It's not just about weight, it's about density. Spodumene is about twice the weight if fresh cut wood on a ft^3 basis. A truck load of 80k Spodumene is going to be putting it's weight down over a much smaller foot print, and wear & tear on a road doesn't necessarily scale linearly so it's going to wear the roads significantly faster than wood. In my area there are highways where cargo trailers can't drive. The highways they're allowed on require more frequent maintenance.

The issue isn't a show-stopper, but you can't just say "it's a two lane highway, that's enough" and "we already have heavy loads on the road, it will be fine". The are more variables to account for when determining the infrastructure necessary for large industrial operations.