Usage
Cornish stamps are stamp mills that were developed in Cornwall for use in tin mining in around 1850. Cornish stamps were used to crush small lumps of ore into sand like material. Constructed from heavy timber or iron lifters with iron "heads" at the bottom were raised by cams on a rotating axle, and fell on the ore and water mixture, fed into a box beneath. The heads normally weighed between 4 and 8 cwt each, and were usually arranged in sets of four, in timber frames. Small stamps were commonly powered by water wheels and larger ones by steam engines.
Californian stamps were based on Cornish stamps and were used in the Californian gold mines. They were more rapid in action, and the heads and lifters were made to rotate so that they wore more evenly. The other advantage of the Californian stamp was that a single head could crush 1.5 tons of ore as opposed to the Cornish stamps which could only crush 1 ton.
Read more about this topic: Stamp Mill
Famous quotes containing the word usage:
“...Often the accurate answer to a usage question begins, “It depends.” And what it depends on most often is where you are, who you are, who your listeners or readers are, and what your purpose in speaking or writing is.”
—Kenneth G. Wilson (b. 1923)
“Pythagoras, Locke, Socrates—but pages
Might be filled up, as vainly as before,
With the sad usage of all sorts of sages,
Who in his life-time, each was deemed a bore!
The loftiest minds outrun their tardy ages.”
—George Gordon Noel Byron (1788–1824)
“Girls who put out are tramps. Girls who don’t are ladies. This is, however, a rather archaic usage of the word. Should one of you boys happen upon a girl who doesn’t put out, do not jump to the conclusion that you have found a lady. What you have probably found is a lesbian.”
—Fran Lebowitz (b. 1951)