So it seems that saving in the mines and then reloading causes any objects (crates, ores, players) to fall through the ground. Not sure if this was a work-around to remove all the stone that players leave behind after mining, but I doubt it.
On the side it does reveal and/or grant access to the area behind the door in the mines.
(Potential Spoiler Below)
The most reliable way to reach the "Crypt" is to stand next to the rock shown below and save, go back to the main menu and then reload and you will fall through the floor (along with any items you had next to you).
You will then be on top of the ceiling of the crypt, which will be invisible to you. Make sure you stand on top of the invisble section, not the rocks that protrude through the ceiling, then save, main menu and reload and you will fall into the main area.
You can see the same shadowy figure that you sometimes see in the woods between your house and the mines. Even inside the crypt he dissapears whenever you approach him, but you can see him in more detail because of the light. It's skeletal (potentially missing it's lower half of it's body) wearing a black hooded cloak and iron pauldrons and has a light (maybe a crystal the same colour as the Fear Crystal) in the centre of it's ribcage that persists a little after the body dissapears. It's floating above an open sarcophagus, which I haven't experimented with yet but it might be possible to put items inside. The chest at the foot of the stairs is the same as the one by the river and spawns 2 ingots or a grip and an ingot.
Leading out of the crypt is obviously the way in. A relatively simple parkour challenge where you get teleported back to the church if you fall in the glowing green pools. Climbing all the way up leads to the door in the mines and a passageway that is blocked by what looks like a cave-in.
So the questions are:
- Can we interact with the figure and his sarcophagus?
- Can we open the door inside the mines to access this legitimately?