18.104.22.168 Reserves and Ｒesources
By the end of 1997, 312 bauxite deposit districts had been explored in China. They are distributed in 19 provinces, autonomous regions and municipalities directly under the Central Government, with retained reserves of bauxite attaining to 2.276 billion tons, in which 0.702 billion tons are of categories A+B+C, accounting for 31% of total retained reserves.
According to the Mineral Commodity Summaries data of 1996, the bauxite reserves of the whole world are estimated at 23 billion tons, with reserve base being 28 billion tons. Countries with more abundant bauxite resources are: Australia (reserve base--7.9 billion tons), Guinea (reserve base--5.9 billion tons), Brazil (reserve base--2.9 billion tons), Jamaica (reserve base--2.0 billion tons), India (reserve--base1.2 billion tons), and Hungary (reserve base--0.9 billion tons). Bauxites of our country are inferior to those of all above-mentioned countries in both the quantity and quality. Comparing the reserves of categories A+B+C of our country with the reserve bases of these countries, we are far behind them.
Nevertheless, China remains to be relatively rich in bauxite resources. The North China Platform, the Yangtze Platform, the South China fold system and the south-east coast--all these four metallogenetic regions have more or less favourable conditions for bauxite formation, and especially the Central Shanxi-Northern Shanxi, the Western Henan-Southern Shanxi, and the Northern Guizhou-Central Guizhou metallogenetic zones are more favourable, with a great potential of bauxite resoruces; the Western Guangxi-Eastern Yunnan and the Southern Sichuan-Northern Guizhou, metallogenetic zones, however, have also a certain potential. Based upon the analysis of known geological background and the metallogenetic conditions, it is proposed that the total reserves of bauxite in China may reach as many as 5 billion tons.
The bauxite deposits in China are mostly distributed in Shanxi, Guizhou and Henan provinces and Guangxi Autonomous Region, with their reserves making up 90.9% of the country's total (Shanxi--41.6%, Guizhou--17.1%, Henan--16.7%, Guangxi--15.5%). The total reserves of other 15 provinces, autonomous regions and municipalities having bauxite deposits only make up 9.1% of the country's total.
The bauxite deposits (occurrences) in Shanxi are mostly distributed in five large districts and 42 counties, such as Xiaoyi, Jiaokou, Fenyang, Yangquan, Yuxian, Ningwu, Yuanping, Xingxian, Baode, Pinglu, etc., totaling 67,000 km2 in area, with the explored bauxite reserves ranking first in China. It is estimated that the bauxite resources in this province may reach as many as two billion tons.
The bauxite deposits in Henan are concentrated in three districts and ten-odd counties to the south of Yellow River and the west of the Beijing-Guangzhou Railway, such as Gongxian, Dengfeng, Yanshi, Xin'an, Sanmenxia, Shaanxian, Baofeng, Lushan, Linru, Yuxian, etc., totaling more than 30,000 km2 in area, with the explored bauxite reserves ranking second in China. It is estimated that the total bauxite resources in this province may attain to one billion tons.
The bauxite deposits in Guizhou are mostly distributed on both southern and northern sides of the "Central Guizhou Uplift", in more than ten counties such as Zunyi, Xifeng, Kaiyang, Weng'an, Zheng'an, Daozhen, Xiuwen, Qingzhen, Guiyang, Pingba, Zhijin, Goujiang, Huangping and others, covering 2,400 km2 in area, with the explored bauxite reserves ranking third in China. It is estimated that the total bauxite resources in this province may exceed one billion tons. The bauxite deposits in Guangxi are mostly located within those counties, as Pingguo, Tiandong, Tianyang, Debao, Jingxi, Guixian, Napo, Guohua, Long'an, Yongning, Chongzuo and others, with the explored bauxite reserves ranking fourth. It is estimated that the total bauxite resources in this region may attain to 0.8 billion tons or more.
The bauxite deposits in Shandong are mainly located within such counties, as Zibo, Xintai, Hongshan and others, with the explored bauxite reserves making up 3% of the country's total.
In addition, there are also bauxite deposits occurring in Hainan, Guangdong, Fujian, Yunnan, Jiangxi, Hubei, Hunan, Shaanxi, Sichuan, Xinjiang, Ningxia, and Hebei provinces (regions).
Fig. 3.9.1 and Table 3.9.1 indicate the major bauxite deposits in China and the state of their development and utilization.
According to Liao Shifan et al. the bauxite deposits in China can be divided into palaeoweathering crust bauxite deposits and laterized bauxite deposits. The palaeoweathering crust bauxite deposits in China were largely formed in the Carboniferous period. The bauxite deposits of the Middle and Late Carboniferous are distributed in the northern provinces such as Shanxi, Henan, Hebei and Shandong, while the bauxite deposits of the Early Carboniferous are distributed in the central part of Guizhou. Another important metallogenic epoch of weathering crust bauxite deposits is Permian. The Early Permian bauxite deposits are largely distributed in the provinces such as Sichuan, Guizhou, Yunnan, Hunan and Hubei, while the Late Permian-Early Triassic bauxite deposits are mainly located in the provinces (regions) such as Guangxi, Yunnan, Sichuan, Shandong, Hebei and Liaoning.
