Devon Doosan Addition

Wed 18 Jan 2017

Devon Doosan Addition

If you have ever worked on a construction site in Devon in the past 50 years, the chances are that at some point you have used stone which has been mined out of the Linhay Hill quarry on the edge of Dartmoor in Ashburton. The Linhay Hill quarry became home to the family business Glendinning in 1958, when the company founders Ernest and Jack Glendinning took over the ownership of the quarry from its previous owner. Since those days the operation has expanded rapidly and an ever expanding portfolio of products are produced there. Since those early days the business has gone from strength to strength and today the business employs well over 230 people in Devon & Cornwall. The core product at the Linhay Hill site is carboniferous or Devonian limestone, which is used for or in the manufacture of asphalt, concrete, agricultural lime, concrete blocks, hardcores, chippings, and decorative concrete and industrial products.

The extraction process follows a familiar pattern to those at quarries all around the world. Following drilling and blasting, the “as-blasted” material is primary processed through either a mobile impact crusher (Gipo) or mobile jaw crusher (Kleeman). The poorer quality material is scalped off and sold as a fill material or is put through a washing plant on site to produce a washed limestone sand, which is used in the manufacture of concrete. All other primary processed material is fed into the secondary plant, where it may pass through either a secondary or tertiary crusher or sometimes both. It is then screened out into single sizes, ranging from 250mm down to dust with a variety of sizes in-between.

The Linhay Hill quarry typically produces between 500,000 – 600,000 tonnes per annum, but during the past 12 months this output has increased to an impressive 750,000 – 800,000 tonnes. This output is in addition to 150,000 tonnes of gritstone that the company also extract from an additional quarry operation in Bude in North Cornwall. As one might imagine in an operation like this a lot of plant goes into the quarry and often never comes out again. At Linhay Hill the fleet consists of 1 x Hitachi ZX850, 1 x Volvo EC460, and the latest arrival the Doosan DX700LC. The wheeled loading shovel fleet is primarily dominated by Volvo and Caterpillar, with the Volvo machines drawing a lot of praise from quarry manager Neil Gibbs. On the articulated dump truck side of things Volvo is once again the preferred make of choice, including two older A35 models, 3 x A35D’s and 2 new A40E models, these machines are also supported by a Terex TA35 model. Rigid haul trucks are represented by a Terex TR70 model and an ageing Euclid R60. These machines are also joined by a Caterpillar D6MXL dozer, which is used on general clean-up and tip work around the quarry.

For over a decade the Hitachi ZX850 had been the primary excavator in the quarry and is still a reliable and trustworthy machine in the Linhay Hill fleet, but it was felt that another heavy excavator was needed. As a company Glendinning had had little if any experience with the Doosan brand but the price offered was extremely attractive and simply could not be ignored when compared to competitive manufacturers machines in that size bracket. Before taking the plunge the quarry management drew on feedback from other operators with experience of this particular machine, both in the demolition and quarrying industries. This feedback proved to be extremely positive, highlighting few if any faults with the Korean machines.

On the day of Earthmovers site visit, the “new kid on the block” was busy loading blasted rock from the face onto the Terex TR70 rigid truck and a Volvo A40E articulated hauler. The new 70 tonne class machine was ably assisted by an older Volvo EC460 excavator, which is deployed with a hydraulic breaker to tackle any oversize rocks which have survived the initial blasting intact, breaking them up into more manageable pieces before being loaded prior to transport to the crusher.

Talking about the old Volvo machine, Operations Director Adam Somerscales said, “When the Volvo EC460 was purchased in the early 2000’s, it was around the time that Volvo had recently acquired Samsung excavators. Therefore the Volvo EC460 was effectively a Samsung excavator re-badged and repainted in Volvo livery. This machine was built in South Korea and therefore gave us confidence as to the quality of South Korean machinery. This machine has performed admirably in the various applications it has been used, namely Uplyme Quarry, near Lyme Regis, Pigsdon Quarry near Bude and more recently in its secondary breaking application at Linhay Hill Quarry. So the experience with this machine was also a major factor in the decision to purchase the Doosan DX700LC”.

Supplied by long established local dealer Kellands, the 71099kg (156748lb) Doosan DX700LC, which coincidently was one of the first examples of this model to be sold into a quarry, is powered by a Stage 3B emissions compliant 6 cylinder “common rail” Isuzu AH-6WG1X diesel engine, which offers a power output rating of 345kw (463hp). Working in conjunction with the machines e-EPOS electronic control system the machine delivers increased power but with reduced fuel consumption and this fuel consumption has certainly been noticed by the team in the quarry.

The machine was certainly making light work of digging and loading the rock, thanks in part to an impressive bucket digging force of 33.3 tonnes. Additionally the operator is aided in the dig by the fitment of a power boost button, which increases the digging force by up to 9% and this function was clearly noticeable as the machine was pulling through the heavy rock in the quarry floor. Doosan’s excavators have always had a reputation for being fast machines, especially in the slew and even for a machine of this size, it was pretty swift in that department, with a slew speed of 7.1 rpm quoted by Doosan. The machine looked well balanced and stable too, sitting on its long undercarriage and with a wide footprint of 4000mm the machine remained rooted to the spot during the loading operation.

The machine features 4 work mode settings consisting of Power, Standard, Economy and Lifting mode. Working in these tough conditions I am led to believe that the operators preferred setting is the power mode. The machine was supplied with a full package of extras, which includes fall from height protection on the upper structure, operator walkway featuring a rear ladder for safe access and egress, check valve guarding and a bucket tipping ram guard.

The operator charged with the new Doosan is Darren Randle who said “So far I’ve been very pleased with the new excavator and have found it to be an excellent piece of equipment with good digging power and great comfort in the cab, which can only be a good thing for those of us who operate these machines for long shifts”. The cab, although the older style, is still very well appointed as we have come to expect from later Korean machines, spacious and ergonomically well laid out and with all the creature comforts expected in a modern excavator. Noise level inside the cab is a very pleasant 76dB (A) and even when stood outside beside the machine noise level is a low 107.7 LwA. Of course it’s not all state of the art equipment down in the quarry, as previously mentioned kit comes in and often doesn’t leave and there were a number of classic items of kit to be found, like a Michigan loading shovel and a late 1990’s example of an O&K RH30E in face shovel configuration, which although still a runner is rarely used on the frontline anymore.

As for the Doosan DX700LC, well it’s still early days with the machine in the quarry, but so far the machine has been performing extremely well and is sure to remain a long term fixture in the Glendinning fleet.

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