Laserfiche WebLink
acid-forming material nor is a hazardous material. NEI will conduct regular ABA and <br /> TCLP testing of the feedstock, at the material owner's expense, during milling to <br /> ensure the feedstock character remains non-acid forming and nonhazardous. <br /> Feedstock sampling by NEI as grab sample per 20,000 tons of feedstock. Even <br /> though ABA results between -20 and +20 are indicative of non-acid producing <br /> material, NEI will limit accepted feedstock 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. The slurry fines pass <br /> through a dewatering screen, is tested for pH, and continues on to recirculate. The <br /> concentrate is collected in 55-gallon drums and prepared for 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 /> [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 twice daily immediately after the dewatering screen. The bypass <br /> circuit will allow diversion of up to one full circuit volume of water. Water with pH <br /> lower than 6 will be diverted to a holding tank. Quicklime (calcium oxide) will be <br /> added in a dry form and mixed within the holding tank as needed to attain a pH <br /> above 6. The diverted process water will be neutralized, allowed to settle for no less <br /> than 24 hours, tested for pH and reintroduced into the circuit once the pH has <br /> stabilized. <br /> The quicklime will be palletized and delivered in 50-lb. bags with up to 2,000 <br /> lbs. stored on site at any one time. The pallets will be tarped and stored inside the <br /> mill building. <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 /> byproduct materials will be stockpiled outside the building. Stockpile pads will be <br /> concrete to prevent contact with and impact to soil. Prior to any period of extended <br /> shutdown or temporary cessation, feedstock and byproduct materials will be hauled <br /> to either the owner of the material or to the 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 />