2022-06-13_PERMIT FILE - C1980007 (2)

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West Elk Mine 2.04-121 Rev. 08/94- TR71, 06/95- PR06, 03/06- PR10;05/22- MR462 The wind patterns of Site 3 significantly differed from those at Sites 1 and 2. Drainage flow at Site 3 came out of the south. In fact, there was a small component of the wind out of the south- southwest which opposed the major drainage flow at the lower levels. This indicated that Site 3 was above the major drainage flow at the lower levels and was simply measuring the light drainage from the higher terrain above it directly to the south. Periods of upslope flow also indicated that the terrain to the south of Site 3 dominated the winds at that site. Upslope flows were from the north, with few exceptions. Temperature The average diurnal variations in air temperature over the spring quarter at Sites 1 and 3 are presented in Figure 13. Data from the summer quarter are presented in Figure 14. The primary point of interest in both figures is the timing of the early morning temperature increase. During the spring, the temperature began its daytime climb an hour earlier at Site 3 than at Site 1. The air temperature during the summer quarter at Site 3 began its climb an hour earlier than at Site 2, which preceded the climb at Site 1 by an hour. This indicated that the cold drainage flows diminished in intensity and vanished at the upper sites first. The vertical mixing and resulting upper-level flow coupling, which brought the relatively warmer upper-level air down to the surface, began with Site 3 and proceeded then to the level at Site 2, and finally reached Site 1 deep within the canyon about two or three hours after sunrise. This was easily understood by realizing that the canyon and mountain sides were heated faster than the canyon floor when the sun is low, as during the early morning. Relative Humidity and Precipitation The relative humidity at Site 2 averaged 58 percent during the summer quarter. Too little data exist for the spring quarter to make a meaningful comparison. Although this value seemed high, it should be remembered that the site was within a deep mountain canyon sitting at the base of a large mountain range. The average relative humidity during the summer ranged from a 30 percent to 88 percent. The highest humidity occurred during extremely cold drainage flows. The lower average relative humidities occurred during unstable upslope flows. Overall, relative humidity ranged from five percent to 100 percent. The total accumulated precipitation at Site 2 for the summer period was l.60 inches. Because of the low data recovery at Site 2 during the spring, the reported accumulation of 0.17 inches was not believed to be representative of the springtime precipitation. Air Quality Limited sampling at the West Elk site indicated relatively low concentrations of total suspended particulate matter even with the aridity of the region. The particulate data collected over the reporting period (March 1977 - March 1980) are presented in Exhibit 25. During this reporting period, measured particulate values did not exceed the federal secondary standard for particulates or