2024-05-17_REVISION - M1977493 (3)

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Permit M-1977-493—Climax Mine Technical Revision 37 (TR-37) 1-1 Introduction A soil assessment of the Climax Mine permit area was conducted for the development of this permit amendment. This soil assessment uses updated mapping and soil map unit descriptions developed from soil surveys performed by the United States Forest Service (USFS). The White River and Pike National Forests conducted soil mapping on Forest lands adjacent to the Climax property in 1995 using Natural Resource Conservation Service (NRCS) approved mapping techniques and nomenclature (USFS 1995a, USFS 1995b). Climax soils were mapped as part of this delineation. An overlay of the USFS soil mapping for the White River and Pike National Forests has been overlain on the Climax base map (Figure AM-06-1- 01). Mapping and soil map unit descriptions for the Climax permit area from these reports and NRCS soil series descriptions are contained in Appendix I-A and were used to determine: 1) Estimates for reclamation cover salvage depths (combined topsoil and subsoil); and 2) Stockpile volumes. This existing information is considered sufficient to address all the requirements listed in DRMS Rule 6, Section 6.4.9. Therefore, no site specific soil surveys were conducted. 1-2 Goals & Objectives The goals and objectives for this updated soil assessment are to: ■ Use recently updated Order 3 mapping collected by the USFS; ■ Determine the location and extent of different soil types in the permit area, and, in particular, soils within the affected area boundary; ■ Identify physical characteristics that may limit soil suitability and salvage; ■ Serve as a general guideline in predicting the availability, quantity, and quality of the soil materials suitable for use as reclamation cover; and ■ Address and meet the requirements contained in Colorado DRMS Rules and Regulations pertaining to soil information and salvage. This soil assessment will provide the information necessary to develop a consistent soil-handling plan for the lands to be disturbed within the proposed Climax Mine affected area. Specific soil handling guidelines are also discussed in Exhibit E: Reclamation Plan. 1-3 Physiography The natural development of a soil is dependent upon its vegetation community; in fact, if undisturbed, both soil and vegetation evolve interdependently. The natural developmental stages leading to a stable or climax vegetation-soil unit are governed by several factors including the type of soil parent material, general climate, topographic characteristics of the site (microclimate), various organisms, and time. The developed soils within the Climax landscapes have been heavily influenced by variations in vegetation and topographic position. Alfisols occur on the forested slopes, while Mollisols occur on well-drained meadow lands both above and below timberline and under aspen forests. Inceptisols and Entisols occur mostly in the alpine, but are also observed below timberline. The soil order Histosols has developed both above and below timberline within wet bottom lands dominated by willows. 1-4 Soil Classification and Descriptions Alfisols are generally forested soils in the Climax area, with one exception being the sites on which timber was cleared. These deforested areas presently are dominated by grasses and other herbaceous species. The Alfisol soil type has developed under a cold and acidic environment due to the decomposition of acidic foliage (needles) dropped from spruce, fir and pine trees. Fungal organisms dominate the decomposition process and liberate organic acids which illuviate along with clays to produce a subsoil argillic horizon. The typical Great Group is the Cryoboralfs,which are cold, forested soils on mountain slopes in the Climax area and are included the Leadville map unit (Appendix I-A). These soils vary in depth, but often there is a Exhibit 1 1-1 March 2024