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Lorencifo Caravan Mine -Geology Technical Repoli • Sodium Adsorotion Ratio The average sodium adsorption ratio was 13.67 with a range of 0.03 to 44.50. According to Wyoming DEQ Guidelines overburden with SAR values above 15 aze not suitable for reclamation success. Since SAR values exceed 15, a two-foot thick layer of top soil cover will be placed over the overburden and should have a good reclamation suitability. Molybdenum The average molybdenum concentration was 0.5 mg/Kg with a range of < 0.5 mg/Kg to 3 mg/Kg. According to the Wyoming Guidelines, molybdenum concentrations which exceed 1 mg/Kg are marginal for revegetation. However, only one sample collected was above the analytical method detection limit. This sample was obtained from borehole BH-2 at the 135.75- 140.5. Only 4.75 feet of the overburden was determined to have a molybdenum concentration above the analytical method detection limit. Since this small carboniferous shale layer will be mixed with the remaining overburden it is anticipated that molybdenum concentrations would fall below 1 mg/Kg. Therefore, revegetation problems are not anticipated. Acid Base Potential • The average acid base potential concentration was 60 tons/KT with a range of 250 tons/KT to -26 tons/KT. According to the Wyoming Guidelines, unsuitable acid base potential concentrations are < -5 tons/KT. Only 16 feet of the overburden material had -5 tonslKT concentration or lower. Since the remaining overburden material will be mixed with this material, revegetation or hydrologic problems are not anticipated. Coals All parameters analyzed were within acceptable ranges. Additional analyses of coal quality were conducted on coal seams anticipated to be surface mined. Data for the O, P, Q and N coal seams are summarized and presented in Tables GS and G6. Underground Mine Cores were obtained from six boreholes (MWl through MW6) and examined and submitted for laboratory analyses of salts and toxic elements listed in CDMG's "Guidelines for the Collection of Baseline Water Quality and Overburden Geochemistry Data." The coal to be mined during the underground mining consists of the I seam (Primero) and the R seam (Ciruela). C~ Geology-475/April 17, 1997 15 (revised 4/21/97)