Minecraft wiki entry for Things_not_to_do, associated text: However, if the player has potions of Fire Resistance to survive surprise lava and/or falling into a lake or river, and wants a ton of netherrack, then they could dig a tunnel without much worry with an Efficiency enchanted pickaxe. A player without active fire resistance must make any nether tunnels at least two blocks wide with one side of the floor a block higher than the other, so that if the player does hit surprise lava, it is channeled to the lower side. The player should always stand on the high side of this type of tunnel.