REDACTED Letter Presents Avalanche Hazard Observations For
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November 20, 2015 (b) (6) Environmental Restoration 2140 North Redwood Rd, Suite 10 Salt Lake City, UT 84116 801-209-0368 (b) (6) PN: 54056AV Subject: Avalanche Hazard Observations for The Gold King Mine Project Site Gladstone, Colorado (b) (6) , This letter presents our observations of our cursory evaluation of the avalanche hazard associated with the Gold King Mine Site and access road near Gladstone, Colorado. We visited the site on November 19, 2015 and met with (b) (6) and Mr. Steve Way of the Environmental Protection Agency. There was a significant winter storm in the area this week with 30 inches of new snow and 2.65 inches of snow water equivalent. The avalanche hazard bulletin from the Colorado Avalanche Information Center (CAIC) had the avalanche hazard at High on Tuesday and Wednesday November 17 and 18. We visited the portal at the Gold King Mine and observed several potential avalanche paths on the access road from Gladstone to the mine and on the slopes above the mine. Cursory examination of the avalanche paths on Google Earth show that the starting zones of the potential avalanche paths above the Gold King Mine are between 34 and 36 degrees. There are numerous avalanche paths on the north facing slopes along the access road that are not obvious avalanche paths because they run through timbered slopes. We observed numerous small slab avalanches and tension cracks in the snow from the recent avalanche cycle on the north facing slopes adjacent to the access road. There are large avalanche paths on Bonita Peak to the east that have the potential to reach the access road. The steep mine dumps adjacent to the Gold King Mine site are steep enough to have small avalanches reach the access road, which would be large enough to bury a person but not big enough to destroy a vehicle. The avalanche paths on the slopes above the Gold King Mine are southwest facing and have the potential to run from an elevation of 12,183 feet down to the portal at about 11,480 feet. We conducted a snowpit to test for instabilities in the snowpack near the elevation of the portal. We encountered 61 cm (2 feet) of snow with the snowpack demonstrating an upper level weak layer. We were not able to access the upper part of the slopes where the starting zones of the avalanche paths are located. The snowpack exhibited Moderate instabilities and I would rate the avalanche hazard above the mine at Moderate for this week through the weekend. Due to the relatively warm daytime temperatures this week and moderate winds, I believe the avalanche hazard will remain at Moderate for the access road and Gold King Mine area until the next storm system. We did encounter a potential weak layer of surface hoar snow crystals at the surface of the snowpack, which are not hazardous currently, but could become a weak layer with subsequent PN:54056AV November 20, 2015 Page 2 snowfall. I must emphasize that these observations are cursory and were based on limited field work. There may be areas that are more unstable than we observed and avalanches are possible in the area. We recommend that all personnel that access the site have avalanche rescue gear with them including an avalanche beacon, shovel and probe pole. We recommend against any foot traffic along the access roads and that personnel should stay in their vehicles when crossing potential avalanche paths. At the portal site, personnel should either be in their vehicles or in the tunnel underground to avoid avalanche areas. The proximity of the Gold King Mine to the Silverton Mountain ski area may be problematic once the ski area commences avalanche control with explosives. Sympathetic avalanches, which occur in areas adjacent to avalanche paths where explosives are used, have occurred in the Velocity Basin area adjacent to the ski area during their control work in the past. During high avalanche hazard conditions, it may be possible for explosive work at the ski area to trigger avalanches near the Gold King Mine site. We also observed the access road to the Red-Bonita Mine and remotely observed the slopes above the Red-Bonita mine from the access road below the mine dump. It appears that the Red- Bonita mine is also in an avalanche path and that the access road crosses numerous avalanche paths. We understand that access to the mine involves the use of heavy equipment to plow the access road. The access road adjacent to the mine dump has steep slopes and plow equipment has the potential to undercut the slope and cause an avalanche. The equipment operator should have avalanche PPE and have a spotter if access to the Red-Bonita mine will be opened. We feel that there is a serious potential for avalanche hazard at the Gold King Mine site and access road during the winter season. While the hazard is at moderate this week, with additional snowfall the hazard will increase. We recommend following the CAIC avalanche hazard bulletin daily. If the CAIC avalanche bulletin has the avalanche hazard at Considerable or High, we recommend no access to the site until the hazard drops to Moderate. We recommend that winter operations should not continue through the winter months at the mine without a full scale avalanche winter operations plan and active avalanche forecasting. We recommend additional avalanche hazard observations if conditions change due to new snowfall or wind loading. Avalanche hazard can vary depending on a number of factors including but not limited to; snow pack height, snow layer type, wind speed and direction, and meteorological factors before, during and after a storm cycle. We provided cursory observations of the potential avalanche hazard for the subject avalanche property, but extraordinary snow or weather phenomena can produce unexpected avalanches in areas that have no evidence of previous avalanche activity. PN:54056AV November 20, 2015 Page 3 Please contact us if you have any questions, or if we may be of additional service. Respectfully submitted, Engineering Geologist/ Avalanche Specialist Trautner Geotech TRAUTNER rll=t(11J(tJ•rm1 .