Otto Stuhaug Tonnesen was a Norwegian citizen resident in South Africa from 1905 or earlier and in Johannesburg from about 1908 to around 1915. He passed the Survey Certificate Examination
of the University of the Cape of Good Hope in 1905 and in 1908 became a member of
the Chemical, Metallurgical and Mining Society of South Africa. At this time he was a mine surveyor at the East Rand Proprietary Mines, Ltd. In 1909 he
published a paper on 'Stope measurement' in the society's Journal (Vol. 9, p. 375), followed a few years later by a paper on
a 'Simplex stope measuring instrument' (1912, Vol. 13(1), pp. 8-10). In 1915 he
was granted a United States patent for an improved method for mounting rock
drills.
In 1917 O.S. Tonnesen, presumably him, was a mental patient in the Cape
Province. And in 1930 Othar Stuhaug Tonn, formerly known as Otto Stihaug
Tonnesen, died in Natal.
