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ANALYTICAL COMPARISON BETWEEN REGRADED SPOILS AND ADJACENT OVERBURDEN DRILL HOLES AT TRAPPER MINE, 1985-87. Introduction Soil and overburden analysis is necessary in the premining phase of the coal mining operation in order to predict what characteristics the spoil material will exhibit after mining. Experience in overburden sampling at Trapper Mine over the last ten years of operation has identified strata which have shown to be indicators of potential chemical and physical problems. High clay content overburden tend to be associated with high ESP or SAR values. Also, over- burden up to 50 feet above the lowest mineable coal seams generally appear at the surface to become part of the subsoil for supporting vegetation. The replacement of these lower lithological strata on the spoil surface which may have higher-than-desired mineral content may be of little concern from a reclamation standpoint. The mixing of regrade surfaces during spoil regrading is of primary importance to ensure adequate subsoil composition. In order to focus on what Trapper considered a potential spoil problem, Trapper Mine proposed and CMLRD agreed to abandon its current program for sampling in-place overburden and provide yearly analysis and reports on regraded spoils. The annual report will demonstrate that a surface spoil layer exists with acceptable physical and chemical properties. With the addi- tion of suitable topsoil, these regraded spoils provide a suitable medium to promote plant growth and successful reclamation. This report is a composite of three years of spoil data collection and will provide baseline information for future spoil sampling reports. 4.1 Methods Composite samples were taken on approximately 50-ft to 100-ft centers for each mapping unit. Mapping units in 1985-1987 were determined by visual and textural difference with no size limitation, however a minimum sampling density of approximately one sample per five acres of reclaim area will be performed in the future. Each sample was a composite from the top four inches of spoil material. Future sampling will be composite samples from one foot into the spoil material. The samples were analyzed Eor pH, EC, CaC03, O.M., N03-N, P, K, Zn, Fe, Mn, Cu, Se, Ca, Mg, Na, SAR, % Saturation, texture, Hg, F, Total S, and acid-base potential. If a large negative acid-base potential was found, then additional analysis to include pyritic Sulfur and SOq-S was run for that sample. The final mapping units were then transferred to the spoil history map, I-1. Each delineation on this map was identified as to year sampled, texture, and lab analysis number. Overburden sampling in the east panel was run concurrently with the exploratory drilling program. In order [o keep the samples free from drilling contamination and as representative of their natural conditions as possible, the following procedures were followed. 1) Continuous cores if possible were taken down to the last seam of mineable coal and including the lithologic strata immediately beneath that coal seam. . _~ cont.