A NEW CONCEPT FOR TREATING LEACHATE AND CONTAMINATED
RUNOFF WATERS FROM A TACONITE TRANSSHIPMENT FACILITY
Amir A. Metry, Project Manager
Michael E. Harris, Project Manager
Roy F. Weston, Inc.
West Chester, Pennsylvania 19380
INTRODUCTION
General Background
Iron is the fourth most abundant element in the earth's crust;  however, native iron is
rarely found because iron combines readdy with other elements such as oxygen and
sulfur.   Iron oxides (magnetite, hematite and limonite) are the most prevalent form of
iron found in nature, followed by carbonates, silicates and sulfides.   Generally, these
iron ores are reduced to iron in a blast furnace.   The iron from the blast furnace is then
refined in steelmaking furnaces to make steel, the number one engineering metal.
The most important source of iron ore in the United States is the Lake Superior
district.   Parts of this district are located in the states of Minnesota, Michigan and
Wisconsin and include the Mesabi, Cuyuna and Marquette ranges, respectively.   The other
districts are the Northeastern (Pennsylvania, New York and New Jersey), Southeastern
(Alabama) and Western districts (Texas, California, Utah, Nevada, Wyoming and Missouri).
To be classified as an ore, iron-bearing mineral deposits must be capable of being mined
and reduced to iron commercially.   When the unaltered iron formation contains 20% or
more iron in the form of magnetite (Fe304), it is called taconite.   This type of iron ore
is amenable to beneficiation processes, making it increasingly important as a source of iron.
The term "beneficiation" as it is applied to iron ores means to improve the ore's
chemical and/or physical properties.   Increasing the iron content of the ore is referred to
as "concentration";   while improving the physical structure (by increasing the size of the
particles) is referred to as "agglomeration".   Taconite ores are ground to 200 mesh or
finer and then concentrated by using magnetic separating drums.   The original ore contains
25 to 30% iron when taken from the mine, and the concentrated ore contains 60 to 65%
iron with 2 to 8% sdica.
To increase the particle size to that desirable for blast furnace feed (0.25 to 1.0 in. in
diameter), the concentrated ore is agglomerated.   Numerous methods are available;  however, sintering and pelletizing are the most commonly used.   The Taconite Transshipment
Facdity in this study receives ore from a pelletizing process.   In the pelletizing process, the
ore is ground to minus 200 mesh, mixed with the proper amount of water and bentonite,
and then rolled into small balls (0.375 to 0.75 in. in diameter) in a balling drum or disc.
These pellets are then dried, heated to 2200 to 2500 F to bond the small particles
together, and finally cooled for shipment.
The beneficiation and agglomeration processes take place at the mine site;   from there,
the pellets are transported to the blast furnaces.   The economics of transportation cause
the pellets in this study to be shipped by rail to the Taconite Transshipment Facility
where they are either stored or transferred directly to ore ships for transportation to the
blast furnaces.
Taconite Leachate and Water Quality
Several impacts could be expected from the discharge of untreated leachate and/or
contaminated runoff waters into surface or subsurface water bodies.   Suspended solids,
which are primarily iron oxides, cause steam discoloration;   in addition to aesthetics, they
will have the following impact:
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