Particle Size Analysis of Shale-rich Mined Clay from Appalachian Ohio

摘要

Clayey soil found in coal mines in Appalachian Ohio is typically used for constructing Recompacted Soil Liners (RSL) in landfills. The suitability of mined clay for RSL in Ohio is first decided by its clay content. Even though the standard sampling and processing techniques should not produce different grain-size distributions, mined clay from Appalachian Ohio is an exception. This discrepancy poses a challenge to the geotechnical engineers who work on prequalification process of RSL material. This paper describes a laboratory investigation conducted on mined clay from Appalachian Ohio to determine how and why the standard sampling and/or processing methods affect the grain-size distributions. About a 10 percent decrease in the clay content was consistently observed in the samples obtained from clayey soil stockpiles, compared to those collected during reverse circulation drilling. It was discovered that the fragments of shale in underclay was responsible for the discrepancy.