TALC

Talc is a mineral of hydrous magnesian silicate with a sheet structure. It has relatively high insulation and thermoinsulation properties, high melting point and strong oil-adsorbing performance. It is mainly applied as a filler, coating in papermaking industry and pulp pitch-controlling agent. And then it can be used for filling materials in roofing products (asphalt felt, roofing paper board, asphalt shingle, roofing board). It can also be used for batch material in ceramics, filler in coating (paint) and white pigment, filling material for rubber, electric cable and plastics and insulation material. In addition, it has also wide application in textile, cosmetics, pharmaceutical industries, carving and sculptural arts and so on. 

As early as 5,000~6,000 years ago talc had already been used in sculpture in China. The application of talc as a drug can be traced back to more than 2,000 years ago. In 763 A.D. talc was firstly exploited in the Longsheng mine, Guangxi. Since 1890 the recent Chinese talc industry had gone through all kinds of twists and turns. In 1949 the production of talc was only 3,848 tons. Since 1949, the talc industry in China has had a major development. Up to the 1970s three large talc production bases taking Haicheng in Liaoning, Longsheng in Guangxi and Laizhou in Shandong as the centers respectively and a lot of medium-sized and small talc mines have been set up. In 1997 there were 138 talc mining-processing enterprises in the whole country with an annual production of 4.07 million tons of industrial talc raw materials.

4.15.1 Resources

4.15.1.1 Reserves and Resources

Talc is one of the advantagerous mineral resources of China. More than 120 mineral occurrences were discovered. The reserves are abundant. Up to the end of 1997,45 occurrences (8 large, 18 medium-sized, 19 small) with retained reserves have been explored. The retained talc ore reserves of categories B+C+D grades amounted to 250.48 million tons, and ranked second in the world. 

In 1997, among retained talc ore reserves in China, these of categories B+C  accounted for 33%. The percentage of reserves of categories B+C in the major productive mines which had gone through exploration or detailed reconnaissance, was rather high. There were also some large and medium-sized mines, which have low percentage of reserves of categories B+C, and which had only gone through reconnaissance work and the extent of geological work was low. Among occurrences with retained reserves, 32 occurrences (5 large, 14 medium-sized, 13 small) have been developed with retained ore reserves of 128 million tons, accoun-ting for 51% of the total retained reserves, and which could satisfy the needs for industrial production of talc before 2010. The occurrences, which can be selected to be exploited in the near future, were 11 ( 3 large, 2 medium-sized, 6 small ) with retained ore reserves totaling more than 20 million tons, accounting for 48% of the total retained reserves. Two occurrences with retained ore reserves totaling near 2 million tons, accounting for 1% of the total retained ore reserves, are difficult to exploit at the moment.

4.15.1.2 Characteristics 

The distribution of 25 large and medium-sized talc occurrences with retained reserves in China in 1996 is shown in Fig. 4.15.1. The talc occurrences are distributed in 16 provinces (municipalities, autonomous regions). The talc occurrences in southern China and northern China are distributed evenly in general. Nevertheless the occurrences in the west part are clearly less than those in the east part. The talc occurrences are mainly distributed on the Liaodong Peninsula and Shandong Peninsula and in East China and South-central China areas. The retained ore reserves of talc in Liaoning, Shandong Provinces and the Guangxi Autonomous Region account for 52% of the total retained reserves of the country. The talc occurrences in Liaoning are distributed in the area of Dashiqiao-Haicheng-Benxi. There are altogether nine occurrences (1 large, 4 medium-sized and 4 small ) with total retained ore reserves of more than 48 million tons, of which the Fanjiapuzi deposit, Haicheng City, is superlarge in size with the retained ore reserves of more than 35 million tons, and there are also some small occurrences in the Xiuyan-Fengcheng area. 6 talc occurrences (1 large, 3

Fig. 4.15.1Map of distribution of talc occurrences in China
1. Yaolin, Jiangyuan County, Jilin, 2. Erdaohe mining area of Lianshanguan Talc Mine, Benxi County, Liaoning, 3. Xiaoyushu mining area of Lianshanguan Talc Mine, Benxi County, Liaoning, 4. Maer Yu, Haicheng City, Liaoning, 5. Fanjiapuzi, Haicheng City, Liaoning, 6.Shandaohe, Huanren County, Liaoning, 7.The western mining field, Mengya Asbestos Mine, Qinghai, 8.Dongpingou, Ningshaan County, Shaanxi, 9. Fengzishan, Laizhou County, Shandong, 10. Leeboshi Kuang, Qixia County, Shandong, 11.Zhifan, Bendu County, Shandong, 12. Haiyang talc mine, Haiyang County, Shandong, 13. Huangyan, Nanchuan County, Chongqing, 14. Chuanhe, Xiushan County, Chongqing, 15. Qiapeng, Baojing County, Hunan, 16. Zhengxu, Shangliu County, Guangxi, 17. Maanshan, Shangliu County, Guangxi, 18. Xitan, Guanfeng County, Jiangxi, 19. Lanrong, Chengpu County, Hunan, 20. Guping, Longsheng County, Guangxi, 21. Jizhua, Longsheng County, Guangxi, 22. Tongzishan, Longsheng County, Guangxi, 23. Yanqian, Yudu County, Jiangxi, 24. Changji serpentine associated talc occurrence, Putian County, Fujian, 25. Dalang, Yangshan County, Guangdong.

