4.7.1.1 Resources and Reserves
Up to the end of 1997, 109 barite occurrences had been explored in China, with retained barite ore reserves of 366.55 million tons. They are widely distributed in 21 provinces (regions and municipalities), of which Fujian, Shandong, Hunan, Guangxi, Guizhou, Shaanxi and Gansu have retained reserves greater than 10 million tons. According to the Mineral Commodity Summaries 1997, the world's barite reserve base was 480 million tons of barite. China's categories A+B+C barite ore reserves in 1997 were 65.23 million tons (amounting to about 32 to 40 million tons of barite). In comparison with the barite reserves bases of va-rious countries, China ranked first in the world, while the United States and India ranked second and third respectively.

4.7.1.2 Characteristics of Resources

China's barite deposits are distributed in 21 provinces (regions and municipalities). Guizhou has the largest reserves, accounting for 34.2% of the total; next are Hunan (15.2%) and Guangxi (10.6%). The reserves of the above-mentioned three provinces (region) plus the reserves of Gansu, Fujian, Shandong and Fujian total 90.7% of the national total reserves. The high-grade deposits (with a BaSO4 grade £¾ 92.5%) are concentrated in Guizhou and Guangxi. Geographically, most reserves are distributed in central China, taking up about 70% (Fig. 4.7.1).

Characteristics of barite deposits of China included:

1) Barite deposits of China occur in all geologic ages, mainly in Cambrian, Devonian, Ordovician and Mesozoic strata. Bedded barite deposits are concentrated mainly in the Cambrian and less commonly in the Devonian, occurring in tectonically active fold belts (regions) and deep-water basins of platforms. Vein deposits are mostly hosted in the Devonian, Ordo-vician and Triassic, mainly occurring in carbonate platforms where geological structure is relatively stable.

2) In terms of reserves, China's barite resources are mainly distributed in central China; in terms of grade, almost all high-grade deposits are concentrated in Guizhou and Guang-xi; the deposits are dominated by large and medium-sized ones, and only the Dazhubian deposit, Tianzhu, Guizhou, and the Gongxi deposit, Xinhuang, Hunan, contribute more than half of the reserves of large and medium-sized deposits of China.

3) China's major superlarge and large barite deposits usually consist solely of barite-type ores, belonging to bedded barite deposits. The ores have relatively simple mineral and chemical compositions and are of pure quality. For example, the orebodies of the Gongxi barite deposit, Xinhuang, Hunan, generally occur as beds varying in length from a few dozens of meters to a few dozens of kilometers and in thickness from 0.3 to 7 m, commonly from 1 to 2 m. Ore is composed dominantly of barite and calcite with the barite content in the range of 55% to 99%.

4) Many deposits in China produce barite as a by-product. For example, dressing tests have been carried out on barite in iron ore from the Jingtieshan iron deposit, Sunan County, Gansu Province, by the Gansu Jiuquan Iron and Steel Co. and other enterprises, and the total use of the ore has been studied.