Discovery and geological significance of ultra-large low-grade gold deposit in Dadonggou, Liaoning Province

The Dadonggou Gold Deposit is an ultra-large low-grade gold deposit. It discovered by Liaoning Fifth Geological Brigade Co., Ltd. in recent years. The geological structure of the mining area is located at the western end of the Liaodong Section of the Jiao-liao-Ji Paleoproterozoic Orogenic Belt. The ore bearing strata and lithology are carbonaceous sericite phyllite in the second section of the Gaixian Formation of the Liaohe Group. The large scale gold bearing structural alteration rock belt is controlled by horizontal（or gently inclined） shear structures, and gold mineralization is widely distributed in the belt. The gold content is relatively uniform, generally ranging from 0.3×10⁻⁶ to 1.0×10⁻⁶, with a few samples can reach 1.0×10⁻⁶ to 3.0×10⁻⁶. Ring the ore body according to the low-grade index, the gold resources in the mining area can reach over a thousand tons; the occurrence state of gold minerals in the ore body is simple, with good selection and metallurgical technology indicators, shallow burial depth of the deposit, and huge economic potential. The geological characteristics of the deposit are unique, with low Au grade, large scale, obvious layer control properties, and later hydrothermal superposition and transformation characteristics. It can be called the “Dadonggou style” gold deposit, which has profound implications in ore deposit studies. It can promote greater breakthroughs in the exploration of similar gold deposits in the Liaodong gold deposit area through in depth research.