The mining area is located in the northern margin of Ningwu Mesozoic volcanic fault basin and the northwest side of Fangshan Yang Xiaodan fault zone. The strata in the mining area are Triassic Zhou Chong Village Formation, HuangMa Qing Formation, Fanjiatang Formation, Jurassic Xiangshan Formation and Tertiary Chishan Formation. The mining area is a semi-dome anticline structure inclined to the southwest, and its core is pyroxene diorite porphyrite. Ore bodies occur in the inner and outer zones of the contact zone between intrusive rocks and surrounding rocks. There are five ore bodies, namely Phoenix Mountain (including Xiaozhang Mountain in Li Lishan), Biandan Mountain, Niu Shan and Sun Xiangshan, with Phoenix Mountain as the main one. The ore body is layered with irregular veins. The main ore body is 2700 meters long, with the maximum inclined extension of 1.050 meters and the false thickness of 2-1.654,38+00 meters, with an average of 28 meters. The mineral composition is mainly hematite, pseudohematite and magnetite, followed by specularite, limonite, pyrite and chalcopyrite. The ore is in granular texture and mosaic texture, dense block, loose, banded, primary breccia and secondary breccia structure, with primary breccia structure as the main structure. The ore is of medium quality. Generally, the grade of rich ore is 49.45%, the grade of lean ore is 34.52%, and the average total iron is 43.77%, sulfur is 0.2 14%, phosphorus is 0.475%, and vanadium pentoxide is 0.26%. The genetic type of the deposit belongs to volcanic hydrothermal deposit.
Fenghuangshan Iron Mine is an old mine discovered at the beginning of this century. Therefore, there are many Chinese and foreign people who have investigated and studied the mine, but there are few legacy materials.
According to the China Iron Mine Records (Dinggelan 19 14, Sweden), employees of Hanyeping Company went to the mine in the late Qing Dynasty (1904) and the results were "beautiful", so Chen Qi was involved in the Ministry of Agriculture and Commerce at that time.
19 14, Governor Feng of Jiangsu asked the Ministry of Agriculture and Commerce to send a specialist to investigate the mine in detail. Chang Gelan was hired as a consultant, so he came to 10 to investigate the mine and build a shallow trough. It is estimated that the ore content of the mine is 40 million tons.
From 65438 to 0920, the Jiangsu provincial government ordered Zhang Yiou, director of industry, to discuss the details of the plan. 192 1 year, with 20 shallow ditches and 3 horizontal lanes. Liu and Zhao Rujun are in charge of this work, and Swede Anderson is the consultant. They think that there are two kinds of ores, soft and hard, and it is estimated that the amount of ore above the ground nearby is 4.3 million tons.
193 1 year, Xie, Sun Jianchu, Chen Kai and Cheng inspected the mining area, and thought that the ore body "seems to extend downward along the horizon, or may reach near the horizon, but the thickness should be slightly reduced." ..... For the sake of prudence, only the above 2 million tons are considered as reliable quantities ". This time, no engineering exploration was done, but only sampling and testing, and the results were compiled into the Iron Mine Records in the Lower Yangtze River (Geological Special Report 13).
Period 1936, Zhu Tinghu, Yuan Jianqi, etc. I went to the mining area to investigate the geology of Nanjing and Jiangning County, mainly to collect rock samples and study the genesis of the deposit. They believe that the deposit is a "medium-low temperature hydrothermal deposit". He is the author of the Geological Report of Jiangning County in Nanjing, which was not published by the Geology Department of Central University until 1948. Previously, Yuan Jianqi published the article "Geological Genesis of Fenghuangshan Iron Mine in Nanjing Suburb" in the 3rd issue of Volume 3 of Geological Review, which was published in 1938. Zhu Tinghu, Yuan Jianqi and others estimate that the iron ore in Fenghuangshan is 2.4 million tons.
