I wanna preface this by saying I had genuinely no idea how to draw the inside of the mineshaft interior especially with my Google Drawings art style. 

Anyhow, I feel like it wasn't uncommon for players who came across those pits in the mineshafts for the first time, to try and jump in and explore further only to be met with death. (Me included) After I saw the backrooms movie and the scene where Bobby goes down the slope with the rope attached to him, it gave me this idea. 

Sometimes when finding these holes there will be a peg above it, sometimes with a nylon rope, sometimes empty. You can tie the rope around yourself to repel into the pit and explore an area deeper underground. If you untie the rope or a fellow employee takes the rope off of the peg, you're trapped. If a peg doesn't have a rope attached, you can take another rope you found at some other point and attach it. 

I think this would add a really cool exploration/horror aspect to the mineshafts, dropping yourself into an even deeper, darker, more cramped area (maybe you'd need to crouch) with limited mobility due to the rope. You better hope nothings waiting for you at the bottom, or worse, at the top. 

Also I imagine to get back up, you'd need to climb the rope, so no two handed items would spawn at the bottom of the pit. When the rope is tied around you, it'd take up an inventory space (could be the utility spot if open) and you could take rope back and sell it for a small amount of money like keys. 

Mineshaft Concept: Nylon Ropes