At present, only Zhou (Ji)-Chang (Ji) Highway (National Road 105) passes through the mining area, crossing the Huaihe River to Fuyang in the north and connecting Huoqiu and Lu 'an in the south. There are boats sailing on the Huaihe River in the north, which can go downstream to Huainan and Bengbu.
The geological structure of Huoqiu Iron Mine is located in the western margin plain of Hefei Depression. Sinian, Cambrian and Ordovician strata are exposed in Silichangshan Mountain at the junction of Anhui and Henan in the west of the mining area, and the rest are widely covered by Quaternary (40-200m thick). It has been proved by exploration that the iron ore body is produced in the Neoarchean ancient metamorphic rock series, which is a deposit formed by regional metamorphism caused by iron-siliceous sedimentary construction, commonly known as "Anshan-style" iron ore, including magnetite and specularite. Magnetite is mainly produced in schist and gneiss strata; Specularite (or mixed type) mainly occurs in schist, dolomite and marble strata. Its protolith formation is equivalent to fine claystone-claystone-iron silicalite-carbonate rock, representing a transgression sedimentary cycle. The sedimentary environment, according to the original rock formation and the characteristics of ore beds, belongs to shallow sea facies deposition, and iron and silicon are precipitated by colloid. Ore-forming materials mainly come from ancient land, and may also be indirectly related to submarine volcanic activity. See table 3- 1 for ore body scale and basic characteristics.
Table 3- 1
Material composition of ore: magnetite is the main magnetite, followed by a small amount of hematite, ilmenite, magnetite and siderite. Gangue minerals are mainly chronological (a few minerals in Lilaozhuang deposit are magnesite, serpentine and dolomite), followed by amphibole, amphibole, tremolite, biotite and garnet, and some minerals are actinolite, diopside and a few muscovite, chlorite, glaucophane and amphibole. The specularite is mainly specularite and magnetite, which can be interchanged with each other and produced singly or mixed, followed by a small amount of hematite and siderite; Gangue minerals are mainly chronological, followed by a small amount of biotite, actinolite, hornblende and tremolite, and sometimes diopside, chlorite, glaucophane and muscovite. The ore contains a small amount of sulfide, pyrite is common and generally distributed, and chalcopyrite and pyrrhotite are occasionally seen. The oxidation zone is mainly pseudohematite and semi-pseudohematite, accompanied by secondary oxidation, and a small amount of hematite and limonite.
See Table 3-2 for the average content of main chemical components of ore.
The content of associated beneficial elements in ore is very low, which has no industrial significance. In addition to sulfur and phosphorus, the content of other elements in harmful impurities is also very low, which belongs to low sulfur and low phosphorus iron ore.
The process of discovery and exploration of Huoqiu Iron Mine is to find the iron ore through the aeromagnetic anomaly zone, large-scale magnetic survey on the ground, delineating the anomaly range, finding out the anomaly distribution position, analyzing the anomaly characteristics, and then through drilling verification. The whole process embodies the painstaking efforts and wisdom of the vast number of geological prospecting team members and is the result of collective efforts.
1957, when the North China 904 Aerial Survey Team of the Ministry of Geology conducted 1 ∶ 1 10,000 aeromagnetic surveys, explored oil storage structures and looked for oil in this area, a nearly north-south magnetic anomaly zone was found in the west of Huoqiu County, numbered C-57- 102. The maximum abnormal value is 620 NAT, and the gradient changes greatly. The anomaly range is delineated by the 200 NAT isoline, which is about 40 kilometers long and 4-5 kilometers wide, starting from Madian in the south and reaching Huaihe River in the north, with a total area of about 200 square kilometers. It can be inferred that the anomaly is caused by the long and narrow linear extension of basic intrusions or iron-bearing igneous intrusions, and it is likely to occur in the north-south fault zone.
