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Bil! Lyle, /darado Mining Company <br />November 23, 1005 <br />Page 2 <br />Acid-base accounting (ABA) tests were performed to characterize the net neutralization potential (NNP), <br />acid generation potential (AGP), and acid neutralizing potential (ANP) of the material contained in the <br />repository. The results of the ABA tests are summarized in this Technical Memorandum. <br />Reuositorv Materials <br />From June to October 2004, IMC removed underground utilities in the Pandora Area of the Idarado <br />Legacy Development Property in accordance with the MFG Inc. (MFG) Management Plan for <br />Miscellaneous Mill-related Wastes prepared for and approved by San Miguel County. Common with <br />many historic mining community developments throughout the western United States, tailing had <br />typically been used in the past as bedding for many of the underground utility lines in the Pandora Area. <br />The utility removal involved the excavation of overlying and adjacent native soil and tailing bedding for <br />[he utility lines, and transport of the mixed soilltailing material to the repository. The utility lines were <br />typically buried at depths ranging from approximately six to ten feet below ground surface, and were <br />typically bedded with tailing from approximately six inches beneath to approximately 12 inches above the <br />lines. As such, the majority of the material volume excavated from the utility trenches and placed in the <br />repository consisted of native soils overlying or adjacent to the utility lines. Several of the utility lines <br />consisted of transite (asbestos-cement) pipe. All transite pipe was managed and handled by licensed and <br />trained asbestos abatement personnel with the pipe being poly-wrapped, labeled, transported and disposed <br />in accordance with local, state and federal requirements at an off-site licensed facility. Materials <br />consisting of native soil, remnant mill waste or development rock, and concrete debris from excavation <br />and demolition of the Gold Run Mill foundation ruins and roadway surfaces were also placed in the <br />repository in 2004. <br />From April to October 2005, IMC removed tailing and mill-related debris within the Liberty Bell Area of <br />the Idarado Legacy Development Property in accordance with the Management Plan for Miscellaneous <br />Mill-related Wastes. Historic ore milling operations were conducted from approximately 1897 to 1921 at <br />the Liberty Bell Mill. The Liberty Bell Mill was likely shutdown in the early 1920's, and was removed <br />and/or demolished at an unknown time in the past. The material removed from the Liberty Bell Area <br />consisted mainly of tailing and mill-related debris overlain with native soils. The majority of the debris <br />removed from the Liberty Bell Area consisted of buried timbers associated with the Liberty Bell Mill, <br />The excavated material transported to the repository consisted of a mixture of native soil, tailing, and <br />mill-related debris. <br />