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<br />. ! <br /> <br />Critical Policy Issues for Oil Shale Development 41 <br /> <br />ecosystems but also to local and downstream municipal, industrial, agricultural, and <br />recreational users. <br />Water quality threats associated with oil shale operations depend on the techni- <br />cal approach employed (mining and surface retorting or in-situ retorting) as well as <br />the location of such operations. For mining and surface retorting, potential sources of <br />water pollution include mine drainage; point-source discharges from surface opera- <br />tions associated with solids handling, retorting, upgrading, and plant utilities; and <br />leachate from spent (i.e., retorted) oil shale. For mine drainage and point-source dis- <br />charges, state-of-the-art waste treatment technology available for mining operations <br />and petrochemical processing can be applied to eliminate or control emissions. The <br />primary threat to water quality is generally considered to be spent shale leachate <br />(Harney, 1983). Laboratory and field tests have shown that the salt content of <br />leachate from freshly processed shale (derived from surface retorting) is significantly <br />higher than that of raw shale. The spent shale leachate will also contain small <br />amounts of the soluble forms of the same toxic substances that are of concern with <br />regard to air pollution, such as arsenic and selenium. <br />The salinity of the spent shale leachate is a significant issue because of the <br />importance of salinity management in the Colorado River and the sheer magnitude <br />of spent shale that would be generated by an oil shale industry producing a few mil- <br />lions of barrels of shale oil per day. Damage in the U.S. portion of the Colorado <br />River Basin arising from elevated salinity is estimated at between $500 million and <br />$750 million annually (Bureau of Reclamation, 2005). Salinity control in the Colo- <br />rado River is one of the "four key water goals" stated in the bureau's 2004 Annual <br />Report. An industry producing 3 million barrels of shale oil per day would annually <br />generate over a billion tons of spent shale per year.? All disposal options, whether <br />mine refill or surface piles, leave spent shale potentially exposed to underground and <br />surface water flows. <br />A num~er of approaches are available to minimize leaching and prevent direct <br />or indirect contamination of surface waters. Many of these have been developed, <br />tested, and implemented since oil shale development was last considered. However, it <br />is not dear that these methods can be applied to mine refiIJ and whether these meth- <br />ods represent a permanent (i.e., hundreds of years) solution that will be effective after <br />the site is closed and abandoned. <br />As discussed in Chapter Three, establishing the technical viability of thermally <br />conductive in-situ conversion requires understanding the impact of the retorting <br />process on groundwater flow and quality-a process that will take a number of years. <br />Currently available information also is not sufficient to predict the transport and tate <br /> <br />7 Calculated assllming oil shale yielding 30 gallons of oil per ron, resulting in the generation of slightly over one <br />ton of spent shale per barrel of shale oil. <br />