What could be safer than putting a well-trained driver behind the wheel of a 300-tonne open-pit haulage truck? How about no driver at all? Not a human driver, at any rate.
Although autonomous technology has been around for a long time, autonomous haulage trucks have only been in use for a couple of years, and only by a handful of companies in a few mines, including Rio Tinto’s West Angelas Mine in Australia and Codelco’s Gabriela Mistral Mine in Chile. Mining giant BHP Billiton, together with Caterpillar, began a program in 2008 to automate mine haulage trucks, driven by concern for driver fatalities.
In spite of its promise, the industry remains cautious about this technology and is waiting to see the results from mines using these trucks.
Juliana Parreira at the University of British Columbia has been studying the potential benefits of using autonomous haulage trucks in open pit mines and is offering a tool for project managers who are considering this technology. She uses ExtendSim — a simulation software package that helps project managers define the improvements in their mining systems if they replace manual haulage trucks with autonomous ones. She is studying a number of key performance indicators (KPIs) that include safety, productivity, fuel consumption, tire wear, and operating and maintenance costs.
Autonomous haulage trucks remove operators from high-risk areas in transporting large quantities of mining material, but do they improve productivity?
“All manual processes have variations,” said Parreira, “and manual systems are going to be irregular in terms of speed and position on a haulage route. But an autonomous truck doesn’t need to stop and it can maintain a set speed. It can become a more constant process.” Not only does a truck not have to take lunch breaks or go home at the end of a shift, its performance can be set to optimum breaking and accelerating points, reducing fuel consumption and tire wear.
It sounds ideal, but autonomous technology is expensive and extensive, requiring infrastructure such as communications towers, data networks, precise GPS and the automated systems on the trucks themselves, which include highly sensitive object-avoidance sensors. “The cost-benefit analysis is complex and it is important that the technology be properly characterized,” said Parreira. Only after careful study to define the extent of positive improvements and cost reductions can a mine consider applying the technology. “It depends on the particular mine and situation which may require adaptation to accommodate an autonomous system. The overall utilization and mechanical availability increase together with the life of the equipment to compensate for any deterioration in cycle time.”