|
|
A delivery of giant Hitachi mining excavators from CablePrice ushers in a new era at the Stockton opencast mine on the West Coast.
The following September announcement formalising the Stockton Alliances agreement also came with news of one of the country’s largest single orders of plant and machinery. Included amongst its largest items are two Hitachi EX1200-6 111-ton and two Hitachi EX1900-6 192-ton mining excavators from CablePrice that form the core of the alliance's new excavation fleet. Stockton Mine produces high-quality hard coking bituminous coal for export to steelmakers in Asia, South America and South Africa. The very low ash content of some Stockton coal means it can also supply niche markets in other countries for activated carbon and silicon metal manufacture. Located high on a plateau in the Buller coalfield, between 400 and 1100 metres above sea level, the mine is around 30 kilometres north of Westport on the West Coast of the South Island. The plateau presents a number of environmental and health and safety challenges, including very high rainfall, scarcity of topsoil, and material in the rock which can affect water chemistry and the presence of native species and plant communities of particular conservation interest. As such, the alliance places significant emphasise on the health and safety of its 650 directly-employed staff and up to 100 additional contracted personnel, as well as protecting, conserving and rehabilitating the environments natural ecosystem. Solid Energy chief executive officer Dr Don Elder commented in announcing the formalising of Stockton Alliance with Downer EDI Mining; “To maximise the mine’s value and to operate it safely we needed a step change in operational performance. This required a substantial investment in skilled people, in new fit-for-purpose plant and equipment, and in systems.” Solid Energy’s South Island alliance and development manager, Steve Bell, adds; “In wanting to bring in as fast as possible the knowledge of best-industry-practice Solid Energy relied heavily on our alliance partners mining expertise.”
To get to the coal seam below the mines hard layer of sandstone, rock is fractured by blasting then the overburden is removed by the two EX1900-6 192-ton excavators and transported for blending by off-road dump trucks. At the coal seam one EX1200-6 will work exclusively performing coal extraction, while the other has been set up to be interchangeable between overburden removal and coal extraction, as demand requires it. The excavators are powered by Cummins engines producing 760hp (567kW) SAE gross on the EX1200-6 and a massive 1086hp (810kW) SAE gross on the EX1900-6. The EX1200-6 and EX1900-6 have been specified with 7.55 metre and 8.30 metre BE booms and 3.4m and 3.6m arms, respectively. The EX1200-6 excavator for coal extraction is fitted with an 8.0 cubic metre coal bucket, while when clearing overburden the other is fitted with a 6.7 metre rock bucket and produces 512kN of bucket digging force and 425kN of arm crowd force.
With safety as another of the Alliances core focuses, the mine enforces a stringent attitude towards health and safety compliance, applying a ‘take five’ preliminary work check process and lock-out system on all maintenance work conducted on machinery, as well as specifying all machinery with additional safety and maintenance equipment, including several emergency stop locations to ensure optimal comfort and safety for the operator, and performance by the machinery. Each machine has been fitted with a fire suppression system, exterior cameras for enhanced visibility and, to eliminate blind spots, additional HID lighting for greater visibility, power ladders for easy and safe access, automatic lubrication systems for regular and consistent maintenance, and a satellite monitoring system for advanced machine management and monitoring. Steve Bell refers to it as the “Rolls Royce” of health and safety for machinery, but stresses that with the extreme weather conditions, which can include working in thick fog and heavy precipitation – the region gets around five metres of rainfall per annum – such safety precautions are essential. He also says with a one hour trip each way to and from the mine, the Alliance is conscious of the need to provide the best levels of comfort and safety for operators who are away from home for at up to 14 hours a day.
Landed in New Zealand in early December, the delivery and assembly of the four excavators began in the build up to Christmas, with some preliminary work taking place at CablePrice’s Greymouth premises prior to transporting the units up to the mine for full assembly at the mine’s assembly pad. With both EX1200-6 111-ton excavators assembled prior to Christmas, the final assembly of the two 190-ton EX1900-6 - and finishing touches to all excavators - were being completed in mid January. The assembly included nine CablePrice technicians drawn from the company’s Greymouth and Christchurch branches, several outside contractors including the hire of 45 and 50-tonne truck cranes, an aerial platform, a cherry picker and 32 truck loads to transport the various components of the four machines to the mine. Speaking from Stockton at a final inspection of the machines, National Equipment sales manager for CablePrice, Andrew Crane says; “It’s very pleasing to be this close to commissioning of all four machines with everything pretty much having run smoothly to date. The team from the Greymouth branch have done a great job working in ever-changing conditions and have stuck to the assembly schedule well. The Alliance has also been very accommodating of our staff onsite. We are now looking forward to the next phase, where our machines get to prove their productively and reliability to the alliance.”
Following operator and technical training on both models, the giant excavators will be commissioned and sent to work in early February. Over the next 18 months Solid Energy will be progressing a number of other major long-term capital projects, infrastructure improvements, and health and safety upgrades designed to ensure the mine can return to full production when market demand increases, and with operations that are safer, more efficient and more productive. This includes developing the area of the former Millerton Underground Mine and the Cypress extension immediately to the east of the current operational area. The commissioning of the giant Hitachis, as the first stage in the Alliances’ new direction for Stockton, is symbolic of the large scale change the mine is undergoing, and ushers in a new era for the country’s largest opencast coal mine.
Q&M Vol.7 No.1 February-March 2010
|
In May last year state-owned enterprise Solid Energy entered into negotiations with Downer EDI Mining to form an alliance agreement to jointly manage and operate its largest asset, the Stockton opencast mine in Buller.
A key focus of the alliance was to minimise the variation of plant on site to improve efficiencies in maintenance and parts control. When it came to selecting the large scale extraction fleet Steve says; “Solid Energy took the advice of their alliance partners on the proven capability and reliability of Hitachi’s mining excavators and their strong presence in New Zealand. With experience of Hitachi mining equipment in Australia, Downer EDI Mining felt the Hitachi EX1200-6 excavators’ size, manoeuvrability and reliability suited the site at Stockton and was well proven for coal.” He adds; “The EX1900-6 excavators were chosen to match the dump trucks that the Alliance will be running – a combination of 55 and 100 tonne rigid off-road trucks – to extract and transport the projected 1.6 – 1.7 million tonnes of coal from the mine in 2010, heading back towards two million tonnes as the market picks back up.”
Both EX1900-6 excavators will have a 12 cubic metre rock bucket fitted and can produce 671kN of bucket digging force and 620kN of arm crowd force. The EX1200-6 sits on 700mm double bar grousers, while the EX1900-6 sits on 800mm steel shoes.
Alliance maintenance planner and mechanical engineer, Mark Wellby, who has come to Stockton from Downer EDI Mining in Brisbane Australia, says; “Once commissioned, the machines will be working between 22-23 hours a day with breaks only for smoko, scheduled services and refilling.” The four machines have been fitted with a fast refuelling device to save time in filling the 1470 and 4140 litre tanks, as well as fast re-fill of grease and other lubricants for further time saving, and enhanced environmental management through reduced spills. Mark has managed the machines specifications and the assembly of the machinery by working closely with CablePrice’s site co-ordinator and Greymouth branch service manager, Scott Alison, to ensure the massive assembly task has to date taken place without incident.
Stockton Alliance maintenance manager, Steve Powyer, who also relocated to the alliance from Downer EDI Mining in Australia, says; “CablePrice Greymouth branch’s strong reputation on the coast and their delivery promise definitely added weight to their company’s tender submission and to date we have been very satisfied with their communication and performance.”