Jiangda Yulong Copper-Molybdenum Mine (8)

Yulong copper-molybdenum mine is located in the west of Qingni East District, Jiangda County, eastern Tibet, 8 kilometers north of Sichuan-Tibet Highway, 140 kilometers west of Changdu Town and1/84 kilometers east of Chengdu. The mining area is 4560-5120m above sea level.

The mining area is a NW anticline with two wings composed of Upper Triassic sandstone, shale and limestone. Himalayan adamellite porphyry intruded along the axis of anticline, and mineralization occurred in porphyry body, surrounding rock and contact zone, with a total area of 2. 1 km2. The deposit belongs to porphyry type and is a large copper-molybdenum deposit. 198 1 year, the Tibet Geological Bureau approved 6.62 million tons of copper reserves, of which 6.5 million tons can be used. In addition, the proven associated molybdenum reserves are 6.5438+0.5 million tons, iron ore reserves are 86.96 million tons, and pyrite reserves are 6.5438+0.78 million tons. The prospective reserves of other associated minerals are: silver 3 1, 8 1 ton, tungsten 59800 tons, gold 28 tons, bismuth 8 17 tons, cobalt 22000 tons, zinc 72300 tons and platinum group metal 3.4 tons.

This deposit consists of three ore bodies. Ore body I is a tubular ore body composed of ore-bearing granite porphyry and ore-bearing amphibole in its contact zone, with a surface area of 0.6 square kilometers, an average thickness of 33 1 m, and an average grade of copper of 0.52% and molybdenum of 0.028%. Orebodies Ⅱ and ⅴ are layered orebodies with internal contact zone, with average thickness of 44m and 69m respectively, and average copper grade of 1.75% and 2.5% respectively. The main minerals in the deposit are pyrite, chalcopyrite, molybdenite and chalcocite. The main ore type forming industrial ore bodies is veinlet disseminated sulfide ore, in which 1 ore body is disseminated ore, and the grade of copper concentrate is 22.3%-23. 14%, which is easy to be selected. Except disseminated ore, mixed ore, oxidized ore and copper-bearing brown iron ore, No.I and No.V ore bodies are all refractory. The hydrogeological conditions in the mining area are simple. The buried depth of ore bodies is 0- 18m, and most of them are exposed on the surface.

"Yulong" means "malachite ditch" in Tibetan. It is widely rumored that Zhao Erfeng, Minister of Kangzang in Qing Dynasty, once mined here in the late Qing Dynasty. Up to now, there are still several mining pits and mining relics on the surface of Yulong mining area. 197 1 year, hammers and hoes were found in ancient mining pits, and it is speculated that lead, silver, copper and other ores are mainly mined.

The discovery process of the deposit is tortuous, but it conforms to the objective law. As early as 1966, the masses He Dajiang and Basangwangdui of the First Geological Brigade of Tibet heard the local herder Jiang Shen say, "When the weather is fine in Yulong Valley, the stones in the ravine are colorful and dazzling." He Dajiang and others thought that this phenomenon might be caused by ore, so they braved the heavy snow to explore the ditch and found many iron caps and a large number of malachite stones. They think that this mine is similar to Daye Iron Mine, and it is worth further study. During the period of 1967, the geological formation composed of Fu Xingbao and Ma Zhenqing, the first geological brigade of Tibet, used large-scale geological mapping, magnetic survey, trench exploration and sampling to check the occurrence. It is found that the magnetic anomaly intensity is high, the copper content in the ore body is high, and there are many useful metal elements. It is considered that it is a skarn deposit dominated by iron and copper, with an estimated iron ore reserve of 27.7 million tons. It was suggested that further work should be carried out.

