The Physics of Placer Mining
Physic 211
University of Alaska Fairbanks
November 27, 2013
A placer deposit is a secondary mineral
deposit that has a natural concentration of heavy
minerals caused by the effect of gravity on moving particles.
When heavy, stable minerals are freed from their matrix by
weathering processes, they are slowly washed down slope into
streams that quickly winnow the lighter matrix. Thus the heavy
minerals become concentrated in stream, beach, and lag
(residual) gravels and constitute workable ore deposits. Minerals
that form placer deposits have high specific gravity, are
chemically resistant to weathering, and are 
durable;
such minerals include gold, platinum, native copper, and
various gemstones (Encyclopedia Britannica 2013). To
mine placer deposits it is necessary to remove a large amount
of unwanted material from the small amount of sought after
mineral. To do this various methods and machines have
been developed and all of them based on basic principles of
physics. I've choose three to discus here; the shaker
screen, the stamp mill, and the sluice box.
durable;
such minerals include gold, platinum, native copper, and
various gemstones (Encyclopedia Britannica 2013). To
mine placer deposits it is necessary to remove a large amount
of unwanted material from the small amount of sought after
mineral. To do this various methods and machines have
been developed and all of them based on basic principles of
physics. I've choose three to discus here; the shaker
screen, the stamp mill, and the sluice box.