Mining Tires

Inflation pressure should be checked daily prior to operation, at the start of each working shift on cold tires. Cold pressure is when the internal air temperature is the same as the ambient temperature.

If your fleet operates 24 hours a day, seven days a week, the difference between cold and hot pressures should be established for every season, every cycle, and every wheel position separately. This enables hot pressure evaluation and stabilization, determining the correct pressure when warm. This can be done by adjusting cold pressures on a vehicle after servicing in the workshop, then repeating the process immediately after at least four hours of operations.

Indoor: cool, dark, and dry area.

Outdoor: cover the tires with a waterproof cover.

Positioning: place tires vertically, never stack tires not mounted on rims on top of another.

Debris and chemical: never expose the tires to water, oil, fuel, and lubricants.

Bead protector and steel band: never remove it until you’re ready to mount the tire.

If your tire has been used, have a sticker or tag showing its OD (outer diameter) for reference.

Type of equipment to handle earthmover and haulage tires:

• Forklift
• Mechanical loader
• Craned with textile straps

Do not use:

• forks from forklifts, chains, and hooks to lift
• metal slings, chains, cables, or cords as they can damage beads

Use:

• a smooth clamp and handle by the tire tread with ease on the sidewall
• a boom attachment on a forklift and handle through the tire’s center
• only flat textile slings or straps and secure through the tire center
• hands or clamps with pins and only handle by the tread area

For a visual guide, we’ve created a guide on handling large earthmover and haulage tires.

Maximizing your mining tire life starts with proper operation. Ensure the operator is properly trained.

Never do the following when operating a rigid dump truck:

• no abrupt starts and stops
• no sudden/hard braking
• no excessive speed
• no sharp turns
• no steering the wheel while stopped
• no overloading

Ensure road condition is good. Avoid greasy and oil surfaces, stones, and rocks when driving. If possible, maintain the road condition with graders and other equipment so your mining tires don’t run into sharp debris.

Always conduct a preshift inspection with specific attention to the tires. Report any abnormal tire, wheel, or site conditions to maximize safety. Pay special attention to the following attributes in your preshift operator check:

• air pressure
• tire conditions
• load management
• dump and load area
• wheel components
• road maintenance

For details, we have created a rigid dump truck operator awareness guide for you to learn more.

It’s vital for operations to inspect their mining tires daily to maximize tire life and productivity. When inspecting tires daily, be sure to check the following:

• The external appearance of the tire
• Rims and valves
• Inflation pressure

MAXAM offers a guide on identifying some common radial OTR and mining tire damages, if you still need further assistance on damaged tires, please contact your local MAXAM rep.

TKPH / TMPH is average tire load (metric tons) x average speed (Km/h or miles/h). It calculates the load-speed-time factor to ensure that the load is within the tire’s temperature limits. Knowing your site’s TKPH/ TMPH requirements play a vital role in selecting the correct rubber compound.

Inflation: tire inflation pressure is dependent on load/overload, type of service, tire type and location on the vehicle, and designed (percentage) deflection of the tire. Keep in mind that published inflation pressures are for standard loads only, so when overloads are encountered, inflation pressure should increase by 2% for each 1% of overload, and max out at 14% of 7% overload.

Overloads: all tires should carry equal loads, overloading can cause potential tire and rim issues such as casing and heat fatigue, radial cracking, inner liner failure, a greater chance for impacts, and reduced rim life. Overloads happen when there are uneven payload distribution, load transfer, field modifications (sideboards), larger beds and buckets, and high material density.

Grade: haul roads affect the life of your tires and their conditions. The ideal haul road is straight with no grades, or grades should be minimized in terms of height and length. Best grades are 5% – 8%, which will reduce tire slip and increase overall fuel economy. Keep in mind that for every 1% change in grade, the load will transfer 2%.

Underfoot conditions: tires that run on a rutted road can have potential sidewall and tread cuts, as well as stress on the casing when your rigid dump truck enters and leaves the rut.

Curves: the fewer curves rigid dump trucks have to drive around, the better for the tires. The benefits of reducing curves at your surface mining pits include:

• eliminates high lateral tire forces, thus extending tire life
• reduces wear and tear on both the tires and truck
• more consistent speeds
• reduces spillage, thus less damage to tires
• faster cycle time

In this article, we discuss more on the factors that affect your mining tire’s life and recommendations for improved mine conditions.