Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr
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AUTONOMOUS MINING work procedures—and to establish autonomous haulage processes that worked for the mine," said Dan Hellige, Caterpillar's mining solutions manager. "Because the trucks were often operating 24/7, we were able to make technical changes and see results quickly. That data guided us in making a number of improvements." Caterpillar reported that its team made two significant software updates and several minor updates as the feature set evolved. Improved travel-path planning and increased top speeds produced a significant reduction in cycle times, the company added, while refinements in the system and mine procedures also improved truck utilization by about 20% during the trial. Operating Concepts Caterpillar told E&MJ; that in order to guide trucks safely and productively without a driver in the cab, it has brought together a number of specialized building blocks within its MineStar suite of systems and technologies. GPS/GNSS provides the position location information for the trucks, and all possible haul routes are plotted with satellite data. Algorithms determine the optimum route for each truck, with the mine map being continuously updated in real time. www.e-mj.com For example, when dumping on the ground, the system tells the truck where to position itself, taking into consideration the last load dumped. The loader or shovel operator signals the truck that it is full via a keypad in the loader cab, and the system tells the truck to drive away. Each truck has an onboard object-detection system that enables it to maneuver around any obstacles, and can stop the truck if necessary. The loader operator then spots the next empty truck and signals the system that the truck should back up under his bucket. A system that Caterpillar calls Proximity Awareness sends a constant stream of data about each truck's location and speed, and the availability of the loader, thus preventing traffic jams and associated delays. The human controller, working inside a building on the perimeter of the site, can instruct a truck or the whole fleet to stop in case of an emergency. In addition, the controller can intervene to bring trucks in for scheduled maintenance and refueling, but otherwise, the trucks steer themselves and select the appropriate speeds based on sensor data and the traffic around them. Komatsu describes its autonomous haulage system as involving information and communication technologies such as high precision RTK-GPS and dead reckoning technology for its navigation system, an obstacle-detection system, a wireless communication network and a fleet-management system to control the trucks. Information about the haul route and speed is sent wirelessly from the fleet-management system to the trucks on the move, as they ascertain their position by using GPS information. For loading, the fleet-management system guides the trucks to the loading site, based on the position of the bucket of the GPS-fitted, man-operated hydraulic excavator or wheel loader. After loading, the system directs the trucks with to the dump site for unloading. Using GPS and the wireless network, the fleet-management system controls all equipment in the mines, including other equipment and vehicles that are man-operated, to prevent collisions—if the obstacle-detection sensors detect another vehicle or person inside the haulage area during autonomous operation, the trucks stop immediately. GPS is one of the key technologies on which Komatsu's autonomous haulage system relies to locate the exact position of the trucks and to control them on their predetermined course. According to the Japanese JANUARY 2014 • E&MJ; 35