The Simmer and Jack Proprietary Gold Mines - east of Johannesburg, South Africa. The company which was founded in 1887 by the German August Simmer and Scotsman John Jack. The gold deposits were very large indeed, but could only be extracted from the pyrite with great difficulty and expense using contemporary technology (cyanide process). In the foreground can be seen a row of cylindrical froth flotation cells - part of this dangerous process. The original mine was closed down in 1969.