2008-09-04_HYDROLOGY - M2007044 - Laserfiche WebLink

Home Browse Search

J Untreated Water (control sample) - DO levels decreased slightly during the first 24 hours that the sample was open to the atmosphere from 6.30 mg/L to 5.93 mg/L, then increased slightly over the following 48 hours from 5.93 mg/L to 6.15 mg/L at 72 hours into the test. T-Floc B-21L (polymer flocculent) - Tested at 30 mg/L, DO levels consistently increased from 5.79 mg/L (before addition) to 6.77 mg/L. Magnafloc 110-L (polymer flocculent) - Tested at 0.63 mg/L, DO levels initially increased from 6.04 mg/L (before addition) to 6.55 mg/L within 5 minutes, but decreased slightly over the next 24 hours to 6.33 mg/L. Sodium Metabisulfite - Tested at 13 mg/L, DO levels initially increased from 6.24 mg/L (before addition) to 6.37 mg/L within 5 minutes, but decreased slightly over the next 60 hours to 5.82 mg/L, followed by an increase to 5.99 mg/L at 84 hours. The above results indicate that the Magnafloc 110-L and sodium metabisulfite create a slight decrease in DO levels until the oxygen demand of the solution is met. However, at the concentrations that these chemicals were added during the June 24-26, 2008 WET test (the same concentrations they were tested at), the decrease is not sufficient to explain the large drop observed during the initial stages of the WET test. Initial DO levels observed prior to conducting the failed WET test were at a low during the first day (4.58 mg/L) but increased the following 5 days (6.68 to 7.50 mg/L). Similarly, a sample collected on June 24 indicated that chemical oxygen demand (COD) was at 56 mg/L (the highest recorded during discharge sampling), but was at 14 mg/L in a sample of discharge collected on June 26. A batch run of mine water was treated on July 28-31, 2008. DO levels were monitored and COD samples were collected on a daily basis. The results of the DO field tests are attached; the COD analytical results are not yet available. The DO field test data indicates that the treatment process decrease oxygen levels slightly, but not to the level where it would impact aquatic species. Conclusion Energy Fuels believes that the low DO levels may have been an isolated event. However, this cannot be confirmed until all analytical results are received. Prior to the June discharge, water was pumped from the treated water tanks to the untreated water tank for cleaning purposes and installation of bird ladders (required by the BLM). Some precipitant from these tanks was pumped over along with the water. It is possible that the treated water and precipitant created a higher COD than normal, resulting in low DO levels during the initial discharge from the treatment plant. Energy Fuels is currently investigating the need for use of the Magnafloc 110-L flocculent and sodium metabisulfite in the treatment process. The mine sump has been Frier y I'trels, Inc. w vv, tv.energy, fileis.coni 44 Union Blvd., Suite 600 Lakewood, Colorado 80228 Phone: 303-974-2140 Fax: 303-974-2-141