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iii iiiiii-iiiiiiiii STATE OF COLORAllv DI~ISIO~Y OF ~b11NERALS AuD GEOLOGY D~p.inmcnt ni .V mural Re,nurcc~ I ;1 1 Sherman 51., Roum '_ I S Drm er, Culnmdn 110_'0] Phrnie: i.'J;~ A6u-35h7 April 1~, 1999 DIVISION O F MINERALS GEOLOGY a EC~nnnrloN MIN IN G•SAfETY Bdl Owero Me William A Bear, Jr. e~rvemur Bowie Resources Limited c'"°E `o,lc"" E.ecun~e Dnecm~ Bowie No. 2 Mine ~c~n,el e (n~~ P.O. Box 483 Dwivon Direanr Paonia, Colorado 81428 Re: Gob Pile, Bowie No. 2 Mine, Permit No. C-96-083, Bowie Resources Limited Certified Mail No. Z 434 941 460 Dear Mr. Bear: The Division has reviewed the February 24, 1999 geotechnical report by Lambert and Associates that was submitted to the Division by Jim Stover. Based on our review of the report, the Division believes that the report shows that portions of the refuse pile were not compacted to achieve 90 percent of the Proctor density, as is required in Rule 4.10.4(3)(b). The Division also believes that one of the causes of the compaction deficiency may have been that subsoil had been added to overly wet coal refuse during the placement process. This addition of subsoil had been done without first demonstrating that the new material properties could result in a stable pile, as is required in Rules 4.10.1 and 4.09.2(3)(a). Finally, the Division believes that compaction testing should have been performed on the approximately 20 feet of refuse material placed at the bottom of the refuse pile, while that portion of the pile was being built, as is required under Rules 4.09.1(11)(a) and 4.10.2(2)(b). Therefore, the Division is issuing Notice of Violation No. CV-99-004 for failure to construct the permanent coal mine waste bank according to the regulations and the approved designs. The Division bases its determination conceming inadequate compaction on the geotechnical data from boring number 3 of the Lambert and Associates report. In that data, there were three samples which achieved relative compactions of 80 percent, 87 percent and 84 percent of the Proctor standard. Although the other six samples in boring number 3 met or exceeded the relative compaction level of 90 percent, the fact remains that the compaction test results from the boring hole on the outslope of the refuse pile show that a portion of the refuse pile did not achieve compaction that would be in compliance with the regulations and with the permit application designs. The Division bases its decision conceming the unapproved addition of subsoil with coal refuse on the Division's field inspection of February Z, 1993, on the results of the logs of the test borings in the February 24, 1999 Lambert and Associates report and on information provided in the permit application. Examination of Volume IV of the permit application shows that the geotechnical stability