2.7. Others

This includes mainly two deposits: the Bayan Obo and Shilu in Inner Mongolia and Hainan, respectively.

The Bayan Obo deposit is a world famous super-large iron-niobium-rare earth deposit with extremely rich minerals and elemental assemblages. However, due to the complexity of the iron deposit, there is no unified view on the origin of this deposit. Most believe that the formation and original deposition of iron ore associated with later hydrothermal fluid alteration, which means the iron ore was enriched by alteration on the primary ores. The mineral composition of the Bayan Obo mine is extremely complex. A total of 71 elements have been discovered and the mineral species have reached more than 170 species. There are five major ore bodies, with the iron deposits mainly occurring in the 8th member of the Bayan Obo Group. Proven reserves reach 1.6 billion tons [7–10].

Shilu iron deposit in Hainan Province was hailed as "Asia's largest iron ore rich", and ore mineral is mainly hematite, associated with cobalt, copper and nickel. At present, there is no unified understanding of the ore-forming mechanism of Shilu iron ore deposit. Some argued that formation of Shilu iron ore is mainly due to multiple remodeling and enrichment that is, the formation of iron ore deposits is affected by "volcano-sedimentary metamorphism + structural transformation + hydrothermal". A total of 38 iron ore bodies have been found, most of which are yielded in the 6th layer of Shilu Group. The proven iron ore reserve has exceeded 450 million tons and the grade is high (the average grade of iron ore is 51%) [11, 14, 15].

#### 2.8. Comparison of major iron ore deposits from domestic and abroad

Iron ore resources are distributed in a few countries and regions with high concentration. 75.6% of the world's iron ore reserves are distributed in Russia, Ukraine, Australia, Brazil, Kazakhstan and China. In general, there are more iron-rich mines in the southern hemisphere and less in the northern hemisphere [12]. Among the top 100 iron ore production projects in the world [13], 76 are related to BIF and the output of these 76 BIF-related iron ore projects also accounts for 87% of the world's iron ore production (Figure 1). The giant iron deposits in China are all BIF type and were yielded in craton. The largest one hosted about 4 billion tons of iron and was formed in Middle Archeozoic. However, it was low grade, whereas to the giant iron deposits abroad, they are various from skarn-related type, Kiruna type or magmatic type for the metallogeny. Besides, they are not restricted to Precambrian. For the tectonic background, they could develop on craton, as well as on active continental margin.

sedimentary metamorphism type, accounting for 54% of the total number; followed by magmatic type, accounting for 17%; and the contact metasomatism-hydrothermal iron deposits are dominated by small and medium-sized, while the large ones accounting for only 13%; weath-

Figure 2. The proportion of different types of iron ore for metallogeny (A) and the proportion of large ones of all six iron

Figure 1. World's top 100 iron ore production projects with different metallogeny and the global proportion of iron ore

The Chinese Iron Ore Deposits and Ore Production http://dx.doi.org/10.5772/intechopen.76729 7

China's iron ore sources are mainly three parts, the first part from the domestic ore, the second part from the overseas rights and interests of ore and the third part from overseas imports of ore. From 2011 to 2015, the proven reserves of iron ore continued to increase. In 2015, the reserves of iron ore reached 20.76 billion tons (note: different from the US Geological Survey

ered leaching type do not yield large iron ore deposits (Figure 2).

3. Iron ore supply and demand in China

production of various types.

ore deposit types (B) in China [4].

Among more than 2000 iron ore deposits identified, the contact metasomatic-hydrothermal iron deposits account for 39% of the total iron ore deposits, followed by sedimentary metamorphism (28%) and sedimentary (20%), weathered leaching (7%), volcanic (3%) and magmatic (3%) iron ore are in small numbers. However, most of the large iron deposits are characterized by

Figure 1. World's top 100 iron ore production projects with different metallogeny and the global proportion of iron ore production of various types.

Figure 2. The proportion of different types of iron ore for metallogeny (A) and the proportion of large ones of all six iron ore deposit types (B) in China [4].

sedimentary metamorphism type, accounting for 54% of the total number; followed by magmatic type, accounting for 17%; and the contact metasomatism-hydrothermal iron deposits are dominated by small and medium-sized, while the large ones accounting for only 13%; weathered leaching type do not yield large iron ore deposits (Figure 2).
