Interesting. I'd like to know why this is much superior to a normal Archimedes screw though? <br>You can drive it anywhere up the shaft which is good, and you can keep the bearings away from the product; but other than that I can't see real benefits. Why would it product less dust?,(reply>), most likely less dust due to less material being crushed by the metal screw, the material is only being push upward by the same material so it is less harsh, the hardness of the material doing the 'force' is equal. there might be dust created by the scoops but since it at the bottom of all the material being scooped the dust is not allowed to become airborne