With off-road tires used in mining operations accounting for as much as 20 percent of a mine's total operating costs, the name of the game becomes keeping those giants healthy and happy.
The tires-some approaching 10 to 12 feet in diameter-can cost tens of thousands of dollars each. Replacing, changing or servicing them when they become worn or damaged, or when conditions dictate the need, is laborious. The downtime required can result in a significant loss of productivity.
Of course, any company that can find a way to reduce these tire costs for its customers is going to have the attention of mine operators, and there are a number of companies pursuing just such technology. Among current projects or developing technologies are:
* Temperature and pressure monitoring systems;
* Two-piece tires with easily removable treads; and
* Tire and rim management systems.
Several companies, including Goodyear, Bridgestone/Firestone, Fuller Brothers Inc., Michelin North America Inc., Yokohama Tire Corp. and Continental Tire North America Inc. are at various stages of developing or commercializing these systems that warn of conditions that could lead to tire damage or failure.
With most of these systems, computer chips within each tire transmit data to a receiver, which may be located on the vehicle or at a central control point at the mine. When temperature or pressure problems are detected, corrective action can be taken before the tire fails.
According to Tom Walker, general manager for Goodyear OTR tires worldwide, evaluation of such an ``intelligent tire'' system continues at sites in the U.S., South Africa, Chile and Australia. Additional systems are being evaluated at the USX iron ore mine in Virginia, Minn., and at Elkview Coal in Sparwood, British Columbia. The company has more than 200 transponders in service.
Among the first sites using the system was an iron ore mine in British Columbia. There, each of a 240-ton truck's six 40.00R57 tires was fitted with the intelligent transponder, which records tire temperature and pressure. Sensors-about the size of a hockey puck-are fastened to the tires' inner liners, where they measure cavity temperature and pressure and transmit data every three minutes. The data can be logged and manipulated through a mine management system.
An in-cab receiver, which can be programmed with each tire's identification and the truck number, logs data then sends it ``upstream'' to the mine management system unit in the cab. Based on the mine's preference, the data can then be viewed at mine dispatch or downloaded onto a laptop computer, or viewed in the truck.
Goodyear also has developed a new Temperature Prediction Model that enables operators to know when tires are entering the heat danger zone. Again, armed with such forewarning, the operators can take steps to keep the tires out of that zone by putting the vehicle on a different route, performing tire maintenance or making other changes.
Bridgestone/Firestone (BFS) is in the final testing stages of its OTR tire chip monitoring system, with improvements to its radio and sensory performance in the works. Jeffrey P. Asay, marketing manager, technology services, Bridgestone/Firestone Off Road, said: ``We are hopeful that we are close to a commercially viable product. We must now consider how to best position this product in the marketplace.''
The BFS system was first introduced at the MINExpo show in 1996. It uses a data reader along a haul road that communicates with the tags in a vehicle's tires as it drives past. Data is transmitted to a network server and placed on a secure Web site, where it can be accessed from anywhere in the world.
Yokohama likewise has been developing chip technology, including its own chip and hardware readers.
It can be used for tire identification applications and to monitor and indicate operational criteria such as temperature, inflation and other data, according to Tom Griffing, Yokohama national technical services manager.
As with other systems, Yokohama's works with an embedded chip within the tire structure that sends a signal to a transponder. The actual readout of the information takes place within the operator's cab of the vehicle. Yokohama also has an alternate system that reads data through a hand-held monitor. The company said it has been testing this technology for several years in the U.S. on both medium truck tires and on vehicles running in mining operations.
According to Mr. Griffing, the technology is not yet commercially available. ``It is envisioned that it will be used commercially before it is used in passenger or light truck vehicles,'' he said.
Fuller Brothers, the Oregon-based producer of tire additives and protective products, is making significant progress with its tire monitoring technology, which it calls its Tire Analysis System (TAS). The company has its first five-year contract in place and is fielding inquiries from a number of mines in various regions of the world.
Morry Jones, vice president of sales for the company, said Fuller Brothers is currently working with one of the largest coal mines in western Canada, implementing the TAS system on approximately 30 trucks.
``We are doing this in three phases,'' Mr. Jones said. ``Phase One is approximately 80-percent complete (and involved installing) necessary hardware for trucks and tires. Phase Two is approximately 70-percent complete. Phase two consists of interfacing our systems with one of the largest third party mine dispatch systems. Beta testing could start as soon as mid- to late-February 2002.
