Deep Impact
Visitors to Hillhead 2010 will have the opportunity to see one of the largest Tesmec Rock Hawg machines in action – the TRS1475
One of the key tasks for any quarry manager is to look at cost-efficient ways of improving productivity in the quarry. It is their responsibility to contain costs, to meet tighter aggregate specifications, to reduce production of both fines and oversize, and to comply with environmental regulation, as well as health and safety regulations.
With technologies evolving and emerging all the time, quarry managers are continually looking at solutions that offer safer, more practical and efficient processes, which, ultimately, lead to improved production and reduced costs.
In July Westquay Trading introduced the largest Tesmec Rock Hawg machine operating in the UK – the 110-tonne TRS1475 – with a live demonstration event at Lafarge’s Whitwell Quarry, near Worksop, Nottinghamshire.
The new machine was recently purchased by trenching contractors A.J. Gammond Ltd (who also own a smaller version of the Rock Hawg, the TRS1150) to provide specialist plant hire trenching equipment for both large-scale construction projects and the bulk excavation of level rock surfaces.
In operation, the Rock Hawg resembles that of a surface miner but it cuts, trenches and fragments rock in a single process. Powered by a six-cylinder Caterpillar C16 engine (630hp), the TRS1475 has a 3.8m-wide drum, a maximum cutting depth of 600mm and is capable of extracting up to 300m3 of solid rock or minerals per hour.
Westquay Trading say the Rock Hawg trenchers have already been a success in a number of industries, including civil engineering, demolition and the utilities, providing a cost-effective and productive alternative to traditional trenching, excavating and reclamation.
It has also shown great potential in the quarrying sector. At Whitwell, Lafarge had to construct a new haul road to provide access to new reserves on the opposite side of a public highway, but the project was not as straightforward as quarry manager Shane Tompkin had hoped for.
‘With a newly built bridge and major highway nearby, it was impossible to use blasting methods to extract the rock for this new haul road,’ he explained. ‘Initially, we used traditional excavating diggers and breakers, but these machines were not built for this type of work, which slowed our progress. So, we decided to look for a large-scale, purpose-built machine designed for the primary excavation of rock and came across the Rock Hawg.’
A.J. Gammond proposed the use of the TRS1150 and the machine has managed to dig out over 500m3 of rock in a short timescale, with the added benefit of the extracted material being reused.
Utilizing powerful ‘reverse cut’ technology, the Rock Hawg can reduce solid rock into aggregate and sand, thereby eliminating the need for drilling, blasting, ripping, hydraulic hammers and primary crushing.
The size of the material produced is determined by the physical properties of the stone and the configuration of the drum (operators can choose from three digging speeds: 0–114m/min; 0-160m/min; and 0-206m/min).
The Rock Hawg also causes much lower vibrations, meaning minerals can be excavated with minimal disturbance if they are in close proximity to existing buildings, roads, neighbourhoods etc.
Mr Tompkin has been so impressed with the Rock Hawg technology that Lafarge are considering using the larger TRS1475 model to extract limestone deposits close to a village where blasting is not feasible.
‘When used in the right application, the Rock Hawg can be a viable economic and environmental alternative to drilling and blasting,’ he explained. ‘It has proved to us not only to be advantageous in constructing haul roads, but also a potential production tool in quarries.’
Another notable project that the Rock Hawg has worked on was a cut-and-cover tunnel construction at Aggregate Industries’ Westleigh Quarry, in Devon, where, due to the sensitivity of the site, it was impossible to use drilling and blasting methods.
The use of a road planer had also been tried but with unsatisfactory results. As a result, A.J. Gammond were approached and a Rock Hawg unit has since helped Aggregate Industries overcome the obstacles on this uniquely challenging project (a detailed case study will be published in a forthcoming edition of QM).
