3.6.1.1 Reserves and Resources   

As reported in 1998, the world's total of vanadium reserves was 10 million tons and that of vanadium reserve base amounted to 27 million tons. Countries relatively rich in vanadium resources are South Africa, Russia, China and the US. Category A+B+C (industrial) reserve of V2O5 in China is 9.49 million tons, equivalent to 5.315 million tons of metal vanadium. If such an industrial reserve is comparable with the reserve base of foreign countries, China would rank third in the world, next only to South Africa and Russia.    

It is known that 98% of the world's total vanadium reserves occur in V-Ti-magnetite deposits. The world's total vanadium reserves amount to over 40 billion tons, which are concentrated primarily in the former Soviet Union (having nearly 40% of the total) and the US (25.6%), subordinately in China, Canada, South Africa, Norway, Australia and Sweden. Based on the present rate of mine production, the world's total vanadium reserves are enough for mining for more than 150 years (Tan Ruobin, 1994). Of the world's total of vanadium, 83.3% comes from V-Ti-magnetite deposits; but of the total of the Western countries, only 73% is derived from these deposits.    

As of 1997, China had explored 109 vanadium deposits. The retained V2O5 reserves of the country total 26.161 million tons, of which 9.44 million tons (36.1% of the total) belong to category A+B+C. During the past 30-odd years, the country's retained reserve of vanadium ores have increased by nearly 2.5 times (see Table 3.6.1).

Table 3.6.1 China's retained vanadium reserves over the past years(¡Á106 t V2O5)

China's vanadium resources are estimated roughly at more than 200 million tons. In the Panzhihua-Xichang region there are 11.775 billion tons of predicted V-Ti-magnetite ore reserves (Fu Wenzhang, 1996). Four known deposits in the region contain a total of 29.43 million tons of V2O5 in the ores (calculated on the average grade of 0.25% V2O5). In the stone coal belt extending from southern Anhui, Zhejiang, southwestern Jiangxi, Hunan to northeastern Guangxi there are over 100 million tons of V2O5 (Wang Yongwen, 1988). In northwestern, northeastern and southwestern Hubei there are 16.0 billion tons of explored stone coal reserves (Liu Zhonghong, 1991) which contain as much as 80 million tons of V2O5 prospective reserve (calculated on the basis of half -0.5%- of the average V2O5 grade). Henan Province has 270 million tons of stone- coal prospective reserve (Zhang Wenxian, 1991), or 675,000 tons of V2O5 prospective reserve if calculated in terms of the grade of 0.25% V2O5. Therefore, even if the small volcanic vanadium deposits (totalling about hundreds of thousands of tons of V2O5 reserves) are excluded, the above-mentioned regions and belts have a total of over 200 million tons of V2O5 resources.   

Vanadium deposits of China are distributed in 20 provinces, municipalities or autonomous regions. The provinces or autonomous regions with over 1 million tons of V2O5 are: Sichuan (12.762 million tons), Hunan (3.668 million tons), Anhui (2.348 million tons), Guangxi (2.031 million tons), Hubei (1.729 million tons) and Gansu (1.259 million tons). They have a total of 23.797 million tons of V2O5, which is equivalent to 90.96% of the country's total.

The geographical locations, origins, sizes,grades and mining conditions of major deposits are listed in Table 3.6.2.

China's vanadium deposits are concentrated mainly at one "point" and along one "line". The "point" refers to the Panzhihua-Xichang region in Sichuan Province, in which the V2O5 reserves add up to 15.1251 million tons, accounting for 57.8% of the country's total. In origin, the deposits are mostly of magmatic V-Ti-magnetite deposits. The Panzhihua and Taihe iron deposits are under regular mining and the Hongge, Baima, Anning, Baicao and Zhonggangou iron deposits, all large or medium-sized, are not mined at present. Thus a large volume of vanadium resources is preserved. The "line" refers to Hunan, Sichuan, Hubei, Guizhou, Guangxi, Zhejiang, Anhui,Jiangxi and Guangdong in the southern part of the country, where a black sequence containing vanadium occurs. The vanadium deposits are

Table 3.6.2 China's major vanadium deposits

sedimentary ones in the lower Paleozoic black sequence. Comparatively large deposits include the Xinkaitang stone coal deposit in Hunan, the Dafeng vanadium deposit in Guangxi, the Yangjiabao vanadium deposit in Hubei and the Nijiangkou stone coal deposit in Hunan. Statistics of 12 known stone coal districts in provinces of southern China indicate that the V2O5 reserves in the black sequence amount to 7.4072 million tons, constituting 28.5% of the country's total. The vanadium in the sequence is mainly adsorbed on clay minerals (such as illite and hydromica) and carbonaceous substances, with a little occurring as independent minerals such as roscoelite and goldmanite.

Other deposits are sporadically distributed in Xinjiang, Gansu, Jilin, Shaanxi, Shanxi and Hebei.   

Relatively large vanadium deposits in other areas are: the Fangshankou V-P-U deposit (sedimentary) in Gansu, the Pingtaishan P-V deposit in Xinjiang, the Damiao V-Ti-magnetite deposit (magmatic) in Hebei, the Tadong iron deposit in Jilin, and the Aoshan iron deposit (volcanic) in Anhui, etc.   

In stone coal, the vanadium occurs principally in roscoelite, hydromica, biotite, muscovite and illite, with some in organic substances and such minerals as goldmanite.   

3.6.1.2 Characteristics of Resource   

Vanadium resources in China have the following characterisitcs:   

1) Widespread resources and relatively concentrated reserves.

Vanadium resources are widely distributed in 20 provinces, autonomous regions or municipalities and relatively amassed in Sichuan, Hunan, Anhui, Guangxi, Hubei and Gansu. Deposit types are chiefly magmatic (V-Ti-magnetite deposits) and sedimentary (deposits in black sequence).   

