The concept of automation is neither new, nor achievable by installing a few robots. Maurice Jones cuts through the hype.
Much has been said and written in praise of mining automation as though it is the panacea for two of the industry’s main worries, safety and efficiency in the face of lower commodity prices.
Firstly though, what is it? It is defined by the Oxford English Dictionary as ‘The use of automatic equipment in manufacturing or similar processes’ whereas ‘automatic’ is defined as ‘Operating by itself without human control’. Thus any process that involves human control is not automation, and much that is called automation is actually remote control including the major applications of advanced technology in mining today.
Neither is automation in mining new. Apart from its use in mineral dressing, it had been installed in longwall coal mining in the ‘70s, although dropped through technical difficulties, and has been employed for rail-bound transport at LKAB’s Kiruna iron-ore mine in Sweden for many years. Seven 500-t-capacity electric shuttle trains are controlled from the 775m level to carry ore from ore passes to crusher stations. The mine, which has eight production areas, also uses automated operation of load-haul-dump vehicles.
A new main level at 1365m depth, 320m deeper than existing levels, will also have a remote-control shuttle-train system but on wider, 1.435m gauge, track. It is scheduled for completion in 2017. Midroc Electro is contracted to provide the new train transportation with Bombardier Transportation as sub-contractor. The latter will provide its fully automated driverless Interflo 150 train controls.
Efficiency and safety
However overcoming the technical difficulties in remote-control and semi-automatic processes has produced many achievements for the industry, particularly for those mining companies that can afford the capital investment. These achievements include great improvements in efficiency and safety in their own right, coupled with the ability to integrate data collection and processing into mine management software to ensure accuracy and the most economical instructions issued to operators.
The push for automation includes a necessity for a reliable, high-capacity communications network that carries many benefits ancillary to automation in relation to data collection and transmission including voice communication, cctv, performance data, tracking for plant and personnel location (including searches in the case of an emergency) and real-time integration into mine management computer software for monitoring, analysis and reporting. Various types of communications network have been utilised but the most recent and apparently popular approach is to emulate office-type local area networks, with wireless links to mobile equipment (WLANs) but using ruggedised hardware, especially within the working areas.
The development process towards automation in the extractive processes has been advanced for both blasthole drilling and rock transport, but has gone further with the latter, both underground and on the surface. It is clear that if the means of transport is on a fixed frame, e.g. by belt conveyor or rail-bound, then there are less variables and uncertainties to be taken into consideration in devising the control algorithms. However if the means of transport is trackless then there are likely to be several factors to be taken into consideration such as:
1. Prevention of personnel from entering the working route unless halted and ‘locked out’;
2. Avoidance of obstacles including other vehicles and intruders;
3. Adhering to the selected route, especially underground where GPS is unavailable, and making adjustments accordingly;
4. Accurate ‘spotting’ of driverless trucks in the most beneficial positions adjacent to face shovels, loaders, etc;
5. Allowances in algorithms for tolerances and ‘slack’ in the drive and steering mechanisms of trucks.
All these factors require complex control algorithms and often innovative approaches to their developments to ensure minimal problems in operation.
Following rock transport, the second most popular group of mining plant to receive recent attention from automation developers is rock drilling for blastholes. Recently surface drilling rigs have been announced as ‘automation ready’ by the main manufacturers (Sandvik Mining and Atlas Copco), following the development of suitably accurate control methodology using GPS.
Underground, with the reliance on surveyed reference points, development has so far been restricted to the simultaneous semi-autonomous control of up to six long-hole production drilling rigs by one operator using a remote-control console and pre-programmed drillhole parameters. One manufacturer referred to the development of autonomous jumbo drilling rigs for underground development and some types of production as ‘still the stuff of science fiction’. Although this is another target for such advanced developments computer-assisted drilling for ‘intelligent’ jumbos provides many befits without full automation.
The development of semi-autonomous mobile mining equipment has reached its perhaps most advanced and certainly most extensive application in Australia, and especially in Western Australia iron-ore mining open pit truck fleets. As might be expected the investment has come from the largest owners, Rio Tinto, BHP Billiton and the Fortescue Metals Group. Such developments not only increase capacity to achieve greater economies of scale in the face of lower world commodity prices but also removes some personnel from repetitive tasks in a relatively inhospitable environment.
