I just came across your email to me about the ruins of an old mill. Thomas Sissons did have a mill on the Portneuf River (near where the old railroad bridge crosses the river. I spent some time looking for the old mill, but only found some rocks that looked like they had been part of a foundation, but nothing much else. I know they also had a brick house out near the road - then called the "Back Range" (the road that passes by the anglican church. Would love to see your photos, and anything else you have found.
Clark