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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 832-8106 <br />V <br />November 22, 2004 <br />Mr. John Lohr / <br />CEMEX Inc. V _ <br />P.O. Box 529 <br />Lyons, CO 80540 <br />RE: CEMEX, Inc., Lyons Quarry; Permit No. M-1977-208 <br />QTR-04; Adequacy Letter ~ <br />Dear Mr. Lohr: <br />COLORADO <br />DIVISION OF <br />MINESRALS <br />GEOLOGY <br />REC LAM ATION•MINING <br />SAFETY•S<IENCE <br />Bill Owens <br />Governor <br />Russell George <br />Exetu[ive Director <br />Ronzld W. Cattany ' <br />Division Director <br />Natural Resource Trustee <br />The Division received Technical Revision (TR-04) for the Lyons Quarry, Permit No. M-1977-208 <br />operated by CEMEX, Inc. The Division staff has reviewed the TR-04 proposal for the CEMEX, Inc. <br />Lyons Quarry, including the cover letter, the Proposed Sampling and Analysis Plan, Lyons Quarry, <br />and the Evaluation of the Potential Impact of Ponded C-Pit Water on Groundwater Quality in the <br />Dakota Sandstone. The Division has the following comments related to these reports. <br />1. The cover letter composed by John Lohr, Plant Manager, states, "Cemex will submit a <br />ground water mitigation plan to the Division if an exceedance of any of the five water quality <br />pazameters are observed in three consecutive monitoring events," This statement is made in <br />reference to the sampling and monitoring of C-pit water, A-pit water, a new, downgradient <br />monitoring well, a new, downgradient compliance well, and the Off-site Dakota Formation <br />well. Division policy requires that a mitigation plan be filed with, reviewed by, and approved <br />by the Division as a portion of this technical revision. Therefore a mitigation plan must be <br />filed prior to the Division's approval of TR-04. <br />2. The cover letter composed by John Lohr, Plant Manager, states," Cemex will control surface <br />drainage into C-pit to the extent practical however our analysis indicates that drainage <br />controls are not warranted. West of C-pit the Boulder Feeder Canal and to some extent the <br />Swede Ditch essentially function as drainage diversion ditches." The Operator has not yet <br />quantified the seepage from the above-listed water features into the C-pit. The Division may <br />accept the conclusion that the Boulder Feeder Canal and Swede Ditch serve as diversion <br />ditches relative to C-pit, once the degree of seepage from these ditches into C-pit has been <br />established, but the amount of seepage must be quantified for the Division. <br />3. Under Analytical Protocol, the Proposed Sampling and Analysis Plan Lyons Quarry states, <br />"CEMEX proposes to remove thallium from the list of analytical parameters. Past sampling <br />has shown thallium to be either below detection limit or well below the numeric protection <br />level standard." The Division does not approve of removal of thallium from the suite of <br />analyses to be measured in samples taken from the site. The inclusion of thallium in the <br />analysis of samples for the site was originally proposed by CEMEX. Although the thallium <br />levels have been below standards during past sampling events, the reason for monitoring and <br />sampling at the site is to continually monitor conditions and identify changes. The Operator <br />Office of <br />Mined Land Reclamation <br />Office of <br />Active and Inactive Mines <br />Colorado <br />Geological Survey <br />