In a paper written by V. Srajer, of CANMET’s Coal Research Laboratories in Devon, Alta., and entitled Review and evaluation of truck dispatching systems at surface mines in Canada, several systems were reviewed. Among them were Philippi- Hagenbuch’s Computer Integrated Mobile Equipment Operations system, which was tested by CANMET at the Gregg River mine in Hinton, Alta.; an in-house system developed by engineers at the Lac d’Amiante asbestos mine in Black Lake, Que.; Glenayre Electronics’ Mine Dispatch Support System, which was tested at the Lornex mine near Logan Lake, B.C.; and Wenco International’s Production Monitoring and Control System (PMCS). PMCS is used at the Balmer and Greenhills mines in Sparwood, B.C., and at Suncor’s oil sands mine in Ft. McMurray, Alta. A trial system has been installed at the Wabush mine in Labrador, Nfld.
The Wenco system consists of four components: pit control, truck dispatch, management information and data communication. The PMCS comprises custom-designed data-gathering and encoding hardware that receives and transmits data mounted in production equipment, radio repeaters when needed, a radio communications system interface, a twin micro- computer-based dispatcher and pit monitor display, and a similar micro- computer that provides current and historic management information. Equipment operators have dash- mounted data sets. The Monitor computer, the heart of PMCS, is the main interface between Pit Control, acting as dispatcher, and mine staff.
Glenayre’s Mine Dispatch Support System was developed to achieve the following objectives: establish a data collection system that does not depend upon input from equipment operators; build highly reliable field hardware; provide a system that assists dispatchers without making decisions itself; and, finally, design an expandable system that can be upgraded to include automatic decision-making algorithms.
In a separate paper presented by James William White of Modular Mining Systems of Tucson, Ariz., and entitled Automated haulage control worldwide, it was revealed that Modular Mining has installed its DISPATCH system at 11 mines around the world.
In Canada, Modular Mining’s systems have been installed at Quintette Coal’s mine in British Columbia and at Iron Ore Co. of Canada’s Carol Lake project near Labrador City, Nfld. At Quintette, the system was installed in 1983 to handle the Dispatching needs of nine excavators and 20 haul trucks. According to White’s paper, Quintette ran several tests to determine performance. In one such test, the system ran for four days in the unlocked mode. During the next four days, DISPATCH was run “locked out.” In this case, the Dispatcher allocated trucks to shovels while the operators still received assignments and entered information using on-board computers. Shift foremen were in the pit to monitor the operation. From time to time, the Dispatcher was asked to change haul truck allocations. The Dispatcher could see pit problems on his screens, but he couldn’t suggest changes to shift foremen.
During the final four days of the test, the system was again unlocked. Comparative production figures established by mine engineering showed that production improved by more than 10% during the unlocked phase versus the locked-out period of operation.
White’s paper noted that Iron Ore Co. ordered a DISPATCH system for its Carol Lake project in 1984. Carol Lake can produce 22 million tonnes of concentrate per year. Waste removal is carried on continuously and can reach 11 million tonnes per year. Ioc ordered the system for 26 trucks and 10 shovels. After operating for several years, the DISPATCH system has improved production rates by reducing truck and shovel idle time, reassigning trucks away from “down” and “delay” shovels, and allocating truck resources better. DISPATCH also indicates to Dispatchers the trucks and shovels that are operating under unusual conditions or with problems.
One dispatcher, quoted in White`s paper, said the system “gives lively, instant recall of data and makes the dispatcher’s job more interesting. The dispatcher now knows the location of mine personnel and equipment. The only way to relocate personnel is to first check with the dispatcher. It has saved time.” Off-Highway Haulers
Caterpillar Inc. recently introduced two new mechanical drive, off-highway haulers in the size ranges GVW 230 tonnes and 290 tonnes. The trucks, referred to as the 785 and 789, have payload capacities of up to 136 and 177 tons respectively. Currently, there are 70 such fleets operating in the world. The information that follows was taken from a paper presented by P. J. Holman of Caterpillar Inc.
Among the new or newly designed components on the 785 and 789 are the torque converter, which mounts directly to the flywheel housing and incorporates a lock-up clutch; a new 6-speed, Cat-designed transmission; a new bevel gear/pinion set and a new differential; and final drives that are new, double reduction simple planetaries situated within the rear wheels.
In terms of performance, tests from mines in Arizona and Nevada (both coal and copper) revealed that the 785 had a 23% to 26% production advantage over other mechanical haulers and a 6% and 7% disadvantage over 170-ton electrical haulers. It had a 43% advantage over a 120-ton electric truck. It beat the other haulers in terms of gross percentage efficiency, clocking 83% to 84% against efficiencies of between 71% and 76% for the other trucks. Holman’s paper states that “in the six direct drive gears (up to 15% effective grade), the 785 and 789 have a power train efficiency that averages 81% to 85%, compared with electrical trucks that run in one gear ratio with a power train efficiency generally in the 72% to 76% range on typical effective grades. This greater efficiency in the 785 and 789 is reflected in more tonnage per litre of fuel consumed because less horsepower is required for a given load and speed on grade.” Maintenance
In a paper entitled Titan hauler fleet modifications and planning systems, written by B. Konowalec of Mine Mobile Planning, Syncrude Canada, a maintenance procedure for electric- drive haul trucks was presented. Konowalec said the current hauler fleet consists of fifteen 3315C and eighteen 3315B Titan 170-ton trucks. The Mine Mobile Maintenance division consists of fleets and shops under the direction of a manager who is assisted by two Maintenance Advisers and five Area Supervisors. Production and Maintenance Area supervisors meet daily to review maintenance problems and schedules.
Improvements made to the fleet over the course of operations include using Michelin XRB 3600X51 radial tires to supplement suspension effectiveness and to increase traction/ flotation; replacing original brushes and brush holders with a heavier duty D79 design (another upgrade is planned to D89); redefining traction motor rebuilds to eliminate flashovers and ground faults in rebuilds; and improving engines (the installation of tube and shell coolers, pressurized radiators, metal induction piping, all of which led to the movement of engine benchmark hours to 15,000 from 10,000 hours.) Many other changes were made to improve efficiencies, Konowalec noted. And the basic concept for sound maintenance still applies: “Systems, resources, trades personnel and management must all work towards a common objective, with controls in place.” Re
sistance Measurements
In a paper entitled The Analysis of Mine Haulage Economics Using Direct Rolling Resistance Measurements, R. J. Kolada of CANMET described a trailer that can be towed behind a small truck and measures rolling resistance using a computer data acquisition system and deration rates (a measure of power loss from engine wear and a number of other lesser factors). The data compiled can evaluate the productivity of an entire haulage fleet and predict the effect of any changes to mining operations or haulroad conditions.
The trailer has three main sensors for measuring rolling resistance: a load cell, an inclinometer and a velocity sensor.
To obtain additional information on road conditions, accelerometers (to measure road roughness) and instruments to calculate the rate of rotation of the trailer wheels (for traction measurement) can be added. Measuring rolling resistances and deration precisely can pare operating costs of an open pit mine to the bone.
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