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Proposed Action <br />Direct and Indirect Impacts: The reviewer utilizes worse -case dust emission scenarios, which <br />are typically utilized in environmental analyses, as estimated by the CDPHE based on <br />preliminary Air Pollution Emission Notification (APEN) for a new point source as completed <br />by the applicant (CDPHE, 5/26/2010). Disturbance of the approximately 5 acres /yr and mine <br />operational activities would include direct adverse impacts of approximately 10.69 tons /year of <br />total particulate matter on an uncontrolled basis and 2.85 tons /yr on a controlled basis. <br />CDPHE approximates that 4.86 tons /year of PM10 of this total PM estimate would be emitted <br />from the site on an uncontrolled basis, while 1.16 tons /yr would be emitted on a controlled <br />basis in a worst case scenario. <br />This projected worst -case PM10 estimate approaches the CDPHE threshold of 5 tons /year for <br />uncontrolled PM10, the latter state standard that would trigger requirements for a CDHPE <br />Mining Operations Fugitive Particulate Matter /Control Plan. However, CDHPE's worst -case <br />PM10 estimate for the Fairplay Mine is far below the 50 /tons per year State of Colorado <br />threshold that would require a higher level of air quality modeling analysis, controls, and public <br />involvement. <br />The immediate context of the dust emissions include proximity to <100 homes in rural <br />subdivisions, a popular recreation destination, and the town of Fairplay. Some exposure to <br />fugitive dust suspended in the air, or transported in the air from the mine site during operation <br />hours for people living near or recreating adjacent to the facility will be a direct adverse impact <br />of the proposed action. Indirect impacts beyond the nuisance effects of dust could include <br />aggravation of such health conditions as asthma for those people who suffer the disease and <br />who are exposed to the mine fugitive dust. On a county -level and regional scale, any new <br />particulate matter emission (< 10.69 tons /year total PM) from the proposed Destiny Mine is <br />minute relative to Park County dust emissions, let alone Colorado. The low estimated level of <br />emissions, atmospheric dispersion, and the physiographic separation from the new point source <br />from Class I areas, will result in negligible perceptible degradation to regional haze near any <br />Class I area. <br />The proposed Destiny mine diesel generator will also generate nitrous oxides (NOx) and <br />carbon monoxide (CO) as a direct adverse impact. NOx levels are not presently high in Park <br />County, according to EPA data, while CO levels are relatively high when compared to other <br />counties. CDPHE has estimated that in a worse -case scenario, the proposed Destiny Mine will <br />emit approximately 12.6 tons /year of NOx and 2.89 tons /year of CO. This CDHPE estimated <br />rate of NOx emissions from the proposed Destiny Placer mine surpasses the state 5 tons /year <br />NOx threshold and will require an applicant Air Pollution Emission Notice to the State of <br />Colorado. The estimated CO emission rate does not reach this permitting threshold and neither <br />NOx nor CO emission estimates approach the 40 tons /year state threshold that would require <br />higher level of analysis, controls, and public involvement. On a county -level and regional scale, <br />again any new NOx and CO emissions from the proposed Destiny Mine are minute relative to <br />Park County and Colorado. <br />The reviewer assumes an operational life of the Proposed Destiny mine greater than 5 years. <br />The reviewer also assumes adherence to fugitive dust and engine emissions mitigations <br />discussed below that will be applied to control PM10, CO, and NOx migration off BLM <br />administered lands. <br />16 <br />