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• Topsoil and Spoil Monitoring <br />SCC monitors the salvage, storage, and redistribution of soil and spoil handling operations at Seneca <br />II-West Mine. Spedfic programs include documenting soil recovery, verifying soil redistribution <br />thickness, determining final graded spoil suitability, detern+ini a soIl fertility, evaluating plant rooting <br />characteristics, and completing an annual soIl balance. <br />Soil fertility and spoil quality samples aze collected periodically from soil/spoil samples, which aze <br />randomly located using a 500-foot grid. Post mine so$ pits, dug with a backhoe to a five foot depth, <br />are used to evaluate plant-rooting characteristics and to compaze soil/spoil profile data with site- <br />specific revegetadon data. These pits aze located using an intensity of one pit per twenty five acres. <br />Post mine soil pits aze placed within reclamation blocks that have been soiled and seeded for a <br />minimum of three years. Similar minimum time frames aze used for monitoring post mine <br />vegetation. The permanent vegetation has generally established sufficiently after three to four years <br />to evaluate interactions between rooting depths and soil/spoil quality. <br />Topsoil Replacement <br />In developing the topsoil replacement plan; SCC gave consideration to the replacement of varying <br />thicknesses of topsoil within specified portions of the reclamation azea. In addition to areas in which <br />the "standazd" mean replacement thickness (1.6 feet) is conducted, consideration was given to <br />replacement of both "thinner" and "thicket" soils in various locations. Soil replacement thickness of <br />• 2.5 to 4.0 feet was determined appropriate on selected north slopes, swales, along minor ephemeral <br />drainages, and other locations conducive to the establishment of aspen and associated tall shrub <br />species. Consideration was also given to replaang reduced soil thickness (e.g., 6 inches) within <br />specific locations to potentially enhance the establishment of a number of the shrub species that aze <br />typically assoaated with relatively shallow rocky soils. The overall vegetation diversity within the <br />reclaimed aeeas is enhanced by such variation in topsoil replacement thickness. <br />TopsoIl is replaced with Caterpillaz 637 scrapers (see Photo 2), at variable replacement depths based <br />on slope grade, aspect, and vegetation type to be planted. SCC is required, by Permit C-1982-057 <br />and Section 4.06.4(2)(6) of Colorado's Regulations for Coal Mining, to document and record the soil <br />replacement thickness for each reclamation block using a minimum sampling intensity of one hole <br />per five acres. <br />Slopes of 30% or more require special techniques to improve moisture retention and reduce erosion. <br />"Hummocking", is the process of pock-mazking the replaced topsoil with dozer dips, or by track hoe <br />(Photo 3). <br />Revegetation Program <br />Initial consideration in the development of the peananent seed mines and seedling planting lists <br />included the antidpated reclaimed site conditions and the desired revegetation communities to <br />achieve apost-mining land use for livestock grazing and wildlife habitat. SCC uses appropriate <br />seeding and planting techniques to achieve a rolling post-mine landscape and lasting ]andfotm where <br />a permanent, productive, and varied vegetation of predominately native speces is established (see <br />Photo 4). Specific goals which factored into the permanent seed mixes and seedling lists <br />included rapid and long-term surface stabilization, ease of establishment, maximum use of <br />