4.11.1.1Resources and Reserves

By the end of 1997, China explored 400 phosphate occurrences, with 13.326 billion tons of retained reserves of phosphate rock, of which categories A+B+C reserves were 6.693 billion tons and category D reserves were 6.633 billion tons and the high-grade phosphate rock with a P₂O₅ content of 30% contributes 1.135 billion tons and low-grade phosphate rock with P₂O₅ <12% contributes 2.307 billion tons. In addition, there are 7 occurrences where phosphate is associated with other useful minerals, with reserves of 8.38 million tons P₂O₅. According to the Mineral Commodity Summaries, 1999, the world's phosphate rock reserves were 12 billion tons with a reserve base of 35 billion tons. If we compare China's categories A+B+C phosphate rock reserves with the reserve bases of other countries in the world (the average grade of China's phosphate rock is 18.45% P₂O₅ and that of the world's phosphate rock is over 30% P₂O₅), China's phosphate reserves rank third in the world, following Morocco and the United States.

4.11.1.2Characteristics of Resources

(1) Geographical distribution

Phosphate deposits of China are widely distributed in 27 provinces (regions and municipalities), relatively concentrated in Yunnan, Guizhou, Sichuan, Hubei and Hunan provin-ces. The retained phosphate reserves of the 5 provinces total 9.915 billion tons, accounting for 74.40% of the total retained phosphate reserves of China, and rich deposits with P₂O₅ >30% are almost all concentrated in the 5 provinces. The distribution of China's phosphate occurrences is shown in Fig. 4.11.1.

Among the administrative megaregions (above the provincial level), the foremost source for phosphate at the present time is the Southwest Megaregion (including Yunnan, Guizhou and Sichuan), where there are 124 phosphate occurrences and 6.318 billion tons of retained reserves, accounting for 47.42% of China's total reserves, of which 982 million tons are retained reserves of high-grade phosphate rock with P₂O₅ >30%, making up 86.52% of China's total reserves of high-grade phosphate rock; the south-central Megaregion (including Hubei, Hunan, Guangxi, Guangdong and Henan) is second with 145 phosphate occurrences and 3.659 billion tons of retained reserves, accounting for 27.46% of the total national reserves, of which only 152 million tons are retained reserves of high-grade phosphate rock with P2O5 >30%; the third is the North China Megaregion, followed successively by the East China, Northwest China and Northeast China megaregions.

In the order of phosphate reserves of various provinces, Yunnan Province ranks first, where there are 42 phosphate occurrences and 2.884 billion tons of retained reserves, accounting for 21.64% of the national total, of which 394 million tons are contributed by high-grade phosphate rock with P₂O₅ >30%. Guizhou Province is second with 51 phosphate occurrences and 2.574 billion tons of retained reserves, taking up 19.32% of the national total. This province not only has large phosphate reserves, but the phosphate rock is also relatively good in quality: the reserves of the high-grade phosphate rock with P₂O₅> 30% are 486 million tons, accounting for 42.82% of the reserves of high-grade phosphate rock in China. Hubei Province ranks third, with 1.866 billion tons of retained reserves, accounting for 14.00% of the country's total, and 130 million tons of retained reserves of high-grade phosphate rock with P₂O₅ >30%, making up 11.45% of the national total. Hunan Province is fourth with 1.731 billion tons of retained reserves of phosphate resources, accounting for 12.99% of the national total, but the quality of the phosphate rock is poor. Sichuan Province ranks fifth, with 860 million tons of retained reserves, accounting for 6.45% of the national total, of which the reserves of high-grade phosphate rock are 103 million tons. Apart from the above-mentioned 5 provinces, the remaining 25.60% reserves are scattered in 21 provinces and regions such as Shandong, Shaanxi, Qinghai and Shanxi.

(2) Characteristics of resources

     1) Abundant phosphate resources but too concentrated distribution

     Phosphate is one of China's dominant mineral resources with very large resource and reserve potential. However, the distribution of phosphate resoruces in China is very uneven. 74.40% of retained reserves are concentrated in Yunnan, Guizhou and Sichuan provinces in Southwest China and Hubei and Hunan provinces in South-central China. Except for Sichuan Province where phosphate production can supply most of its demand, phosphate needed in most regions of China relies on the supply by Yunnan, Guizhou and Hubei, thus resulting in the situation that "phosphate in the south and west is transported to the north and east". This situation has had much influence on transportation, material supply of phosphate fertilizer and costs of products.

     2) Less high-grade phosphate rock and more low-grade phosphate rock

     The presence of abundant phosphate resources is a strong point of China but the pre-sence of less high-grade phosphate rock and more low-grade phosphate rock is a weak point. The retained reserves of high-grade phosphate rock with P₂O₅ >30% in China are only 1.135 billion tons, accounting for 8.51% of the total explored reserves. The average P₂O₅ grade of China's phosphate rock is only 18.45% and the reserves of the phosphate rock with P₂O₅ <18% take up about half of the total reserves.

     3) More refractory phosphate rock and less easily dressed phosphate rock

     Phosphorite reserves make up 85% of China's retained phosphate reserves and most of the phosphorite is medium- and low-grade. Some high-grade phosphorite can be directly used as material for the production of high-efficiency phosphate fertilizer, but most of it can be industrially used only through dressing. Low-grade phosphorite generally has relatively high contents of harmful impurities and the phosphorite grains are fine and closely interlocked; so dressing is difficult.

     4) More thin to moderately thick, inclined to gently inclined phosphate beds that are difficult to mine and less phosphate bodies that are suitable for large-scale, high-intensity mining

     Most of China's phosphate deposits are very old in age and strongly lithified and the phosphate rock is densely cemented; moreover, over 75% of the phosphate beds are inclined to gently inclined and thin to moderately thick. Such occurrence characteristics bring a series of technical problems in high-intensity mining and usually cause a heavy loss, a high dilution rate and a low recovery of phosphate.