WHAT’S NEW Underground Equipment A manless truck

Four years ago, at about the Fsame time it decided to market continuous mucking machine, Inco Ltd. laid plans to develop a rapid truck haulage system to keep up with these high production rates. The mucker loads underground mine trucks at a rate of 1,000 tons per hour, but there were no underground trucks that could handle that much material. A co-operative development program between Inco and a major electrical manufacturer was unsuccessful, setting back the project by about a year. As a result, the loader has been available through Continuous Mining Systems of Sudbury, Ont., for about a year but without a truck that can keep up with it.

Now, working with the Urban Transportation Development Corp. (utdc), a Crown corporation based in Toronto, assembly of a fully automated electric truck with the capacity to haul 70 tons of ore is about 90% complete, says Len Kitchener, senior advisor of Inco’s mines research department.

The truck, which runs on an electric trolly system in a drift measuring 14 ft wide and 12 ft high, will get its first underground test run on the 3,600-ft level of the Copper Cliff North mine — Inco’s research mine — in Sudbury early this year.

It has been designed to navigate short mine haulageways with numerous sharp corners (with a minimum turning radius of 25 ft), which are not suited for conveyor belts, and to side- dump the ore in an orepass, then return to the drawpoint for another load. Tramming speeds will likely be about eight miles per hour on level roadways and about two miles per hour on ramps that ascend at a grade of 18%-20%.

A hydrostatic drive system was chosen for its low cooling requirement and ease of individual control. Multi- disc Rockwell hydraulic brakes were applied to all eight of the truck’s non- driven wheels.

Some innovative new technology has been incorporated into the unit to solve some of the anticipated problems of unattended underground haulage. At least one component will be patented, according to Kitchener, who unveiled the truck at a symposium on mine automation in Sudbury last fall.

Kitchener says they think they’ve solved the problem by developing a unique connector — one that ensures contact is not broken even on relatively rough haulage roads. This is the component that Inco will likely patent.

Another important design feature of the truck has been the flexibility required to re-program the unit to perform under different mine operating conditions. Essentially, a mine planner has to tell the truck where to go, where to turn, where to stop and where to dump according to mine layouts. So the machine has to be easy to instruct without compromising its abilities, Kitchener says.

Inco and utdc have chosen to use a Gould Modicon programmable controller and a Siemens computer connected to a controller by a low- frequency Cyplex radio system. Using the trolley wires as a carrier, this system has become the main controlling component of the truck.

Location markers, attached to the trolley lines indicate where the truck should either slow down, stop, turn or dump. When the truck passes a location marker a signal is transmitted to the Gould controller which in turn signals the Siemens computer to make the appropriate steering , pump or motor adjustments. At a dumping station, for example, the controller signals the computer to activate dumping cylinder controls. About six minutes are required for loading and about one minute is needed for dumping.

Ultrasonic sensors at each corner of the truck scan an area 15 ft to 18 ft ahead and 8 in to 10 in above the floor level. If an obstacle is detected or if the truck strays from its guided path, the truck stops. For safety, no one is permitted to enter an area where the truck is operating.

Two trucks operating in tandem on the same level should be sufficient to meet the daily production requirements of a medium-size mine using the osciloader.

Once perfected, the truck will play an important role in Inco’s plans to automate its ore production cycle.

Some other new pieces of underground mining equipment which are already available on the market include: