Quarrying & Mining Magazine
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Crushing game 

An increasing workload has seen KB Contracting & Quarries expand and upgrade the equipment in its operations, recently buying a new Sandvik crusher and screen, a Hyundai loader and a Bomag roller from Porters in Christchurch. 

WITH A SELF-EXPLANATORY name, KB Contracting & Quarries does exactly that – contracting and quarrying. Based in Christchurch, the firm has been in business for 40 years.
The contracting side specialises in new urban road construction and reconstruction work – something they’ve been getting plenty of in the years since the earthquakes did so much damage to the city’s infrastructure. The contracting side is backed by the company’s quarry operations, which it uses to source and process aggregates.
KB owns and operates quarries at Miners Road and McLeans Island Road and also has a stock yard in Maces Road, enabling it to guarantee the quality and supply of materials on the projects it undertakes. Its contracting half provides a variety of earthmoving services in the construction of subdivisions and other large-scale operations.
KB has supplied a large portion of the bulk fill and roading materials on almost all of the new motorway projects around Christchurch and the city’s State Highway 1 upgrade. This is in addition to the rebuild work, which has taken the bulk of its aggregate supply over the past few years.
All this work has necessitated some new gear in one of its quarries.
“There’s a certain amount of equipment upgrade as well as expansion,” explains quarry manager Declan Close when asked about the company’s recent acquisition of new equipment.
They recently purchased a Sandvik QH441 mobile hydrocone crusher and a Sandvik QA451 mobile doublescreen from Porter Group, along with a Hyundai 760-9 loader.
The loader has been put to work in the distribution yard alongside the quarry. There it is kept busy loading trucks with aggregate, while the operator enjoys the latest in comfort and performance, with optimal strength, speed and reliability.
Back in the quarry, the new Sandvik crusher is central to the whole operation.
“This is the third crusher in the quarry,” says Declan. “The whole plant is designed around this type of crusher and this new one is our biggest, able to process 500 tonnes an hour.”
It produces a range of materials, from road base and various chips to specialist products.
Sandvik describes the QH441 as one of the most flexible and heavy duty cone crushers in the market today, one specifically aimed at large-scale aggregates producers. It says the crusher provides uninterrupted productivity and requires minimal operator intervention.
The machine features a variable crusher speed via the engine to manipulate product gradation. And a camera overseeing the crushing chamber allows the operator full visibility of the feed material entering the crushing chamber.
Designed for optimum fuel economy and low operating costs, a level sensor above the crushing chamber controls the automated variable speed feed conveyor to ensure maximum production, reduction and shape.
“The new crusher has allowed us to develop specialist products that can be used in various applications, from sports field construction to specialist drainage and roading solutions,” says Declan.
Working hand in hand with the crusher is a state-of-the-art screener.
Described as the ultimate screening solution, the Sandvik QA451 is the only screener in the world with a triple decked doublescreen screening system. Declan says this means the machine can produce four different products at once, from crusher dust up to various sized chips, sands and specialist drainage products.
“It processes between 300 and 400 tonnes an hour, depending on what we’re doing with it,” says Declan. “We generally utilise it for products 40mm down, but it will do from 65mm down.”
Sandvik says it developed this machine to enable massive stockpiling capabilities.
“The QA451 is a formidable solution with two inline 3×1.5 metre screen boxes, a large feed hopper and extended conveyors. We have designed the QA451 to work in closed circuit with our tracked crushers. You can optimise the feeding position to upstream units as the fourth product conveyor slews and raises/lowers hydraulically.
“To provide ultimate flexibility the QA451 can also work as a stand-alone screening and stockpiling system. In this mode, the unit can produce four sized products with fifth oversize material scalped off at the grid.”
Declan says the company went with Sandvik as they knew it was a superior brand for applications such as theirs.
“The service and backup from Porters has been excellent,” he says. “They’re one of the top suppliers, and their service was definitely a contributing factor in our choice.
“It’s been a big investment for our company but it’s proved very successful so far.”
A final part of that shopping spree at Porters was for a new Bomag roller which is working in the contracting side of the business, compacting the company’s aggregates on various roading projects around Christchurch.

This article first appeared in Q&M‘s December- January issue.

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