Table 3.9.1 The principal bauxite deposits of China
Note: Bauxite deposits with reserves more than 20 million tons are classified as large, those with reserves between 5~20 million tons-as medium-sized, and those with reserves less than 5 million tons-as small.
The current lateritic bauxite deposits of China are mainly formed in low-latitude areas such as Fujian, Hainan and Guangdong, because of burning hot weather, abundant rainfall and existence of basalts liable to weathering in these areas. As concerns the Nansha Is land. and Zhongsha Is land, although they are located also in the low-latitude area, and have the wealther suitable for bauxite formation, yet these islands have been uplifted to become a continent for too short a time, only for 10,000~30,000 years, to experience weathering, so it is not possible to form bauxite deposits there.
Some typical bauxite deposits are outlined as follows:
The Ke'e bauxite deposit, Xiaoyi County, Shanxi was explored as early as in 1960, and then the exploration of the Bujiayu sector followed. The cummulative explored bauxite reserves attain to 62.656 million tons, with the grade of ores averaging 64.36%. The bauxite deposit began to be mined by Shanxi Aluminum Factory in 1986.
The Pingguo bauxite deposit, Guangxi, is 1,750 km2 in area, and there are accumulative ores all along the whole length (132 km) of the bedded ore-bodies. The primary ores were explored as early as in 1959~1961, but they are no good because of their high sulfur content (1.5%~7%). Later the accumulative ores began to be explored in 1974, with cummulative explored bauxite reserves attaining to 126.098 million tons, with an average grade of 64.69%. The accumulative ores are of high industrial value because they are suitable for open-cut mining and have high aluminum content and low sulfur content.
The Xiaoshanba bauxite deposit in Xiuwen, Guizhou, which began to be explored in 1957, has cummulative explored bauxite reserves attaining to 20.264 million tons, with an average ore grade of 67.91%. The Wulongsi mine was put into operation in 1979.
The Goujiang bauxite deposit in Zunyi, Guizhou was explored in 1989, and is possessed of reserves reaching 11.12 million tons, with an average grade of 53.62%. The ore bed is very complicated in geometry, with a lot of barren windows, and has a low ore-bearing coefficient--about 0.5. The ore bed varies greatly in thickness from 0.7 to 11.5 m (occasionally 83 m), with four intercalations of carbonaceous rocks, or poor coal.
The Zhangyaoyuan bauxite deposit in Xin'an, Henan was explored from 1961 to 1964, as a refractory clay deposit. It was put into mining in 1966, with cummulative explored bauxite reserves being 9.497 million tons.
The Wangcun bauxite deposit in Zibo, Shandong is located in the northwestern part of the Zibo basin. A detailed prospecting was carried out in 1956 and a preliminary and detailed exploration conducted during 1964~1965. It was put into open-pit mining in 1966, with cummulative explored bauxite reserves totaling 2.945 million tons.
The Penglai bauxite deposit in Hainan is a modern lateritic one. Prospecting and exploration were carried out in 1959~1961, with cummulative explored bauxite reserves totaling up to 21.906 million tons, with an average grade of 44.4%. The deposit being located on the top of a gentle hill at an altitude of 30~60 m, is a Tertiary to Quaternary basalt-weathering lateritic idrargillite deposit, with ore-body composed of laterite, resulting from basalt weathering, and bauxite ore aggregates, in which laterite makes up 70%~80%, while the bauxite aggregate accounts for 20%~30% (weight percentage).
The bauxite deposits of China are generally concentrated in distribution, and furthermore a majority of them are large and medium-sized deposits. There are 31 large deposits with their reserves more than 20 million tons each, their aggregate reserves accounting for 49% of the country's total, and 83 medium-sized deposits with their reserves ranging between 20~5 million tons each, their aggregate reserves making up 37% of the country's total.
The bauxite ores of our country are of poor quality, and the diaspore ores, difficult to process and power consuming, occupy more than 98% of the country's total in terms of reserves.
Another unfavourable factor of the bauxite resources of our country is that there is only a small number of bauxite deposits which are suitable for opencut mining. According to the statistics their reserves only occupy 34% of the country's total.
Unlike the laterized bauxite deposits abroad, the palaeoweathering crust bauxite deposits in China are commonly accompanied paragenetically by and associated with various other useful minerals. In areas of such bauxite deposits, coal beds of economic value and high-quality limestones are often found to occur in the overlying formations. Paragenetic semi-soft clay, hard clay, and iron and pyrite ores are present in the host rock series. In the bauxite ores Al is associated with a multitude of useful elements such as Ga, V, Li, REE, Nb, Ta, Ti and Se, of which Ga, V and Se are also of economic significance. In these areas the above-said associated mineral resources constitute industrial deposits together with bauxites.
The bauxite deposits of our country are mostly highly investigated. By the end of 1994, 32.5% of the total retained bauxite reserves had been uerifide through exploration, and 55.8% of those through detailed survey.