Laserfiche WebLink
of toxicity does not exist with respect to molybdenum. All surface water and groundwater samples <br />evaluated by the mine are below the detection limit. <br />SAR values in 38.6 percent of the samples were above the suspect level of 15 described in the <br />Wyoming guidelines. The weighted average value is 8.74. Many of the samples were con- <br />taminated with drilling mud, drilling foam, or other drilling fluid. Ken• cited a study that showed <br />that drilling fluids dramatically increase SAR values above samples taken from highwall or drilled <br />with air. None of the drillholes were drilled using air; therefore, all samples were deemed <br />contaminated, and their value for determining SAR found questionable. Acid-Base Potential <br />analysis did not indicate a potential problem with acid-forming material. Overall, the interpretation <br />of the overbwden analysis showed that only nickel and selenium were found at levels that were of <br />any concern and that the mixing of the overbwden during haulage would dilute the few samples <br />that were in the suspect range. A discussion of the analysis and interpretation can be found on page <br />779-1ba of the permit application. <br />Groundwater <br />There aze predominately three aquifers of interest in the Marr pemut azea: the Sudduth coal <br />aquifer, upland terrace deposits, and alluvial deposits. The coal aquifer has moderately poor yields, <br />except where it is faulted. The water is slightly alkaline and total dissolved solids concentrations <br />average 500 mg/I. The water is acceptable for stock and limited domestic use. <br />See the April 15, 1993, addendum to the December 9, 1992, Findings of Compliance for Permit <br />Renewal for discussion of upland terrace deposits. <br />Alluvium is found sporadically along all draws draining the mine site, next to the Canadian River, <br />and adjacent to the Illinois River neaz the loadout. Monitoring has been performed along the draw <br />and adjacent to the tipple on the Illinois River. The discontinuous alluvium within the draws <br />draining the Marr permit area is predominately composed of clay with isolated sand and gravel <br />lenses. However, the permeability of the alluvium adjacent to the Illinois River is much higher and <br />is estimated to be 2500 gallons per day per square foot (gpd/ftZ). <br />Surface Water <br />The surface hydrology of the general azea, including the mine plan azea, consists of the high <br />altitude, semi-and environment found in the upland parks of the Central Colorado Rocky <br />Mountains. The average annual rainfall for the azea is 11 inches. The major soil moistwe rechazge <br />and runoff periods occw during the snowfall and subsequent thawing times of the winter and <br />spring. Climatologic records indicate increased precipitation during the summer months; however, <br />due to increased evapotranspirational effects during this warmer period, there is less impact to soil <br />moistwe levels. <br />The mine plan area is drained by ephemeral and intermittent stream systems. Starting at the north <br />end of the permit area and proceeding southward, one finds the Sudduth, Williams, Bush and <br />Bolton Draws. The Marr Strip drainage systems roughly parallel each other and flow to the <br />northeast where they join with the Canadian River, approximately one mile east of the permit azea. <br />Marr Mine Permit Renewal OS <br />17 Mazch 2006 <br />-9- <br />