South Wales based KJ Services are probably best known for the work they undertake stripping and refurbishing construction and mining equipment at their vast HQ in Rhymney. Formed in 1970 as a plant hire provider, the company has diversified into a variety of sectors including contract crushing.

Until recently, the core of their own hire and contract fleet has consisted of Caterpillar and Komatsu equipment as they have been seen as a reliable and productive choice within the industry. This has changed in recent months with the company taking delivery of their first Kobelco excavator to service a long-term contract crushing operation in the South West.

The new excavator, an 84 tonne SK850LC-10 has been specifically taken into the fleet to service a 2 million tonnes per year crushing contract. “We have been in the quarry for a number of years producing up to 850,000 tonnes of high-quality limestone.” Liam O’Sullivan, KJ’s quarry supervisor explains. “The quarry has recently won a number of additional contracts and have asked us to increase the production to meet the new targets. Our original 52 tonne Caterpillar excavator was too small to do this, so we had to look at bringing in a larger machine and crusher.”

With the need for a large excavator for the contract the company looked at both Caterpillar and Komatsu along with a number of other manufacturers before deciding on the Kobelco. A relative unknown in the UK at this weight range, the KJ Services team were impressed by the build quality of the excavator. “It looks a very solid and well put together excavator.” 

The company are already customers of Molson Group having a large fleet of crushing and screening equipment from them. “We know the Molson team very well.” Jay commented “Their Terex Finlay kit is excellent quality and their service and back up is second-to-none. This gave us the added confidence in taking the 850 on board.” The decision to change brands for their prime mover in this quarry was helped by a number of contributing factors including the ever-present issue of fuel consumption. “We operate over a dozen items of plant on this site alone and the fuel usage can be eye-watering some weeks.” Jay comments “From speaking with Molson and some of their customers, the feedback we have had on fuel use has been very good. Back up is another big issue for us. We need the excavator to be working 12 hours a day, 6 days a week so we need the reliability and the back-up that Molson supply to us already with our Terex Finlay equipment.”

The SK850 rides on a pair of mechanically adjustable track frames which push the overall width of the machine out to almost 4.5m and are shod with 650mm pads. Sturdy steps bolted to the frames allow access to the cab and upper structure aided by well-placed grab handles. Access to the refuelling pump, AdBlue tank and grease barrel compartment is from the offside of the excavator whilst a pair of large doors cover the large cooling pack to the rear of the machine. One neat feature is that the grease bucket is linked to a grease gun on a retractable reel housed in a compartment to the front of the upper structure and allows the operator, Dave Painter, to pull the gun out and grease every point on the machine from ground level. The cab side of the excavator is similarly accessed with the pump compartment to the rear. Just in front of this compartment there is a smaller doorway providing access to the front of the engine bay. This safe access means there should be very little need to climb on top of the upper structure. The cab is same as found on smaller Kobelco excavators and is finished to a high standard, and typical of most modern construction machinery, comes with a high specification including air conditioning, heated seat, Bluetooth connectivity and an intuitive, easy to navigate touch screen. Dave has already installed a floor mat and his cleaning gear inside the cab. “I’m in here all day, every day and I want it to be a decent and clean workspace. I won’t be out polishing the machine itself but will clean it off when I get the chance to.” He comments. Dave is very complimentary about the layout of the Kobelco cab… 

“I’ve not been in a new Kobelco before, but I think it’s very well laid out…“

…the joysticks are light and there’s just enough feedback through them.” 

The quarry specification excavator has been fitted with a substantial up and over protective cage to the front screen and cab top to minimise any potential damage from stray rock. Both the centre bars top and bottom are hinged to allow the front window and sunroof to be cleaned when necessary. The quarry spec is topped off with chevrons to the counterweight along with a white noise travel alarm and blue strobes to the rear of the machine.

The quarry the company are operating in is split into two areas with the railhead and tarmac plant situated within the original quarry footprint, the current extraction area is over 1000m away and can only be accessed via a tunnel through the existing high wall. Transporting blasted material back through the tunnel and into the existing plant was seen as being an expensive and time-consuming option. So, when KJ won the contract, a separate mobile material processing plant was set up adjacent to the extraction operation. Blasting is carried out on a regular basis to drop anything up to 50,000 tonnes at a time. Once the material is on the floor, the team load the primary crusher with the resulting product being loaded and transported the short distance to a large stockpile where it is then fed into the crushing and screening train. 

Dave points the Kobelco towards the freshly blasted material and through a combination of using the front end equipment and tracks, makes a path up onto the pile of material and proceeds to feed the large, 1000 tonne per hour capacity Gipo R170FDR impact crusher. “We have rented this crusher while we are waiting for our new one to be delivered.” Liam explained “They are excellent crushers and ideal to help us meet our targets.” The Swiss built crushers have a reputation for capably handling almost anything thrown at them with relative ease. 

The Kobelco isn’t your usual ME quarry spec machine and is fitted with a standard 8.25m boom and 3.6m dipper “We need a combination of both reach and breakout.” Jay explains “An ME machine would require us to have the crusher right by the side of the excavator and would mean more moving and repositioning on each blast.” A direct 5.2m3 MST rock bucket is the finishing touch for the excavator. “The MST buckets seem to be the way forward for us.” Liam explains “They are built well made products and are designed to our specifications, they aren’t the cheapest buckets available, but their build quality is something else.” 

Five separate products can be processed with the material initially being fed into a Terex Finlay 883+ inclined screener. Two Powerscreen cone crushers deal with the oversized material with the final products being discharged from the conveyors of a pair of Terex Finlay 2-deck screeners, a 693+ and 696. A fleet of Caterpillar 745 articulated trucks haul the material from the Gipo to the stockpile and then from the processing area back to the quarry’s main stockpiling areas. Loading the trucks is taken care of by a pair of Caterpillar 980M wheeled loaders. “They are a good shovel.” Liam comments “The drivers like them which is good.” A third shovel is also on site as a back-up machine should one of the front-line loaders break down whilst the Cat 352 that was once the quarry’s production excavator also stands on the side lines ready to step in should the Kobelco suffer any downtime. 

It is still early days for the Kobelco but so far, the management team at K J and the site teams seem to be very impressed with the Japanese quality. “Molson have come up with a very good package for us.” Jay comments “The build quality looks to be on a par, if not better than what we already have in the fleet and as long as it remains reliable and productive, I can’t see there be any issue in us adding more Kobelcos as and when we swap machines.”