Laserfiche WebLink
4.0 CONCLUSIONS <br />An annual site chazacterization methane assessment was performed east of the Golden Eagle Mine i:n Weston, <br />Colorado to determine whether methane concentrations in monitoring points have changed over time. <br />The average methane concentrations have shown a decreasing trend in the existing original 22 points that <br />have been monitored since Mazch 1999 (an average decrease from 53.7 to 29.3 percent). Additionally, <br />average methane concentrations have decreased in the existing 35 points monitored since the last monitoring <br />report in 2004 (an average decrease from 38.4 to 32.3 percent). Vegetation was observed to be recovering <br />during the 2005 sampling event in azeas where methane concentrations had decreased. <br />Measurements from the mine's airshafts indicated that there were high methane concentrations in the Former <br />mine workings. The measurements taken from the south airshaft in 2005 indicated a concentration of 88.6 <br />percent methane. The north airshaft was inaccessible during the 2005 monitoring event because it has been <br />reclaimed. The mine workings have represented a potential source of methane in the azea; however, water <br />monitoring studies indicate that the mine workings have been inundated, which should minimize any potential <br />for methane seepage to the surface. The effected azea of vegetation during the 2000 survey was about 146 <br />acres. The effected area of vegetation during the 2005 survey was about 32 acres, the same as in 2004. <br />No imminent hazards aze associated with the methane seepage other than stressed or dead vegetation. <br />Methane would only be a human or animal health concern within a confined space. <br />292-Meth_(i L29.05).doc 4-1 <br />