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The “Mining & Processing Basics”
section on this website describes basic mining and
processing methods used in the precious metals industry and
includes a glossary of metals & mining terms:
Learn about
"Surface &
Underground Mining Methods" used to extract ore from a mine
and deliver the ore to a processing plant for recovery of
gold, silver, and other precious metals can be viewed by
clicking on the above links:
View our two "Method Flowsheets" describing ore processing methods
used to
recover precious metals as a concentrated product or as a
refined and
relatively pure metal:
View our "Glossary
of Mining Terms" which describe both mining and processing
methods, as well as basic terms used in all engineering and
financial disciplines used in the minerals industry.
Basic Mining Methods
Mining is done by open pit methods on
the surface or by underground methods requiring tramming and
hoisting of the ore to the surface. Open pit mining
includes excavating low-grade waste rock to a disposal dump
area and haulage of ore-grade material to a processing
area. Underground mining requires access to higher grade
ore by way of a vertical shaft or decline to the deeper
mineralization. The ore is delivered to the processing area
by haulage to the shaft in underground tunnels (drifts) and
hoisting ore to surface in a shaft. All of this material is
drilled, blasted, and transported by truck, tram, or
conveyor.
Processing is done by heap leaching or
milling methods. Low operating cost heap leaching methods
are used to recover precious metals from lower grade
material that contains recoverable metal at a relatively
coarse size using crushing only. Milling of ore involves
both crushing and grinding of the ore to a fine size in
order to liberate the mineral and metal values so they can
be recovered by gravity and leaching methods to a
concentrated or relatively pure metal product. The waste
material (called tailings), is disposed of and impounded in
a disposal area.
Both mining method and processing
method will be determined by economics of recovering the
precious metals. The economics, or feasibility of a
project, is determined from the location and grade of the
ore body and from the results of test work used to define the
optimum metal recoverable from the ore.
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