Denis Fletcher Kelsall was a chemical engineer. He was Chief of the CSIRO’s Division of Chemical Engineering from 1974-1978, and of its successor, the Division of Mineral Engineering, from 1978-82. During this latter period he was also Chief of the Division of Applied Geomechanics from 1979-81.
He was elected a Fellow of the Australian Academy of Sciences and Engineering in 1976. A detailed biography, ‘Kelsall, Denis Fletcher (1918-1982)’ by Ian D Rae, published in Australian Dictionary of Biography, 2007, Volume 17, Melbourne University Press and can be found at the following link http://adb.anu.edu.au/biography/kelsall-denis-fletcher-12724.