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Mr. Dan Mathews January 4, 1983 Page 2 As per will be analyzed suspect levels. Parameter Analyses our discussion December 30, 1982, the overburden samples for the parameters listed below with the following pA Electrical conductivity Sodium Adsorption Ratio Selenium (if pH is greater than 8 Boron (if pH is greater than 6.4) Lead (if pA is less than 5 or greater than 10) Suspect Level _ less than 5 or greater than 9 greater than 12 millimohs/cm greater than 15 4) greater than 2 ppm greater than 8 ppm greater than 20 ppm Remedial Measures If suspect levels of the parameters to be analyzed are encoun- tered, the Division will be notified upon receipt of the analyses and remedial measures taken. Usually, overburden drilling is accomplished at least two weeks prior to mining and laboratory analyses can be obtained in one week, and possibly two to three days if requested. Therefore, if suspect levels of toxic materials are detected, the following remedial measures will be undertaken following consultation with the Division. 1. An assessment of the suspect level will be conducted to determine if mixing of the suspect material with acceptable material will provide an adequate solution. Dollhopf, et. al. (1981) found that mixing of Fort Union Formation spoil by a dragline operation pro- vided the following results: "when the problem material constituted less than five percent of the total overburden volume, such material was essentially .not detecable in the spoil pile. When the prc.;lem material constituted 5 to 158 of the overburden volume the material often could not be detected in the spoils 508 of the time; although the volume of the problem material detected in the spoils was generally less than that found in overburden, indicating partial dilution occurred. When problem material exceeded 158 of the overburden volume it was always found in the spoil pile, generally to a smaller extent, again indicating partial dilution." The mixing concept will likely be more useful at Colowyo than in a dragline operation, because the spoil material may be mixed over a much larger area, both vertical anc' horizontal. If suspect material is encountered, mixing will be analyzed with respect to the then present dumping configuration.