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Southwestern
<br />Ecological
<br />Services
<br />b 3
<br />37 East Colorado Avenue • Denver, Colorado 80210-3105 • (303) 722-9067
<br />September 3, 2008
<br />Jared Ebert - <-,-,----- • 7 0 Email with mail followup
<br />Division of Reclamation, Mining and Safety
<br />Room 215
<br />1313 Sherman Street
<br />Denver, CO 80203
<br />RE: 12esponse to second ar1P gtiacw letter of August 15, 2008. Daniels Sand Pit #2 amendment 3.
<br />Permit: M-1973-007 L-'
<br />Dear Mr. Ebert:
<br />Your August 15, 2008, letter contains two items that still need to be addressed. With regard to a notarized
<br />damage agreement letter from the Johnson Family Trust, Mac Shafer of Transit Mix will work on that. Considering
<br />the difficulties in the past, it might be a bit before that is done. Hopefully, not too long though.
<br />With regard to the second item, source and location of slope backfill materials, a description is probably more
<br />useful than another new map. The main area for slope backfilling will be around the south side of the new sediment
<br />basin and in the vicinity of the J Property, once that is mined. Of course, if the J Property is not mined for some
<br />reason, then the backfilling would involve the existing working face just as is the case around the rest of the south
<br />side and the sediment basin.
<br />The backfill material is already stockpiled at the top of these areas. If you recall from the inspection, after we
<br />drove from the bottom of the pit up to where the water treatment facility is located, there were large stockpiles of
<br />material in that area. The same kind of stockpiles, although less prominent, are also around the perimeter of the
<br />south side where the new sediment basin is located.
<br />To address your question and for bond calculation purposes, the response needs to be broken into two parts.
<br />The first part considers the case where the J Property would not be mined. That is, the reclamation would involve
<br />the site as it exists along the south side of the pit. The second part considers the case where the J Property would be
<br />mined.
<br />The southwest corner would be dealt with in the same fashion under both situations. Basically, the stockpiled
<br />material at the top of the slope above where the sediment basin will be established, would simply be pushed over the
<br />side and blended with the sediment basin. This could be done prior to constructing the basin, during basin filling,
<br />and after the basin is completed. It would probably be most effective if done after the basin is finished as the
<br />material would spread out a short ways across the finished basin surface, helping to create more of a bowl shape.
<br />But, in essence, this reclamation, which includes the majority of the slopes to be backfilled, would involve pushing
<br />stockpiled material immediately adjacent to the location where it is needed. Push distances around the south, east,
<br />and, to a small extent, the west side of the sediment basin would probably be less than 100 feet. I suspect, if you
<br />used 100 to 125 feet as a nominal push distance it would be pretty representative of the situation. Backwall height in
<br />this area would be about 10 to 20 feet. So, it is not a big wall, even if it needed to be done right now.
<br />The southeastern corner of the current pit, along with the southern side of the Little Johnson Reservoir area,
<br />will not be influenced by the sediment basin and therefore will require a full height backfill. The areas around the
<br />sediment basin, if done at the end, would constitute a backfill height of generally about 10 to 15 feet with a few
<br />places reaching up to 20 to 25 feet. These are lower because most of the backfilling is accomplished by the sediment
<br />basin.
<br />In the areas not reduced by the sediment basin, backfill heights will average about 35 feet if the Little Johnson
<br />Reservoir and J Property areas are mined or about 50 feet if they are not mined. But in both cases, the material is
<br />already in place at the top and when combined with cut and fill grading, would be easy to finish. If the J Property
<br />and the Little Johnson Reservoir are mined, then there will be a large amount of additional backfill material available
<br />from immediately adjacent lands that are to be mined but are currently undisturbed. In both cases though, push
<br />distances are fairly short, but longer than for the overall sediment basin perimeter. Furthermore, to reclaim the
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