Surface mining offers more value, economy

Today?s mineral prices are driving mine operators to explore new methods to extract mineral seams,? says Mark Cooper, senior director of specialty excavation for Vermeer Corporation. ?In Australia, operators must follow a 10m setback from a high wall for blasting. That?s 10m of material and a significant amount of money that they just leave. Mines can?t afford to leave these deposits behind, based on today?s market prices.?

Now mine operators have a technology to help them capture these difficult mineral deposits. Precision surface mining allows mine operators to selectively extract mineral seams in surface mining applications.

The process utilises Vermeer?s Terrain Leveler Surface Excavation Mining (SEM) unit. The unit was created when Vermeer took a rock trencher, removed the trencher attachment, and added a patented tilt-head milling attachment with top-down cutting action.
Top-down cutting allows the cutter teeth to gain penetration without using the machine?s tractive effort to drive the teeth into the minerals. As the unit travels forward and the drum rotates, the teeth on top of the drum advance over the top of the mineral surface. As the teeth come down toward the mineral surface, they impact on the mineral.

Operators can also control material sizing. Increased tooth penetration increases the material size and decreased tooth penetration reduces the material size. This can be done by changing the drum depth.

A patented drum tilt system allows the operator to control grade in both the lateral and longitudinal directions and the unit can dig up to 685mm (27 inches) deep and 3657mm (144 inches) wide in a single pass.

Precision surface mining produces a smooth floor that can minimise wear and tear on mine trucks and loaders, especially on machines with rubber tyres. This can also allow the use of off-road trucks in place of mine trucks in many cases.

Producing small-sized material in a uniform configuration allows minerals to be handled more efficiently than product produced by drilling and blasting. The uniform product size also allows more efficient settings on secondary and tertiary crushing systems, savings that can continue well past the primary crushing stage.

Where the desired minerals are in thin layers, precision surface mining can follow the layers and help prevent unwanted mixing of materials. Since it is entirely possible that all layers are economically valuable ? but not compatible ? the ability to separate them through precision surface mining provides benefits over drilling and blasting. Precision surface mining allows this process to be closely controlled so that almost all available products are recovered, resulting in a product of higher quality and value.

?We?re looking at somebody digging with a garden shovel versus somebody cutting out pieces with knives,? says Mark. ?It?s just a different way of approaching mining. Vermeer believes we can offer mines the ability to chase smaller seams and product located in corners that current methods don?t allow mines to go after economically.?

Precision surface mining also gives mine operators the ability to react quickly by increasing mine production in a short period of time. The capital costs to expand or open a mine are significant, and can require up to three years of planning and installation before the mine is operational.

?An iron ore mine in Australia recently purchased T2155 Terrain Leveler SEM units and portable crushers to quickly increase mine capacity, in order to chase spot prices in the market,? says Mark. ?Precision surface mining gives mines this type of flexibility. Since the Terrain Leveler SEM is a production machine, the mine was up and running in a matter of months versus years.?

Precision surface mining will also incorporate high technology communication in the future by using Global Positioning System (GPS) technology and two-way data communication. ?Think of OnStar in your vehicle,? says Mark. ?This remote two-way data communication system will be able to transmit engine and machine functions and receive GPS or mining plan information to the machine.?
An engineer could create a mine plan in the office and send the data to the Terrain Leveler SEM.

The operator can pull the plan up on the screen and go to work based on the new mine plan in front of him.
?That?s the future of precision mining,? says Mark. ?Efficiently capturing more value out of the mine.?

Source: Vermeer Corporation

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