Nice to see this thread active, so much good stuff.
I agree, the mine entrance is nicely modeled. And I understand the need for game compactness.
But! (of course)
Why the heck would any miner dig into that tiny pile of rock when he can just dig straight down! I live smack in California's Gold Country and been up and down the Mother Lode many times, and visited a few hard rock mines. No self-respecting miner would do that. I guess you can go with that they are a bunch of novice gold miner's who didn't know better!
Living so close to the mighty Sierra Nevada mountain range gives me a different perspective. Around here, thousand foot peaks are just little tiny foothills. Real mountains rise up into the 10,000 foot range - and higher. I always cringe when I read about the battle of the Monogohela and the 'steep' mountains that had to be overcome. Yeah, I know, time period and all - and hauling artillery and supplies, but out here such a 'mountain' is an easy hike.
Again, lovely work and looking forward to what else you have to show us.