New Sandvik hydraulic breaker for Mill Hill Quarries
Slate and decorative stone producer uses a BR2577 breaker to put a modern spin on an old quarry
MILL Hill Quarries Ltd were established more than 50 years ago and today have three sites in Devon and Cornwall, including Trevillett Quarry, near Tintagel.
Originally founded by Welsh slate miners during the 19th century, Trevillet Quarry had many owners and several periods of closure before being acquired by Mill Hill Quarries in 1990.
The site contains two valuable beds of slate – a fine red-veined variety suitable for decorative architectural facing products, such as walls and paving slabs, and a fine-grained blue-grey variety which is ideal for roofing tiles.
Mill Hill Quarries have employed a series of Sandvik breakers at the site since 2002 when they purchased a Rammer G80, later followed by two m18 breakers, all supplied by local dealers M&M Plant.
Today the company is using a 1.7-tonne Sandvik BR2577 breaker mounted on a Doosan DX300LC hydraulic excavator to break out virgin ground for building blocks on the quarry’s upper levels.
Lower down, the same breaker has replaced the gangs of men who, in the past, would have carefully levered out the blocks of good quality blue-grey slate after blasting, prior to cutting and dressing as roofing tiles.
With an impact rate of 450 to 750 blows per minute, the new BR2577 features Sandvik’s Fixed Blow Energy system that ensures optimum impact energy with every blow, regardless of hydraulic flow fluctuations. Other key features include a Soft Blow Sensor which reduces the power and frequency of the breaker for softer rock, and Idle Blow Protection which protects against blank firing.
Describing the new Sandvik BR2577 as ‘one of the best breakers he’s used’, quarry manager John Ferrett said: ‘We liked the previous breaker but this one is even better. There are several new features on this breaker that make extraction more efficient and generate far less waste. The flat base of the casing, for instance, makes penetration better, deeper, and more accurate. Maintenance access is also very easy; the greasing is done automatically and there are now no bolts to constantly tighten on the new flat base.’
Mill Hill Quarries’ managing director, Mandy Hopkins, highlighted several other significant benefits. ‘This is an environmentally sensitive site with a working chemical plant on the western edge of the quarry and a hamlet to the immediate north of the site,’ she said.
‘Blasting is now confined to the lower levels, and then only small amounts of pyrotechnic breaker capsules are used once a week to free 20–30 tonnes of slate. The breaker is a lot quieter than the previous model and certainly faster, both of which mean that noise pollution is kept to an absolute minimum.’
She continued: ‘Being able to use the breaker to break out the slate block means there is no need for a gang of workers on the ground. The health and safety implications are immediately apparent. Another advantage is that the breaker can turn the rock on its edge and separate the block by breaking the rock horizontally, greatly reducing pre-production time and minimizing waste.’
Mandy Hopkins added that although Mill Hill Quarries were already familiar with Sandvik products, the purchase of the new BR2577 had forced the company to rethink its equipment procurement and replacement policy.
‘Company policy is usually to trade-in hydraulic breakers after three years when a traditional warranty expires,’ she explained, ‘but Sandvik’s new lifetime warranty presented us with an interesting option.
‘We always take good care of our breakers, so the lifetime warranty gives us a lot more flexibility and the option to hold on to equipment a little longer. In the current economic climate, a lifetime warranty certainly gives us more confidence.’
