Changlongshan Iron Mine (Taochong Iron Mine) is located in Taochong Village, Diggang, Fanchang County. It is 7.5 kilometers away from Digang Wharf on the Yangtze River in the west and is connected by a road and a mining-specific railway line. It is 15 kilometers away from Fanchang in the southeast and is connected by a road to Fanchang Station of the Wuchang-Tong Railway Line.
The origin type of the deposit is a skarn-type high-temperature hydrothermal deposit. The geological structure is where the middle section of the northern wing of the Honghuashan fan-shaped anticline dips westward. The ore body is obviously controlled by fractured structures between the upper and lower wings of horizontal folds formed by edge bending. The deposit is interspersed with pre-mineralizing diorite porphyrite, microcrystalline diorite and syenite porphyry dykes. The main changes in the surrounding rocks near the ore are skarnization, epidotetization and carbonatization.
The ore bodies are distributed on three mountain ridges: Dashantou, Xiaoshantou and Jinshidun. The general trend is 80° to the northeast and is 1150 meters long intermittently. The surface ore bodies tilt to the south and the deep ore bodies to the north. pour. Its inclination is generally steep from the surface to 50 meters above sea level, tilting 60°-90° to the south. At an altitude of 50-200 meters, the ore body tilts gently to the north, with an angle of 15°-30°, and is strictly controlled by interlayer faults. The large and small Shantou ore bodies are larger in scale and are the main ore bodies of Taochong Iron Mine. They are 380 meters long on the surface, with an average thickness of 45 meters. The highest exposed altitude is 350 meters, the lowest extends to minus 200 meters, and the slope extends up to 800 meters. The ore body is produced near the contact zone between skarn and limestone, and can be divided into upper and lower layers according to its spatial position. The upper ore body is produced at the contact point between the top of the skarn and the limestone of the Qixia Formation; the lower ore body is produced in In the contact zone between the bottom of the skarn and the limestone of the Huanglong Formation, the ore body is sickle-shaped in profile - like a layer.
The natural types of ore bodies include: ① Metasomatic limestone iron ore, whose gangue minerals are mainly calcite and quartz. Among metallic minerals, the content of false hematite and specularite is high, while the content of magnetite is low; ② Metasomatic (skarn) type iron ore, its gangue minerals are mainly garnet, diopside, Calcite and quartz are the second largest, followed by calcite and quartz. Among metallic minerals, the content of magnetite is high, while the content of pseudohematite and specularite is low.
The main types of ore industry are:
1. Striped ore, metal minerals and gangue minerals are produced at intervals in strips, the strips are narrow and uniform in width, and have fluidity for metasomatism. Made of cleavage-structured limestone.
2. Massive ores, metallic minerals are in the form of sheets and closely embedded in radial shapes, while gangue minerals are embedded in the gaps between the crystals of metallic minerals, or occur in lumps and agglomerates of metallic minerals.
The ore material composition, the metallic minerals are hematite (accounting for 29.7%), mirrorite (accounting for 19.69%), magnetite (accounting for 11.79%), magnetite and siderite , limonite, a small amount of chalcopyrite. The gangue minerals include garnet, hexagonite, calcite, quartz, etc.
This deposit was discovered and mined earlier, and the exploration lasted longer.
After being discovered by Zhang of Hanyeping Company in 1911, the businessman raised 100,000 yuan to establish Yufan Company for mining. Soon after, it was plundered and mined by the Japanese imperialists, and 3.5 million tons of ore was mined. During this period, some Chinese and foreign geologists came to the mine to conduct geological surveys.
From 1931 to 1933, Xie Jiarong came to the mine to conduct geological surveys, filled in a 1:2000 geological map of the deposit, and included it in the book "Iron Ore Records of the Lower Yangtze River", with an estimated iron ore reserve of 464. Thousands of tons.
From 1940 to 1941, the Japanese Kamiyama Shoki filled in 1:2000 and 1:10,000 mineral deposits and regional topographic and geological maps in the mine, and constructed 12 boreholes, but the existing data is incomplete.
In 1952, Xu Keqin of Nanjing University and other students came to this area to fill in a 1:50,000 regional geological map of southern Anhui, and wrote the "Southern Anhui Regional Geological Report".
