WHAT’S NEW Open pit equipment Automatic Excavators

When you look for trends in an industry, the lea ders are often the b ig guys. Well, by far the biggest open pit mining operations in this country are Alberta’s oil sands operations north of Fort McMurray. It is here, in northern Alberta, where you now see a trend toward automation that will likely be seen elsewhere in open pit mining equipment in the years ahead. Unmanned bucketwheel excavators, automatic conveyor belts and on-board microprocessors in haul age trucks connected to a central control centre by vhf radio links could find their way into the oil sands mines over the next year or so.

Manually operating the huge bucketwheel excavators at the Suncor and Syncrude mines is relatively inefficient, according to T. S. Golosinski, of the University of Alberta. And microprocessor-based technology is ready to be used in these big, continuous surface mining operations.

Speaking at the International Conference on Innovative Mining Systems at Penn State University in Pennsylvania last October, Golosinski said: “Automation appears to be an answer to the problem of the under-utilization of excavator potential and frequent production peaks which cannot be handled by belt conveyors.”

A number of microprocessor-based automation systems are available to the two companies, but one proposed by Krupp of West Germany appears to be a front runner, according to Raj Singhal, group leader of canmet’s Advance Mine Technology Centre in Devon, Alta.

The Krupp unit is a central control unit located in the operator’s cabin, consisting of a keyboard, a video display monitor and a printer. To this will be connected up to seven peripheral modules located on the superstructure, undercarriage and loading unit of the bucketwheel excavator.

After entering information regarding the physical characteristics of the block of rock to be mined, the control unit calculates the block geometry and checks input data against the limits of the excavator design. Direction and speed of hoisting, slewing and crawler movements are selected by the control unit. Automatic operation can then proceed.

“My experience with similar systems implemented elsewhere indicate that production rates can be increased by 20% together with a substantial increase in working time of the whole mining system,” Golosinski says.

When it comes to conveyor belts, partial automation and full remote control is already in place. Automatic, instantaneous start-up shortens downtime substantially and interlocking of all conveyor system components prevents damage. Accessories include TV monitors and load- measuring devices.

No totally automated conveyor system is working in any oil sands mines at present, but implementation is likely if bucketwheel excavators can be successfully automated.

Other mining equipment used in the oil sands is more difficult to automate because of the discontinuous nature of the work, but improvements in efficiency are still possible. Systems which provide real-time performance data to truck operators, for example, should enable drivers to react quickly to changing operating conditions. Two simple weighing and reporting units were recently introduced by Teledyne and Caterpillar. They give real-time data of payloads of loaders and haulage trucks respectively. More advanced systems could become an integral part of a mine- wide management system.

Such a system, which would include truck-weighing and maintenance management information, would assist mine management in making decisions which most affect mine efficiency and performance. Individual pieces of mining equipment with on- board microprocessors could be linked by vhf radio to the central mine management centre. There, the signals can be processed and analysed, information stored and decisions made.

Although automatic truck control has been tried, it is not yet commercially available. Also, it is believed that the discharge from ore-stackers, which have recently been introduced into open pit mining, is more difficult to control than material dumped by trucks. This makes it difficult to control the structural strength of waste piles. It is for these reasons that ore- stackers cannot be justified in oil sands operations and will have to be confined largely to heap leaching gold operations. Work is continuing, however, to further evaluate this alternative.

Some other new open pit mining equipment that has recently become available includes: