Environmental Aspects of Phosphate and Potash Mining United ...

Waste disposal
Environmental Aspects of Phosphate and Potash Mining
Phosphate rock and potash minerals are frequently
found in association with a variety of other minerals
that may have an economic value if recovered and separated.
Salt is commonly found either in association with
potash ore, or as separate salt orebodies, adjacent to or
near the potash orebody. Many operations recover salt
for purposes such as industrial grade salt or road deicing.
Complex potash ores frequently occur in association
with magnesium chloride. The potential exists for the
magnesium to be separated and converted into a variety
of magnesium products.
Igneous phosphate deposits are frequently associated
with a variety of minerals such as: niobium, titanium,
zirconium, baddeleyite and copper. In many instances
these are recovered and marketed.
Recovery of these products could assist the economics
of the operation by creating additional revenue
streams. An environmental benefit arises by meeting
some of society's demand for certain minerals without
disturbing additional land area.
Maximizing Resources Through the Recovery of
Co-products
In Jordan, the Arab Potash Company produces potash
fertilizer from carnallite ore precipitated through solar
evaporation of the Dead Sea brines. In conjunction
with this operation, the brine resource is also used to
produce:
Industrial and table salt from the halite precipitated
in the initial series of evaporation ponds;
Raw materials for the cosmetic industry.
Planning and construction are underway to produce
magnesium oxide, bromine, chlorine, caustic potash
and other derivatives. Further into the future, projects
aim to produce potassium nitrate and upgrade the
magnesium oxide to magnesium metal.
The development of these associated co-products up
to commercial production permits synergies while
maximizing the use of the available resource.
Although the life of reserves of phosphate rock and
potash ore vary depending on factors such as the production
cost, market prices and technological
development, the total available resources are finite in
the long term. Currently, extraction and beneficiation
have been focused on the easily recovered, higher
grade minerals. There exists a wide range of more
complex, lower grade minerals that could have an
increasingly important role in the future for the production
of mineral fertilizers. Research is being
carried out to develop beneficiation techniques that
can handle the complex mineralogy and contaminants
of these materials and bring these potential resources
into commercial production. These will help to extend
the supply of mineral fertilizers as far into the future
as possible.
Removal of Dolomite Contamination in Phosphate
Rock Ore
In Florida (USA), The Florida Institute of Phosphate
Research has been involved in research into methods
to separate dolomite from phosphate rock. The
dolomite increases the consumption of acid during
processing. A new flotation technique has been tested.
Commercial application of this technique would
allow phosphate orebodies with a high dolomite content
in the central western Florida area to be mined,
extending the life of the resource.
3.6 Waste Management and Disposal
The beneficiation of phosphate rock and potash typically
produces large volumes of waste that may cause a
variety of adverse environmental effects if not managed
and disposed of in a safe, stable and
environmentally sound manner.
Figure 3.6.1
Potential environmental effects : waste disposal
Wastes to surface
storage impoundments
and piles, underground
backfilling, deep well
injection, or release
to the environment
Land surface disturbance
Water contamination
Air emissions
Stability
Aesthetic changes
Major environmental concerns are typically related to:
Land surface disturbance from the construction
and operation of large waste disposal impoundments
such as dams, ponds and stacks;
Surface and ground water contamination by
wastes such as fines, tailings effluents and brines;
The safety and stability of the storage facility.
Failure can result in extensive and widespread offsite
effects.