``When this phase is complete,'' he said, ``the mine, through its dispatch system, would receive real-time warnings and alarms (pressure & temperature).''
The third phase, according to Mr. Jones, is approximately 55-percent complete and involves development of the communication package that transfers historical data from each of the trucks to the database.
Regardless of monitoring systems or prediction models, these large and expensive OTR tires can and will fail from time to time and the treads of all of them will eventually wear out. Depending on weather and mine conditions, the need to change tires to a different tread pattern also will continue to exist.
It is because of these eventualities that Goodyear continues to refine its two-piece tire technology. The company first introduced the concept in October 2000 at MINEexpo in Las Vegas, and development and testing is ongoing. The two-piece tire consists of a steel-cord casing and a separate band which mates a steel belt package and tread. The latter unit can be removed or changed as needed, either in the field or at a maintenance facility.
Mr. Walker said the concept that Goodyear has developed will substantially reduce equipment downtime associated with tire removal and replacement. Removal and replacement of the tread/belt assembly takes less than half the time required for conventional tire changing, he added.
The system ``uses the existing wheel assembly and is compatible with most vehicles,'' Mr. Walker said. The attachment of the tire casing to the belt/tread package is entirely mechanical, he explained. No heat, chemicals or hardware are needed. Rather, air pressure locks the pieces together.
In addition to the time and cost savings the system offers, Goodyear said the two-piece OTR tire concept provides additional advantages. For example:
* Operators can switch quickly to cooler-running or more cut-resistant tread compounds when operating conditions change.
* The tires are more efficient to ship. Each unit can be shipped in two smaller pieces instead of as one large unit.
* Specially constructed restrictor belts that are part of the belt package keep the centerline of the tire flatter, producing a larger footprint and more equal load distribution.
Since Goodyear announced the two-piece tire 16 months ago, testing and development work has progressed. ``Continued field testing with 33.00R51 tires has been very promising,'' Mr. Walker reported. ``We have accumulated thousands of hours of testing at different mines around the world.''
Testing also continues at Goodyear's San Angelo, Texas, proving grounds as the company further refines the two-piece tire system. ``Once we complete our long-term testing,'' Mr. Walker said, ``we will introduce the product to the global commercial marketplace.''
Both Goodyear and Bridgestone/Firestone offer computer-based management systems that they claim will improve efficiency and reduce costs for operators of vehicle fleets, including those used in mining operations.
Goodyear has introduced the EM Track II, its newest version of its EM Track tire management system. EM Track II is a multi-lingual, Windows-based tire management program that helps operators make tire choices based on real information in order to obtain a true assessment of cost-per-hour/mile.
EM Track II allows users to choose the correct tire for the application in question; manage inventory; project tire replacement; compute cost-per-hour and update tire and vehicle databases, Mr. Walker said. ``In addition to adding the versatility of a hand-held Palm unit, we have improved EM Track II's Windows functionality, database design and security options,'' Mr. Walker said. ``It is also backward compatible with existing tire data.''
Goodyear said that with EM Track II, users can easily track tire maintenance, including inflation, rotation, repairs and retreadings; perform tire removal analysis; calculate cost-per-hour; and predict tire needs. There are 35 graphs and 24 tire reports available.
Bridgestone/Firestone's TreadStat Tire & Rim Management System is applicable for either single- or multi-user applications at a major mine where purchasing agents, tire shop associates and management all can access the system simultaneously. TreadStat's flexibility, according to Mr. Asay, allows it to be loaded on a stand-alone computer, a peer-to-peer configuration, a Local Area Network (LAN) or a Wide Area Network (WAN).
The system's ability to compress file size enables a mine to fit its entire database containing hundreds of vehicles and wheel positions into a file that is well under a single megabyte. That database is fully sortable and searchable, the company said.
Michelin said its Total Tire Control (TTC) tire management tool is one way the tire maker continues to help customers obtain maximum value for their tire dollars.
Officially introduced in 2001, Total Tire Control is a comprehensive PC-based tire management software program designed to assess the performance of tires and rims. Offered in North America exclusively through Greenville, N.C.-based Michelin, the company said this powerful management tool allows users to:
* Monitor tire-related components of earthmoving fleets;
* Rapidly identify problem areas; and
* Implement solutions for such problems.