A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2019; you can also visit the original URL. The file type is application/pdf.
application/pdf
W.B. Jr. Tarpley, P.L. Howard, G.R. Moulder. "Efficient ultrasonic grinding: a new technology for micron-sized coal. Quarterly technical progress report no. 4, June 16, 1980-September 15, 1980." (1980)