Minecraft wiki entry for Mining, associated text: Due to the open nature of a quarry, many players choose to build an intricate base floating in the quarry, and then fill in the unused space with dirt, gravel, sand and stone. If done correctly, an underground base will be undetectable from the surface, especially when grass grows on the surface above it. For extra stealth, consider planting trees in the open area. A player might deter miners by placing a large lava lake over the base. This will also decrease hostile mob spawns around the base.