Table 3-2 Average Content of Main Chemical Components in Ore
During the period of 1959, the provincial geological bureau thought that the abnormal zone was located in the west of Hefei depression, and the basement might be an ancient metamorphic rock series, which had the premise of searching for "Anshan-style" sedimentary metamorphic iron ore and good metallogenic geological conditions. Therefore, the Geophysical Exploration Brigade of the Provincial Geological Bureau 103 was instructed to carry out the ground magnetic survey of C-57- 102 aeromagnetic anomalies, with the scale of1:50,000-1:25,000 and the working area of 6 14 square kilometers, of which/kloc-. After the work, 12 local high magnetic anomalies and some low-slow magnetic anomalies in Zhou Ji, Zhangzhuang, Lilaozhuang, Fanqiao, Da Tangtou, Caolou, Dengxian Primary School, Zhouyoufang, Li Lou, Li Gui Zhuang, Wuji and Renji were circled. (Later exploration proved that Fanqiao-Da Tangtou, Dengxian Primary School-Zhouyoufang and Lilaozhuang-Wuji anomalies belong to Fanqiao, Zhouyoufang and Wuji anomalies respectively, so they are actually nine local high magnetic anomalies. The long axis direction of these abnormal isolines is basically the same as that of aeromagnetic anomalies, except that Li Laozhuang and Fanqiao are nearly east-west, and they are nearly north-south banded. The maximum anomaly is above 1 1000 NAT (Zhangzhuang, Wuji), the minimum anomaly is 1200-2 100 NAT (Fanqiao, Li Laozhuang), and the rest anomalies are 3370-5600 NAT. Through surface magnetic survey, the distribution position, scope and characteristics of magnetic anomalies are further found out, and it is speculated that the possibility caused by "Anshan-style" sedimentary metamorphic iron ore is great. The research results provide sufficient data basis for finding iron ore.
1959 in the second half of the year, most of the geological technicians of the provincial geological bureau, mainly Yan Kunyuan, the chief engineer of the bureau, agreed and supported the verification of magnetic anomalies in order to understand the nature of the anomalies. At that time, Geological Team 337 of the Provincial Geological Bureau (1958 was established, 1962 was revoked, and 1966 was resumed) worked in western Anhui. After 1990, it was cancelled and merged into Team 3 13 of the Provincial Bureau of Geology and Mineral Resources. According to the decision of the Provincial Bureau of Geology and Mineral Resources, team leader Su Bo, technical director Huang and geological technicians Yin, Hong Kan and Wang organized the construction team to go to Huoqiu. According to the local anomalies delineated by surface magnetic method, they first selected the better Zhangzhuang high magnetic anomaly for drilling verification, and saw two layers of iron ore at the hole depth 14 1 m, with the maximum false thickness 180 m, thus finding out that the magnetic anomaly was indeed caused by sedimentary metamorphic magnetite. After Zhangzhuang abnormal prospecting, Team 337 set up Huoqiu Iron Mine Task Force, and Li presided over the technical work. In order to understand the properties of other major magnetic anomalies, 1 month 1960 drilling verified Zhou Ji and Wuji anomalies, and also saw the same type of iron ore bodies. 1960 In the second half of the year, in order to strengthen iron ore exploration, the Provincial Bureau of Geology transferred Chen Kexing from the Bureau of Geology and Mineral Resources to Team 337 as the technical director. After analyzing and studying the three verified abnormal occurrences, the technicians of Chenhe detachment first decided to make a general survey and evaluation of Zhangzhuang anomaly, and control the middle section of the deposit with a 400× 200m grid, and the occurrence was good. By 1962, due to the contraction of the national industrial front, Team 337 was cancelled, the magnetic anomaly verification of Huoqiu Iron Mine was suspended, and the general survey of Zhangzhuang Iron Mine was stopped. 1962 In the first half of the year, Li and Liang Shanrong compiled the geological report of phase survey and obtained 64.94 million tons of iron ore reserves. According to the control data and the analysis of abnormal distribution characteristics, further work can increase the reserves and the scale of the deposit can reach a larger scale.
1966 in the second half of the year, the provincial geological bureau re-established the 337 geological team to station in this area, and continued to verify magnetic anomalies and explore iron ore in Huoqiu area. Captain Su Bo, technical director and main geological technicians Li and Pan made specific arrangements for the iron ore geological work in this area. While making a general survey and evaluation of the Wuji and Zhou Ji anomalies that have been verified for prospecting, other anomalies were drilled and verified one by one to find out the nature of the anomalies. From 1966, 1 1 to 1969, the magnetic anomalies of Caolou, Lilaozhuang, Zhouyoufang, Li Lou and Fanqiao have been verified successively, and the same type of iron ore bodies have also been seen.
It is worth mentioning that the Bayi No.10 Team of East China Metallurgical Exploration Company discovered iron ore bodies when verifying the reorganization anomaly during drilling in May 1966, and exposed the Wuji anomaly through drilling holes, and carried out gravity survey in Wuji and its south area (the purpose was to find rich ore, but no rich ore was found after the work, and it was evacuated in the same year). The results of its work provide a certain data basis for the future exploration work of Team 337.
