The mine from what I could see of it, looked like a cut and fill type operation. That is where a dug out section has been opened up by ore removal, then when the next section is opened up, the waste goes in to the last section that was just opened up filling that section up behind them. Much less waste has to be carried out that way.
The wood they faced the cabin with are called slabs. We got a uhaul truck full of them from a lumber mill 14 feet long for 15 cents each back in the 1970s for a fence. When they cut those off they are left with a clean square log that can be further sawn into dimensional boards.
