The Factors Influencing Cone Penetration Resistance as a Measure of Compaction in Minespoils

Cone penetration resistence as a measure of compaction was used to evaluate minespoils from the Luscar geological formation of the Alberta Rocky Mountain Foothills across the plant available moisture range. Three soil
textures, two salinity levels and six moisture tensions were tested. There was a well defined relationship between cone penetration resistence, or strength, and moisture tension. Average minespoil strength at 1/3 and 3 bars moisture
tension was 40% and 72% of that at 15 bars tension, respectively. Because each minespoil has a different range of cone penetration resistence, depending mainly on texture, an absolute relationship between moisture tension and strength
could not be developed. By normalizing the strength values, whereby all values were divided by that obtained at 15 bar moisture tension, a predictive equation relating strength to moisture tension is reported (r² = 0.92) that is applicable to a wide range of minespoil textures. Clay content. and salinity had a significant effect on minespoil strength. Penetration resistance was 2.5 times greater at 33% clay content than at B% clay. Minespoil strength of saline spoils was 1.25 times that of non-saline spoils. The salinity effect increased as salts precipitated upon drying the minespoil strength at 15 bars moisture tension in saline minespoils was 1.4 times that of non-saline minespoils.