2013-04-11_REVISION - C1981018 - Laserfiche WebLink

Home Browse Search

With respect to potential ozone formation, the county level analysis of the emissions inventory suggests the region is potentially NOx limited (background biogenic VOC emissions not shown in EPA NEI). Therefore, to effectively limit any potential for ozone formation due to area emissions, control methods should focus on reducing NOx emissions. By continuing to limit the minor reaction species, ozone formation potential from area emissions should remain small. The reader should be advised that only full scale photochemical grid modeling (which is beyond the scope of this EA) can reasonably predict the limiting reactant. The BLM provides the above assertion based on reasonably available literature analyzing potential ozone formation in rural areas during the typical ozone season (i.e., summer). The Deserado Mine sources (including all of the diesel fired mobile sources) and associated processing equipment are not significant sources of NOx or VOC emissions (see earlier discussion on CMM VOC data limitations), the photochemical reactivity potential of methane in the troposphere is considered negligible (40CFR51.100 (s)), and therefore the mine's operations are not expected to contribute significantly to any regional ozone formation potential. The Deserado Mine produces relatively insignificant quantities of PM2.5 emissions as compared to the total Rio Blanco County inventory. The majority of the mine's PM2_5 emissions are from process equipment and fugitive dust sources. These sources are not stack based dispersion sources which generally means that there is only a limited potential for the emissions to become effectively entrained in ambient air with sufficient buoyancy to produce measurable offsite impacts. This is primarily due to the low release height and near surface air turbulence that leaves the particles temporarily close to the ground where they are subject to removal by impaction on nearby horizontal and vertical surfaces, including ground, vegetation, and other structures. For this reason, it is not expected that the mine would have significant impacts regional PM2_5 air quality standards. Potential Impacts Analysis for Greenhouse Gas Pollutants According to the U.S. Global Change Research Program (2009), global warming is unequivocal, and the global warming that has occurred over the past 50 years is primarily human - caused. Standardized protocols designed to measure factors that may contribute to climate change, and to quantify climatic impacts, are presently unavailable. As a consequence, impact assessment of specific impacts related to anthropogenic activities on global climate change cannot be accurately estimated. Moreover, specific levels of significance have not yet been established by regulatory agencies. Therefore, climate change analysis for the purpose of this environmental assessment within this air quality section is limited to accounting for GHG emissions changes that would contribute incrementally to climate change. Qualitative and quantitative evaluations of potential contributing factors are included where appropriate and practicable. The analyzed methane emissions associated with the Deserado Mine are relatively low when compared to other Colorado underground coal mines. Methane emissions estimates are provided in the direct emissions table above. The estimations are based on current emission levels at the Deserado Mine (2009, 2010, & 2011). Approximately 10.5 percent of U.S. emissions of methane come from underground coal mining activities (EPA 2010). Based upon the Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990 -2010 (Draft), Februraty, 27, 2012, and the Final Colorado Greenhouse Gas Inventory and DOI- BLM -CO- 110- 2012- 0023 -EA 26