I had already learned how hard and long and dismal a task it is to burrow down into the bowels of the earth and get out the coveted ore; and now Ilearned that the burrowing was only half the work; and that to get the silver out of the ore was the dreary and laborious other half of it.
We had to turn out at six in the morning and keep at it till dark.
This mill was a six-stamp affair, driven by steam.Six tall, upright rods of iron, as large as a man's ankle, and heavily shod with a mass of iron and steel at their lower ends, were framed together like a gate, and these rose and fell, one after the other, in a ponderous dance, in an iron box called a "battery." Each of these rods or stamps weighed six hundred pounds.One of us stood by the battery all day long, breaking up masses of silver-bearing rock with a sledge and shoveling it into the battery.The ceaseless dance of the stamps pulverized the rock to powder, and a stream of water that trickled into the battery turned it to a creamy paste.The minutest particles were driven through a fine wire screen which fitted close around the battery, and were washed into great tubs warmed by super-heated steam--amalgamating pans, they are called.
The mass of pulp in the pans was kept constantly stirred up by revolving "mullers." A quantity of quicksilver was kept always in the battery, and this seized some of the liberated gold and silver particles and held on to them; quicksilver was shaken in a fine shower into the pans, also, about every half hour, through a buckskin sack.Quantities of coarse salt and sulphate of copper were added, from time to time to assist the amalgamation by destroying base metals which coated the gold and silver and would not let it unite with the quicksilver.
All these tiresome things we had to attend to constantly.Streams of dirty water flowed always from the pans and were carried off in broad wooden troughs to the ravine.One would not suppose that atoms of gold and silver would float on top of six inches of water, but they did; and in order to catch them, coarse blankets were laid in the troughs, and little obstructing "riffles" charged with quicksilver were placed here and there across the troughs also.These riffles had to be cleaned and the blankets washed out every evening, to get their precious accumulations--and after all this eternity of trouble one third of the silver and gold in a ton of rock would find its way to the end of the troughs in the ravine at last and have to be worked over again some day.
There is nothing so aggravating as silver milling.There never was any idle time in that mill.There was always something to do.It is a pity that Adam could not have gone straight out of Eden into a quartz mill, in order to understand the full force of his doom to "earn his bread by the sweat of his brow." Every now and then, during the day, we had to scoop some pulp out of the pans, and tediously "wash" it in a horn spoon--wash it little by little over the edge till at last nothing was left but some little dull globules of quicksilver in the bottom.If they were soft and yielding, the pan needed some salt or some sulphate of copper or some other chemical rubbish to assist digestion; if they were crisp to the touch and would retain a dint, they were freighted with all the silver and gold they could seize and hold, and consequently the pan needed a fresh charge of quicksilver.When there was nothing else to do, one could always "screen tailings." That is to say, he could shovel up the dried sand that had washed down to the ravine through the troughs and dash it against an upright wire screen to free it from pebbles and prepare it for working over.
The process of amalgamation differed in the various mills, and this included changes in style of pans and other machinery, and a great diversity of opinion existed as to the best in use, but none of the methods employed, involved the principle of milling ore without "screening the tailings." Of all recreations in the world, screening tailings on a hot day, with a long-handled shovel, is the most undesirable.
At the end of the week the machinery was stopped and we "cleaned up."That is to say, we got the pulp out of the pans and batteries, and washed the mud patiently away till nothing was left but the long accumulating mass of quicksilver, with its imprisoned treasures.This we made into heavy, compact snow-balls, and piled them up in a bright, luxurious heap for inspection.Making these snow-balls cost me a fine gold ring--that and ignorance together; for the quicksilver invaded the ring with the same facility with which water saturates a sponge--separated its particles and the ring crumbled to pieces.
We put our pile of quicksilver balls into an iron retort that had a pipe leading from it to a pail of water, and then applied a roasting heat.
The quicksilver turned to vapor, escaped through the pipe into the pail, and the water turned it into good wholesome quicksilver again.
