2012-10-05_REVISION - M1977342 (12)

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TR -18 to Permit M- 1977 -342 Environmental Protection Plan 13. CLIMATE Information regarding climate was developed during the planning and early construction phases of the Henderson Project. This data is found in Section 3.1 of the Mining and Reclamation Permit. A more detailed description of baseline climatic data in the vicinity of the Mine and Mill, based on records from stations located near these facilities, is described below. The climate in the Henderson Mine and Mill area includes long, snowy, cold winters and short, cool summers. Snow is possible throughout the year, with the heaviest snowfall occurring between the months of November and April. Baseline climatic data for the vicinity of the Mine was obtained from the Western Regional Climate Center (WRCC) (www.wrcc.dri.edu) for "Jones Pass 2 E" (Station #054397), elevation 10,328 feet AMSL. Data is available for the years 1961 -1973; although this range of years is shorter than desired, the elevation and location of this station offers a satisfactory analog for climate conditions at the surface area of the Mine. The station is located at 39.77° N, 105.85° W. Annual precipitation values for the most recent five -year period that data is available are presented in Table 2 along with the average annual precipitation. The greatest annual precipitation recorded for this site occurred in 1969, and the monthly precipitation values for that year are presented in Table 2. Table 3 shows the mean monthly temperature and the monthly average maximum and minimum temperature for the most recent five -year period that data is available. Baseline climatic data for the vicinity of the Henderson Mill was obtained from the WRCC for "Dillon 1 E" (Station # 052281) and "Williams Fork Dam" (Station # 059096). The Dillon station is located approximately 16 miles SSE of the Henderson Mill, in the Town of Dillon (39.63 °N, 106.04 °W, elevation 9,065 feet AMSL), with data observations from the year 1893 to the present. The Williams Fork Dam station is located approximately 14 miles northwest of the Henderson Mill site (40.02 °N, 106.13 °W, elevation 7,650 feet AMSL) with data observations from the year 1982 to the present. Annual precipitation values for the most recent five -year period that data are available for these two stations are presented in Table 4 along with the average annual precipitation. The greatest annual precipitation record for the Dillon station occurred in 1936, and for the West Fork Dam Station occurred in 1985, and the corresponding monthly precipitation values for these years at each station are presented in Table 4. Tables 5 and 6 show the mean monthly temperature and the mean monthly maximum and minimum temperature for the most recent five -year period that data is available at these stations. Mean wind speed data are available in limited quantities via the on -site weather stations maintained by Henderson (see below). However, wind direction data are not currently available at any stations near the Mine or Mill. Generally, winds exhibit typical mountain flow patterns, and vary significantly from location to location because of the rugged topography. The National Climatic Data Center of NOAA provides information regarding high winds for Grand and Clear Creek Counties. A wind speed of 60 knots (69.0 miles per hour) was reported in the town of Kremmling in Grand County (40.06 °N, 106.39 °W, elevation 7,313 feet AMSL) on June 6, 2003; a wind speed of 94 knots (108 miles per hour) was reported for Squaw Mountain in Clear Creek County (39.68 °N, 105.5 °W, elevation 11,509 feet AMSL) on October 26, 1995; and a wind speed of 63 knots (72.5 miles per hour) was reported for the Town of Georgetown in Clear Creek County (39.72 °N, 105.70 °W, elevation 8,520 feet AMSL) on May 22, 2006. Based on this information, it is likely maximum wind gusts may reach 70 to 80 miles per hour. Climax Molybdenum Company Henderson Operations October, 2012 Page 33 of 40