Through the verification of the above-mentioned magnetic anomaly data and the preliminary evaluation of the anomalies in Zhangzhuang, Zhou Ji and Wuji mines (the latter two deposits are only controlled in the middle of the anomaly, and their scale has reached large deposits), combined with the comprehensive analysis of the distribution characteristics of various magnetic anomalies, the Provincial Geological Bureau and its subordinate 337 team unanimously believe that Huoqiu magnetic anomaly zone is a prospective area with rich iron ore reserves, thus affirming Huoqiu iron mine and listing it as one of the important bases for iron ore exploration in Anhui Province.
After the verification of magnetic anomalies, the focus of work is to evaluate the industrial value of ore anomalies. Therefore, a large number of exploration and evaluation work of Huoqiu Iron Mine began in 1970s. During this period, 8 deposits were explored successively (i.e. exploration in Zhangzhuang and Lilaozhuang and general survey in Zhou Ji, Zhouyoufang, Caolou, Jiji, Wuji and Fanqiao), and 6 deposits were evaluated. In 1980s, based on the general survey, only Fanqiao and Wuji were investigated in detail, and the newly developed northern section of Li Lou deposit was also investigated. After 20 years of exploration and evaluation, rich geological achievements have been made, and the industrial value of each deposit has been affirmed. The exploration and evaluation of each deposit are as follows:
The exploration of Zhangzhuang Iron Mine (1970- 1974) has a drilling workload of 24,300m, and the geological report was compiled and submitted by Li, Li, Hu Zufu and Ma Yu 1974 (some work needs to be supplemented after being audited by the Provincial Reserve Committee). 1979- 1980 for supplementary exploration, with a drilling workload of 6,208 meters. 198 1 Submit supplementary work instructions to verify iron ore reserves1990,000 tons.
The initial exploration of Lilaozhuang iron mine and magnesite (1971-1975) has a drilling workload of 32,600 meters, which was compiled and submitted by Li, Li, Li, Li, Ma Yu 198 1 year. The proven iron ore reserves are 43,579,300 tons and the symbiotic magnesite reserves are 3,328,900 tons.
The general survey of iron ore in Zhou Ji (1967— 1970) has a drilling workload of 29,000m, and the geological survey report was compiled and submitted by Dong Peinan, Li, Ye Mingfu and Yu 1979. The proven iron ore reserves are 654.38+37 million tons.
Reconnaissance of HeXie Iron Mine (1974- 1980), drilling workload is 25,900 meters, and the geological survey report was compiled and submitted by Wang Yingchun, Xu Mingde and Ma Cheng qin in 1980. The proven iron ore reserves are 6.581.94 million tons.
The general survey of Zhouyoufang Iron Mine (1975-1977) has a drilling workload of 15900 m, and the geological survey report was completed and submitted by Wang Yuxiang, Wang Zhihua, Du Jingshan and Yu Changming in 1978. The proven iron ore reserves are 95,499,400 tons. After the report is submitted, a section will be built at the southern end, with an increase of 654.38+0.52477 million tons, bringing the total proven iron ore reserves to 654.38+0.65438+0 million tons.
According to the general survey of Caolou Iron Mine (1976- 1978), the drilling workload was 10600 m, and the geological survey report was completed and submitted by Wang Yuxiang and Wang Zhihua in 1979. The proven iron ore reserves are 4.8 million1.58 million tons.
General survey-detailed survey of Fanqiao Iron Mine (1978- 1983), drilling workload 15600 m, and detailed geological report was compiled and submitted by, Yong and Tu 1983. The proven iron ore reserves are 48.3427 million tons.
General Survey-Detailed Survey of Wuji Iron Mine (1977- 1985), with a drilling workload of 53,400 meters. The geological report of detailed survey was compiled and submitted by Zhou Lunyi, Xu Mingde, Cai Zhiyong and Zhong Nianlu in 1983 (Wang Yingchun and Wang Wenxin presided over the general survey for some time). The proven iron ore reserves are 248 million tons.
The general survey of the northern section of Li Lou Iron Mine (1980 ——1988) drilling workload10200m, and the geological report of the general survey of the northern section of the deposit was compiled and submitted by Wang Yuxiang and Gan Shengdong. The proven iron ore reserves are 654.38+0.36 billion tons (the southern section of the deposit has been controlled by a few projects, but the ore bodies along the strike are still not controlled, and its reserves are estimated to be above 654.38+0.5 billion tons).
The geological report submitted by the above exploration work has been reviewed and approved by the relevant competent department at a higher level. The accumulated proven iron ore reserves are 65.438+0.04 billion tons, which is an important large-scale iron ore in Anhui Province and one of the important iron ore resource bases in East China and even the whole country.
