6 Basic Steps to Extend Tire Life at Your Mine: Part 2 of 3

Posted by on Jul 17, 2012 in Equipment | 0 comments

6 Basic Steps to Extend Tire Life at Your Mine: Part 2 of 3

I want to thank everyone for their comments, LinkedIn messages and e-mails on my last blogpost, the first of this three part series on how to extend tire life at your mine. Through this blog, I have met lots of friends around the globe and appreciate everyone’s support. I want to remind everyone again to participate in two of my industry involvements, the first being the CIM (Canadian Institute of Mining) Mining Standards and Guidelines Committee (MSGC) which has open membership; and the NWMA Mining conference where I am chairing the high technology session.

I also want to give a special thank you to Adam Gosling from TyreSafe Australia for proof-reading my blogpost. You can check out their website here.

With that, I will continue onto the Part 2 of this 3 part series, which is the third and fourth step to improve tire life at your mine operations:

3. Road Maintenance & Rock Removal

Site maintenance includes not only surface preparation (making sure the road is smooth and free of debris such as large rocks which may puncture a tire) but also designing haul roads with the understanding of how the tires will respond to the road.

It is important to design a haul road which is wide enough to accommodate safe passing and which will drain water properly (water is a smooth road’s worst enemy!). Also – curve radius and road grade play a role in your tire life. The key is to design curves to minimize tire slippage and load transfer. For example, a tire path radius from 40m to 15m (outside position) will increase your slip percentage by almost three times!

The design of a haul road must account for the tire loads being experienced. It does not help the overall program to simply doze a path “just that way” and expect haul trucks to perform. If it is a semi-permanent road, then it should be prepared  as a constructed roadway and not only will your tires thank you, but your fuel economy will also pay for the cost many times over. It is simple physics – rolling resistance causes your truck engine (and tires) to work harder to accomplish the same task, not to mention it will go slower uphill loaded with a higher rolling resistance.

As for the design steepness of the road, the general guideline I’ve used is to keep uphill below 8% and downhill loaded below 5%. Having said that, Adam from Tyresafe Australia pointed out that most haul roads are generally at 10% and mine planning engineers prefer this; he brings up a good point between keeping a balance between what is good for the overall mine design and what is good for the truck & tires. Your truck OEM should have a weight transfer bulletin for downhill loaded that your dealer should have access to. Basically, for a 240 ton truck, a 10% uphill grade transfers approximately 10% of the weight to the back and a 3% super elevation transfers another 5% of the load from one side to the other.

Regarding road maintenance, remove rocks from the road that may have been a result of haul truck spillage. There should also be clean up machines at load outs to keep the area clear of obstacles that will not only damages tires, but also slow your trucks down. If there is excessive spillage on the ramps where your grader is constantly cleaning up, then your shovel operator may be overloading the trucks or distributing too much rock on the rear of the truck. It indicates a lack of operator awareness and training should be considered. Spillage is death to tires! Encourage operators to call up any spillage evident and reward their vigilance. See my blogpost on the technologies and benefits to improving haul road condition on what the correct load distribution should be on a haul truck.

Lastly – Road maintenance is essentially preventative maintenance; it prevents having trucks lined up in the tire bay awaiting fresh rubber, if it is even available!

 

4. Equipment Maintenance

After taking care of the road, it is time to take care of the tires itself with a tire rotation program; and utilizing chains & bucket rock deflectors as needed.

On whether to brand new mount tires on the front or rear, there are two schools of thought. Some mines achieve higher hours with installing new tires on the rear, giving the new tire a chance to flex and grow into its natural shape in a lower stress environment; and then rotating the tire to the front at half-life. If this practice is done on a loader, this will also reduce the chance of losing a brand new tire to a cut. The other strategy is to put new tires on the front due to the fact that potential for cut damage in hard rock is such that if a tire is cut, it does not get put onto the front position again.

Before I left CC&V Mine, we were looking at buying a new production loader (which the mine did end up purchasing) and at that time, I did a lot of research and study into the use of chains, chatting with a few mines that used chains on the front tires of their LeTourneau L1850 and L2350 loader. I would say that everyone recommended the use of chains on these large wheel loaders including the equipment and tire OEM.  Be sure to consult with your tire and chain supplier (channel through the engineer, not the sales person) on what the correct air pressure should be with the tire and chain set-up.

Lastly in the application of loaders, look at retrofitting your bucket with rock deflectors. This can be done with your loader OEM or as Adam suggested to me, a simple solution is to use worn out dozer corner tips as the deflector – it is easy to source, a good recycling method with standard bolts and no special parts required.

 

Thank you to everyone for reading Part 2 of this 3 part Tire Series. Please share this blogpost and my site with your friends and colleagues using the links provided below.