Course 6 - Longevity
Updated: Jun 17
“How long do your mats last?”, is probably the most common question we get.
We do know that that the mats last at least four years and probably a lot longer than that. That’s in wet/dry/wet/dry conditions with tired trucks with 90,000-100,000 lbs. and regular traffic. See videos and stills below. (Disclaimer: These mats were made from rejected timbers. Your results may be better.)
We also know that our Eucalyptus timber mats are in rental fleets across the east coast and those mats consistently come back as majority Grade A mats, and some Grade B, even two and three years after purchase.
Ultimately, longevity is a function of five variables:
1. The quality and geometry of the raw material,
2. The manufacturing process,
4. Local conditions, e.g., is it wet, rocky, or freezing, etc., and
5. Use type (e.g., machines with grousers, or tired vehicles).
Let’s dig into quality and geometry a bit by looking at a tree cross-section, courtesy of the US Forest Service Laboratory “bible” Wood as an Engineering Material.
And, here's a simplified view:
Square timbers mean no wane, no rot, no bark, and no air. Because there’s more Eucalyptus heartwood in the mat, it performs better.
If your mat doesn’t have square timbers it means that you are buying a collection of logs, not a timber mat. Square timbers are a buyer’s best friend. It’s geometry. If you have round-ish timbers then you’ve got wane, bark and sapwood. Those parts of the tree aren’t strong. Wane, bark and sapwood evolved for different reasons, not structural strength as with the heartwood.
Furthermore, when we use bolts in timber mats, we expect them to be biting into heartwood, not sapwood, wane or bark. If bolts are fastened through the spongier sapwood you can imagine the result – loose bolts as the sapwood, bark or wane begins to dry out, peel off, or lose its moisture. Once the bolts start to loosen the integrity of the mat as a whole drops.
Manufacturing Process: We continue with a uniform manufacturing process that ensures – to the extent possible with a biological material – that every mat is the same. We reject any timbers that don’t make the grade.
We add end plates; we use standardized bolts.
The result is the same mat design but with better materials.
Handling: We can’t control handling. Our customers can. Some of those customers are gentle with mats; others handle them more aggressively. There’s simply no way to protect a timber from a fork in the side, or to protect a leading edge when a dozer wants to go up on the mat without any transition material.
The best answer was given by a customer. He said, “Our handling is brutal. World Forest Group’s Eucalyptus mat starts with better materials, square edges, no wane, no bark, no air”. The overall quality of mixed hardwood mats is lower than Eucalyptus.”
Local Conditions: We can’t predict local conditions. We can try to test our mats in ways that many users may find helpful. See for example our drop tests, mine tests, and the testing done on our thinner 4", 5", and 6" mats. Check out the Testing page here.
The linked video below shows our mats after three and a half years use at our manufacturing facility. Reminder that these mats did not make the grade and were rejected in our quality control process. Any mats sold to our customers are of better quality.
Also, take a look at the video below, which shows a “knife test”. In this case it’s with a screwdriver being driven into the back side of a rejected mat, 42 months after being placed on the ground.
Use Type: Tired vehicles are obviously a lot less demanding on timber mats than vehicles with grousers. You might not need a full 8” Eucalyptus mat; a 6” or 6.75” mat is likely to do the job just as well.
Questions? Contact us.