The mining factory

PARKES, Australia. Rio Tinto/Northparkes Mines in central New South Wales, Australia, has successfully implemented Sandvik Mining’s AutoMine loading system over the past three years – and is now moving towards 100 percent autonomous loading.

For Northparkes management, underground block cave mining is regarded as a “rock factory” – and the more factory operations that can be automated, the more safety and productivity can be increased and costs lowered. While Northparkes’ materials-handling system has been fully automated for years, the requirement for manually operated loaders kept the rock factory vision from being fully implemented – until Sandvik’s AutoMine loading system. “By automating the loader fleet, we increase the utilization, which we do by being able to operate across shift changes and through blast clearance times,” says Matthew Betts, Northparkes’ manager for infrastructure and mine design for the project. “It means we get more tonnes out of the mine. More tonnes means more copper produced. For us automation is a key enabler for Northparkes to produce at a lower unit cost, and mine deeper, lower-grade ore bodies cost-effectively in the future.”

What is automine loading?

AutoMine loading allows remote operation and supervision of an automated underground loader or truck fleet from a surface control room. The autonomous fleet is operated in an area that is isolated from personnel and other equipment, greatly enhancing underground mine safety. Driving (tramming) and dumping are fully automated, while bucket loading is performed using tele-remote operation. A single system operator is able to manage the operation of multiple automated machines. A wide range of Sandvik underground loaders and trucks can be fitted with the AutoMine onboard package.

Successful underground block cave automation is also beneficial for Rio Tinto’s operations around the world, as it moves from open-cut operations to large underground block caving operations at a number of sites. “They are looking at Northparkes and what we have achieved to see what they can adapt to larger block caves in areas such as Mongolia and the United States, which are operating in much more difficult conditions than we do here,” Betts says. Northparkes has a long history of innovation on site and has been involved with loader automation for nearly 10 years. Joe Cronin, Northparkes’ LHD automation manager, says the mine has traditionally been regarded as a test mine for technology for Rio Tinto globally. AutoMine loading system’s successful implementation at Northparkes sets the stage for rolling out the system to other Rio Tinto underground hard rock mines. “There’s an old expression within Rio Tinto that ‘if it doesn’t work at Northparkes it’s not going to work’,” Cronin says. “We’ve got a very high level of experience at the mine, very high levels of technical expertise, and we have a large majority of staff who’ve been here for more than 10 years.” Northparkes can therefore more readily conduct technology trials, because it has the experience needed on site and can facilitate the tests safely. As of early December 2012, 40 percent of the mine’s loading operations were automated and delivering productivity benefits. This will soon expand to 80 percent, with 100 percent autonomous operation planned to start during 2013. Some of the immediate benefits that mine management is seeing relate to shift changes and blasting re-entry. “On some days, there’s potentially up to two hours where there’s no one on the level with manual loader operation,” Cronin says. “Now, even though there’s no one in the mine, the loaders are continuing to produce.” It’s now possible to plan and be a lot more strategic about how to draw from the level. “We’ve probably gone from about 20 or 21 hours a day of utilization up to 23 hours or even more,” he says. Safety is another major advantage of an automated load and haul system. Betts says the environment is safer for the operators working with AutoMine loading. “The underground environment is hazardous, and they’re exposed to vibration, noise and dust,” he says. “By automating the fleet we remove them from that environment and bring them to a controlled office environment.” Cronin agrees, even though he describes Northparkes as a highly stable mine with good geology. “We don’t have problems with mud rush, high temperatures or rough roads that cause vibration. But potentially for other mines within Rio, where those situations may occur in the future as deposits get deeper and we have to extract them in more challenging environments, this type of technology will allow the extraction of those resources without putting any personnel at risk.” The next stage at Northparkes is to continue the rollout of automation across the other zones in the level. “We’ll work with Sandvik right across this level to get the system optimized and make it as efficient as possible, which is something we’d expect to do in the next 12 months,” Cronin says. Sandvik has put together AutoMine loading as a full package to suit the mine’s coming needs. “It’s got the loader automation side, the traffic management and the production management side, as well as the interface to our SCADA system,” Cronin says, referring to the company’s Supervisory Control and Data Acquisition system for monitoring remote operations from a central location. “Having had Sandvik on site for some time and them knowing our mines and our procedures, it was easy to work with them for this implementation.” Talking to Sandvik Mining’s personnel responsible for the implementation of AutoMine loading at Northparkes, it’s obvious that they take enormous pride in their achievement and the close working relationship with the Northparkes team. “Northparkes has a really good reputation as a mine,” says Ben Rix, Sandvik Mining’s acting Northparkes Mines performance contract manager, who describes the relationship as a partnership. “Under our service contract we maintain all the mobile equipment in the production fleet, plus we are now responsible for the automation infrastructure and the onboard automation equipment on the machines. We work around the clock, 24 hours a day, seven days a week, 365 days a year to keep the machinery running for production. There have been challenges on the way to get the system to work and operate to a level where the mine can also be productive, so from a Sandvik point of view the achievement has been really satisfying.” Ashleigh Braddock, Sandvik Mining systems engineer for mine automation, has been fascinated to observe firsthand the transformation going from manual to automated operation. Automation systems in mining, especially in underground mining, make for a new environment. “In the past, those machines have been essentially mechanically operated, so to be working with advanced electrical machinery plus the automation systems is a shift that’s very interesting culturally to watch,” Braddock says. According to Teemu Lintula, Sandvik Mining’s automation product line manager, the cooperation with Rio Tinto and Northparkes has been highly beneficial and has given Sandvik valuable feedback to further develop its products. “We are now looking forward to continued collaboration with Rio Tinto with its Argyle Diamonds project, and we are also aiming to further develop our systems,” Lintula says. “Northparkes has set the bar high and is pushing us forward in achieving those goals.”

