WASHING, OR HYDRAULICKING.
Charging the Sluices.—The
tunnel and sluices having been completed, water is turned into the
pipes and washing commences. The sluices are run half a day in order to
pack them. The water is then shut off and a charge of quicksilver is
put into the upper 200 or 300 feet of sluices, a small quantity being
distributed along the entire line except the last 400 feet. In a 6-foot
sluice the first charge will be about 3 flasks. The undercurrents are
charged at the same time and a little quicksilver put into the tail
sluice. Quicksilver is added daily during the run, in gradually
lessening quantities, the object being to keep the mercury uncovered
and clean at the top of the riffles ; and therefore the charge is
regulated by the amount exposed to view. At the North Bloomfield Mine,
where the main sluice is cleaned up nearly every 12 days, the amount of
quicksilver used in a run varies from 14 to 18 flasks. A 24-foot
undercurrent will require a charge of from 80 to 88 pounds of
quicksilver.
In
charging the riffles all splashing of the quicksilver should be
avoided. When it is sprinkled into the sluice (a practice to be
condemned) it divides itself into minute particles, the bulk of which
is easily carried off by the swift stream, while the lighter portions
will float even in the clear water. The buoyancy of these small
particles is very considerable.
Top
water from mining sluices often yields minute globules of quicksilver,
and float quicksilver containing gold particles (microscopic) has been
taken from the surface of the water twenty miles from where the amalgam
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