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Show • 38 IMMIGRANTS' .A.ND SETTLERS' GUIDE wide and twelve feet Ion h mated to be about $25 g t ro~gh the " cap " is t• !rom 60 to 100 feet deel·er$;gnnw~ foot, if the sha~: i~ . o 160 .feet deep, and so' . per oot .if it is fi·om 10 mcreasmg with the de on m proportwn, the ex e 0 drawing the rubbish top!~~ ~~~consequent difficul~y ~; Much, of course d d ace. rock through ~hich t~~e~h:ft ~pon the hardness of the large .Proportion, or the who{s su?k. In some cases a ~~atnht, Is dekfrayed by the gold f~unofd tdhe .expenses of the e wor . Ind d . uring the . great depth witho~~ e' some m~nes have been s~~g:oess ncountermg the " cap " at all. a METHOD OF R AISING THE ORE The quartz IDI" II s are w·th b • fsompe ~istance from the 'sha}ts o ~t .a single exception er1ormed by . I mines Th h · . ' times b h an ordmary "wh' ,; e mstmg six h y a orse or mule and s ImJ worked some- .orse-power eng· . ' ometimes by a fi would b b me, a ten 0 fifi ve or depths e etter when the shaftsr a teen-horse engine . • re worked to great PROCESS OF EXTRACTING THE ORE . The usual method of . . Simply described as folio extrac~mg the gold may be fo~:edt~h~~ ~~:vy stamp~, '::hich'~:uo~~~~ cr~shed to metallic I po":der Is mixed with . With great d p a.tes, havmg slight 'd water, run over :!ai~mdeared with quicksilver. ~~!es on their surface, e . ' s part of the gold . Two new IS now in pr?cesses of separatin th 'b d extensive operation g e ore, which are scri e : ' may be thus briefly de- THE FREIBERG pAN so called from th ' vented, Freiberg,e G!;:a~f t~e place where it was in- , y-Is a wooden tub o f per- TO THE NEW STATES AND TERRITORIES. 39 haps eight feet in diameter, and three feet high, with a false bottom of iron, upon which move in a circle four muliers of stone or iron, attached to the arms of a central upright shaft. This shaft propels the mullers by the power of steam. In this pan or tub are deposited from time to time quantities of pulverized quartz, with the gold dust intermingled. Water is let in to the depth of ten or twelve inches, and a stream of it allowed to run constantly. This water escape5 at an orifice made at the proper height, and carries with it all floating dust. The water is warmed by steam, and kept at a uniform temperature. The motion of the muliers destroys the chemical affinities of the different substanceR, and allows the quicksilver to take it. This pan is coming into use in several mills. A large mill will soon be built in Nevada to make use of this process. THE BERTOLA PAN, which takes its name from the Spaniard who invented it, is more extensively used and promises better for all kinds of ores. It is about half the size of. the Freiberg pan, and entirely of iron. rrhe dust is operated upon in the same way by both pans, water, and stone muliers being used. The chemicals, however, in the Bertola method, are deposited with the dust, while in the Freiberg they are not. What chemicals are used is still a secret, carefully guarded by those who make use of the Jll'ocess. Many large mills are adopting it with great confidence. Messrs. Cook & Kimball have thirty pairs of pans in operation in their large mill, Central City. They are also about to erect an immense mill for a new company in New York, on Clear Creek, for the purpose of operating one hundred and. fifty pairs of pans. The friends of this process are very confident of its entire success. The above-named methods of operating upon the ore are designed to overcome chemical affinities, difficulties which cannot be obviated by the common process. .t-\..11 |
