Arizona citizen., 1877-10-20
Dry Placer Gold Machines.

ceNeTdl Ol tDeSe macnlneS nave re
 gently been invented, and according to
 the description of one in the Denver
 Times, it would be the very one 10 in.
 troduce in various parts of Arizona
 The invention is by Dunhem & Ben.
 nett, of Denver, and several persons
 who witnessed the practical operation,
 as below described, have seveTally con- tracted for seven, ten and fifteen of the machines, and still others are arrang- ing to use them. Here is an extract from an article we find in the Times
 The machine, which is portable, be.
 ing mounted on wheels, weighs about
 40O0 pounds, exclusive of an 8-horse
 power engine and boiler req tired 10
 run it, is placed upon a mine in the
 South Park, about ten miles east from
 Hamilton, and one mile south of Tar Iyall creek. This mine was chosen
 more as test than for any hope of prof
 it, it being an abandoned mine, and
 the gold being extremely fine. On this mine can be had nearly all kinds of dirt, from black bottom clay and mud 10 the ordinary gravel deposit; and in fact, for thorough and severe test, no better spot could have been selected. Two experienced miners, working here with the sluice, cleaned up little less than six dollars, for their joint labor for six days. At the end of six-day run, during which much non-pay dirt was put through Ct being necessary to handle the latter in searching for the pay streak,) the machine cleaned up $9994, as stamped by the Denver mint. And when it is taken into considera- ton that the sixty odd square feet of copper surface was new and rough, with a number of rIvited seams, and that they were not cleaned with view of taking all the gold, :t will be eyiIentI that as much more was saved. The nee essary expense of running is from ten 10 twelve dollars per day, and this will decrease as experience is gained; but takla highest figure of expense, and lea, out of consideration the gold saved and absorbed (sO to speak, by the sixty feet or surface, the mint as- says show a clear profit C. the machinel of twenty-five dollars fOrNthe first six days run. Experienced mill men have estimated the gold saved and still on the plates at from $75 to Sl00, and it. is fully believed that the next week s run will not fall short of $500, which l will leave a net profit of 1925 to the machine, and this on mine where if ty cents per day to the man cannot be had with the sluice.
 During the six days all kinds of dirt were put through the machine-clay, | fine sand and gravel-each in their turn was tried with the same result, save | that the coarse material was handled d little more expeditiOusly Heavy sod, six inches thick to ten by twelve inches wide, and two feet long, were dumped in and came out torn to shreds, and perfectly washed from dirt. Instead of 800 pans per hour as claimed by the inventors, the capacity of the machine was found to be from 1000 to 1900 pans per hour, or 80 to 100 cubic yards per day of ten hours, varying little with the kind of dirt being dressed. Duringi the trials the tailings were frequently tested by careful banning, both by in- terested parties and persons present as spectators. No gold was found at any time by any person in the tailings-the machine having taken up, so far as known, every particle. The water re- quired to run thIs machine may be drawn from a good we'll, and though a dump for tailings is always desirable, it is not essential in this machine.