medium-sized, 2 small) distributed in Pingdu, Laizhou (Yexian), Qixia, Haiyang and so on, Shandong Province have a total of retained reserves of more than 43 million tons, of which the Lee Boshi Kuang mine ( Qixia County ) is of superlarge size with retained ore reserves of more than 33 million tons. In Guangxi there are 2 large talc mines and 1 medium-sized mine distributed in Longsheng County, and 1 large and 1 medium-sized talc mines in Shanglin County. The total retained talc ore reserves are more than 29 million tons. In the above-mentioned 3 areas the talc mines not only have large reserves, but also the quality of talc is superior, and the retained occurrences have already been exploited. They are 3 major talc occurring areas and 3 major talc-producing areas in China too.

Jiangxi and Qinghai are also talc occurring areas in China. The retained reserves (74.21 million tons ) in Jiangxi Province stand first in the country. They mainly occur in the Xitan black talc ore district of Guangfeng County (ore reserves are more than 68 million tons ) and Yanqian ore district of Yudu County. They have not been exploited yet. The retained talc ore reserves in Qinghai Province are 41.17 million tons. They  mainly occur in the west mining section of the Mengya asbestos mining field, Mengya Town. The retained ore reserves of talc associated with asbestos are more than 40 million tons and also haven't been exploited. 

In addition, there are some medium and small sized talc occurrences distributed in Chengbu, Baojing and Leiyang of Hunan Province, Putian and Zhenghe of Fujian Province, Chuanhe and Nanchuan of Chongqing municipality, Jiangyuan of Jilin Province, Ningshaan of Shaanxi Province, and Xinyi, Gaozhou and Yangshan of Guangdong Province. There is one small-sized talc occurrence respectively in Yunnan, Sichuan, Gansu, Beijing and Henan. These occurrences have mostly not been exploited.The talc deposits in China are divided into 3 categories: carbonate type, ultra-mafic  type and sedimentary type.

The deposits of carbonate type are distributed widely and  large-sized. The retained reserves of this type account for 55% of the total. The ores are mainly of low-aluminium and-iron steatite and carbonate-talc types. The content of talc is between 50%~70% or more. Its whiteness is 80%~92%. The quality of hand-sorted products is superior. The deposits of the category can be divided into 3 subcategories: ¢Ù Regional metamorphosed hydrothermal metasomatic deposits. They occur in magnesian carbonate rocks of the Precambrian metamorphic. The orebodies take a bed-like or lenticular shape. The size of deposits is considerable large. The occurrences of this subcategory are those in Haicheng of Liaoning Province, Jiangyuan of Jilin Province and Qixia, Laizhou and Pingdu of Shandong Province, which formed in the Proterozoic ( Lulianian Period ), as well as the Longsheng talc deposit in Guangxi, which formed in the early Paleozoic (Caledonian Period). ¢Ú Magmatic hydrothermal metasomatic deposits. They occur near contact zones between magnesian carbonates rocks and intermediate-acid or acid intrusive rocks, or in fissures between layers or fracture zones of magnesium-carbonate-rich rocks outside rock bodies. The sizes of deposits vary. The occurrences of this subcategory are those in Yudu of Jiangxi, Haiyang of Shandong and Mianning of Sichuan. ¢Û Paleokarst and hydrothermal metasomatic deposits. They occur in Carboniferous dolostone containing cherty bands and chert concretions. The size of deposits is rather small. The grade of ores is relatively low. The talc occurrences of this subcategory are those in Yangshan of Guangdong, as well as Hunan and Guangxi. 

The retained ore reserves of deposits of ultramafic rock type account for 17% of the total reserves. The ore bodies were formed by alteration of ultramafic rocks. The examples are the talc occurrences in Putian of Fujian and Mengya of Qinghai and etc. The sizes of the deposits vary. The composition of ore is complicated. The quality of ore is poor. The deposits of sedimentary type are those of newly discovered type in recent years in China. The retained reserves of deposits of this type account for 28% of the total reserves. They are mainly distributed in Jiangxi Hunan and Sichuan. The sizes of deposits are various. For instance, the Xitan talc occurrence in Guangfeng County, Jiangxi, is superlarge in size. The ore is black talc which occurs in the upper Sinian Dengying Group of Neoseries of Sinian Period and is mainly of siliceous-calcareous composition. 

