|
Some of the minerals produced, such as coal and salt,
are ready to use right after they have been mined. These are referred to
as "dig and ship." It may be necessary to wash or treat these commodities
in different ways to enhance their quality, but their properties remain
essentially unchanged.
However, most metals usually occur in nature combined with other
materials which is called an ore. Ores need to be treated, usually with
chemicals or heat, to separate the metal from its host material. These
processing techniques can be very complex and expensive, but they are
the only way to recover the metal of interest. The table below shows ore
minerals for the listed elements.
|
Ready to ship
|
|
element |
oxide |
sulfide |
carbonate |
|
mercury |
cinnabar |
|
|
|
tin |
cassiterite |
|
|
|
lead |
minim |
galena |
cerrusite |
|
copper |
cuprite |
chalcopyrite |
malachite |
|
silver |
|
argentite |
|
|
iron |
hematite |
pyrite |
siderite |
|
