Running with Robotics
Step by step, Rio Tinto’s concept of highly autonomous mining is materializing in Western Australia’s Pilbara iron ore district
By Paul S. Grad
Automation will also provide a better overall view of the operations, leading to a better understanding of the site environment. Rio Tinto External Relations Manager Gervase Greene said functions such as marketing will be consolidated, with better results and lower costs. “Combining management in one area under one roof enables you to look at the whole of the production cycle,” he said.
Although bits and pieces of automation have been introduced to mines in various parts of the world, the MOF vision is the first instance in which a single, completely integrated system is being developed. The project will give Rio Tinto the experience and the technology to allow adding value across all its current operations, as the system could also be used in coal, bauxite, metals and other enterprises.
The company’s iron ore operations in the Pilbara have expanded to a capacity of 220 million mt/y and are expected to expand still further. In the Pilbara, Rio Tinto operates 11 mines: it wholly owns Hamersley Iron’s six mines; it operates the Hope Downs mine (50:50 joint venture between Rio Tinto and Hancock Prospecting Pty. Ltd.); the Channar mine (Rio Tinto, 60%); the Eastern Range mine (Rio Tinto, 54%); and the Robe River Iron Associates’ two mines, Mesa J and West Angelas (Rio Tinto, 53% of both mines). Rio Tinto also operates three shipping terminals and the largest privately owned heavy freight rail network in Australia.
In future all mining operations will be controlled from an operations center (OC) in Perth, 1,500 km away; however, a lot of the mine information will be kept on site, in centralized databases in the Pilbara. The control of rail operations, for example, will see much of that data kept within databases located in the OC, but it will still be important to have access to that information from multiple points across the system.
There are still many people in the mines, observing and supervising the mine operations from mobile cabs. In all likelihood, Greene said, with MOF there will be more people there than now. He said there will always be a need for on-site personnel. The OC will allow a better oversight of the process and better planning and integration of the efforts of those on site. “And there will be considerable opportunities for greater leverage of the manpower and assets on site as we expand into the future,” Greene said.
At this time, the OC is still under construction and only partly populated. It is a two-stage process and the main control room has been completed. The adjoining offices, which will eventually house planners and associated functions, is near completion. Already working in the OC are the personnel controlling the east Pilbara mines, and the dynamic scheduling and utilities personnel. The truck, mine, rail and port schedulers will be able to review in real time whether the product blend is right. If not, they will order the necessary changes to the sequence of operations.
Late last year, rail operators moved to the OC, followed by the controllers of the Cape Lambert port. Teams controlling west Pilbara mines and other facilities will progressively move into the OC. When completed, the OC will accommodate about 320 employees, who will monitor, control and manage Rio Tinto’s mines, ports and rail systems, all from a single location. It will allow optimizing product mix and the whole operation from mine to ship loading, in real time.
The OC will receive a mind-boggling amount of data from many sources, including a large number of mine site-based CCTV cameras, and many site-based voice mobile radio channels. The TV cameras and screens will enable all relevant aspects of the production process to be monitored from the OC, to the point of watching the ore as it cascades off the conveyor belt onto the stockpile or into the crusher. The voice channels will be used by the operators, drivers and others at the site.
To handle all that data, the primary communications link between the OC and the Pilbara operations will be by optic fiber cable. There will actually be two cables— physically separated to ensure redundancy in case of significant systems failure. There will also be a satellite-based back-up, as an added contingency.
Under an alliance with Komatsu, Rio Tinto has been testing Komatsu’s FrontRunner Autonomous Haulage System (AHS) with driverless trucks at the West Angelas mine. There are presently five Komatsu 930E autonomous dump trucks in operation there. This is the system’s second deployment following delivery of the first fleet to Codelco’s copper mines in Chile. Other Komatsu equipment in service at West Angelas includes the PC5500 hydraulic excavator, D475A bulldozer, WD900 wheel dozer, and GD825 motor grader.
Artificial intelligence onboard the truck “learns” the geography of the mine and “draws” a map of the mine in the truck’s memory. Together with onboard sensors such as radars and lasers, this makes it possible for the truck to move quickly, efficiently and safely through the mine. The truck keeps sending the information it acquires to the supervisory center, which in turn processes and analyzes the data, and then sends instructions such as target course and speed to the truck. The truck always moves according to the instructions from the center, which coordinates all activities within the mine. The trucks’ top speed is 50 km/h. The fleet control system prevents collisions with other trucks or other equipment. The obstacle detection system will cause vehicles to reduce speed or stop when necessary.
The truck is automatically guided to the loading spot after computing the position of the bucket of the GPSfitted hydraulic excavator or wheel loader. The truck interacts with manned equipment including excavators, graders, wheel dozers, bulldozers and light vehicles. Manned equipment is also fitted with GPS and communications software.
