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Prior to the Surface Mining Control and Reclamation Act of 1977, mining activitiesproduced vast amounts of untreated mine waste and overburden material. Surface contour miningtechniques commonly proceeded uphill leaving behind a series of spoil piles which were emplacedin a semi-linear fashion. This relationship between location and relative time since emplacementis leveraged using a chronosequence approach to understand the pedogenesis of parent materialsto technosols. The study site was in the Huff Run Watershed (Mineral City, Ohio) with a series ofeleven spoil piles along an elevation transect in subwatershed #25 (HR-25). Bulk density, loss-on ignitionas a proxy for organic matter, and particle size analyses were used to determine changesin physical properties along the transect. X-ray fluorescence spectroscopy and X-ray diffractionwere used to determine elemental and mineralogical composition, respectively, of the spoil piles.Results of this work show that, with an increase in inferred age of spoil there is a loss of bulk soildensity, an increase in organic matter content, and a loss of both coarse rock fragments and of fineparticles. Results of chemical characterization show that the piles are dominated by overburdenmineralogy and that bulk chemistries reflect the mineralogy with notable variation within theminor and trace elements. Findings of this work suggest that the (1) cumulative effects ofbiological activity, primarily the colonization by plants, is likely responsible for major physicalchanges that occur on decadal time scales like the accumulation of organic matter and decrease inbulk density; (2) short-term mechanisms like the physical weathering by slaking and illuviationare responsible for the observed changes in particle size distributions across the transect; (3) smallvariations in the relative contributions of parent material confound any presence of elementalweathering signatures; (4) spoil materials dominated by overburden materials may still representa future source of toxic metal release through their accumulation in organic matter or secondaryoxides. This work supports the continued application of chronosequence frameworks to mine spoilpiles and further proposes that end-member mixing methods be applied for its improvement.