For 30 years, my father-in-law, Basil Isaac, who has died aged 86, was a popular teacher of geology to mining students in the heart of the south Wales coalfield. He also laid claim to the second biggest head in Wales.
Born at Llanbradach, near Caerphilly, Basil was himself the eldest son of a miner. He attended Caerphilly grammar school and, too young for second world war service, joined the Air Training Corps aged 14 (saying he was 16). While being measured for a uniform he learned of his exceptional head size. He completed a degree in geology at Cardiff University in 1948 and a diploma in education the following year, incidentally passing an IQ test at "genius" level and writing a national Eisteddfod prizewinning essay on the south Wales coalfield.
After a first job as a science teacher at Redditch county high school in Worcestershire, in 1954 Basil became a geologist with the National Coal Board at Nottingham, where a method he developed for estimating the movement of coal seam floors was adopted by the British Coal Survey. He also taught part-time at Nottingham technical college and in 1958 was appointed geology lecturer with the Glamorgan College of Technology (now the University of South Wales).
He became principal lecturer in 1975, responsible for co-ordinating Earth Sciences. Alongside college work, he took an MA in education at Cardiff University, served on examination committees for the Council for National Academic Awards, the University of London and others, and lectured for the British Association for the Advancement of Science.
Basil was fabled as a speed reader; colleagues would jokingly flick a tome in front of him then ask for an opinion on the contents. In retirement, he wrote and lectured on industrial history and gemstones and contributed a chapter to a history of the University of Glamorgan, A Community and Its University: Glamorgan 1913-2003 (2003). He was a fine public speaker, offering up extensive knowledge and impeccably timed anecdotes in a clear-voiced valleys accent. His comic self-deprecation was as integral to his character as was his gentlemanly manner, sense of fair play and concern for his students' welfare.
Basil is survived by Ruth, his wife of 59 years, his children, Martin, Stephen and Susan, granddaughters, Elsa, Mair and Jessie, and his brother, Clive.