Definition of "prospector"

A large number of prospectors have crossed over the divide to the British head waters of the Yukon, in search of the rich diggings found by a lucky few last year.

1886 June 9, “Geographical Notes”, in Science, volume VIII, number 179, New York: The Science Company, page 27

The south polar region of Promethei Planum developed a Bermuda Triangle reputation. Satellites detected intermittent mass concentrations and magnetic field shifts. In 2148, prospectors working near Deseado Crater discovered an underground complex: a Prothean observation post. The odd phenomena were generated by the operation and discharge of a mass effect core, struggling to function despite fifty millennia of neglect.

2008, BioWare, Mass Effect (Science Fiction), Redwood City: Electronic Arts, PC, scene: Protheans: Mars Ruins Codex entry