treatment for water with elevated parameters might be acceptable as long as the migration was <br />minimal in TR-04 in acknowledgement of the close proximity of the well and the lack of a <br />reference background. CEMEX agreed to notify DRMS within two weeks should any of the <br />seven analytes selected exceed the most conservative standard established in the compliance <br />well, and evaluate increased monitoring and remediation at that time. That notification was <br />replaced with this quarterly report under later technical revisions, and the establishment of CEM- <br />004 and CEM-005 as the compliance wells. <br />Under TR-8 & 9, compliance wells were drilled into the Fort Hayes and St. Vrain alluvial aquifer <br />(CEM-005, CEM-004). No water has presented in CEM-005, which replaces CEM-001 as the <br />compliance well. The purpose of these wells in each TR is to detect the presence of a "plume" of <br />water migrating from C-Pit. While variations in water quality parameters are observable in both <br />CEM-001 and CEM-004, neither shows indication of a plume. Any detectable increase in <br />selenium is likely background selenium in the surrounding media and irrigation waters, <br />particularly in CEM004 which is surrounded by grazing and heavy irrigation. The compliance <br />well, CEM-005, still shows no migration of water. The purpose of monitoring for seeps and <br />springs and measuring the water level in C-Pit was to ensure there is no migration to the alluvial <br />formation. CEM-001 shows a delayed response in water level, but there is apparent attenuation <br />of water quality parameters between CPit and the well. <br />The purpose of the piezometers and CEM-003 was to help identify potential sources of water. To <br />date it appears the Boulder Feeder Canal was a large source of the inflow, and that has been at <br />least partially mitigated. <br />At this time, CEMEX will continue observations and sampling for at least another irrigation <br />season before reevaluating any if monitoring and/or remediation modification is required. <br />If there are any questions on the above information or the attachments, please contact me at <br />(303) 823-2125. <br />Sincer , <br />Steven C. Nordstrom, CEMEX <br />Environmental Engineer <br />5134 Ute Hwy PO Box 529 <br />Lyon, CO 80540 <br />Encl.\ Analytical Laboratory Reports, Environmental Sciences Corporation <br />Cc: (via email) <br />Alan Notary, Brown & Caldwell