A profitable mine, with reference to the “Bonanza Mine”; hence, any piece of good luck in an investment.
1866. The Saturday Review, concerning the mine itself. (N.E.D.)
1878. He had put all his available means in a new and half-developed mine, and was sinking on the vein with tireless energy, in the daily hope of striking a bonanza.—J. H. Beadle, ‘Western Wilds,’ p. 46. (Italics in the original.)
1881. The Star-route Cases a Fat Bonanza.—Heading in The Critic (Washington), Dec. 23.
