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iii iiiiiiiiiiiiiii 1399 STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY Deparimenl of N, rural Resources 1313 Sherman SC, Room 215 Dnnver, Colorado 80203 Phone: 1303) 855-3557 FAx: (303)832-8106 DATE: August 1, 2001 TO: Byron Walker ~~ DIVISION Ofi MINERALSi GEOLOGY"I' R E C L A M A T I O N MINING•SAFETY Bil I Owens Governor Grep E. Walther FROM: Joe Dudash ~ Execuhve Director x(m~ichacl B. Loop RE: Request for Assistance, Compaction Data, Bowie No. 1 Mine, Permit No. C-81-VJI~;ion Doc°°` Bowie Resources Limited I am requesting your assistance in the review of compaction data for the backfilling work [hat is still being performed at [he West Portal of the Bowie No. 1 Mine. I would like to know if you see any red flags in the data. Attached to this memo is the compaction data. More compaction data will be coming. The operator is using a standard of 85 percent relative compaction for the field work. The permit application page, which is attached to this memo, states that the fill will be compacted [o at least 90 percent of the maximum standard Proctor density. In a telephone conversation in November of 2000, [ had asked Basil Bear about the 85 percent relative compaction standard that Bowie was going to use. Jim Stover called me and said [hat the 85 percent compaction standard had been agreed [o by Jim Pendleton for future reclamation work at the Bowie No. 2 Mine, due to the expansive soils at that site. Stover said he was assuming that Bowie No. 1 also had expansive soils. (Should Bowie have to prove this?) I have attached three items that pertain [o the Bowie No. 2 compaction discussion. They are: I. A memo, dated January 29, 1997, from Jim Pendleton to David Berry. On pages 3, 4 and 5 of the memo, Jim Pendleton expressed his concern about the operator's plan to compact at 85 percent and requested more information. 2. A letter from Maxim Technologies, dated January 31, 1997. In this letter, Maxim provided the results of consolidation and swell testing. 3. A tnemo, dated February l9, 1997, from Jim Pendleton to David Berry. On page 1 of the memo, Jim Pendleton stated that Maxim had provided verification that soil swell would not degrade the slope stability of reclaimed fills. Jim Stover said that they will perform strength tests with the compaction achieved in the field. At a 4H: I V reclaimed slope, he is expecting [he factor of safety to be around 5.0. If you need any additional information, please let me know. Attachments cc: Sandy Brown (without attachments) Dan Hentandez (without attachments) c:\ms97\bowie 1 \cofnpactmemo I