The Clifton clarion., 1889-05-08
CLIFTON, GRAHAM CO.,, ARIZONA: WEDNESDAY, MA
CONCENTRATION OF ORES.
A Series of Descriptive Articles Showing
 the Various Methods Employed.

| the Various Methods Employed.
 Believing that few short articles
 on the treatment of ores by concen-
 tration might interest some of your
 readers. perhaps benefit few. will.
 with your permission, submit what
 follows. do not claim any original
 ity in what have to say, but only aim
 to elucidate, as clearly and concisely
 as the subject will admit of, few of
 the leading principles involved in
 what is one of the most important
 branches of ore treatment. viz
 The Mechanical Concentration of
 Ores.
 In Arizona, as in most countries, the various metals, gold, silver, copper
 and lead. do not occur, as some sup | pose, in the form of bricks with
 company stamp on, but as ores of a greater or less degree of purity
 The purest of the ores are sent direct
 to the shelter without previous treat
 ment. The more impure ones, and
 those are by far the most plentiful.
 must first be treated either by anal gamation or by concentration, pre- yious to smelting.
 When the concentration on large scale of any ore is contemplated, the most obvious thing to be done is. first to find out whether the ore is capable of being concentrated. and if so whether it will pay for the erection of the proper works. This can easily be done by pounding some of the rock i to q pulp. washing the pulp in a gold pan or shovel, and assaying the resi- due and tailings. should the result be favorable. the next thing in order is to find by experiment to what ex- tent the process of crushing ought to be carried. so as to determine the class of crushing machinery to be em- ployed; this experiment requires con- siderable patience, and ought to be carried out with great care.
 Having thoroughly sampled the mine intended to be worked. the large sample should be carefully broken by hand, so as to obtain a clean Separa- ton of the mineral from the rock This result can. be best attained by breaking the largest rocks with hammer, on flat plate. taking care to remove the clean ore and the clean rock from the influence of the ham, mer as the breaking or crushing eX- pertinent proceeds, until all of the sample is reduced.
 The crushing part of the business being thus settled, the next thingis to find how much ore and rock there is of each size, in any series of sizes. About the best way to get at this, is to use number of small selves, with holes in them of say l-2. 3-8, IA. Is, 1-16 and 1-32 inches in diameter. and by their means separating the crushed material into as many lots as there are selves, recrushing those pieces which will not pass through the largest holes. In this way will be found the average quantity of each size which may be expected in practice in the mill, and the intending builder will be able so to plan his mill that it will do the most work with the least eX- penditure of power. It is always ad- visable to crush and treat ores as coarse as possible, consistent, of course, with clean separation; because, in coarse crushing the ore can be treat ed quicker and cheaper, and there is less loss than in crushing and sizing fine. Cases in which the entire body of ore has to be crushed fine will be looked after later on.
 Having shown how the initial sam pie is crushed by hand work, l will now mention some of the modern svs- tems of machine crushing. The ma chine known as the "crushcr" or rock . breaker is the mostapprcved machine  for primary crushing. Of this ma chine there are several makers each with separate plan for applying the crushing force, but will only men, ton three. First. there is machine called The Greatest Crusher on Earth" The frame of this machine is the section of a hollow cone, and the fixed jaw is fastened round the inside, and is corrugated; rising through the center of this cone is a shaft which carries the movable jaw, which is also a cone and corrugated. By the appli- c ltiDn of suitable Uenrinor ba1nv,- tho