Minecraft wiki entry for Ultra_hardcore_survival, associated text: Caving in UHC mode is what you make it. Generally, people either try to go super fast or super slow. The goal of going super fast is to beat mob spawns through the caves and gain materials more efficiently. You can light behind you with torches if you want, especially if you plan to go back out the way you entered. If you run through placing torches you might want to not even mine ores to get through faster. The other approach is to go through caves very slowly. A lot of people will recommend this, although, for competitive or time-based environments, it's generally more efficient to just run through. When caving slowly, always block off mobs and attack their feet.