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Mining Wastes
Wilbert Aureo
Mining Process
• Mining, in its broadest sense, the process of
obtaining useful minerals from the earth’s
crust. The process includes excavations in
underground mines and surface excavations in
open-pit, or opencut (strip) mines.
•
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Mining Wastes
• Waste from extractive operations (i.e. waste from
extraction and processing of mineral resources).
• is one of the largest waste streams in the world.
• It involves materials that must be removed to
gain access to the mineral resource, such as
topsoil, overburden and waste rock, as well as
tailings remaining after minerals have been
largely extracted from the ore.
Mining wastes
• Mine wastes: Open-pit mining Underground
mining Mineral processing Hydrometallurgy
Produces waste rock : either barren host rock
(referred to as “spoils” in coal mining), or “ore”
that is too low-grade, overburden soils and sands.
Produces processed solid wastes that includes
tailings and sludges with different physical and
chemical properties. Tailings can be used as
mining back-fill , but are generally contained on
surface. Also produces mill-water and other
processing waste-water also produced, as well as
atmospheric emissions .
Tailings
• the waste left after ore has been extracted from
rock.
• Tailings composition: Tailings consist of a liquid and
solid component : generally about 20 – 40 weight
percent solids (Robertson, 1994). The composition of
both is highly site-specific , depending on the ore and
gangue minerals and the nature of the water (fresh
or saline) and processing chemicals used.
Microsoft® Encarta® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.
Mine Tailings
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Sulphidic Mine Wastes
• Sulphidic mine wastes: Sulphide wastes are
the biggest problem on mines because of
potential for generating acid mine waters
Acid Mine Waters
• “ Acid mine drainage ” (AMD) refers to a
particular process whereby low pH mine water
is formed from the oxidation of sulphide
minerals .
Waste Rock
• Waste-rock disposal – rock dumps: “Waste-rock”
is rock emerging from the mine that will not be
processed further. It is either “ore” that is below
the cut-off grade, or is simply the barren hostrock to the mineral deposit. Rock dumps contain
an wide variety of different rocks and minerals
that is site specific , depending on the nature of
the ore deposit and the host-rock. If sulphide
minerals are present in any of the rocks, there is
the potential for acid mine drainage.
Wastes on Air
• Environmental contamination and pollution as
a result of improper mining, smelting and
waste disposal practices has occurred, and still
occur , around the world (Lottermoser, 2007).
Health Concerns
• Human Eating Contaminated Fish
Danger to the Environment
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