Abstract:

The deep exploration project of Yinshan copper polymetallic mine in Dexing，Jiangxi Province undertaken by Jiangxi No.4 Nonferrous Geological Exploration Team has achieved important exploration results. The newly proved resource reserves （331+332+333） are 540 000 tons of copper，230 000 tons of lead + zinc，57 tons of gold，914 tons of silver and 5.93 million tons of sulfur. It is equal to increasing the scale of a large copper mine，a large gold mine，a medium-sized lead-zinc mine and a near large silver mine. In this deep exploration，the original geological logging of more than 100 000 meters of drilling and more than 17 000 meters of tunnel has been carried out. 35 900 basic analysis samples have been taken and various rock and ore test samples matching with the exploration stage have been sent for inspection. In order to further expand the prospecting in the deep part of Yinshan，evaluate the prospecting potential in the deeper part of the mining area and predict the favorable space for ore generation，through the detailed geological observation and recording of various prospecting projects in the deep exploration，combined with the rock and ore test work，further systematically summarize the results of the exploration report，analyze and study the basic geological conditions and metallogenic characteristics of the deposit formation，so as to extract the results.The new understanding includes：（1）Yanshanian Yinshan subvolcanic body is closely related to mineralization，3# dacite porphyry is related to copper gold mineralization，5# quartz porphyry is related to lead zinc silver mineralization.（2）The altered quartz diorite in Caledonian period appears in many places on the outer side of the 3 Ying’an porphyry in Jiutong district，which，together with sericite phyllite and blasting breccia，forms the ore bearing surrounding rock in the Ninth-Xishan district.The opened magmatic activity channel is favorable for the emplacement of the 3 rock body related to the mineralization in Yanshan period.（3）The two flanks of Yinshan anticline are associated with the fracture structure belt，which is the main ore controlling structure.The northwest wing is associated with the East-West fracture structure belt，which is extremely developed with a wide strike and a long extension length. The south-east wing develops the North-South fracture structure belt，which is characterized by a short strike and a scattered distribution，which results in the north-west wing of Yinshan anticline controlling the occurrence and distribution of most ore bodies.（4）The location and shape of the orebody are directly controlled by the main fault and its associated network fractures on both sides. The sulfide vein continuity in the main fault controls the continuity of the ore body. The fine network vein ore is the main mineralization type，and the thick and large ore bodies are often composed of several main fault surfaces close to each other，such as the Ninth-Xishan District copper ore body.（5）The hydrothermal alteration associated with mineralization is a low-temperature alteration combination mainly composed of sericitization，carbonation and chloritization，which is lack of high-temperature potassium silicate salinization of porphyry deposits.The deep orebody of Yinshan copper polymetallic mine has not been closed，especially the outer contact zone on both sides of the deep 3 Ying’an porphyry at the turning part of Yinshan Ninth-Xishan area and the deep part of known orebody inclined extension are the best direction for subsequent ore prospecting.

Key words: deep prospecting, mineralization characteristics, prospecting direction, Yinshan copper poly-metallic ore, Dexing, Jiangxi Province