An operator interacts with the truck via a screen. The truck “requests” permission to approach or pass. The excavator operator indicates where he wants to load the truck by raising his bucket and the truck moves to that point autonomously. The task of loading the trucks is still performed by skilled human operators, but this will also see increasing automation in future.
A control system divides a manually defined dumping area into dumping nodes and tells the truck exactly where to dump each load. After ore is delivered from the trucks to the crusher, an impact hammer automatically fragments oversized rocks for crushing. This task was already performed remotely by an operator in the OC in Perth late last year.
Rio Tinto has also signed a global supply agreement with Terex Mining. The agreement includes drills and hydraulic excavators. Terex drills operating there include SKSS-12, SKSS-15, SKF-12, and SKF-15. The current power train configuration is Cummins QST-30 engines and Sullair 1,500 CFM at 100 psi compressors for down-the-hole (DTH) drilling. The Terex blasthole drills include a remote control and automation system custom built for Rio Tinto. They combine GPS navigation and track encoders to position themselves, tilt-meters to jack and level themselves, and drilling sensors.
At the mines, Rio Tinto is drilling most holes with a position accuracy within half a hole diameter—150 mm. An autonomous equipped drill moves smoothly from one hole location to the next, and drills 6 m/h faster than a manned drill— at rates between 10 m/h and 350 m/h in the same hole. It can be switched from rotary to hammer percussion drilling as required, and can stabilize a hole by collaring, injecting water and back-reaming. It drills to its assigned depth within 10 mm tolerance. It can produce straight rows of holes, and it can drill holes in complex patterns. An operator can switch the rig between manual, remote and autonomous operation, depending on the terrain and complexity of the required task.
During the past few months, an autonomous-capable machine has drilled more than 30,000 m in remote control mode and several thousand more in autonomous mode. The rig has been controlled by a human operator in a control cab up to 800 m from the rig. The operation of the rig has, so far, been a test of the reliability of the wireless data exchanged between the rig and the operator. Gradually, the cab will be removed and control will move first to the West Angelas site office, then to the OC in Perth. In a few months the rig will be joined by two or three more.
Automation of the train transporting the ore to the port facilities, about 350 km from the mine, for loading onto ships has undergone technical and related viability tests to Rio Tinto’s satisfaction. Rio Tinto has a single driver per train. The train stretches over 2.5 km in length and usually consists of 230 cars. Greene said, “We cannot find enough train drivers to maintain our expansion forward and the ones we are hiring are getting older and harder to replace.”
He said automated—i.e., driverless— trains have been around for some time, but not on long-haul railway networks on such a scale. However, the automated train operations (ATO) project is suspended at the moment. Greene said this was due to the sudden collapse of world steel markets in late 2008, as a result of the global financial crisis, and because of Rio Tinto’s own need to reduce capital and operating expenditure wherever possible. The ATO project was always designed to accommodate a major expansion of the Pilbara operating capacity. The financial crisis lowered the urgency of that expansion and therefore the urgency of the ATO project. The project is now under review and a decision is yet to be reached on its future.
The coordination of trucks, mines, rail and ports will be crucial to the efficient and costeffective operation of the mines. Any delays could be very costly, and it will be the task of the personnel in the OC to ensure there is a precise coordination of all activities.
Rio Tinto will employ General Electric’s “ecomagination” strategic initiatives to help address many environmental issues that might arise in the MOF project. Ecomanigation, according to GE, aims to “address challenges such as the need for cleaner, more efficient sources of energy, reduced emissions and abundant sources of clean water.” Under the initiative, GE will focus its industrial capabilities on solar energy, hybrid locomotives, fuel cells, lower emission aircraft engines, efficient lighting and water purification technology. GE said it will “establish partnerships with its customers to tackle the most pressing environmental challenges and double its research spending to develop the products and services they need.” Rio Tinto currently uses a large number of GE Dash 9 locomotives in its rolling stock inventory.
Recently, Rio Tinto and BHP Billiton started negotiating a merger of their West Australian iron ore operations. The deal, which would create the world’s largest mining operation, is awaiting the completion of various regulatory processes.
The proposed deal has caused great concern around the world. Steelmakers say the market, already concentrated on three major suppliers—Rio Tinto, BHP and Vale SA—will be reduced to two. There is considerable concern that the merger will dominate the world market. The merger deal values the proposed iron ore operation at more than US$140 billion.
The joint venture agreement states that “the owners (BHP and Rio) will license on a non-exclusive, royalty-free basis to the joint venture all intellectual property and technology used in the respective West Australian iron ore businesses and grant the joint venture the rights to make enhancements.”
Rio Tinto and BHP have filed applications for combining their Pilbara iron ore operations with the Australian Competition and Consumer Commission (ACCC) and the European Commission. The ACCC is scheduled to hand down its decision by February 24. The companies said they expected the authorities and shareholders to give their approval in the second half of this year.
Paul S. Grad is a freelance journalist based in New South Wales, Australia, specializing in science and engineering topics.