Conveyors improve production in quarries

Conveyors have always played a key role in quarry operations but new developments are improving their potential to boost productivity

High fuel costs were driving more quarries to consider conveyors as an alternative hauling option in many quarries in Europe. But conveyors can also offer benefits when it comes to stockpiling and the latest developments have extended the advantages to mobile machines.

Ireland-based 466 Telestack has introduced a new range of high capacity mobile stockpiling conveyors to the European market recently. One of the first of the new TC621 conveyors is already working in a quarry in Sweden, which is successfully using the system to help manage its increasing production.

"The new conveyors are the first of their kind in the industry and offer the ability to produce large capacity stockpiles from mobile crushing and screening equipment," said Telestack director Malachy Gribben. "Being able to stockpile more material means that quarry operators do not need to have a wheeled loader continually working to re-handle the aggregates. The cost difference can be huge - typical owning, operating and maintaining costs for a wheeled loader can be €65 per hour but for these new conveyors, it's about €20 per hour." The unit being used at the Swedish quarry has a conveyor length of 21m with a discharge height of 10m with a capacity to handle up to 600tonnes per hour to create a maximum stockpile size of 2820tonnes. The conveyor comes with a diesel hydraulic drive as standard but the unit supplied to the Swedish quarry has been fitted with an electric drive to fit with its existing machine fleet and on site services.

According to Gribben, other benefits of the TC-range conveyors mean that the material remains within specification and safety on the site is also improved as there is less traffic. "For a wheeled loader to produce the same size of stockpile, the operator has to drive up on the pile," explained Gribben. "This not only causes compaction of the graded materials but also has safety implications too. For neighbours near the site, the conveyor also produces less noise."

Dust management

Minimising noise is one benefit of conveyors but some designs do add the potential for creation of dust and this is something that 460 Sandvik has been working to mitigate. The result is a telescopic chute that can retract as the stockpile grows. "With the telescopic chute we create a better working environment and reduce operational costs, clean-up costs and production losses. Overall, an improved operation economy," said Sandvik Mining and Construction global product line manager for wear protection and screen media Johan Renmarker.

Belt technology

According to 663 Smiley Monroe sales manager England Jeremy Cross, quarries are trying to lower spending across the board and it is no different when it comes to conveyors.

"There are new products that have been developed to offer a longer service life and reduce the potential for down time," he said. "Materials like 4420 Toughflex have a more resilient fabric carcass that is less vulnerable to piercing, which is ideal for contractors looking to work in quarrying and recycling. But cost is driving the industry more than engineering solutions at the moment, so many still tend to opt for standard conveyors." Nonetheless, Cross believes that technological advances in terms of spillage and positioning of transfer point are filtering into the market. "The wide availability of belt scrapers has helped to improve performance as there is no reason for material to be returned on the belt and cause early wear on the mechanisms.

"OEMs such as 447 Powerscreen have also started to add glide trackers as standard on new machines and this helps to ensure the conveyor tracks straight and prolongs its service life," he said. "This is being driven by maintenance issues and the need to minimise downtime - Sandvik in particular is looking more at whole life costs and the customer experience." Even without funds to invest in new conveyors, Cross said that quarries can improve performance of their existing equipment with just a few simple steps. "Look after the feed points, loading, tracking and rollers," he said. "Carry out regular checks that are timed according to the loading and type of material and not just service hours as a conveyor carrying large lumps of material or aggregates that are sharp or abrasive may wear more quickly."

Rapid repair

When it comes to replacing conveyor belts there are three options - cold vulcanisation, hot vulcanisation and mechanical fasteners. Hot techniques required expensive equipment and skilled operatives and mechanical fasteners create the risk of belts not tracking straight and loss of metal items into the feed material.
Cold vulcanisation offers the best approach for fast on site repairs and to ensure repairs are carried out to a high standard, Sandvik has now developed a kit to give operatives on site all the necessary equipment along with easy to follow instructions.
According to Sandvik, the kit has been tested by a number of its dealers and repaired conveyor belts have been put through their paces in a number of challenging operations from crushers through to scalping screens.
Sandvik global service manager Conor McAleer said, "The technique has been used for 25 years by our Australian dealer but the kit will bring the benefits to a wider number of quarries. Initial interest has been strong in remotely located quarries - we have sold nine to Angola already." Instructions for the kit are to be translated into French, German, Spanish and Italian.