Getting Gold

count the quantity and quality of the lode stuff to be operated on, and ascertain by analysis what are its component parts, for, as before stated, the treatment which will y

lant until he was fully satisfied as to the character of the bulk of the ore he would have to treat. It would be well for the poc

lode stuff contains a proportion of sulphides of various metals, wherein a part of the gold, usually in a very finely divided state, is enclosed, and on this gold the mercury has no influence. Also many lodes contain hard heavy ferric ores, such as titanic iron, tungstate of iron, and hematite, in which gold is held. In others, again, are found considerable quantities of soft powde

, and when the material is rich enough in gold to pay for the extra cost of treatment,

ator. Of these there are many before the public, and some do excellent work, but do not act equally well in all circumstances. The first and most primitive is the blanke

gainst the flow of the water and pulp, and by this means the heavier minerals are gathered towards t

fairly good work, but it is by

cles, whether of gold or base metals containing gold. There has also been devised a rocking table the action of which is analogous to that of the ordinary miner's cradle. This appliance, working somewhat slowly, swings on rockers from si

sisted of an endless band of strong cloth or closely woven matting, run on two horizontal rollers placed about seven feet apart, one being some inches lower than the other. The upper is caused to revolve by means of a handl

s of the Frue vanner forty years ago i

d from the upper end, and the concentrates collected in a trough containing water in which the band is immersed in its passage under the table; the lighter particles wash over the lower en

n when the stone under treatment contains no deleterious compounds the simple action of grinding the hard siliceous particles has a bad effect on the quicksilver, causing it to separate into small globules, which either oxidising or becoming coated with the impurities contained in the ore will not reunite, but wash away in the slimes and

which they were never intended. It cannot be too clearly realized that the correct order of procedure for extracting the gold held in combination with base metals is-first, reduction of the particles to a uniform gauge and caref

lly be found effective in saving the concentrates. In theory it is an enlargement of the alluvial mine

uired being to prevent over roasting and so slagging the concentrates; or not sufficiently calcining

conditions, an effective amalgamator. The introduction of steam under pressure into an iron cylinder containing a charge of concentrates with mercury is said to have produced good resul

s called to an American invention, in which the same result was stated to be attained more effectively by blowing the mercury spray through the triturated material by means of a steam jet. I had already encountered a difficulty, since found so obstructive by experimentalists in the same direction, that is, the getting of the mercury back into its liquid metallic form. This difficul

g the material in the form of a thin pasty mass to a settler, as in the old South America

ian Mining Standard, and was head

om an unexpected quarter. The despised Chilian mill and Wheeler pan, discarded at many mines, will solve the probl

gamation without overflow was put to a crucial test, in each case with the gratifying result that ninety-six per cent of the precious metal was secured. What this means to the Great Mercury Mine, for instance, can easily be imagined when it is understood that notwithstanding all the latest gold-saving adjuncts during the las

f the battery is used, ordinary precautions, of course, must be taken to prevent waste, or the dust becoming obnoxious to the workmen. The ore is then transferred to the Chilian mill and made to the consistency of porridge, the quicksilver being added. When

id's gruel, put it into a little berdan pan made from a "camp oven," which I had used for treating small quantities of concentrates, and from time to time drove a spray of mercury, wherein a small amount of zinc had been dissolved, i

der educated intelligence it will prove a powerful agent in their extraction. About fourteen years ago I obtained some rather remarkable results from s

ntained in suitable ores can be converted into its mineral salt, and being dissolved in water, re-deposited in metallic form for smelting; but lode stuff containing much lime would not be suitable for chlorination, or the presenc

ed on in vats with water, and introducing chlorine gas at the bottom, the mixture being allowed to stand for a number of hours, the minimum about twelve, the maxim

nch was pumped in. The cylinder with its contents was revolved for two hours, then the charge was withdrawn and drained nearly dry by suction, the resultant liquid being slowly filtered through broken charcoal on which the chloride crystals were deposited, in appearance much like the bromo-chlorides of silver ore

s, from which it was conveyed to the chlorinating shed. Here were long rows of revolving barrels, on the Newbery-Vautin principle, but with this marked difference, that the pressure in the barrel was obtained from an excess of the gas itself, generated from a charge of chloride of lime and sulphuric acid. On leaving the barrels the pulp ran into settling vats, somewhat on the Plattner plan, and the clear liquid having been drained off was

by the admixture of bisulphate of sodium (instead of sulphuric acid, which is a very costly chemical to transport) and chloride of lime. Water is then pumped into a strong receptacle containing the material for treatment and p

ning of the process. In each case it is an air cushion, induced in the one process by the pumping in of air to

in vats, and subjected to the action of solutions of cyanide of potassium of varying strengths down to 0.2 per cent. These dissolve the gold, which is leached from the tailings, passed through boxes in which it is precipitated either by means of zinc shavings, electricity, or to the precipit

n the box, to cause all pure gold and zinc to fall to the bottom, the zinc shavings are taken out. The precipitates are then

ld deposition from a cyanide solution was given by Mr. A.

n of cyanide of potassium and other chemicals of known percentage is run over the pulp and left to stand a certain number of hours, depending on the amount of metal to be extracted. It is then drained off and another charge of the same solutio

de of potassium with gold is as

O + H2O = 2

cyanide of gold and

e latter, it will be about 10 ft. long, 4 ft. wide and 1 ft. high-and is partitioned off lengthwise into five compartments. Under each partition, on the inside or bottom of the 'box,' grooves may be cut a quarter-to a half-inch deep, extending paral

cket, so it may be moved either up or down as des

and earth. The sides or partitions of each compartment dip into the mercury, wh

ct with the mercury and extended above it, to allow the

ing negative. The dynamo is started, and a current of high amperage and low voltage is generated, generally 1

quid, which brings a fresh and saturated solution of electrolyte betwee

lectrolyte by the electric current is being accomplished, the gold and silver are set free and unite with the mercury, and are also deposited on the plates or discs of copper, forming amalgam, whi

e desired percentage, or strengthened with cyanide of potassium and other chemic

old and silver), which are precipitated into the mercury and form amalgam, leaving hydrocyanic acid; this latter combines with the potassium hy

itudinally, which spreads the mercury, the solution is agitated and comes in perfect contact with

the solution, for it is used over and over again indefinitely; but when

d silver, need be run to waste, which is in itself an enormous saving over t

the cost of recovery less; the loss of gold, silver, and cyanide of potassium reduced to a minimum; the use of caustic alkali in such quantity as may be desired to keep the cyanide solution from being destroyed by the solidity of the pulp, and also sometimes to give warmth, as a wa

, which we know cannot be done in the 'chlorination process'; besides, th

will, I think, be the future cheap method of recovering fine

0,000 tons of pulp per month, the cost should not exceed 8s. per ton, but that may be cheapened by labour-sa