Nanominerals and ultrafine particles in sublimates from the Ruth Mullins coal fire, Perry County, Eastern Kentucky, USA

Mineral sublimates from the Ruth Mullins fire in abandoned underground and surface mines in the high volatile A bituminous Middle Pennsylvanian Hazard No. 7 coalbed, Perry County, Kentucky, were examined by optical mineralogy, X-ray diffraction (XRD), and high-resolution–transmission electron microscopy (HR-TEM). Optical examination revealed the presence of salammoniac and a fine, unidentified fibrous mineral. XRD also showed the presence of salammoniac, along with trace amounts of quartz, kaolinite, and, possibly, phengite. Both cubic and dendritic salammoniac forms were observed with HR-TEM. Gypsum, jarosite, with cubic pseudomorphs after pyrite, and Fe-minerals, including Cr-bearing hematite in association with jarosite, were observed with HR-TEM. Dehydration of jarosite can lead to the formation of less hydrous Fe-sulfates and hematite.

Research Highlights
► Ultrafine minerals are found in inorganic deposits from an eastern Kentucky coal fire.
► Salammoniac is ubiquitous, present in both cubic and dendritic forms.
► Glassy Al–SI spheres with an anglesite coating were noted by HR-TEM.
► Trace elements are associated with the mineral phases.
► Trace elements are associated with fullerene carbons as nanoparticles.