Gavin Hildick-Smith (sometimes Smith, G. Hildick) started his career in mining as a pupil of H.W. Hughes, the author of a well-known textbook on coal mining. He was awarded a BSc Honours degree in mining at the University of Birmingham and received a post-graduate scholarship from the Institution of Mining and Metallurgy (London). The scholarship enabled him to come to South Africa for training at the Ferreira Gold Mine. In 1940 the University of Birmingham awarded him an MSc degree for his dissertation on Drilling dust problems.
During his long and distinguished career on the Witwatersrand Hildick-Smith managed the following mines at different times: The Ferreira, Ferreira Deep, Bantjes, sections of the East Rand Property Mines and of the Crown Mines, the Robinson, C.M.R, Nourse, and Modder B mines. As mine manager he devoted time also to the prevention of accidents, encouragement of first aid and ambulance work, and the improvement of health conditions on the mines. He gave particular attention to the prevention of silicosis by means of the electrical precipitation of dust, the ozonisation of mine air, the filtration of mine water, and the removal of drilling dust by filtration.
Hildick-Smith became a member of the Chemical, Metallurgical and Mining Society of South Africa in 1910 and served as its president for 1917-1918. A paper by him on 'Drilling dust problems', published in the society's Journal, earned him its gold medal in 1940. In 1960 he was elected an honorary life member of the society's successor, the South African Institute of Mining and Metallurgy. In 1919 he represented the local branch of the Institution of Mining and Metallurgy (London) on the Joint Committee of Technical Societies. Later in his career he published two papers, 'Drilling dust problems and their solution' (1942) and 'Shaft pillars and shaft spaces' (1946) in the Papers and Discussions of the Association of Mine Managers, Transvaal.