The Laowangzhai gold ore of Mt. Ailao occurs in the metamorphosed late Paleozoic rocks consisting of the epizonal sandy slate, graywacke and volcanic rock of marine facies. Strong magmatic activities and wide-spread faults are found in this area. There are compression-thrust fault zones striking E-W and NW-SE fault zones showing the features of brittle-plastic ductile zone in this area. They are the major ore-controlling structures. In addition, a few small-scale faults striking NE-SW may cut the said fault...