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where A = free or unoccupied surface adsorption sites, C, = total dissolved adsorbate <br />remaining in solution at equilibrium, and A, = amount of adsorbate on the solid at <br />equilibrium. <br />Transport modeling simulations conducted at similar sites as CM -25 were conducted by <br />Kearl (2005). The modeling was very conservative and followed NRC guidelines for <br />high -level waste repositories. Using published uranium Kd values for transport <br />calculations in sand and clay materials, it was determined that after 1000 years, the <br />relative concentration of these at depths of less than 100 feet below the base of the waste <br />rock pile would be 1 /1,000,000 of the initial concentration. The only variable that <br />changes for concentrations of radium 226 leached from waste rock would be the sorption <br />coefficient. Values published by Ames et. al. (1983), Carbol and Engkart (1997), and <br />Bragea et. al. (2008) all report sorption values for radium that are consistently higher than <br />published values for uranium. This would result in lower transport rates for radium <br />compared to uranium as predicted by the modeling studies. <br />As previously discussed, once mining resumes at CM -25, representative ore samples will <br />be submitted for SPLP testing and the results evaluated and reported to the DRMS. <br />14.3 Acid Mine Drainage Potential <br />As discussed in Section 6.1.1, there is a low potential for the development of acid mine <br />drainage from the waste rock or ore stockpiles due to the chemical nature of the rock <br />forming minerals. Salt Wash sandstones are commonly calcareous, meaning that calcium <br />carbonate cements the sand grains together forming sandstones. Water percolating <br />through the waste rock or ore stockpiles would be expected to become alkaline due to the <br />rock chemistry of the rock. EPA Method 1312 (Synthetic Precipitation Leaching <br />Procedure) requires an acidic solution with a pH of 5.0 be used for the tests. <br />(15) Construction Schedule Information <br />This site has been fully reclaimed. Construction of stormwater diversion and <br />containment structures, as well as portal construction and mine yard facilities are outlined <br />in Table 7 below. <br />O'Connor Design Group Inc. T - 22 <br />