Minecraft wiki entry for Mining, associated text: After the cardinal directions are done, players have their as many connections as they care for, continue adding onto their bottom hubs, only with straight pushes. The bottom hubs will branch in all directions except backwards, unless the player are going with an open or mine variation, and each of those hubs may spread in the same direction so long as it's not backwards for the original hub. If they positioned well in the first central hub and push size, they will be scraping a long in a fairly wide tunnel along the same height the player find diamonds. It's easy sailing from here on.