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TCLP testing of the feedstock during milling to ensure the feedstock character <br /> remains non-acid forming and nonhazardous. Feedstock sampling by NEI as grab <br /> sample per 20,000 tons of feedstock. Even though ABA results between -20 and <br /> +20 are indicative of non-acid producing material, NEI will limit accepted feedstock <br /> with ABA results between -10 and +10. <br /> No designated chemicals will be used in milling. GTM relies on a ball mill and <br /> shaker tables that process the slurry via gravity separation. Surfactant may be <br /> added at a rate of 50-100 g/ton depending on the consistency of the slurry. The <br /> slurry fines pass through a dewatering screen, is tested for pH, and continues on to <br /> recirculate. The concentrate is collected in 55-gallon drums and prepared for <br /> shipping to the refiner. <br /> [6.4.21(6)] Designated Chemical and Material Handling <br /> Acid-forming material will not be accepted for milling at GTM. No designated <br /> chemicals will be used during processing; therefore, disposal or detoxification will not <br /> be necessary. <br /> Surfactant, if used, will be stored in a 55-gallon drum inside the metal <br /> building. The drum will be fitted with a pump that injects the surfactant into the <br /> slurry stream prior to the shaker tables. <br /> [6.4.21(6)(b)(ii)] <br /> The process water circulating system includes a bypass circuit in the event <br /> process water pH trends outside of the neutral pH range (6.5-8). Process water pH <br /> will be tested daily immediately after the dewatering screen. The bypass circuit will <br /> allow diversion of up to one full circuit volume of water. The diverted process water <br /> will be neutralized, allowed to settle for no less than 24 hours, tested for pH and <br /> reintroduced into the circuit once the pH has stabilized. <br /> [6.4.21(6)(b)(iii)] <br /> NEI's business objective is to provide an alternative to traditional stockpiling <br /> and impounding mine spoils that are legacy byproducts of historic mining in <br /> Colorado. In addition to reducing the legacy artifacts, construction material will be <br /> produced; converting a mine spoil into a construction industry resource. Adverse <br /> off-site impacts will be prevented by testing feedstock prior to acceptance, periodic <br /> testing of feedstock to ensure chemical character is consistent, regular pH testing of <br /> process water, including a process water diversion system in the event of upset <br /> conditions or trending pH outside neutral values. <br /> Milling activities are enclosed in a metal building. Only feedstock material and <br /> dewatered fines will be stockpiled outside the building. Stockpile pads will be <br /> concrete to prevent impact to soil in the event of an upset condition. Prior to any <br /> period of extended shutdown or temporary cessation, feedstock material and <br /> construction product will be hauled to either the owner of the material or to the <br /> construction industry end user. <br /> [6.4.21(6)(c)] <br /> Approximately 6000 tons of mine spoils are currently stockpiled at the toe of <br /> the slope near the historic mine adits. The material was tested for acid mine <br /> drainage potential. The ABA results indicated the material is not acid mine drainage <br /> producing. The material will be used as backfill for mill construction. <br /> Page 16 of 21 <br />