Minecraft wiki entry for Mining, associated text: The central hub (The first hub made in the mine) will have 4 pushes in each of the cardinal directions, eventually, if players are in need of ores they may choose to go down in one direction until the player have what they need. It is recommended to check the Y-coordinate about now, they may want a push length that will allow them to get to their Y-coordinate value as close as they can to 12. (Lava spawns in caves at 10, and their Y-coordinate is up 2 for the positioning of their head) After the player's decided on the length and finished a push, make another Hub in the same size as above. Continue until they reach the last of their hubs, and they should end it before they hit the bedrock layer, otherwise it won't be very nice looking.