I posted this to VOD for another reason, but, just in case anyone is interested here -
This is the mix, before it goes in the tubes -

You can see that, before packing, it does not look much different to the original sawdust (in the dumpy bag in the background). Its just like very slightly damp sawdust, not like slurry at all -

This is the finished unit -

It would have been packed in to a 4' tube, hammered down, and then sawn into a shorter length. So you are looking at the sawn face.