The Taotie Mine could be entered anytime as long as you met the requirement of being an immortal emperor. The rules were more relaxed here, there was no fixed time for people inside to exit. You can exit whenever you want to and keep 10% of your harvest.
These are the eight most important mines in the Lifelong Realm, and naturally were far more attractive to powerful experts. Also, it contained many mysteries within and frequent bouts of good fortune. Despite so, its rules were much more relaxed compared to the other mines. But then again, this was a kind of strategy as well. So what if this place had many bouts of good fortune within? If the rules were too strict, no one would want to come here to risk their lives in adventuring or to temper themselves. Who then, would come here to excavate the resources?