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TRAUTNERACT411 04 <br />GEOTECHNICAL ENGINEERING, MATERIAL TESTING <br />AND ENGINEERING GEOLOGY <br />December 5, 2011 <br />Mr. Steve Fearn, P.E. <br />Colorado Goldfields, Inc. <br />PO Box 790 <br />Silverton, Colorado 81420 <br />PN: 52519GE <br />Subject: Test Boring Closures and Sealing <br />Kittimac Repository Site <br />Silverton, Colorado <br />Mr. Fearn, <br />This letter provides a brief description of the method utilized to abandon and seal Test Borings KMGT <br />One through Nine and Eleven through Fifteen. The proposed KMGT Test Boring Ten was not advanced. <br />These test borings were advanced between July 19, 2011 and August 18, 2012. The test borings were <br />sealed for abandonment immediately after the boring had been completed. We have attached Well <br />Abandonment Reports (State of Colorado Form Number GWS -09) for each of the test borings advanced. <br />The GPS coordinate locations of the sealed test borings may be found on the attached Well Abandonment <br />Reports. The GPS locations were provided to us by the project surveyor. <br />The test borings were advanced to depths ranging from approximately eighteen (18) to sixty (60) feet <br />below the ground surface elevation adjacent to our test borings. The majority of the test boring depth <br />caved in on itself during the removal of the auger. The remainder of the test boring was filled with an <br />imported one and one -half (1' /z) inch minus aggregate material to a depth of ten (10) feet below the <br />ground surface elevation. The remainder of the test boring was then sealed with a Portland cement grout <br />slurry. We added approximately five (5) to eight (8) percent bentonite clay to the grout mix in order to <br />facilitate achieving a good seal within the test boring. <br />Depending on the subsurface free water elevation, the mixture was either placed directly down the <br />boring or through a tremmie tube. We utilized a tremmie tube in locations where shallow subsurface free <br />water was encountered. As noted in the attached abandonment reports, the quantity of Portland cement <br />and bentonite used to seal the test borings is variable. This is due to the fact that in some test borings, due <br />to the granular nature of the material, the upper portion of the boring became enlarged or flared due to the <br />auger rotation. <br />Please contact us if you have any questions or if additional information is desired. <br />Respectfully, <br />rt <br />Jonathan P. Butler, P.E. <br />Trautner Geotech <br />649 TECH CENTER DRIVE SUITE A - DURANGO. CO 81301 • 970/259.5095 • FAX 970/382 -2515 <br />