Globally respected materials handling and minerals processing systems supplier, TAKRAF, part of the Tenova group, boasts a significant portfolio of diverse and unique references across an assortment of applications; from in-plant conveyors to large scale sophisticated systems with conveyors as the backbone. Three case studies demonstrate its broad spectrum of notable conveyor applications.
A waste or overburden removal system in hard-rock typically consists of a crushing station that feeds conveyable size material to an overland conveyor arrangement that brings it to a stacking facility at the deposit zone. Vast amounts of this overburden must be placed, often in layers, in a continuous operation over a very large area. High capacity extendable and shiftable conveyors are required along with mobile machines that only shut down for short periods of time to relocate or extend. When the waste removal stops so too does the production of ore.
Commissioned in 2013, the conveyors have substituted the numerous heavy haul trucks that would otherwise be required, traveling many kilometers daily, half of the time empty, and burning diesel fuel around the clock. This system requires a vastly smaller labor force to operate and maintain with the majority of servicing conducted during pre-scheduled shut downs. The result is that getting the waste rock out of the way has caused very little impact to the planned production of the mine. Operation for the past 4 years has demonstrated both exceptional reliability and efficiency.
Moving and delivering material underground
With near surface orebodies diminishing, existing mines have to adjust their approach to meet the changing requirements of an aging mine. For many, the alternative is closure or shifting the mining operations to below the surface.
In Indonesia, an underground material handling system was recently commissioned to deliver 8000 mt/h of primary crushed ore from a new block cave to existing mill facilities above ground. The project included six underground conveyors with a total length of 4075 m and an overall vertical lift of approximately 500 m. The design, undertaken by TAKRAF’s USA office, incorporated 6000 installed horsepower per conveyor flight. At full capacity, the mine operation is capable of processing up to 240 000 t a day.
The conveyor system will employ state of the art gearless drive technology with the tunnel conveyors boasting the highest power ever to be installed on a single belt conveyor. Gearless drives do not use a gearbox but only a variable speed motor having high torque throughout its speed range. With the challenges of limited space and accessibility and steep grades, the gearless solution is the main reason such a system can be achieved.
The high power for each drive permits longer flights. Meanwhile, they have a smaller footprint and reduced maintenance and increased efficiency and reliability without a gearbox.
Pipe conveyors and their low environmental impact
Introduced in the 1970’s, the pipe conveyor has evolved as a solution for many of the drawbacks of the conventional troughed belt. Interactions between the environment and conveyed material (such as dust emissions and water absorption/contamination due to rain or snow) are eliminated by encapsulating the material while in transportation.
Further to the advantages of enclosing the material, pipe conveyors can have horizontally curved alignments which allows for elimination of transfers thereby less emissions points, not to mention lower maintenance requirements. Although TAKRAF has successfully developed curved trough conveyors for high capacity overland conveyors, the radii can be much smaller for pipe conveyors which is advantageous for negotiating facilities within a plant without the need for a lot of transfer stations.
TAKRAF pipe conveyors are employed in this plant to handle material that is extremely sensitive to contamination and in several instances curved alignments allow for a more compact plant layout. In this layout parallel pipe conveyors deliver material from the fertilizer plant to a 550-ton capacity bin. From there, another pipe conveyor distributes it to either a storage dome or new stockpile. The 90 000-ton enclosed stockpile is loaded via a travelling tripper car and reclaimed by a TAKRAF portal scraper machine. The reclaimed urea is transported via a reclaim conveyor and another pipe conveyor to a truck/train load-out station. At this load-out station, rail cars or trucks are loaded in an automated single batch system utilizing weigh bins, knife gates, and shuttle conveyors.
These examples of TAKRAF’s recent projects demonstrate how conveyor technology has advanced to meet the current demands and challenges of delivering material needed to produce the equipment and products that feed and enhance the world’s economies.