Minecraft wiki entry for Mining, associated text: Also known as "Digging straight down". While there is a 62% chance of reaching bedrock and a 27% of landing in a cave, the player has a small chance of falling into dangerous places like lava (8%) or ravines (3%) (100 tests) (percentages from a video Mumbo Jumbo produced). If you absolutely must be the crazy one, try this: Put a bed and a chest at the top. Sleep in the bed, and put everything from their inventory into the chest except for pickaxes, ladders, a stack each of gravel and cobblestone, and perhaps some torches. Dig down until the player dies or reaches their target depth, placing ladders above the player as they go. Every 5 levels or so, cut a 2-block high foothold opposite the ladder. If they fell into a cavern and survived, pillar jump back to the hole the player fell out of, and/or build a cobble pillar in front of players, and put ladders on that. If they fall into a cavern and die, the footholds might let them break the ladders below it so they can drop gravel for a pillar, and perhaps retrieve any ore they have found on the way down, but be watch out for the hostile mobs. If the player fell into lava, they can forget about the ore, but perhaps they can drop water to quench the lava.