2) Low-grade ores and by-product vanadium. 

The vanadium is all recovered as a by-product and the ores are all low in grade. In the Panzhihua-Xichang region the grades range from 0.11%~0.44% vanadium, averaging 0.24% (Table 3.6.3); in the black sequence the highest grade is 4.79% and the lowest about 0.3%, averaging about 1%; and of the volcanic-type deposits the grades are generally about 0.20%. Over 92% of the vanadium reserves in China occur in coexisting or associated deposits and, thus, all the vanadium produced in the country is a by-product recovered from ores of other minerals.

Table 3.6.3 V2O5 contents (%) in ore and single mineral of V-Ti-magnetite deposits¡¡in the Panzhihua-Xichang region

Note: Figures in brackets are average contents.

3) Monotonous industrial type of deposit.

The majority of the vanadium deposits presently mined and used in China are genetically of magmatic and sedimentary types, a few of other genetic types, and no placer vanadium has so far been discovered. Besides occurring in black sequence, sedimentary vanadium may coexist with uranium and phosphorus in sandstones, mudstones and their metamorphic series.   

4) Deposits are generally large in size; large and medium-sized deposits are many.It can be seen from Table 3.6.2 that the reserves of 10 large deposits (each containing more than 1 million tons of V2O5) make up 46.7% of the total and those of the medium-sized deposits (each carrying 0.1~1 million tons of V2O5) constitute 47.66% of the total. The two add up to more than 94% of the total.   

5) Low-degree prospecting and small industrial reserves.The reserves obtained in the prospecting stage account for only 45.5% of the total, while those obtained in the stages of reconnaissance survey and detailed investigation amount to 54.5%. In addition, the industrial reserves form only 36.6% of the total.   

Main industrial types of vanadium deposits in China are the magmatic, the sedimentary and the volcanic (porphyrite).   

Magmatic-type vanadium deposits are geotectonically located in platform areas, geosynclinal fold belts, or at platform margins, exhibiting a zonal distribution and controlled by deep faults. They are genetically and spatially closely related to basic-ultrabasic rocks of all times, and occur in the Tianshan-Yinshan, the southern Shaanxi-western Hubei and the Sichuan-Yunnan metallogenic belt. For instance, magmatic vanadium deposits can be found in the Panzhihua-Xichang region of western Sichuan, the Hanzhong area of Shaanxi, and the Yunyang and Xiangyang areas of Hubei. The magmatic type includes two subtypes: the late-stage magmatic differentiation subtype and the late-stage magmatic injection subtype. Their typical deposits are distributed in the Panzhihua-Xichang region of Sichuan and the Chengde area of Hebei. In the former, deposits of the late-stage magmatic differentiation subtype occur in layered rock bodies of the gabro-troctolite-olivine gabro assemblage or the gabro-pyroxenite-peridotite assemblage. These deposits can also be subdivided into the gabro group (e.g. the Panzhihua and Taihe V-Ti-magnetite deposits), the gabro-troctolite-olivine gabro group (e.g. the Baima and Badong V-Ti-magnetite deposits), the gabro-pyroxenite-pyrolite group (e.g. the Hongge V-Ti-magnetite deposit), the gabro-norite group (e.g. the Bijigou and Wangjiangshan V-Ti-magnetite deposits in Shaanxi), and the diabase group (e.g. the Tiefosi-Taoyuan V-Ti-magnetite deposit). Deposits of the late-stage magmatic injection subtype, which are represented by the Damiao V-Ti-magnetite deposit in the Chengde area, occur at the contact between plagioclasite and gabro or in the fracture zone of plagioclasite.   

Sedimentary-type vanadium deposits are controlled by the stratigraphy and lithology of a certain horizon. In China, this type refers primarily to the vanadium deposits in black sequence. They are distributed commonly in the Sino-Korean platform and Yangtze platform, and on the two sides of the Qinling-Qilian geosynclinal fold system, less commonly in the Tarim platform and the South China fold system. Lithologically, they are controlled by Sinian-Early Cambrian, Silurian and Permian siliceous-carbonaceous rocks, allite (claystone) and phosphorite. Commercial sedimentary vanadium deposits presently discovered mostly occur in the so-called "Lower Cambrian black sequence" (i.e. the "stone coal" sensu lato) of the Yangtze platform and the Qinling-Qilian fold system. As for geographical distribution, except a few outcrops in Shaanxi, Shanxi and Henan, no vanadium deposits are present in northern China; most of them are, in fact, found in southern China, i.e. in Sichuan, Guizhou, Guangxi, Hunan, Hubei, Zhejiang, Anhui, Jiangxi and Guangdong, especially in the Zhejiang-southern Anhui-southwestern Jiangxi-Hunan-northwestern Guangxi belt that continuously extends for over 1,600 km. The black sequence consists of black carbonaceous shale, black carbonaceous, argillaceous and siliceous rocks, and black carbonaceous silicalite, and is characterized by a high content of organic carbon (generally 8%~12%). This sequence can be subdivided into the stone coal bed, the phosphorite bed, the vanadium ore bed, and the Ni-Mo-multielement-rich bed, which are collectively called the "stone coal". The V2O5 contents of these beds differ greatly from one another, generally ranging from 0.13~1.00%, and 60% of the ore-bearing beds have a V2O5 grade lower than 0.50%. The lithologic sequence of the vanadium ore bed consists, in ascending order, of the black carbonaceous silicalite, the black carbonaceous silty shale, the vanadium ore and the black carbonaceous shale, and can be divided, in terms of element assemblages, into the V-bearing, the V-Mo, the V-Ni, the V-Ga, the V-U, the V-Mo-U, the Ni-Mo-V and the V-Cd type.