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MAXIM <br />TECHNOLOGIES <br />A DIVISION OF TETRA TECH INC. <br />1/ 1J <br />u <br />September 23, 2005 <br />Mr. Jim Stark <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />Subject: Collom Permit Area <br />Preliminary Alluvial Valley Floor Assessment <br />(Maxim Project Number 5520068.420) <br />Dear Mr. Stark, <br />6178 South Stratler Street <br />Murray, UT 84107 <br />Office 801.269.81 17 <br />Fax 801.269.8308 <br />Maxim Technologies (Maxim) has completed a preliminary review of the proposed Collom permit area in <br />the context of alluvial valley floor (AVF) determinations. This review was completed in accordance with <br />the requirements of Section 2.06.8 of the Regulations of the Colorado Mined Land Reclamation Board for <br />Coal Mining. While this review is not final, it does offer a preliminary review of our findings and is an <br />appropriate starting point for discussions with your staff. Our findings are presented immediately <br />following the excerpted regulatory requirements. <br />Small portions of the Morgan Gulch channel and basin are included in the permit area. However, no <br />disturbance is proposed within that watershed, and any potential alluvial valley floors found there would <br />not be affected by the Collom project development. <br />Requirements of Section 2.06.8(3)(b) <br />(i) Mapping of unconsolidated streamlaid deposits holding streams including, but not <br />limited to, geologic maps of unconsolidated deposits, maps of streams, delineation of <br />surface watersheds and directions of shallow ground water flows through and into the <br />unconsolidated deposits, topography showing local and regional terrace levels, and <br />topography of terraces, flood plains and channels showing surface drainage patterns. <br />Figure 1 identifies the locations of unconsolidated valley fill deposits containing a <br />significant alluvial component. These areas have been further split into a) wetlands, b) <br />valley fill deposits with substantial colluvium and sheetwash content (based on <br />topography and field observations), and c) valley fill deposits (non-wetland and without <br />substantial colluvium and sheetwash). Areas adjacent to channels elsewhere within the <br />permit area exhibit one or more of the following characteristics: a) very narrow and <br />historically uncultivated bottoms (100 feet wide or less), b) significant amounts of <br />colluvial materials, or c) significant amounts of sheet wash deposits originating from <br />adjacent slopes. <br />Nearly all of the valley bottoms have unconsolidated materials to a depth of at least nine <br />feet, even near the headwaters. These deposits have accumulated primarily through <br />erosion and deposition of loess found throughout the project area, especially at higher <br />elevations. Accumulated surface water combined with deeper rooting depth and more <br />loamy textures, relative to many of the skeletal and clayey soils found in adjacent areas, <br />