mornin miss nancy, sorry i didnt see the picture or what was recommended, i'll look for that, but based on yer post above, a neat cement slurry came to mind. you could mix that too a consistency varying from almost water to toothpaste depending on what you need to seal. you could also pump it in w/ a typical trash pump provided the tunnels and such flow downhill, otherwise you'll have a big mess on yer hands.
lets see if anyone has ideas.......
