The raw product feed was a hard rock 500mm blast material (standard blast feed curve), although the material varied in moisture content from day to day. The machines contracted by the mine to process the material were all Sandvik mobile units supplied by nationwide distributor Precisionscreen: the UJ440i heavy-duty jaw crusher, the QS441 secondary cone crusher and the QE440 heavy-duty scalper.
The UJ440i jaw crusher was fed directly by a 980-size front end loader at an average rate of 330 tonnes per hour (tph), with peak loads up to 380 tph. The primary UJ441 jaw crusher was set at approximately a 100mm closed side setting (CSS), feeding directly into the secondary QS441 cone crusher.
The QS441, with a top size acceptance of 400mm, could handle all the in-feed material with fines at a CSS of 30mm. Material was then fed to the QE440 screen for stemming separation, with the other two products, including a P80 50mm minus, being blended together to form the roadbase. A second 980-size front end loader stockpiled the material.
The gold mine was very happy with the contractor’s equipment performance and professional delivery. The QS441 was an ideal secondary crusher for maximising the jaw crusher’s output with its high capacity throughput and large in-feed size.
With a maximum feed size of 760mm, the UJ440i jaw crusher maximises production through its 1200mm x 830mm feed opening, which, coupled with a hydraulic CSS, enables rapid changes through push button operation. Its heavy-duty CJ412 jaw crusher can handle virtually any type of hard rock in any climate, including the most extreme weather conditions.
Quick set-up time and site to site transportability are integral design features that ensure the unit can rapidly process materials in any location.
Both the crusher and unit are manufactured to the highest quality using Sandvik components, meaning the number of spare and wear parts that need to be stocked is minimised. Thanks to automatic and continuous monitoring of the production process by an in-built intelligence control system, the UJ440i enjoys trouble-free and safe operation.
An optional hanging screen is available for the production of two fraction sizes, potentially providing the operator with further avenues for a sound return on investment.
The QS441 is a tracked, self-contained cone crusher with an on-board diesel engine. Incorporating the CS440 Sandvik cone crusher, the QS441 can accept large feed sizes and achieve above average throughput, combined with high product quality. The S-type gyratory cone crusher has proven itself in stationary applications for more than 30 years, and is therefore considered in the mining and quarrying industries to be one of the most reliable, versatile and productive cone crushers in the market today. The gyratory cone is able to accept a feed size up to 90 per cent larger than current standard cones, which allows maximum productivity from the primary crusher, or even enables the S-cone to be operated as a primary crusher on gravel applications.
The QS441 is equipped with a hydroset system that provides both safety and setting adjustment functions. The automatic setting regulation system not only optimises production, it also keeps track of liner wear, thus making it easy to plan liner changes and minimise interruptions in production. The QS441 represents the perfect combination of advanced cone crusher technology and tracked mobility.
With a choice of three concaves, and four bush settings to control the CSS and material gradation, the unit potentially affords the operator more flexibility.
The 36-tonne, heavy-duty QE440 scalper can produce accurate gradings at throughput rates of up to 600 tph, and is also capable of recycling mixed materials. Its stockpiling conveyors are higher and wider than other scalpers in the Sandvik range to efficiently manage increased production capacity and to facilitate larger stockpiles.
The QE440 can be specifically tailored to a wide range of applications, including the screening of heavy overburden at a quarry face, pre-screening and scalping, recycling of construction and landfill waste and separation of cohesive aggregates.
Although this unit was first launched in Australia in 2010, the evolutionary 37-tonne Sandvik QE441 mobile scalper, with a throughput of 700 tph, has since replaced it.