The main minerogenetic epoch of talc deposits in China is the Precambrian dominated by the Proterozoic. For example, a series of deposits of large size and good quality occurring in Liaoning, Jilin and Shandong were formed in this minerogenetic period. The Lower Paleozoic minerogenetic epoch is less common, as exemplified by all occurrences in Longsheng, Guangxi. The ore bodies take the stratoid and lenticular shapes, and occur in dolomite-marble. The ores contain appreciable amount of gangue minerals. The whiteness of ores is poor. In addition, the talc deposits formed in the Middle-Upper Carboniferous are in Yangshan, Guangdong. The talc deposits formed in the Lower Permian are those in Yudu, Jiangxi and Baojing,Hunan. 

Tectonically the talc occurrences in China are mainly distributed in the interior of the paleoplates where there are often deposits with superior quality and large quantity of ore. They are China's main targets for exploitation. And less commonly, they are located in ophiolite areas of subduction zones of the paleoplates. The sizes of deposits are variable. The ore quality is rather poor. 

In general the quality of talc ores in China is superior. According to the incomplete statistics of the average values of ores in different deposits, there are 4 deposits with a content of talc equal or more than 90% or SiO₂ equal or more than 61%, MgO equal or more than 31% in Zhifan of Pingdu City, Shandong, Fanjiapuzhi of Haicheng City, Liaoning, Guping of Longsheng County, Guangxi, and Ma'anshan of Shanglin County, Guangxi. The retained reserves amount to more than 48 million tons, accounting for 20% of the total reserves in the country. There are 11 deposits with talc content of equal or more than 80% or SiO₂ equal or more than 55% and MgO equal or more than 30%. The retained reserves total more than 130 million tons, accounting for 52% of the total reserves in the country. They are distributed in Huanren County of Liaoning, Jiangyuan of Jilin, Liazhou , Qixia, Haiyang of Shandong, Leiyang of Hunan, and Shanglin and Longsheng of Guangxi. There are 4 deposits with talc content of equal or more than 70% or SiO₂ equal or more than 48% and MgO equal or more than 29%. The retained reserves amount to more than 3 million tons, accounting for 1% of the total reserves in the country. The deposits are distributed in Laizhou of Shandong, Chengpu of Hunan, and Xingyi of Guangdong. The retained ore reserves of the above deposits with high-grade or relatively high-grade ores amount to more than 180 million tons, accounting for 73% of the total reserves. There are 11 deposits with rather low grade ore (talc content is equal or more than 50% or SiO₂ equal or more than 36% and MgO equal or more than 27%). 

The retained reserves total 17 million tons, accounting for 7% of the total reserves. They are distributed in Haicheng, Beixi and Dashiqiao of Liaoning, Yudu of Jiangxi, Laizhou of Shandong, Fancheng of Henan, and Xingyi of Guangdong. There are another 15 deposits with a very low average grade of ores. The retained reserves amount to more than 50 million tons, accounting for 20% of the total reserves. They are distributed in Fangshan of Beijing, Benxi and Dashiqiao of Liaoning, Putian of Fujian, Leping of Jiangxi, Baojing of Hunan, Xinyi and Yangshan of Guangdong, Xiuchuan and Nanchuan of Chongqing, Mianning of Sichuan, and Ningshaan of Shaanxi and Mangnai of Qinghai.

Most of talc ores occurring in China are of low-Al and-Fe ore type(Al₂O₃ less than 4% and Fe2O3 less than 2.75%). The whiteness of ores is between 80%~92%, and the quality of ores can be markedly improved through handpicking of them. For example, the ores from the Guping mine and Jizhua mine in Longsheng County, Guangxi are mainly of first and second grades. Their chemical composition is close  to the theoretical values. The ores are superior talc raw material of cosmetic grade. The quality of red talc ores produced in Haicheng, Liaoning are also superior. These talc products enjoy high prestige at home and abroad. Chinese talc ores, in general, can be used through only handpicking. If the ores decontaminated with advanced processing technology, their grades can be further improved. Nevertheless, there are also a part of low-grade ores, such as black talc ores, and the representatives of them are those from the Xitan mine in Guangfeng County, Jiangxi. The retained reserves of them are more than 72 million tons. The ores contain much organic substances. The whiteness of them is poor. Their application is not wide at present.

The main minerals associated with talc are carbonate minerals, such as calcite, dolomite and magnesite, and less commonly chlorite, quartz, tremolite, serpentine and mica. They have not been utilized totally.

Most of Chinese talc deposits are worked by underground mining. Neverthless,  some talc deposits have good mining conditions, for example, the Longsheng talc deposit, Guangxi, is open-cut mined on the mountain slope, and the Zhifang talc deposit, Pingdu County, Shandong, is stoped by the deep open pit mining method.