The world-wide Dachang ore field, 30km long (NS) by 20km wide (EW) and characterized by tin-bearing polymetallic mineralization related to the Yenshanian granitic magmatism, Guangxi, China, is one of four ore fields in the Danchi fold belt, adjoining to the western margin of the Precambrian Jiangnan old-land and forming part of the eastern margin of the Late Paleozoic Youjian fold belt.
A large quantity of metals of various kinds, including Sn, Sb, Zn, Pb, Cu, Ag, Cd and In, has so far been recovered from the Dachang ore field. For instance, more than 10⁶ tons of tin (as metal), equivalent to several times as much as the current world metal production, were fixed in this ore field.
Currently working mines throughout the Dachang ore field are: Changpo-Tongken and Longtaoshan (western part); Lamo and Chashan (central part); Dafulao and Kengma (eastern part). The former two are the major mines in the ore field. The Changpo-Tongken deposits are the largest known tin deposits with ore reserves of about 80×10⁶ tons averaging about 1% Sn and 3.5% Zn and occur as stratiform, veins and networks hosted by upper Devonian limestone and siliceous rocks. The Longtaoshan deposits occur as veins and are hosted by middle Devonian reef limestone, with ore reserves of about 10⁷ tons averaging about 1.5%Sn, 10%Zn, 6%Pb, 5%Sb and 150ppm Ag. The Lamo Cu-Zn skarns, averaging about 2%Cu, 5%Zn and 0.1%Sn, occur at the boundary between the Longxianggai granite and upper Devonian limestone and black shale. Small-scaled and low-grade stratiform deposits and veins at the Dafulao and Kengma mines occur in lower Devonian argillaceous limestone and shale.
From regional viewpoints, it is suggested that the southern part of China, especially areas underlain by the Yenshanian granitoids, still has high exploration potentialities for tin and other rare-metals.