Overburden

Overburden is the material that lies above the area of economic or scientific interest (in mining and archaeology) e.g., the rock, soil and ecosystem that lies above the coal seam or ore body. It is also known as 'waste'. Overburden is distinct from tailings, the material that remains after economically valuable components have been extracted from the generally finely milled ore. Overburden is removed during surface mining, but is typically not contaminated with toxic components and may be used to restore an exhausted mining site to a semblance of its appearance before mining began. Overburden may also be used as a term to describe all soil and ancillary material above the bedrock horizon in a given area.

A related term is interburden, meaning material that lies between two areas of economic interest, such as the material separating coal seams within strata.

By analogy, overburden is also used to describe the soil and other material that lies above a specific geologic feature, such as a buried astrobleme.

From http://en.wikipedia.org/

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/

Ore concentrate

Ore concentrate text

Ore concentrate, dressed ore or simply concentrate is the product generally produced by metal ore mines. The raw ore is usually ground finely in various comminution operations and tailings(waste) are removed thus concentrating the metal component. The concentrate is then transported to smelters where it is used to produce useful metals.

From http://en.wikipedia.org/

Optical granulometry

Optical granulometry is the process of measuring the different grain sizes in a granular material, based on a photograph. Technology has been created to analyze a photograph and create statistics based on what the picture portrays. This information is vital in maintaining machinery in various trades worldwide. Mining companies can use optical granulometry to analyze inactive or moving rock to quantify the size of these fragments. Forestry companies can zero in on wood chip sizes without stopping the production process, and minimize sizing errors.

With more photoanalysis technologies being produced, mining companies have shown an increased interest in these types of systems because of their ability to maintain efficiency throughout the mining process. Companies are saving millions of dollars annually because of this new technology, and are cutting back on maintenance costs on equipment.

In order for optical granulometry to be completely successful, an accurate photo must be taken – under sufficient lighting, and using proper technology – to obtain quantified results. If these requirements are met, an image analysis system can be implemented.

From http://en.wikipedia.org/

Oil shale industry

Oil shale industry is an industry of mining and processing of oil shale—a fine-grained sedimentary rock, containing significant amounts of kerogen (a solid mixture of organic chemical compounds), from which liquid hydrocarbons can be manufactured. The industry has developed in Brazil, China, Estonia and to some extent in Germany, Israel and Russia. Several other countries are currently conducting research on their oil shale reserves and production methods to improve efficiency and recovery. However, Australia has halted their pilot projects due to environmental concerns. Estonia accounts for about 70 % of the world's oil shale production.

Oil shale has been used for industrial purposes since the early 1600s, when it was mined for its minerals. Since the late 1800s, shale oil has also been used for its oil content and as a low grade fuel for power generation. However, barring countries having significant oil shale deposits, its use for power generation is not particularly widespread. Similarly, oil shale is a source for production of synthetic crude oil and it is seen as a solution towards increasing domestic production of oil in countries that are reliant on imports.

From http://en.wikipedia.org/