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ADS-RPT-2021-14 <br />ESS-Nederland Mine _ 60 <br />November 4, 2021 <br />200 Lake Drive, Glasgow, DE 19702 302.731.1700 Fax 302.731.1701 <br />www.gravertech.com <br />Proprietary and Confidential <br />Page 3 of 8 <br />The sample was capped and placed on a shaker table. The sample was contacted at 250 rpm <br />overnight for a total of about 22 hours. The water was removed and filtered with a 0.45 um syringe <br />filter. Samples were preserved with nitric acid and then analyzed by inductively coupled plasma <br />mass spectrometry (ICP-MS). <br />3.2 Kinetic batch testing. <br />3.2.1 Ratio of 100,000 mL/g <br />To a 4 L plastic beaker was added 5050 g of water from Cross. A stir bar was added, and the sample <br />was stirred for 2 minutes. 40 g of water was removed and designated as “Time 0”. To the beaker <br />was added 51.0 dry milligrams of MetSorb® HMRG (moisture of 10.39%). 40 mL samples were <br />removed from the container at the following intervals: 1 minute, 5 minutes, 10 minutes, 30 <br />minutes, 60 minutes and > 18 hours. When a sample was removed, it was filtered with a 0.45 um <br />filter and preserved with nitric acid. Samples were analyzed by ICP-MS. <br />3.2.1 Ratio of 50,000 mL/g <br />To a half-gallon plastic container was added 2040 g of water from Cross. A stir bar was added, and <br />the sample was stirred for 2 minutes. 40 g of water was removed and designated as “Time 0”. To <br />the beaker was added 43.9 dry milligrams of MetSorb® HMRG (moisture of 10.39%). 40 mL <br />samples were removed from the container at the following intervals: 1 minute, 5 minutes, 10 <br />minutes, 60 minutes and > 18 hours. When a sample was removed, it was filtered with a 0.45 um <br />filter and preserved with nitric acid. Samples were analyzed by ICP-MS. <br />3.2.1 Ratio of 1,000 mL/g <br />To a one-liter plastic container was added 943.5 g of water from Cross. The sample was manually <br />stirred. 40 g of water was removed and designated as “Time 0”. To the container was added 896.7 <br />dry milligrams of MetSorb® HMRG (moisture of 10.39%). The container was placed on a shaker <br />table at 250 rpm. The shaker table was stopped prior to and restarted after samples were <br />collected. 40 mL samples were removed from the container at the following intervals: 1 minute, <br />5 minutes, 10 minutes, 60 minutes and > 18 hours. When a sample was removed, it was filtered <br />with a 0.45 um filter and preserved with nitric acid. Samples were analyzed by ICP-MS. <br />3.3 Analytical <br />All samples were analyzed by Graver Technologies and an independent third-party laboratory, <br />Eurofins Test America. Both techniques used an ICP-MS to evaluate the results. Graver’s results <br />were used to quickly determine the analyte concentrations, while the Eurofins Test America <br />results were used based on their knowledge and expertise as a certified laboratory running tests <br />under EPA method 6020B.