Introduction to ancient mining sites: From the Western Han Dynasty to the Wanli Period of the Ming Dynasty (1573), Wanshan has been using the "explosion hole technology" to mine outcrop ore seedlings. Specifically, dry firewood is piled on the outcrop of the ore seedlings, and it is lit and burned for several days and nights. After the mine wall is red-hot, cold water is poured on it to break the rock. The ore is then picked up and hammered to pan out cinnabar or refine mercury.