Need well rotted HARDWOOD sawdust

Know of any old sawmills (or new ones for that matter) with large piles of OLD hardwood sawdust?
It is needed to make some potting soil for some tree propagation (Chestnut, hazelnut, etal)

We are located in the Garden area and are willing to drive up to 50 miles one way to take several pickup loads. Can afford to pay a token fee or a loading fee for relatively clean, well rotted sawdust.

Also old, rotted, well shredded bark would also be OK.

Contact:
vinekeeper@forestfarm.org

Thanks so much.