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="• <br />Page 3 <br />7, Revegetation test plots experimenting with re vegetating various <br />depths of topsoil replaced atop tailing were observed, Tree <br />vegetation growing in the test plots did not appear as vigorous as <br />adjacent vegetation growing on natural soils; the plants appeared <br />dwarfed and somewhat desiccated, <br />When providing results of the quantitative sampling of these plots, <br />please include experimental design specifications, i,e., depth of <br />tailing, depth of topsoil replacement, fertilization and mulching <br />rates, if applicable, seed mixture and application rates, date and <br />method of planting, etc. An illustration delineating plot <br />orientation would be helpful, as would photographs. <br />9. When determining optimal topsoil replacement depths atop tailing to <br />maintain adequate vegetative cover, for surface stabilization, and <br />production, for wildlife forage, the following should be considered: <br />a) the aspect and slope gradient of the test plots should <br />simulate the ultimate feature to be reclaimed; <br />b) depth of tailing should be adequate to preclude plant-roots <br />from penetrating into the substrate below the tailing; thus, <br />water and nutrients from the substrate are not utilized, <br />thereby minimizing false results. Additionally drainage <br />between the tailing and substrate should be provided to <br />minimize the possibility of a perched water table; <br />c) erosion and resulting sedimentation rates should be Evaluated <br />on sloped plots; <br />d) cultural amentments to the tailing may also affect the <br />topsoil replacement depth: <br />i) The final 3 to 5 feet deposition of loamy textured <br />"tailing" would benefit revegetation establishment and <br />growth; in this manner, extreme droughty clay and sand <br />textures are eliminated, thereby improving water- and <br />nutrient-holding capacities. "Waste" rock run <br />partially through the mill may be considered; <br />ii) Additionally, organic matter and fertilizer <br />incorporation into the last 1 to 2 feet of tailing <br />deposition would provide improved nutrient- and <br />water-holding capacities of the medium; <br />iii) blending topsoil into tailing should be evaluated; <br />Thus, the Division is unable to approve the request for reducing <br />topsoil replacement depth, as quantitative data has not been <br />provided, and the questions/suggestions outlined above have not <br />been addressed. <br />