PERMFILE71984 - Laserfiche WebLink

Home Browse Search

Mr. R K Hancock, III Mr. Charles M. Machovec • Apri14, 2005 Page 4 of 10 Model Control Options Due to the lazge number of missing data of the Mt. Zirkel data set, specifically the first two weeks, APCD requested that the MSGPRO option be used. This necessitated the DFAULT option be turned off as these two options are incompatible. However, all other switches normally used in regulatory default mode (e.g., stack-tip downwash, final plume rise, calms processing, etc.) were left on. Source Inputs HG77 Sources The TAHR was chazacterized as 444 volume sources placed along the centerline of the road. The TAHR was assumed to be approximately 60 feet wide (18.28 meters). Following APCD guidance, the center of the volume sources were spaced every 14 meters (haul road width plus 64% of haul divided by 2.15). The initial sigma-y for each volume source was set at 6.97 m, which was calculated from the resultant haul road width plus 64% of haul road width divided by 4.3. Initial sigma-z (3.254 m) was calculated from the height of the haul trucks (13.5 feet) multiplied by 1.7 and divided by 2.15. The • release height (3.5 m) was calculated by taking the height of the haul truck and multiplying by 1.7 and dividing by 2. Modeling of the on-site haul road was also changed slightly to reflect APCD guidance, although the initial modeling inputs were very close. The most significant change to the characterization of the on-site road was increasing the azea source width from 10 meters to 16 meters. This was based on the APCD equation that modeled azea source width should be equal to the actual haul road width (assumed to be 10 meters) + 64% of actual haul road width. The release height and initial sigma-z were also modified slightly, corresponding to APCD guidance and were the same as for the volume sources above. For the wind erosion, the EMISFACT scalazs were also changed to reflect the new Mt. Zirkel data set. These are listed in Attachment A Hayden Power Plant Upon request of the APCD, the two boiler stacks for the Hayden Power Plant were added to the analysis. Data for these stacks were provided by Mr. Roy Doyle of the APCD. Receptors The same receptor grid was used for this analysis as used in the December 2004 • application, with some modifications. As directed by APCD, the 100-meter spaced grid was extended to sufficiently cover the impact area of the TAHR However, upon APCD 44lnvemess Drive East ~ Building C ~ Englewood, Colorado 80112 303/790-1332 ~ Fax 303/790-'7820 www.mcvehil-monnett.com