InfraStructures - October 2021 - The Perfect Tool for an Extremely Challenging Job

The Perfect Tool for an Extremely Challenging Job

At a large quarry in the Midlands, in the UK, Kelly Earthmoving has delivered some enabling works associated with the installation of a cable suspended conveyor that will span nearly 1 km across the quarry. Installing this system has required some serious advanced enabling and civil engineering solutions.

Kelly Earthmoving has been brought on to the site due to its experience and specialist capability. The Irish company has a UK base in Preston and undertakes a variety of specialist work across the country. Whilst having “earthmoving” in its name, the company headed up by Gerry Kelly offers a more specialized service to its long-standing clients.

Not only does Kelly Earthmoving move awkward earth but the company also includes complex ground engineering into the package. From bank stabilization, piling and vegetation management, the wide variety of services offered, and the specialist equipment it runs, puts it in a leading position for the technically demanding projects.

“We already undertake rock breaking and cutting for our existing clients,” explained Mr. Kelly. “But this project has seen us extracting and breaking far more rock than we have ever done on a single job. It’s been a tough but enjoyable project to be involved in but also one that has been hard on the equipment.”

The project has kept the Kelly team busy for 12 months working on 2 separate sites. The terminal anchor point for the suspended conveyor system has now been excavated and construction of a large concrete foundation is underway.
The team has also created a working platform to allow the civil contractor to build a piled wall required to construct the suspended conveyors deflection tower.

From this platform, a slope down through the mudstone and rock leads a second working platform. At this point the team encountered the very hard rock that the quarry is famous for.

“We had a number of options for the removal of the rock head,” explained Gerry Kell. “We looked at sawing sections out, but the rock was littered with enough fractures that allowed us the quicker option of using hydraulic breakers instead.”
Whilst some of the exposed rock was easy to remove, the material below was not and ended up breaking a number of hammers and countless chisels in the process.

“It was getting beyond a joke. Every couple of days we were breaking a chisel or sometimes more,” said Mr. Kelly. “Our usual hammers were struggling with the hard rock so we decided to look at investing in something more reliable and productive to complete the job.

Coyle Equipment Services supplied an Epiroc MB 1200 hammer as a replacement for one of the other ones.
Carefully driving a path through the rock, the 12 t Menzi Muck wielded the MB 1200 hammer with ease despite it being designed for the larger 15-26 t carrier range.

“The Menzi is just a massive powerpack. It will push out over 200 l/min with the Powerline pump, far more than the Epiroc breaker requires,” said Gerry Kelly.

Lift capacity even at its full 6 m reach is over 4 t, making the Menzi an ideal hydraulic attachment carrier. Carrying a hefty 120 mm diameter chisel, the MB 1200 delivers between 340 and 680 blows/min which is more than capable of taking apart the rock Kelly Earthmoving was encountering. Fitted with Epiroc’s AutoControl system, the hammer is able to detect pressure on the chisel. It also detects when the chisel breaks through the material to protect it from blank firing and causing potential damage to the percussion chamber.

Despite having a pandemic and bad weather thrown at them, the Kelly team has delivered an impressive result for the quarry’s project team.

“The men and machines have performed very well on the project,” commented Mr. Kelly. “We don’t take on ordinary jobs, we always like a challenge!”

Source: Epiroc

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