subject: Main Distribution Situation Of Silver Ore [print this page] The retained reserves are 3,336 tons with a silver grade of 146.21 g/t. The discovery and exploration has experienced several partly overlapped stages: exploited as a "vein-like and banded" Pb-Zn deposit, porphyry Pb-Zn deposit, porphyry Ag deposit, and stratabound diplogenic silver and gold deposit. After 20 years of exploration, this large Ag deposit was eventually proved. The first mine, the Yinluling Silver Mine, in the Lengshuikeng ore district was built in 1990 and went into operation in 1992 with a daily ore mining and dressing capacity of 500 tons and an annual silver output of 22.96 tons. The Yindongzi Ag and polymetallic deposit is located in Zhashui County on the southern slope of the Qinling Mountains in southern Shaanxi. The ore district is 3 km long from east to west and 1.5~2 km wide from north to south. Its retained reserves are 2,257 tons with a silver grade of 107 g/t. This deposit was mined intensively in ancient times. In the 1950s geological teams under the Ministry of Geology and Ministry of Metallurgical Industry conducted geological surveys and mineral prospecting. A geological and detailed exploration report was completed in 1981. At present the Shaanxi Silver Mine has been established to carry out further prospecting work. As designed, 99,000 tons of ores are mined and dressed annually, and 140,000 tons of ore were produced in 1991. The Poshan silver deposit is located 24 km to the north of Tongbo County. As early as Southern Qi (A.D.479~502) of the Northern and Southern Dynasties, the mining and smelting of silver was administered by Weishan County and the mine was abandoned at the end of the Ming Dynasty (about 350 years ago). Before 1949 when the People"s Republic of China was founded, limited geological route surveys were done; whereas a great deal of regional geological surveys and ore prospecting were carried out afterwards. In 1975, the No.8 Geological Team of the Shaanxi Bureau of Geology conducted exploration for the Poshan silver deposit and submitted a relevant exploration report, Detailed exploration report of the Poshan silver ore district in Tongbo County, Henan Province, yielding silver reserves of 2,662 tons with a silver grade of 278 g/t. Altogether 13 orebodies were discovered, which are all of industrial value except No.2 orebody. Of these orebodies, No.1 is the largest one, 1,900 m long and 5.38 m thick with a maximum downward extension of 530 m. In 1985, the China National Non-ferrous Metals Industry Corporation set up the Tongbo Silver Mine to deal with the exploration and utilization of this deposit. The designed daily mining and dressing capacity was 800 tons and the annual output of silver was 50 tons. The Jiawula and Qagan Bulagen Ag-Pb-Zn deposit is located in Xin Barag Right Banner, Inner Mongolia. The two deposits lie in the same NW-trending structural belt and are only 6 km apart, which were discovered in 1985 and 1986 respectively. Exploration proved that the Jiawula deposit has Ag ore reserves of more than 1,000 tons, Pb-Zn ore reserves of 800,000 tons and Cu ore reserves of 45,000 tons; while the Qagan Bulagen deposit has Ag ore reserves of more then 500 tons, and Pb-Zn ore reserves of 80,000 tons. The average grade of silver of the Jiawula deposit is higher than 50 g/t. Silver orebodies with grades of 170~200 g/t provide about 50% of the reserves of this deposit.In China, silver mineralization had been extensively developed during a long geological history from the Proterozoic to Mesozoic, especially in the Yanshanian, though silver deposits of industrial value formed in the Archean and Cenozoic have not been discovered so far. Both the number and scale of the silver deposits formed in the Yanshanian are larger than those of other periods.As the professional manufacturer of complete sets of mining machinery, such as cement mill,stone production line, Henan Hongxing is always doing the best in products and service. Spatial distribution shows that all silver deposits in China are widespread in geosynclinal fold belts and platform depression basins as well as volcanic-sedimentary fault depressions in activated platforms. For instance, the Ag deposits in Zhushan, Hubei Province, and Maqiong, Sichuan Province, occur respectively in Caledonian and Indosinian eugeosynclinal fold belts; the Ag-Pb-Zn deposit in Xingshan, Hubei Province, and Bajiazi, Liaoning Province, occur respectively in a depression in the Yangtze platform and the Yanshan basin of the North China platform; the polymetallic deposits in Tiantaishan, Zhejiang Province, and Dexing, Jiangxi Province, occur in fault volcanic basins of activated platforms. A clear tendency has been seen in regard to the distribution of silver deposits: a great number of Ag-rich polymetallic deposits are found to occur in fault volcanic basins of activated platforms and, moreover, these deposits are usually large in size. The syngenetic ore-forming processes are essential to the formation of silver deposits. Ag and Ag-polymetallic ore beds were formed when volcanism and sedimentation produced their wall rocks independently or jointly. These ore beds and wall rocks have the same formation environment or macroscopic geological conditions and they were formed almost in the same period. The ore beds originating from such syngenetic ore-forming processes were subjected to superposition of certain geological events to become industrial deposits. Such deposits are usually characterized by high contents of metallic elements, persistent horizons and large scales. Although some deposits related to intermediate-acid intrusive rocks have been found, they are only of secondary importance and ore deposits of industrial value related to basic intrusive rocks have not been discovered thus far. In other countries, however, silver deposits due to the above two geological processes are fairly noticeable. According to the statistics in 1992, among the silver deposits with silver as the main metal, there are 12 large and 40 medium-sized ones, whose reserves account for 95% of the total reserves of the deposits of its kind, and 29 small ore deposits account for merely 5% of the total. In regard to by-product silver deposits, there are 14 large and 73 medium-sized deposits, amounting to 79% of the total reserves of by-product silver; and 271 small ones, amounting to 21% of the total. There are rich resources of by-product silver in China. The retained ore reserves were 66,146 tons in 1995, making up 58% of the total in that year. However, this estimation is actually less than the reality since the analysis and estimation were not complete. By-product silver has been found in all provinces, autonomous regions and municipalities except Ningxia. Most reserves and ore districts of by-product silver have been proved in Jiangxi, Hubei, Guangdong, Guangxi and Yunnan. In China rich by-product silver deposits are fewer than poor ones and those with a grade higher than 50 g/t have reserves accounting for only 1/4 of the total, while the proportion of poor ore deposits with a grade lower than 50 g/t is as high as 3/4 of the total number. In China most associated silver ore occurs in Ag-Pb-Zn deposits, amounting to 64.3% of the total retained silver reserves; whereas by-product silver ore occurs often in Pb-Zn deposits, amounting to 44% of the total by-product silver reserves, and in Cu deposits, amounting to 31.6%. In addition to Pb, Zn and Cu deposits, silver can occur also in tin, gold and polymetallic deposits as am associated or by product mineral.cement making machine:http://www.hx-china.com/37.html cement rotating dryer:http://www.crusher-machine.com/24.html
