Pyrite oxidation in the Chattanooga Shale has caused serious foundation problems in numerous buildings and structures in Estill County, Ky. Pyrite oxidizes and various secondary sulfates form when excavated shale or shale ﬁll are used in foundations. These secondary sulfates are water- and humidity-sensitive and can form when only minor amounts of water are present in foundation materials. These sulfates form by crystal growth and expand by volume change, which causes subsequent soil expansion and heaving of any foundation materials when the materials are conﬁned. Several structures have undergone expensive remediation to repair damaged sidewalks, ﬂoors, walls, and foundations. Zones of high concentrations of pyrite occur in the Chattanooga Shale across the state, and these mineral zones may be responsible for the high pyrite content in Estill County.
Report of Investigations 18
Digital Object Identifier (DOI)
Anderson, Warren H., "Foundation Problems and Pyrite Oxidation in the Chattanooga Shale, Estill County, Kentucky" (2008). Kentucky Geological Survey Report of Investigations. 20.