subs. phr. (common).—A profitable investment; a store of wealth, material or intellectual.
1641. H. PEACHAM, The Worth of a Peny, in ARBER’S English Garner, vol. VI., p. 249. Some men … when they have met with a GOLD MINE, so brood over, and watch it day and night, that it is impossible for Charity to be regarded, Virtue rewarded, or Necessity relieved.
1830. TENNYSON, A Dream of Fair Women, p. 274. GOLD-MINES of thought to lift the hidden ore.
1882. ‘THORMANBY,’ Famous Racing Men, p. 81. Mendicant … ran nowhere in the Cup … in reality she was destined to prove a GOLD MINE, for ten years afterwards she brought her owner £80,000 through her famous son, Beadsman.
1883. The Saturday Review, 28 April, 533/2. His victory proved a GOLD MINE to the professional bookmakers.
1887. FROUDE, The English in the West Indies, ch. v. Everyone was at law with his neighbour, and the island was a GOLD MINE to the Attorney-General.
