David Ray Mitchell was widely known for many years as the United States’ principal professor of coal preparation engineering. Through his teaching, publications, and practice, Dave Mitchell has probably had a greater impact on coal preparation than any other American. His legacy lives on in his contribution to the education of generations of coal preparation engineers, worldwide.
Coal preparation engineering is often an important adjunct to coal mining, improving the quality of coal by reducing its sulfur and ash content. Professor Mitchell originated the idea of assembling the principal U.S. experts in coal preparation to supply the great unfulfilled need for a book in this specialized field. The result was the outstanding 1943 AIME volume, Coal Preparation, for which Mitchell served as both Editor and as an author. This book quickly became the standard university text, as well as the standard reference book for professional engineers in the field. It has subsequently been updated and revised several times. As of 1996, Coal Preparation was in its Fifth Edition, with one of Professor Mitchell’s former students, Professor J. W. Leonard, as Editor.
A Pennsylvania native, Dave Mitchell served in the Army Signal Corps, Aviation Section in World War I and subsequently received B.S. and M.S. degrees in mining engineering from Penn State and later an E.M. degree from the University of Illinois, advancing from Instructor to Associate Professor. In 1928, Mitchell returned to Penn State as Professor and Head of Mining Engineering, advancing to Division Chief of Mineral Engineering and Associate Dean and Dean of the College of Mineral Industries, the position he held at the time of his retirement in 1964.
Professor Mitchell’s original interest was chiefly in general coal mining, including plant layouts and ventilation systems, and in industrial minerals. With the publication of Coal Preparation, however, his interests moved largely toward coal preparation and coal bin and pile design and flow. This interest subsequently led to work in metalliferous ore processing. He always stressed the need for a quantitative approach in research and engineering, and this attitude played an important role in advancing coal preparation from an art to a firm engineering discipline.
Professor Mitchell was a consultant to many mining companies, served the Pennsylvania Legislature on mine safety problems, and later chaired the Governor’s Committee on Mine Safety. Always busy, Dave Mitchell served as Editor of Mechanization and Utilization magazines from 1938 to 1961, and he authored more than 100 technical papers and several patents.