In the exploration of Huoqiu Iron Mine, Yin Zhicheng, Li Xinxiu, Wang Ziqing and Ma Chengqing successively served as the main leaders of the brigade, and Li served as the technical director of the brigade. The main geological technicians engaged in technical business management are Pan, Bu Bingkun, Zhao Dashun, Ma and Qian Peiming, and the main hydrological and engineering geological technicians are Zheng Wenxing, Kuang,. They all contributed to the exploration and evaluation of iron ore.
When geological exploration is carried out in concealed areas, the work is mainly arranged according to magnetic anomalies. Practice has proved that the first hole for anomaly verification should be arranged at the peak of magnetic anomaly, so that one hole is often effective and the ore breaking rate is 100%. The second step is to drill holes in the trunk section to expose it (generally distributed at the abnormal peak of crosscutting). If the anomaly extends for a long time and has multiple peaks, 2-3 main sections should be arranged to understand the number of layers, distribution characteristics and systematic exposure of strata and structures of the ore body; Then, according to the geological data of main sections, combined with magnetic anomalies or gravity anomalies, comprehensive analysis is carried out, and then appropriate grids are selected for general survey and evaluation. According to the above method, we used the basic grid of 400× 200m to survey and evaluate the deposit. In the evaluation, if the local change of the deposit is large, the engineering control can be appropriately encrypted. This "three-step method" for ore deposit evaluation is targeted and reasonable, and it is also a multi-,fast, good and economical method.
It is an effective method to use multi-arms joint operations to guide the deployment of exploration work, engineering layout and construction in deposit exploration. In the second half of 1970s, Team 337 conducted a gravity survey of1∶ 50,000. In order to cooperate with gravity exploration, the Geophysical Exploration Brigade of the Provincial Geological Bureau conducted an electrical sounding of 1∶ 1 000,000. Three-component measurement, geothermal logging and radioactivity measurement were also carried out in drilling engineering construction. Twenty-four local gravity anomalies were found by gravity survey, with Bouguer values ranging from 0.4 to 2 mgy. Most of the anomalies are consistent (or basically consistent) with the magnetic anomalies of large and medium-sized deposits except some marbles or paleotopographic uplift. Individual deposits (such as Li Lou deposit) are mainly composed of weakly magnetic specularite, and the isoline of gravity residual anomaly extends southward more than that of magnetic anomaly. Therefore, in the process of tracking and controlling the extension of the ore body along the strike, the ore body still extends stably, with no magnetic anomaly but gravity anomaly, and the scale of the ore body continues to expand, becoming the largest deposit in Huoqiu Iron Mine. Another example is three-component logging, which also plays a very good role in finding out whether there are ore bodies in the deep and edge. If the ZK53 hole constructed in Zhou Ji has reached the design depth and no ore is seen, it is inferred that there is an ore body in the deep part after the three-component logging, and the ore body will be seen soon after the construction continues; Some projects end drilling ahead of schedule through three-component logging, which reduces the workload of drilling engineering. Therefore, it is a good way to improve the quality and research level of geological work and speed up the work process by adopting various methods and means to cooperate with each other, learn from each other's strong points and make comprehensive analysis.
In the exploration work, due to the interference and destruction of10 (1966-1976) during the Cultural Revolution, the geological work is in an irregular state, and the quality of some projects is too poor (such as low core recovery rate, poor hole sealing quality, excessive hole inclination, etc.). ), causing a lot of rework and waste; For example, some projects can't make up for it, but they have to exist as historical problems.
Huoqiu iron mine has not yet been developed and utilized. Only Zhangzhuang deposit is Masteel 199 1 development demonstration in the second half of the year, and 1992 carried out geological work in the early stage of development and prepared for development and utilization. The mining scale is initially planned to be 3 million tons/year. After the development and utilization of Zhangzhuang deposit is determined, detailed investigation and exploration of other deposits will be gradually carried out to expand the mining scale. The planned mining capacity can be increased from 3 million tons to 6 million tons or even more than 8 million tons.
By the 1980s, the iron ore exploration and anomaly verification in this area had been relatively high, and the possibility of expanding the prospecting prospect and discovering new large and medium-sized magnetite deposits became less and less. However, except Li Laozhuang and Fanqiao (which have been delineated as syncline distribution), other deposits (such as Zhou Ji, Zhouyoufang and Li Lou deposits) are not completely delineated along the strike; Generally, the vertical depth of each deposit along the dip is only 450-600 meters, and the ore body has not been pointed out, so there is still some potential for further exploration and the possibility of expanding the scale of the deposit.