During his stay in War of Resistance against Japanese Aggression, Japanese Song Tian Kamesao, Yasuo Toda, Hideo Tozhong, Gai Na and Tsuji all visited the mining area. Among them, Dong Zhong Xiuxiong, the squad leader of Class 20 of Mining Branch of Central China Federation of Investigation Organs and a natural science researcher in Shanghai, conducted geophysical and magnetic surveys in 1940 mining area, and wrote two survey reports and 1: 2000- 1: 5000 magnetic isoline. After work, no magnetic anomalies were found in the main ore body of Fenghuangshan Iron Mine, but magnetic anomalies were found in the south of Sunward Mountain, the middle and southwest of the western slope of Niu Shan, the middle of the northern slope of Biandan Mountain and the northern flat of Zhang Xiaoshan. The investigation work of other Japanese is ridiculous.
From August 1955 to February 1956, the pre-investigation team of East China Branch of Geology Bureau of Ministry of Metallurgy sent Wu Zujie and Chen Sisong to the mining area to carry out trench exploration and geological investigation on the main ore body of Fenghuangshan Iron Mine, in which the trench 1 183 cubic meters was explored and the geological exploration report of Fenghuangshan Iron Mine in Jiangning County, Jiangsu Province was submitted.
1March, 956, Lin, head of geological technology of Team 807 of East China Geological Bureau of Ministry of Metallurgy, presided over the deep exploration of the main ore body according to the exploration design submitted by the above-mentioned pre-exploration team. Core drilling is 2554 1 m, shallow hole drilling is 586m, hydrological drilling is 853m, exploratory trench12704m3 and exploratory well is 286m. The final report of geological exploration of Fenghuangshan Iron Mine was submitted in September, 1959. The available ore reserves are 31620,000 tons and the prospective reserves are 51500,000 tons. 1960 In February, Jiangsu Provincial Mineral Reserves Committee approved available reserves of 29.28 million tons and prospective reserves of 6.27 million tons. The related vanadium pentoxide reserve submitted was 22,300 tons, but it was not approved because the occurrence state was not identified.
During the exploration, geologists such as Lin and Yan Caien found that the main ore body of Fenghuangshan Iron Mine is connected with Xiaozhangshan ore body in the north and the ore body in the southwest in the deep underground. After deep drilling, Biandanshan ore body and Niu Shan ore body were discovered. In addition, a rich ore containing breccia ore was found on the unconformity surface between the red bed and the rock mass of Chishan Formation, and its occurrence changed with the ups and downs of the ancient erosion surface of the rock mass, indicating that Fenghuangshan Iron Mine is located in Chishan.
Fenghuangshan Iron Mine was officially mined by Fenghuangshan Office of Japan Huazhong Mining Co., Ltd. in 1940 and 65438+February. At the altitudes of 2 1 m and 49 m, the total length of the vein-passing and vein-passing tunnel is nearly 1 km, which is used for prospecting and mining. By 1945, * * had mined about 950,000 tons of ore, all of which were shipped to Japan. 1In April, 1957, Shandong Mining and Metallurgy Office submitted the preliminary design description of the new construction project of Fenghuangshan Iron Mine according to the interim report of geological exploration submitted by Team 807 at the end of 1956, and carried out the mine capital construction. In July of the same year, the mine was officially produced. 1958 Since April, open-pit mining has been extended to other ore blocks. The mines in Biandan Mountain, Niu Shan Mountain and Sunward Mountain were mined in the third quarter of that year, Xiaozhangshan in the fourth quarter and Li Lishan in the first quarter 1959. 1973 underground mining started in Fenghuangshan iron mine. 1977 ended the open-pit mining in May, and completely turned to underground mining.
During the 28 years from1July 1957 to1June 1985, the raw ore of Fenghuangshan Iron Mine was 109 1 10,000 tons, which made great contributions to the development of the national iron and steel industry. The location of the mining area has changed from the countryside to a mining town with mines as the main body. Since 1986, due to various reasons, the economic benefit of this mine is not good, and it was handed over to Moling Iron Mine (township mine) in Jiangning County for mining in April of 1992.