2012-10-01_REVISION - M1977306 (22)

Home Browse Search

processes such as mining, metal smelting or coal -fired power plants contribute to arsenic in the air, water and soil. The use of arsenic in some agricultural pesticides and certain chemicals used to preserve wood also results in environmental pollution. Arsenic is also associated with uranium deposits and its potential exposure to the environment should be minimized using best management practices such as covering waste rock areas with available soil and vegetation. Vanadium concentrations exceeded State Agricultural Guideline. Since it is unlikely that the arid region along the hillside where the mine portal is located will be farmed, vanadium is not a concern. The gross alpha and radium 226 values in the SPLP tests indicate that radium concentrations are nearly seven times above drinking water standards. The likelihood of radium impacting groundwater resources in the area has been discussed (Section 8.0) and deemed minimal. However, all necessary precautions should be taken to prevent runoff from waste rock areas from leaving the site. This concern is addressed in the Drainage Design Plan found in Appendix II. 14.2 Mobility of Detected Uranium Ore Related Constituents Two factors control the mobility of constituents identified in the SPLP analysis — precipitation and sorption. Limited precipitation in the area combined with high evapotranspiration rates make it unlikely that sufficient precipitation is available to mobilize ore related constituents any significant distances. The most likely scenario is that any precipitation that falls in the area would be contained in the topsoil and used by plants covering the waste rock stockpiles once future mining and remediation is completed. The simplest and most common method of estimating contaminant retardation is based on the partition (or distribution) coefficient, K. The Kd parameter is a factor related to the partitioning of a contaminant between the solid and aqueous phases. It is an empirical unit of measurement that attempts to account for various chemical and physical retardation mechanisms that are influenced by a myriad of variables. The K metric is the most common measure used in transport codes to describe the extent to which contaminants are sorbed to soils. A primary advantage of the Ka model is that it is easily inserted into hydrologic transport codes to quantify reduction in the rate of transport of the contaminant relative to groundwater, either by advection or diffusion. The partition coefficient, K is defined as the ratio of the quantity of the adsorbate adsorbed per mass of solid to the amount of the adsorbate remaining in solution at equilibrium. For the reaction A +C, =A, the mass action expression for K is O'Connor Design Group Inc. U - 25