The exploration work was stopped for some reason until 197 1, and the first geological brigade of Tibet went to Yulong again and began the first detailed investigation of Yulong. Fu Xingbao, as the technical director, used comprehensive means such as geology, geophysical exploration, survey, drilling, pit exploration and sampling to find layered copper bodies in the eastern contact zone, copper mineralization in the altered adamellite in the eastern contact zone, with copper 1.7%, and copper-molybdenum mineralization in the biotite adamellite porphyry in the southern mining area. The geophysical anomalies in the northern part of the rock mass were verified by the adit, which were determined to be caused by granular aggregates and massive sulfide ores composed of disseminated pyrite and chalcopyrite, and the prospecting work made great progress. In the same year, they proposed in 197 1 Geological Survey Report of Yulong Copper-iron Mine Area in Jiangda County, Tibet and 1972 Geological Work Opinions that "Yulong Copper-iron Mine may be a copper-molybdenum compound deposit", suggested to continue their work, and proposed to expose the main ore body in the deep part of the contact zone first. So far, Yulong deposit has been preliminarily affirmed, and the viewpoint that there is a porphyry deposit is put forward for the first time. The survey results of 197 1 and the basic understanding of the deposit have laid a solid foundation for the determination of the type of Yulong deposit and the detailed investigation and evaluation of the deposit.

1972 transferred to the mining area for detailed investigation, and 1976 completed the field work. 1978 submitted the Geological Report on Detailed Investigation of Yulong Copper and Molybdenum Deposit in Jiangda County, Tibet. During this period, he was the technical director of Tang, with more than 200 employees. Taking drilling, geophysical prospecting, geochemical exploration and geology as the main means, according to the geophysical anomalies delineated in the rock mass, the copper-molybdenum ore body was hit in the center of the rock mass for the first time. Based on the comprehensive analysis of the existing data and comparison with similar deposits at home and abroad, technicians confirmed that Yulong copper-molybdenum deposit should be classified as a porphyry deposit as a whole, and the ore body in the surrounding rock is a part of the deposit, which has the characteristics of porphyry mineralization and is likely to be a relatively stable tubular ore body. At the same time, Ning Qisheng, Huang Chongzhi and Chengdu Institute of Geology and Mineral Resources of Chinese Academy of Geological Sciences have studied the characteristics of the deposit and confirmed that Yulong deposit is a typical porphyry copper-molybdenum deposit. Because of the breakthrough in understanding, the adjustment of detailed investigation arrangement was promoted, and the focus of exploration work was moved from contact zone to the interior of rock mass, and the detailed investigation and evaluation of the deposit was successfully completed.

The discovery and evaluation of mineral deposits is a complicated process of recognizing and re-recognizing objective things. The exploration work adopted the most effective method at that time. Using geophysical and geochemical methods such as electrical method, magnetic method and soil survey, anomalies are found in rock mass and contact zone to guide the rational layout of the project. With the enrichment of information and the deepening of research, the understanding is constantly improved and deepened. From the Daye-type iron deposit-the composite deposit of skarn copper-iron deposit and porphyry copper-molybdenum deposit, to the final establishment of the metallogenic model of porphyry copper-molybdenum deposit with the characteristics of "Yulong", this understanding process can never be achieved overnight. The leap in understanding has led to a major breakthrough in prospecting. The discovery and evaluation of Yulong deposit is a milestone in the general survey of copper deposits in the "Sanjiang" area in southwest China. The First Geological Brigade of Tibet has carefully summarized the metallogenic model and prospecting experience of Yulong deposit, and deployed the prospecting work in the belt in time. The whole team braved the harsh natural conditions of the plateau and made unremitting efforts to discover more than 10 large and medium-sized copper deposits and occurrences in Marathon. After 10 years, a porphyry copper belt with a length of about 400 kilometers and a width of about 30 kilometers has been completely determined, which is of great significance for copper exploration in this area in the future. In recognition of this outstanding achievement, the Ministry of Geology awarded the honorary title of "Geological Prospecting Unit" to the First Geological Brigade of Tibet on 1980. 65438-0985, the exploration achievement of Yulong copper mine won the special prize of geological prospecting, and the carp of Tang Dynasty won the honorary title of first-class merit and model worker of the Ministry of Geology and Minerals.