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- ~ > ~ ~ 5737 State Highv.~ay ~3 ,~ ~ ~ Meeker, Colpredo Elo41 G` 0 A L ~ 0 (3C3) 624-:<5'I •Q COMMPANY~o~ F F~ n£~-tam January 4, 1983 Mr. Dan Mathews Colorado Mined Land Reclamation Division 423 Centennial Building 1313 Sherman Street Denver, Colorado 80203 Dear Dan: The following in~ormation is submitted.as a request for a minor revision to Colowyo Mining Permit No. C-019-81, to clarify the overburden sampling program submitted by Colowyo on May 24, 1982. This request is in response to further review by the Office of Surface Mining. The original plan was purposely not detailed, to allow the overburden sampling to be designed as necessary 'to respond to variations in the advancing mine, and in recognition of the lack of information available on toxicities to native plant species. As discussed during • the zeview of Permit No. C-019-B1, Colowyo feels that overburden analyses from normal exploration drill hole sampling may not provide accurate overburden characterization because of rapid facies changes found in the Williams Fork Formation. Therefore, Colowyo agreed with the MLRD to conduct overburden sampling during the overburden blast hole drilling, in an effort to gain more reliable data for overburden characterization. -The following plan has been prepared in response to our December 30, 1982 meeting. Also, rather than establish toxic levels for each para- - meter, we will consider suspect levels. As was evident at our December 3D; 1982 meeting, it is very difficult to determine toxic or even suspect levels of toxic .parameters to the plant species utilized in Colowyo's reclamation plan. This is caused by a lack of information specific to native plant species, especially in regard to rooting zone toxicities, since Colowyo is replacing topsoil to a depth of eighteen inches. Sampling As proposed on May 24, 1982, overburden and interburden samples will be taken from the cuttings produced during blast hole drilling. The Colowyo pit advances approximately three cuts per year, and the .only materials that could be placed at the surface of the regraded spoil are those that are mined by the truck/shovel operation. Therefore, • along the length of the pit, three representative samples will be analyzed for each truck/shovel seam during each cut. In addition, if the material izmnediately below the topsoil is sufficiently soft to allow mining - _ without blasting, three samples will be analyzed to the depth to be mined for the length of the pit along each cut. F.1so, as we have discussed, the regraded overburden will be sampled at the surface at~a density cf one sample ner five acres.