Hans C. Behr, mechanical engineer, completed an apprenticeship in the engineering department of the Union Iron Works in the United States. Subsequently he worked on the design and erection of mining plants at the Comstock silver mines in Nevada and other mines in the western United States. From about 1887 to 1900 he practised in San Francisco as a consulting mechanical engineer, specialising in the design and construction of mining plant. A publication by him on "Mine drainage, pumps, etc" (Sacramento, 1896, 210p) was issued by the California State Mining Bureau.
Behr came to the Transvaal in 1901 to take up the position of consulting mechanical engineer to Consolidated Goldfields of South Africa in Johannesburg, a post he held to at least 1913. He was a member of the (British) Institute of Mining and Mechanical Engineers, the (British) Institution of Civil Engineers, the (British) Institution of Mining and Metallurgy, the American Institute of Mining Engineers, and the American Society of Mechanical Engineers. In 1902 he became a foundation member of the South African Association for the Advancement of Science and was still a member in 1911. In 1902 he also joined the Chemical, Metallurgical and Mining Society of South Africa and, around the same time, the Mechanical Engineers' Association of the Witwatersrand (which became the Transvaal Institute of Mechanical Engineers in 1905). Behr was honorary president (a position in addition to that of president) of the latter during 1906-1907. In 1903 he was appointed a member of the Technical Education Commission for the Transvaal, which recommended the creation of a teaching university, including a school of mines, in or near Johannesburg. In 1908 he was elected a Fellow of the Royal Society of South Africa.
Behr's major contribution to South African engineering consisted of a monumental paper, "Winding from great depths", presented to the Institution of Mining and Metallurgy in London and then to the South African Association of Engineers in 1902. It was published jointly by the two societies as a book-length volume (in two parts, text and plates) and earned Behr the Institution's gold medal. The paper was of great importance to the gold mines, as many deep shafts were then being planned. Its discussion by the members of both societies resulted in 20 written contributions that were included in the publication, with Behr's response.
In 1904 Behr contributed a detailed analysis of "The return pipe system of compressed air power transmission" to the Journal of the Mechanical Engineers' Association of the Witwatersrand (1903-1904, Vol. 2, pp. 313-343). This paper too elicited an extensive discussion and earned Behr the association's gold medal. Two years later he was joint author with E.J. Laschinger* and A.M. Robeson* of a paper on the steam consumption of winders, read before the South African Association of Engineers. Another paper by him contained "Some suggestions for carrying out power and efficiency tests on the mine" (Journal of the Transvaal Institute of Mechanical Engineers, 1908, Vol. 6).
Between 1890 and 1929 Behr registered more than 20 United States patents, most of them for improved methods of hoisting, crushing ore, and subdividing streams of pulp and other liquids. Many of the patents were applied for while he resided in Johannesburg. He was still listed as a Fellow of the Royal Society of South Africa in 1917, but by that time (and at least until 1929) resided in the state of New York.