One of the latest additions is trials by BHP Billiton at the newly opened Jimbelbar mine, 40km east of Newman in the Pilbara region. BHP Billiton is in joint venture with the ITOCHU Corp and Mitsui & Co Ltd. The mining company is also extending its trial of ‘autonomous’ trucks at Jimblebar to the neighbouring Wheelarra operations using six Caterpillar 793-F trucks in four pits. Jimblebar has been trialling six of the Caterpillar 793-F trucks since August 2013, with a second Jimblebar circuit commencing in mid-2014.
Control of the Cat haul trucks is provided within Caterpillar’s MineStar system that can integrate autonomous, semi-autonomous and remote-control operation of mobile plant seamlessly into the mine management computer software. Caterpillar MineStar Command programmes are also available for dozers and, underground, for longwall mining as well as loading and hauling by LHD vehicles.
BHP Billiton that it is committed to pursuing mature and proven technology options that demonstrate value to the business. It continued, “The use of autonomous haul trucks has the potential to introduce safety benefits by removing people for potentially hazardous environments; increasing predictability and productivity of haulage operations, providing new employment and training opportunities for our people and reducing the labour intensity of future mining operations.”
Despite its high investment in such trucks, BHP Billiton has not yet committed itself to such technology, pending the results of the trials. “Depending on the success of the trial,” it says, “the benefits of expanding the use of autonomous haul trucks may be investigated.”
In Chile national copper-mining operation Codelco was the first to order Komatsu driverless haul trucks in 2008 with eleven units for its Gabriella Mistral (‘Gaby’) mine. However, after one truck hit a loader and another a pile of waste in the first year of operation, the trucks were temporarily replaced by manned operation.
Leading the way in driverless trucks deployment in Australia was Rio Tinto, which, last year, increased its fleet to 53 Komatsu vehicles in four different iron ore mines. The tonnage hauled this way increased from 100 to 150 million tonnes in a year, since commencing the programme four years earlier. The investment by Ro Tinto is part of its ‘Mine of the Future’ strategy that has seen investment in a number of initiatives to boost the use of advanced technologies at its mines to improve productivity and safety.
The company expects to run a fleet of 150 Komatsu driverless trucks eventually. So far the trucks are operating at the West Angelas, Yandicoognia, Nammuldi and Hope Downs sites. Rio Tinto’s ceo Sam Walsh commented that the trucks had significantly enhanced haul cycle times, extended tyre life, reduced fuel usage and lowered maintenance costs.
Fortescue Metals Group was the second to commission semi-autonomous haul trucks in 2011 with a fleet of 12 Caterpillar units at its Solomon mine sites.
It is argued that BHP Billiton driverless truck fleet is robotic, not remote-controlled, although all operations are controlled from the company’s Integrated Remote Operations Centre (IROC) in Perth. The same centre also provides computerized fleet management services, train control and fixed plant control over ore transport within and from the Pilbara mines and for the port ship loading facilities. In fact IROC centralises supervision and control of the Company’s entire Western Australia iron ore network.
The reasoning for the BHP Billiton description of the truck fleet is that the trucks have many safety features to automatically prevent collisions with other trucks, whether manned or unmanned. As well as GPS navigation, several scanners are placed in strategic locations around each truck.
Rio Tinto had already been operating a remote operations centre in Perth covering its iron ore mines as part of the Mine of the Future programme. As well as trucks this include autonomous drill-rigs but not trains.
Elsewhere in Australia Mount Arthur opencast coal mine in New South Wales is reported to be scheduling a trial of driverless haul trucks despite local opposition over workforce calculations within the controlling environmental assessment, it is claimed.
Several other major mines owned by large mining companies are testing various levels of automation for haulage and rock-drilling systems.
Whatever one’s view of ‘automaton’ or long-distance ‘remote control’ it is clear that it is the way forward for mining equipment operation. Who is able to apply it is another matter, although parts of the automation package can bring benefits to a wider market.