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Wind Soeed end Wind Direction <br />Because no wind information is available from the Hayden Station, all wind data, including <br />[hat presented in Table 8-3, are based on the most recent twelve months (November 1991 - <br />October 1992) of data collected at Peabody Western Coal Company's Seneca II-W Mine <br />meteorological station located approximately six miles south of the loadout facility. <br />This is the elosest station to the loadout facility that is recording reliable wind data. <br />The nearest station for whieh the National Climatic Center reports surface winds cannot be <br />relied upon to provide a reasonable indication of winds at the loadout area because of <br />distance and topography. <br />The meteorological station at the Seneca II-W Mine is located in the south one-half of <br />Section 16, TSN, R88W, about 500-600 feet east of Hubbe rson Gulch. Elevation of the site <br />is approximately 6,850 feet MSL with sensor height at 33 feet above ground level CAGE). <br />All wind speed values are presented in knots (neuti cal miles per hour). <br />Tables 8-3 end 8-4 list the percent of time (based on hourly average wind occurrences) the <br />wind blew from each of the sixteen 22.5 degree sectors comprising the 360 degree windrose <br />circle. Ninds in the Hayden area come from two predominant general directions as <br />indicated in Tables 8-3 end 8-4. Percentages shown in Table B-3 were calculated using <br />hourly averages with calms considered to be anything less than 1.0 knots. Calm <br />occurrences amounted to 1.4 percent. This method shows 46.9 percent of the total hourly <br />occurrences came from the ESE through SSE (generally SE) directions, while 33.1 came from <br />the WNW through NNW (generally NY) directions. These percentages indicate prevailing <br />winds from the general SE direction. Nighttime cooling causes drainage flow wind movement <br />generally less than 3 knows. This explains the large number of occurrences from the SE <br />direction. If wind occurrences in the 1-3 knot category are treated as calms, the revised <br />percentages shown in Table 8-4 change to 7.2 percent from the ESE through SSE directions <br />and 27.3 percent from the NNW through NNN directions. Calms now amount to 58.1 percent. <br />This indicates [he significant prevailing winds come from the general NN direction which <br />conforms with the general topography of the area. <br />The average wind speed et the Seneca II-W site for this time period was 3.8 knots. The <br />maximum wind speed recorded was 58.6 knots. The average maximum wind speed was 13.6 knots <br />• while the average minimum wind speed was 0.43 knots. <br />3 Revised 03/01/93 <br />