2010-12-17_REVISION - C1981019 (142)

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Baseline Survey of Soil Resources - Collom Mining Area July, 2006 INTRODUCTION During the summer of 2005, Tetra Tech, Inc. (Tetra Tech, formerly Maxim Technologies) completed a soil resources survey within the vicinity of the proposed Collom Mining Project for Colowyo Coal Company L.P. (Colowyo) The soil Survey Area includes potential mine and support areas proposed for disturbance, as well as the remaining portions of the proposed Collom Mine permit area. This survey was conducted to support the mine permit application and attendant reclamation planning. The specific objectives of the soil resources survey included the following: • Describe soil profiles, and classify soils to the series level where such series have previously been identified as part of the existing Natural Resources Conservation Service (NRCS) soil survey; • Sample and analyze physical and chemical properties of representative pedons in the Survey Area; • Prepare a description of map units and components within the Survey Area; • Review the results of field descriptions and laboratory analyses to assess wind and water erosion potential, water holding capacity, and permeability; and, • Evaluate soil suitability for reclamation (i.e. as a growth medium), identify limiting characteristics, and propose suitable salvage depths of the soil found in the Survey Area. In 2006, Catena Consulting, LLC (Catena) was contracted by Tetra Tech to assist in the compilation of this report based on the field effort. This document describes the methods used by Tetra Tech and Catena to achieve the survey objectives, as stated above, and compile this report. Supporting information is included in appendices to this document. METHODS A plan of study (POS) for completion of this survey was submitted to the Colorado Department of Mines and Geology (CDMG) on August 28, 2005. Verbal approval was received from CDMG in early September. The methods employed to collect and analyze soil resource data were generally consistent with this POS. The methods employed to conduct the survey are identified in this section. Data Review The following information was reviewed prior to initiation of the soil survey: • Aerial photography and topographic mapping for the Survey Area, made available from Colowyo; • The geologic map of Colorado (USGS); • Soil survey information from Moffat and Rio Blanco Counties (USDA 2005a; 2005b). Field Investigations A soil resource evaluation and Order II soil resource inventory, including soil sampling and laboratory analysis, were completed for areas that would potentially be disturbed by development of the Collom Mining Project, including areas both inside and outside the proposed mining permit boundary. The Survey Area for this Order II survey mapping included approximately 13,605 acres as shown in Figure I. An Order III survey (displaying much less detail) was completed on approximately 3,240 acres within the proposed permit area, but outside the Order II survey boundary. Together, these surveys comprise the Survey Area and encompass a total of 16,845 acres. The soil survey was conducted according to guidelines provided by the National Soil Survey Handbook (USDA 2003) with modifications as noted in this section. Additional references used included: Soil Conservation Service, Soil Survey Manual, Handbook 18 (USDA 1993), Soil Taxonomy (USDA 1999) and Keys to Soil Taxonomy (USDA 2006). Map unit boundaries were identified by field observation and interpretation of aerial photographs, topographic maps, and other geographic models. • Tetra Tech, Inc.