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United States Department of the Interior OFFICE OF SURFACE MINING /Reclamation and Enforcement BROOKS TOWERS ~.,~ 1020 15TH STREET DENVER, COLORADO 80202 ~'~~~~Q~~~~ ~_ November 2, 1982 Mr. David Shelton, Director Colorado Mined Land Reclamation Division (CMLRD) 423 Centennial Building 11313 Sherman Street / Denver~CO 80203 Dear Mr.rwRJ ton: NOV 031982 i~;fh]FD LAND RECLAMAT101~ r,~;~ ~Jept. of ftatara! Resources In the course of reviewing the CMLRD proposed decision document [forwarded to the Office of Surface Mining (OSM) on September 28, 1982] for the Colowyo Mine, a problem has been identified concerning the Division's finding of compliance with the requirements of Rules 2,04.5 and 2.04.6. If taken as stated, this could result in the OSM not being able to recommend approval of the mining plan. Specifically, the Division has found on page 12 of the proposed decision document (attachment), that the geochemical data provided by Colowyo are insufficient to characterize the chemical properties of the overburden. Further, the Division stated that the collection of additional overburden geochemistry data in the area to be mined within the five-year permit term would provide meaningful and necessary information. Overburden geochemical analysis is a requirement for identifying suitable plant growth medium. Sodic materials have been encountered in the Mesa Verde Formation in the general vicinity of the Colowyo Mine. The solution to the lack of information accepted by the Division involves the analysis of approximately 27 composite samples per year taken from cuttings of overburden blast holes. The specific problems identified by OSM are as follows: 1) The Department of Interior's approval of the 5,500 acre life of mine plan area would be based on the analyses of samples from a single core hole. This is not adequate to characterize such an area, even in general terms. 2) The requirement for sampling just prior to blasting has the appearance of requiring baseline information to be collected after permit issuance. Such information is required by Rule 2.04.6 (Geology Description) as part of the permit application. 3) The use of composite samples would have the effect of averaging values and masking the high values which would adversely affect revegetation success.