Control Engineering

Paul Grayson

Hauling Diamonds - someone has to do it.
November 23, 2007

ABOVE GROUND

My research on the uses of automatic guided vehicles in mining operations started with a story on the Discovery Channel about the 330-ton  930-E Komatsu dump trucks working an open pit mine in Brazil.  It turns out that Peoria, IL, is Komatsu’s Mother Center for mining truck R&D.  A couple of phone calls and I was on a conference call with Kazuhiko Iwata, Executive Vice President, North American R&D  Division. Things were looking good.  Unfortunately the reason he took my call was to ask me what I knew about what they were doing (the Discovery Channel program) and how I had gotten their number (Komatsu telephone switchboard operator) - and to tell me that their work is a secret and they have nothing to say to me.   I contacted the company PR people to see if I could fix this problem (surely there was some information available for public release) and while they thought it would be great PR for the company to help me with my story, it was, after all, up to the head of the R&D division to talk to me or not.  I left several messages but have heard nothing farther from them.  The local Komatsu Dealer also tried to help but his calls also went unanswered.  So here is what we do know:



When driven by people, the trek down the long spiral road cut in the wall of an open pit mine and back up again, as many times possible in a shift, is tedious.  The trucks top speed of 40 mph is quite fast considering the size of the truck, the weight it is carrying, and condition of the road (gravel). The cost of going off the road and tumbling to the bottom of the pit is usually fatal to the driver and wipes out a very expensive truck.  These narrow roads are two way so fatigued drivers sometimes crash into a truck going the other direction.  Since the cab is on the left, mine operators have in most cases switched sides of the road that the trucks drive on.  Driving on the left side of the road puts the cab on the cliff side when driving down the spiral and if trucks hit each other it is usually on the non-driver side giving the driver a chance to survive.  The high costs in lives and capitol equipment is an incentive to automate the process. 

Early progress was made with burying a wire for each of the two lanes in the gravel road.  Later differential GPS was used.  High quality differential GPS (RTK) using a local correction signal can improve the precision of the track that the tires follow to ±0.5".   

A few years ago, the technical journals were alive with glowing stories about how the mining business was embracing driverless and automatic guided vehicles.  Projections were that large numbers of driverless systems would be sold as the mining industry converted large numbers of vehicles to drive themselves.  The majority of the orders evaporated as the mining industry looked at the technology and yawned.  In the years since then there has been sporadic interest in driverless technology and a surge of interest just recently.  Economic pressure is causing all operations to take a closer look at whether or not automatic guided vehicles can improve the bottom line. 

UNDERGROUND 

MacDonald, Dettwiler and Associates Ltd. (TSX: MDA),  is supplying Atlas Copco Rock Drills AB of Örebro, Sweden, with an advanced technology solution for automated navigation of their underground LHD (load-haul-dump) mining vehicles. MacDonald Dettwiler Space and Advanced Robotics Limited (MD Robotics), http://sm.mdacorporation.com/ – part of MDA – has an enviable track record of developing remote control equipment for challenging environments, such as the robotic arms for NASA's space shuttles.  

MDA's sophisticated guidance and control system allows Atlas Copco's load-haul-dump vehicles to navigate autonomously through underground mine tunnels without the need for human intervention. The system senses the tunnel walls, calculates the vehicle location, and guides the vehicle using maps created during training. The solution provides international mining customers with mobile vehicles that offer enhanced safety, improved overall productivity, and reduced maintenance costs.



DeBeers in their their Finsch Mine is using AutoMine by Sandvik to automatic 50 ton TORO trucks.  The mines yield is about one carrot per ton (1cpt) so the more tons moved the more money they make.  Legal restrictions on manned vehicles limit their speed to 16 kph.  Unmanned vehicles on the other hand can reach speeds of 35 kph.  This difference in speed means that the job can be done with fewer trucks, a savings in equipment.  Having no drivers is a savings in labor cost.  Fewer accidents and better utilization of the equipment are all positive financial forces.  AutoMine uses lasers on board the truck to to map the portion of the tunnel network that the truck operates in and to determine the trucks location within the network.  Each vehicle is also part of the computer network that links the entire operation together.





GO ROBOTS !

Posted by Paul Grayson on November 23, 2007 | Comments (2)