Some occupations of members of Queensland's Third Contingent: - ....Alfred Evans and Archibald Andrew Gordon were kangaroo shooters. ....Henry Grubb was a rough rider and kangaroo shooter ....Richard Hegarty was a stock rider and kangaroo shooter ....David Walker was a kangaroo shooter and bush labourer
The use of cyanide to extract gold from tailings - low quality ore - was to spray a solution of cyanide and water over piles of crushed ore and tap the run-off. I understand that the piles of ore were heaped on big metal plates for tapping; sometimes the spraying was just over big piles of tailings and the groundwater was tapped. The run-off contained gold in solution and it could be extracted by a chemical process. Memory fails me on that particular score! I don't know who invented the whole process; it would be /or have been employed by large mining concerns and not by the smaller mines. Using the cyanide process, traces of gold in the tailings were recovered - metal which would have been impractical to otherwise recover.
In addition to Gold Mining in Australia, I would imagine the cyanide process would have been used in South Africa.