Mother Lode (1982)
A film about a man living alone and far away from civilization in a wooden hut, digging a mineshaft for years in search of gold. Very atmospheric and doesn't have any of putting moments in my opinion, despite the rating.
When I wanted to rewatch it 10 years later it was so hard to find that I had to make a post on a movie buff forum with a vague description from memory because I forgot the title.
"Image of a frog inhaling copium"