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exhibits low mobility as iron- and manganese-hydroxides can form, adsorbing radium efficiently <br />(Zwalen, et al. 2007). This could explain why radium concentrations in alluvial ground water <br />and surface water at the site are generally very low, while radium concentrations in the reducing <br />enviromnent of the mine pool are elevated. It could also explain why uranium concentrations in <br />ground water sampled from a historic exploratory core hole discovered in 2010 (permanently <br />sealed January 2011) approached levels observed in the mine pool, yet Ra-226 concentrations <br />were essentially absent. Both theoretical considerations and site-specific data indicate that any <br />potential seepage of mine pool water that could reach oxidizing conditions in ground water <br />regimes closer to the near-surface environment would become subject to geochemical processes <br />that readily attenuate radium and prevent further migration of this constituent. <br />Bonding <br />The estimated cost for design and installation of the in-situ treatment delivery and maintenance <br />systems is $275,000. Annual costs for treatment are expected to be about $50,000. Within two <br />years of initiation of in-situ treatment, concentrations in the mine pool are expected to have <br />reached minimum possible levels and will have respectively stabilized in an equilibrated <br />condition. The appropriate amount of bonding for TR-17 is thus $375,000. <br />References <br />Division of Reclamation and Mining Safety (DRMS). 2010. Schwartzwalder Mine, Pernit No. <br />M-1977-300, Designated Mining Operation Environmental Protection Plan, Amendment <br />AM-02, Adequacy Review. December 14, 2010. <br />Cotter Corporation (N.S.L.). 2010. Schwartzwalder Mine Environmental Protection Plan. July <br />31, 2010. <br />Schott, B. & Wiegand, J. 2003. Processes of radionuclide enrichment in sediments and <br />groundwaters of Mont Vully (Canton Fribourg, Switzerland). Eclogae Geologicae <br />Helvetiae 96, pp. 99-1.07. <br />Zwahlen, Francois, Surbeck, Heinz, and Gainon, Francois, 2007. Natural radionuclides in <br />groundwater as pollutants and as useful tracers, Swiss Centre for Hydrogeology, <br />University of Neuchatel, Switzerland, published in Proceedings of the 12th International <br />Symposium on Water-Rock Interaction, Kunming, China, 31 July - 5 August 2007, <br />Yanxin Wang and Thomas D. Bullen, ed.