Characteristics and status of manganese ore resources in China

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Resource status: As of the end of 1996, 213 manganese ore deposits had been identified on China’s mainland, with total reserves of 566 million tons of manganese ore. Of this amount, 40% corresponded to grades A+B+C, amounting to 227 million tons. Based on an average manganese content of 21% in the ore, the reserves of manganese metal amount to 119 million tons, of which 48 million tons are in grades A+B+C. According to the 1996 edition of the U.S. Bureau of Mines’ “Mineral Commodity Summaries,” the world’s manganese reserves amount to 680 million tons (in terms of manganese metal, the same applies hereafter), with a reserve base of 5 billion tons. South Africa ranks first among them, with a reserve base of 4 billion tons ； Next is Ukraine, with 520 million tons ； Gabon, 150 million tons ； Australia, 72 million tons ； Brazil, 56 million tons ； Georgia, 49 million tons ； India, 36 million tons. When comparing China’s A+B+C grade reserves with those abroad, China ranks after Georgia and before India, roughly in 6th place. Over the past 40 years, China’s manganese ore reserves have increased by nearly six times, rising from 94.37 million tons in 1955 to 566 million tons in 1996 (Table 3.3.6). According to the estimates of the Regional Planning Office of the Chinese Academy of Geological Sciences in 1987, the total amount of manganese ore resources in our country is 2.7 billion tons. It should be noted that the resources of manganese nodules on the world’s ocean floors are extremely abundant. It is estimated that the total manganese nodule resources in the entire ocean amount to about 3 trillion tons, of which approximately 1.7 trillion tons are found in the Pacific Ocean. Manganese nodules contain not only manganese but also abundant copper, cobalt, and nickel. The reserves of manganese, copper, cobalt, and nickel in ocean floor manganese nodules are dozens to thousands of times those in terrestrial deposits. China began investigating seafloor manganese nodules in the late 1970s. By the end of 1989, the Xiangyanghong 16 had conducted multiple voyages, collecting samples at 1,137 stations over an area of about 1.5 million square kilometers in the Pacific Ocean, for more than 2,000 times, and obtaining over 2 tons of polymetallic nodule samples. In 1989, upon approval by the **Mineral Reserves Administration, 301,000 km² of prospective areas were identified using criteria such as the average abundance and grade of minerals, as well as the slope of the seabed terrain. The region contains 1,672.72 million tons of dry ore, of which 15.05 million tons contain copper, 17.73 million tons contain nickel, 4.01 million tons contain cobalt, and 451.63 million tons contain manganese. On February 28, 1991, the 9th United Nations Seabed Committee, at the request of our country, reserved 150,000 km² of that area for China as a exploration zone, thereby granting our country the right to explore and exploit seabed manganese nodules. In May 1994, China’s vessel “Ocean 4” set sail once again for the Pacific Ocean to conduct surveys of manganese nodules, in order to further determine the geological reserves of nodules in the \"development area\" and provide assessments for identifying areas with high concentrations. Resource characteristics: Taking into account the types of manganese ores, their distribution, geological features, as well as the technical and economic conditions in China, the following characteristics can be identified: 1. Uneven distribution of manganese ore resources. Although manganese ores have been identified in 21 provinces, municipalities, and autonomous regions in China, they are mostly found in the southern regions, with Guangxi and Hunan being the most significant areas, accounting for 56% of the country’s total manganese ore reserves. As a result, the exploitation of manganese ore resources is concentrated in Guangxi and Hunan. 2. The scale of these deposits is mostly medium to small. Among China’s 213 manganese mining areas, only 7 are of large scale; the rest are medium or small-sized deposits. This makes it difficult to utilize modern industrial technologies for extraction. Over the years, more than 80% of the manganese output has come from local medium and small-scale mines as well as privately operated mines. 3. The quality of the ore is poor, with low-grade ores being the predominant type. Among China’s manganese ore reserves, those that are high in manganese content – namely manganese oxides with a manganese content of over 30% and manganese carbonates with a manganese content of over 25% – account for only 6.4%; furthermore, some of these high-manganese ores still require industrial processing before they can be utilized. Low-manganese ore reserves account for 93.6% of the country’s total reserves. Due to the low grade, high impurity content, and fine particle size of manganese ore, its technical processing properties are not satisfactory. 4. The mineralogical composition of these ores is complex. Ores with high phosphorus and high iron/manganese content, as well as manganese ores that contain associated metals and other impurities, account for a large proportion of China’s manganese reserves. For example, the Sinian-era \"Xiangtan-type\" manganese ores in the south have reserves of over 100 million tons, and these are considered to be high-phosphorus manganese ores that are difficult to utilize. 5. The ore structure is complex and the particle size is fine. Process mineralogical studies of some manganese ores from China’s main manganese-producing regions—Hunan, Guangxi, Guizhou, Fujian, and Yunnan—have shown that the vast majority of these manganese deposits consist of fine- or ultra-fine-grained grains, which increases the difficulty of separation. 6. Most deposits are of sedimentary or sedimentary metamorphic type, resulting in complex mining conditions. Nearly 80% of manganese deposits in China are of sedimentary or sedimentary metamorphic type; these deposits are widely distributed, with ore bodies that are layered and thin, have gentle slopes, and are deep underground, requiring underground mining methods whose technical requirements are high. The reserves suitable for open-pit mining account for only 6% of the country’s total reserves.