Minecraft wiki entry for Mining, associated text: It is possible to do this method safely, but it is very time-consuming. It's the same as before, except hold ⇧ Shift to cling to the ladder while mining straight down. This way, if they mine into a pit or lava, they won't fall into it unless they unhold ⇧ Shift (⇧ Shift won't let the player move down the ladder, but makes the mining speed slower). If the player does find a cave, they can climb up a little bit, remove the last ladder the player put down, and put a bucket of water there instead. Now they can swim down, and if there was lava under the player, it will turn into obsidian, and will be harmless. They can also dig 1 deep and 2 wide alcoves in the side, giving them a place to put a torch, rest, and most importantly dig the hole deeper as far as they can reach without having to hold onto the ladder.