Proper mining conditions and how to extend tire life
With rigid haul truck tires being one of the highest expenses for your mining operations, maintaining proper mining conditions for the tires plays a key role in extending tire life. In this article, we discuss in depth factors that affect your mining tire’s life and some ways to improve site conditions, ensuring maximum tire life and productivity.
Inflation Pressure
Inflation pressure is dependent on:
- Load / overload
- Type of service
- Tire type and location on the vehicle
- Designed (percentage) deflection of the tire
Keep in mind that the published inflation pressures recommended by your manufacturer are for standard loads. If you overload, inflation pressure should be increased 2% for each 1% of overload and max out at 14% of 7% overload.
Below is a comparison of what overinflation and underinflation does for your mining tires.
Loads
Ensure that the shovel operator controls the specified payload and distributes the load equally on each tire of the equipment because all tires should carry equal loads. MAXAM always recommends operations refer to the pressure load table specific to each tire to determine tire load according to the size and ply, and star rating.
Overloading can cause:
- Casing and heat fatigue
- Radial cracking
- Inner liner failure
- Greater chance for impacts
- Reduced rim life
Grades
Haul roads should be ideally straight for rigid dump trucks because for every 1% change in grade, the load will transfer 2%. Below is an example of the setting level for your front and rear tires on a 777D rigid dump truck and how it affects the tires.
| Load | Tire Life |
| Rated | 100% |
| 110% | 90% |
| 120% | 80% |
| 140% | 50% |
Tire life or cost to fix the grade should be decided by the mine. However, having the downtime might affect overall productivity.
Grades should be minimized for a degree of rise and length. Best grades usually range from 5% to 8%, which will reduce tire slip and increase overall fuel economy.
Underfoot conditions
Ensure the haul road is clean with minimum spillage with rocks by conducting continuous use of graders around the site.
Tires that are being run on a rutted road can have:
- sidewall and tread cuts
- stress on the casing when the truck enters and leaves the rut
| Condition | Tire life |
| Soft earth – no rock | 100% |
| Soft earth – some rock | 90% |
| Shot rock | 60% |
| Shot rock in water | 40% |
- rock cuts
- chunking
- rock cut separations
Curves
The less curves your mine site has, the better, more importantly, negative curves should never exist. Trucks running around curves can:
- Put high lateral tire forces which significantly increases wear and tear
- Inconsistent speeds
- Increase chance of spillage
- Slower cycle time
Curves | Tire life |
| None | 100% |
| Moderate | 90% |
| Severe | 80% |
Maintaining proper mine site condition is a cross-departmental effort, involving mine management, engineering, operations, training, maintenance, purchasing, tire maintenance and tire manufacturers. With rigid haul trucks’ tires being one of the top expenses for mining operations, ensuring the utmost condition of the mine site will significantly increase tire life.
Should you need further assistance, contact your local MAXAM rep and we’ll assist you with your inquiries.
