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<br />packs. Moreover, they could provide background levels specific to Colorado and to the trace <br />chemical analyses techniques in current use by DRI, the independent agency that performed the <br />analyses. The sampling procedures are illustrated in Appendix A. <br /> <br />Table 1. List of Snow Course or SNOTEL nearest each Silver-in-Snow Sampling Location. The <br />upper ten iocations are all ~ithil1. the intended target a.rea and the three lowest entries are all north <br />of the AgI generators, sampled for control purposes. <br /> <br />Snow Course or Elevation Latitude Longitude <br />SNOTEL Name (feet) (del! min) (deg min) <br />Hoosier Pass 11,400 39 22 106 04 <br />Fremont Pass 11,400 39 23 106 12 <br />Michigan Creek 10,600 39 26 105 55 <br />Coooer Mountain 10,500 39 29 106 10 <br />Sundance 11,100 39 34 105 44 <br />Vail Mountain 10,300 39 37 106 23 <br />Grizzlv Peak 11,100 39 39 105 52 <br />Middle Fork Camp Ground 9,000 39 47 106 01 <br />Berthoud Summit 11,300 39 48 105 47 <br />Arrow 9,680 39 55 105 46 <br />Phantom Valley (Control) 9,030 40 24 105 51 <br />Willow Creek Pass 9,540 40 21 106 06 <br />(Control) <br />Rabbit Ears Pass (Control) 9,400 40 22 106 44 <br /> <br />Precise sampling locations were determined with a Garmin GPS 12 Global Position <br />System (GPS) receiver using the NAD27 map datum. The sampling site location data are given <br />in Table 2. At each site, a snow pit was initially dug through the entire depth of the seasonal <br />snowpack using an aluminum shovel. Once the pit was excavated, powder-free laboratory gloves <br />were worn and an acid-washed sampling blade supplied by DR! was used to scrape about 3 cm of <br />snow off the vertical pit wall to remove any impurities. Once the pit face was cleaned, the same <br />sampling blade was used to cut out a vertical column of snow from the clean pit wall. The <br />sampled column was approximately 10 cm by 10 cm in area and incorporated snow from the <br />snowpack surface to about 5 em above ground level. Obviously dirty icy surface melt crusts were <br />discarded from the samples as suggested by Dr. Joe McConnell of DR!. Inclusion of wind-blown <br />dust particles could seriously contaminate the samples if the source was silver-rich soils. No <br />other signs of snowpack melt were observed at any of the sites. Each remaining portion of a <br />sample snow column was transferred to a first-run layflat heat sealed plastic bag supplied by <br />DR!. After sampling was complete, samples were carefully labeled and kept below freezing <br />during transportation to a commercial freezer facility for temporary storage. Once all samples <br />had been collected they were placed in coolers packed with dry ice and shipped to DR! via <br />overnight express service. <br /> <br />16 <br /> <br />