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r III IIIIIIIIIIIII III STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY Depanmeni of Natural Resources 1317 Sherman St., Room ? 15 Denver, Colorado 80207 Phone: (30 31 866-7 587 FA%:130 31 8 72-81 06 DATE: June 19, 1997 TO: Jim Pendleton FROM: Susan Burgmaier~ RE: Bowie No. 2 Mine (C-96-083) ~~ DEPARTMENT OF NATURAL RESOURCES Roy Romcr Governor dames S. Lochhead Executive Director Michael8 Long Division Dirtt log During my inspection of the Bowie No. 2 Mine eazlier this week, 1 became aware of some possible geotechnical concems. David Berry suggested I docun3ent those concerns for you, so that you could decide whether additional investigation on our part is warranted. A site representative for the contractor that is constructing the road and facilities (Larry Whitt) stated that groundwaterhad been intercepted at the road fill located at Station 64+00. Mr. Whitt informed me that a fabric wrapped core drain had been installed, and that a culveR had been placed at the base of the fill to help drain the core. David Jenkel, an associate at J. Stover & Associates, mentioned that the water which drains from the fill "disappears somewhere in the rock", that he hasn't seen where it eventually drains. I asked them if the water had been anticipated when the designs were being developed. They told me that it must have been anticipated, because the core drain was in the plan. Reviewing the plan, I did not find a plan for a core drain. The recommendation from M-K and Maxim, where groundwater is discussed, is that if groundwater is encountered, a qualified person should assess the situation and develop any necessary modifications to the construction plan. I am not sure if this happened, but it did not appear that it did. Until the inspection, [ am not aware that DMG was notified of the groundwater occurrence. During the inspection I also became aware that the large slide located on the eastem/northeas[ernhillside above the portals moved considerably in January or February of this year. David Berry was not aware of this, so 1 thought you might not be either. Joe Dudash, during an inspection in May, was concerned that the embankment for Pond C was compacted against a remnant concrete wall. I looked at it this week, and have the same concern. It does not appear that the concrete wall shows up in any of the design drawings, which would suggest it was not figured into the stability demonstrations. I am not certain that [here has been a geotechnical engineer present during construction. Basil Bear [old me that someone has been doing compaction tests, but I was not introduced to or n3ade aware of any such person.