Sidney Pratt Blackmore, an electrical engineer of Johannesburg, was granted US patent 580657 for a new, non-inductive adjustable carbon resistance in 1897. That same year he was also the principal inventor of the Bladray electrical rock drill, with the assistance of E.J. Way* and R.O.G. Drummond* (US patent 602693, 1898). This percussion drill was tested in various gold mines on the Witwatersrand and was claimed to be much more economical than drills powered by air compressors. The instrument was described by G.A. Denny* and Way in the South African Mining Journal of 28 August 1897. It created considerable interest, with the result that Way read the paper before a meeting of the South African Association of Engineers and Architects on 29 September that year. The paper, with additional notes, was published in the Association's Proceedings (Vol. 4, pp. 24-52). In the extensive discussions following its presentation (pp. 75-88, 101-111, 139-152, 153-155) the expected economic benefits of the new drill and its other possible advantages over air drills were hotly debated. In 1920 Blackmore was granted US patent 1361301 for inventing a special kind of pliers adapted to secure a detonator to a time fuse when preparing for blasting. He was living in Barberton in 1912 and died there in 1958.
Blackmore married Ada Bell Linwood in Cape Town on 6 January 1900. They had at least one daughter.
