Cat 793F autonomous trucks at a loading face.
Mining has always been a challenging industry, and low commodities prices have contributed to those challenges during the last several years. The focus has shifted from producing as much as possible to carefully controlling the cost of getting minerals out of the ground. Miners are focused on getting the most from their capital investments – and mobile equipment automation is proving to be a cost-effective solution.
Automation offers a means to control costs and variability and to improve safety and productivity. New technologies and process advancements make it possible for mines to automate more than a few machines. With each passing year, new advancements automate more and more phases of the mining cycle – with the possibility of a completely autonomous mine site in the future.
But an autonomous mining operation is not something that will be built overnight. The journey to autonomy is composed of a number of building blocks, which can be categorized generally as machine guidance, automation and autonomy.
At all levels, automation helps make operations more predictable and consistent while reducing the number of people working in potentially hazardous areas.
The result is enhanced safety, improved production and increased efficiency.
Caterpillar describes autonomy as a journey, and individual mines start their journey in different places. Some will begin with a technology product such as Cat Terrain, which uses satellite guidance technology for drilling, grading and loading operations. Others start with Cat Fleet, which serves as an operational ecosystem that provides real-time tracking of machines and material movement.
There are different levels of automation, as well. For example, Caterpillar offers truck-spotting and load-positioning technologies that leverage pieces of Cat Command automation to improve manned operations. In the semi-autonomous realm, remote-control dozing allows operators to take control of machines that perform production dozing autonomously.
The significant benefits of automation can be realized with even the simplest of applications. While full autonomy may be the ultimate goal, individual technologies can be used alone or combined in multiple ways to take advantage of immediate productivity, efficiency and safety gains and serve as the building blocks leading to autonomous mining operations.
A Cat 793F CMD mining truck at an iron ore operation.
Autonomous trucks set the pace
By the end of 2017, 100 Cat 793F CMD autonomous trucks will be operating on three continents and in three different applications. The total includes 54 trucks that constitute the largest single fleet of autonomous trucks, which have achieved 20% greater production than manned trucks operating in the same mining complex. This fleet of autonomous trucks operates in a space with more than 150 manned vehicles – graders, loaders, water carts, light vehicles, dozers – and all dispatched through Cat MineStar System.
There have been no lost time injuries associated with the autonomous trucks in the field during the 4.5 years since operations began. The Cat Command for hauling system obviously reduces the number of people working in the active mining area, which reduces exposure to risk. Additionally, the system offers a minimum of 2+1 layers of protection to help ensure safe operation. The autonomous trucks system has also proven reliable – with greater than 99.95% system availability. In short, the system is productive, safe and reliable.
Autonomous trucks achieve performance advantages over manned operations by working more hours each day and by working faster. Higher utilization of 2.5 hours a day on average results from no shift change, no breaks and no lunch.
Refueling and inspection is the only stop on most days.
The Cat autonomous trucks system ensures that the trucks operate consistently – with no difference in operator skill level slowing down truck cycles. All trucks react the same way to environmental variables and drive to the design capability of the truck at all times. The system is fully dynamic and reacts in real-time to changing variables, which leads to continuously optimized assignment and management.
Currently demand for retrofitting trucks for autonomous operation is considerably greater than demand for purpose- built units. To meet customers’ needs, Caterpillar is designing retrofit kits for Cat and other brands of large mining trucks. In addition to retrofit, Caterpillar is expanding the number of autonomous models available from the factory.
A Cat drill equipped for semi-autonomous operation.
Automating blasthole drills
Caterpillar is field testing an autonomous blasthole drill this year in preparation for commercial launch of the Cat autonomous drilling system in early 2018. The autonomous system will be available for Cat and other brands of drills. The system is designed for easy integration with other brands of drills and is configured so that the manual controls remain functional and ready for use when needed.
The system builds on Cat Terrain for drilling technology, which uses satellite positioning technology to show the operator the locations of the holes to be drilled. At the site, Terrain monitors asset utilization and reports on consumables usage and operator performance.
The next step up in drill automation is the semi-autonomous system, which was launched in 2016. This system allows the operator to position the drill at the beginning of a row of holes and then to set up the machine to drill the entire row autonomously.
An optional arrangement includes a remote operator station that can be located near the bench or in a remote location.
This allows a remote operator to position the drill at the beginning of the next row and start a new cycle again, or to manually drill holes from a remote location.
A Cat D11T operating semi-autonomously.
Semi-autonomous dozer operation
Caterpillar is developing a semi-autonomous dozer system that leverages automated functions built into Cat large dozers and remote-control technologies, which are part of the proven Cat Command for dozing capability set. Caterpillar is first to develop such a system for mining dozers and, by the end of 2017, will have 19 Cat D11T dozers working semi-autonomously in field trials at four customer sites.
The system is currently designed for a remotely located operator to manage four machines doing production dozing.
Development work is progressing on push-to-edge applications, and this capability will be offered in 2018.
Through the use of Cat Terrain with Blade Control, Automatic Blade Assist and Auto Carry, the dozer cuts to plan using best practices. When operating autonomously, the dozer optimizes reverse speed. Consistency in operation pays dividends in lower operating costs.
With the operator/controller working from a comfortable, remote station, and fewer operators required, human exposure to health and safety risks is significantly reduced, and fatigue for the single operator is diminished. Another benefit of remote operation is reduced need to stop for shift change, breaks and meals – which translates into higher utilization of each dozer.
Craig Watkins is technology manager for Caterpillar Global Mining.