Autonomous ore loading

At Northparkes, AutoMine is currently operating at the mine’s E48 block cave, consisting of 10 extraction drives with a total of 214 draw points. Six Sandvik LHDs — five LH514Es and one LH514 — have been fitted with the AutoMine system, which allows for safe operation autonomously from the surface control room. The surface operator is only required to operate the loader for a short time in each cycle: simply filling the bucket at the draw point. The loader then trams autonomously with a full bucket to the ROM bin, dumps and returns to the next designated draw point. Currently the AutoMine system is working on 40 percent of Northparkes’ underground operations, a figure that will soon increase to 80 percent. For the rest of the mine’s extraction drives, autonomous operation is planned to start in early 2013.

Northparkes underground technicians Amanda Hartin and Ian Morresy have had experience operating loaders underground at the mine, and they are now responsible for operation of the automated loaders. Hartin finds the automated system a lot more efficient and pleasant to work with. “With manual loader operation, we’d turn up to work, we’d do a shift change meeting and find out our tasks for the day,” Hartin says. “Then we’d head underground, which usually takes about 10 or 15 minutes to tag on, we’d find our equipment, set up our area with barricades and the like, then we’d get to work with the boggers [underground loaders].” Now, with the automated system, she can walk straight into the control room when she arrives at the mine and get to work within a few minutes. “The boggers are already set up for us with the draw points entered for the day,”  she says. “All the operators have to do is bog the draw point, then send the loader on its way to the ROM (run-of-mine) area, and it will tip by itself automatically. Then the loader will turn up at the next draw point where it’s needed and we just go again from there.” “It’s a lot of technology involved, but it’s really easy to use from an operator’s point of view,” Hartin says. As potential interactions with people in boggers are eliminated, the working environment has become better. “There’s also more social interaction up here, because you can talk to the person next to you with none of the radio noise in the background,” Hartin adds. Morresy says the AutoMine system has its benefits. “It’s a good system, it’s an easy system to learn,” he says. “It’s also a system that a lot of people who couldn’t drive big machines could use.” The major difference between the automatic system and manual operation in Morresy’s view is that it’s a lot safer. “It separates our staff from machine operating zones,” he says. “I’ve been underground driving them manually, and when you’ve got boggers in all the drives, it can be a bit hairy at times, so I think this is good.”