Since 1954, Maanshan Iron Works has established a Taochong geological exploration team to explore ore bodies above an altitude of 250 meters. By the end of the year, Jin Weikai and others organized and compiled the "Changlongshan Iron Mine Central Geological Report" . Proven iron ore reserves are 5.5 million tons.
In April 1955, the Nanjing Geological Exploration Company of the Ministry of Metallurgy undertook the exploration work of Taochong Iron Mine, and established the 803 Geological Exploration Team to continue the exploration of Taochong Iron Mine. At the end of 1956, under the chairmanship of Chen Xuan, Zhang Nianxuan and others prepared and submitted the "Changlongshan Iron Mine Central Geological Summary Report" and recalculated the iron ore reserves to 17.89 million tons.
In 1957, the Nanjing Geological Exploration Company of the Ministry of Metallurgy was changed to the East China Branch, and the exploration team was still Team 803. During the exploration process, the relevant personnel involved in the exploration of the deposit, because they could carefully conduct comprehensive geological and geophysical studies, broke the traditional view of ore control, and once proposed that "iron ore is mainly controlled by interlayer fractures (stripping), and its deep ore bodies have The possibility of extending as the rock formations turn from south to north.” At a reporting meeting, Chen Xuan, Zhang Nianxuan, Yu Zhongzhi and others elaborated on this view, which was supported by Engineer Wang Shuping and others from the Geological Bureau of the Ministry of Metallurgy who inspected the work at the time. Later, drilling confirmed that iron ore was found, confirming that deep The iron ore layer has indeed reversed to the north, giving the mine that was about to be discontinued a new lease of life.
In April 1960, under the chairmanship of Chen Xuan, Zhang Nianxuan and others compiled and submitted the "Detailed Geological Survey Report of Changlongshan Iron Mine". Due to changes in industrial indicators and insufficient hydrogeological work, the project was not approved. Afterwards, the ore body was re-delineated and hydrogeological work was carried out. In December 1963, the "Supplementary Report on Geological Exploration of Changlongshan Iron Mine" was submitted.
Iron ore reserves were recalculated to 28.4 million tons, and the Anhui Provincial Reserve Committee approved the report in 1965.
From 1984 to 1986, the Metallurgical Team No. 803 conducted detailed inspections of the edges and depths of the gold stone pier in the Changlongshan Iron Mine. In 1986, Zhang Siyu, Zhou Han and others prepared and submitted the "Supplementary Geological Work Report of Taochong Iron Mine", which added 2.33 million tons of iron ore reserves. The East China Metallurgical Geological Exploration Company approved the report in 1987. At this point, the Changlongshan (Taochong) iron ore exploration has basically ended.
The mine has experienced 30 years of intermittent geological exploration work, and has constructed 96 boreholes, with a drilling volume of 35,500 meters and 842 meters of pit exploration. The exploration investment is 4.416 million yuan, and the average exploration cost per ton of ore is 0.087 yuan. After recalculation by the production and mining department at the end of 1990, the cumulative proven iron ore reserves were 34.46 million tons, and the retained reserves were 23.64 million tons.
Changlongshan Iron Ore is a steeply inclined ore body, with the upper part above 310 meters suitable for open-pit mining, while the lower part requires pit mining.
The natural type of ore is mainly quartz-calcite type. The iron ore grade is rich. The average grade of all iron in the deposit is 45.31%. The harmful components are low. The magnetic and gravity separation methods are used. The raw ore grade is 33.05% and the concentrate grade is 33.05%. Grade 55.98%. The mineral processing recovery rate is 67.96%. The hydrogeological conditions of the mining area are moderate, with a maximum water inflow of 17,833 tons/day and night, which has no impact on mining above 90 meters.
Changlongshan Iron Mine is an old mine. Production resumed in 1954 and moved to underground mining in 1957. Designed by Maanshan Iron and Steel Design Institute in 1989, the mining scale has an annual output of 500,000 tons of ore. It is one of the important iron ore producing areas of Maanshan Iron and Steel Company and plays an important role in Anhui's steel production.