Ore sorting

Ore sorting refers to the process of separating an ore into separate constituent parts. Today, ore sorters are widely used in industrial mineral mines, diamond mines and base and precious metal mines.

Ores are typically sorted to increase the efficiency of other refining processes, by reducing the amount of material to be processed while simultaneously increasing its purity.

Modern technologies

Modern, automated sorting applies optical sensors (visible spectrum, near infrared, X-ray, ultraviolet), that can be coupled with electrical conductivity and magnetic susceptibility sensors, to control the mechanical separation of ore into two or more categories.

Commonly sorted ores

* Base and Precious Metals
o Gold
o PGMs
o Copper
o Zinc
o Nickel
* Industrial Minerals
o Pegmatites
o Limestone
o Calcite
o Dolomite
o Coal
o Magnesite
o Quartz
o Feldspar
* Gems
o Diamonds
o Tanzanite

Reasons for industrial sorting

* Pre-concentrate mill feed into high-grade and low-grade fractions
o Build a smaller mill or effectively increase the capacity of an existing mill
o Remove low-grade fraction that is actually costing money to mill
o Add previously uneconomic zones to reserves
o Manage ore blending programs more effectively
* Sort high-grade ore out of low-grade stockpiles and waste dumps
o Recover value from previously uneconomic waste
* Reduce environmental risks and costs
o Reduce mill energy consumption
o Send acid generating waste rock to appropriately designed dumps
* Optimize multiple process streams
o Send appropriate ore directly to the mill, leach heaps or smelter
* Pre-concentrate ore underground or at remote sites
o Reduce haulage and hoisting costs
o Mine satellite orebodies and sort on site
* Monitor the composition of the mill feed
o Provide real time data to operators for process optimization and work index prediction

From http://en.wikipedia.org/