An analysis of the chemical and physical changes in minesoils within a 20 year period of soil development was conducted on the Coal Valley Mine in the central Alberta foothills. The analysis was based on comparisons between three age classes (5-8, 12-14, and 17-20 years), and undisturbed soils from the surrounding area for a total of 32 profiles. The dominant processes for early soil development within the minesoils were weathering, leaching, and organic matter accumulation. Sodium and magnesium concentrations, sodium adsorption ratios, electrical conductivity, bulls density, pH, and sand content decreased significantly with site age. Aluminum and ammonium concentrations; and organic matter, silt, and clay content increased significantly with site age. Little differentiation occurred within the 40 cm sampling depth for all age classes. The data suggests a relatively rapid return (≤50 years) of tested soil properties in a minesoil to approximate profile averages in an undisturbed soil.