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PRONGHORN <br />November 15, 2014 <br />George Patterson <br />Project Manager <br />Energy Fuels Coal, Southfield Mine <br />P.O. Box 449 <br />Florence, Colorado 81226 <br />George, <br />P.O. Box 4344, Gillette, Wyoming 82717 <br />Office 307 -682 -8254 Cellular 307 - 689 -2358 <br />Attached via e-mail is the Colorado Division of Reclamation, Mining & Safety Well Abandonment <br />form for the recently reclaimed holes & water wells we completed in September. As you and I <br />discussed, this form is a little less than useful in describing the reclamation work we completed. <br />In following are a few short notes on the abandonment slurry and other points of interest. The <br />abandonment slung was principally a high -yield bentonite (plug -gel) mixed with water. This material <br />was used in abandoning the SF series of drill holes back in the 80's when we drilled at Southfield. <br />We modified this mix by adding bentonite chips during the backfill process. We have found that high- <br />yield bentonite will continue to expand in contact with ground waters while cement slurries alone may <br />actually shrink during the setup process. <br />A number of the holes actually caved above their known TD whether they were cased or not. Some <br />of these holes had obstructions in their annulus such as riser pipe, pumps or power cables. Attempts <br />were made in the past as well as during this project to remove the obstructions though not always <br />with success. <br />Holes which were known to be open to the mine works were plugged at the known points of caving <br />or hole obstructions. A suspension plug was placed in these open holes (or their casings) and a <br />limited amount of cement slung in combination with bentonite chips were placed on the plug and <br />allowed to cure. Subsequently high -yield bentonite slurry and bentonite chips were placed in the <br />hole. <br />Each hole was backfrlled nearly to the surface. A plastic octo -plug was placed into each hole or <br />casing annulus on top of the bentonite slurry backfill, generally about 8 -10 feet below the ground <br />surface. A cement slurry was added on top of the octo-plug and bentonite back -fill generally from <br />about 2 -3 feet below the ground surface extending to about 10 feet below the ground surface. Holes <br />having obstructions such as cable or riser pipe could not be octo-plugged. In these cases, extra <br />efforts such as sequential backfills were made to assure a successful seal. <br />