2020-10-27_PERMIT FILE - C1981035 (22)

Home Browse Search

emissions represent only 0.3 and 0.1 percent of the NOx and VOC emissions respectively (excluding biogenic emissions from the NEI). Given that the mines precursor emissions are so low and that the photochemical reactivity potential of CH4 in the troposphere is considered negligible (40 CFR 51.100 (s)), the mine's operations are not expected to contribute significantly to any regional 03 formation potential. However, the BLM did analyze 03 culpability all the mines that produce federal minerals in Colorado cumulatively, via the Colorado Air Resources Management Modeling study (CARMMS). The CARMMS model,the analysis scenarios, and results are all described in the cumulative impacts section below. The CARMMS model was also used to assess PM2.5 impacts (including secondary formation) from the mines producing federal minerals in Colorado. Where a PSD source is located near a Class I airshed (within 30 miles [48.3 km])the AQRVs thresholds set by the applicable Class I controlling agency must be assessed to determine if an adverse impact on the area is likely to occur. Although the King 11 Mine is within 30 miles (48.3 km) of two Class I areas, it is not a major PSD source.The King 11 Mine is classified as minor source of emissions, and according to CDPHE it was not required to provide any air modeling to support its permit application. Given that the mine has very low emissions of AQRV impacting pollutants and that the primary pollutant of concern (particulate matter) is a highly localized pollutant (due to gravitational settling and topological impaction), any potential Class I area impacts are expected to be minor, with respect to direct impacts. The CARMMS analysis did consider AQRV impacting pollutants, which are discussed in Section 2.2.6, Cumulative Impacts. The miscellaneous facility equipment would be the only stationary sources to generate HAP emissions at the mine.The total HAP emissions from all sources at the mine is approximately 6.1 tons and is based on the ratio of HAPs to VOC in EPA's NEI data for Non-Road Diesel Equipment for LPC. These source types represent most of the VOC emissions generated by the mine (see Table 2.2-10). A majority of the mine's HAP emissions (68 percent) would be exhausted through the mine shaft ventilation system (this is true for the equipment's criteria emissions as well), and as such they are heavily diluted by the volume of makeup air required to keep the mine's atmosphere free from CH4 that could accumulate in the underground environment as a result up exposing and removing the coal. Additionally, the mine shaft exhaust air has an initial inertial flux (i.e., vertical plume buoyancy, mechanically induced via the mine vent shaft fan) at the surface which provides for increased dispersion potential as compared to the surface-based equipment exhaust.The EPA(EPA 2016) provides Regional Screening Level values for diesel emissions (as a whole); including a Reference Concentration, defined as an estimate of a daily inhalation exposure to the human population (including sensitive groups)that is likely to be without an appreciable risk of deleterious effects during a lifetime (5µg/m3). Given the minor magnitude of these emissions (including the rate they could be expected to be emitted, about 0.5 grams per second cumulatively across the facility—total HAP grams divided by 3,000 operating hours (assumed minimum), divided by 3600 seconds per hour),and the overall dispersion expected to occur within the facility prior to reaching a fence line, it is highly unlikely ambient air quality would be impacted to a degree that the public (for which the nearest potential receptor is about a 0.5 mile [800 meters] away)would experience an elevated exposure risk based on EPA's exposure assessment guidelines. Therefore, impacts associated with HAP emissions would be negligible and short term. Dunn Ranch Area LBA and Mining Plan Modification 25 Technical Resources Report