Tongling Umbrella Mountain Cement Limestone Mine ()
The Umbrella Mountain Cement Limestone Mine is located in the countryside of Xinjian and Dongdian, 10 kilometers south of Tongling City. There is Tong (Ling)-Qing (Yang) Highway at the southwest end of the mining area. The endpoint of the Ning (Nanjing)-Tong (Ling) railway freight line is only 6 kilometers away from the mine and 4 kilometers away from the Yangtze River, with convenient transportation.
The deposit occurs at the southwest end of the Dajianshan anticline in the Datong-Shun'an complex syncline. The highest point of the mine is 236 meters, the surrounding area is lower than 25 meters, and the relative height difference is more than 210 meters. The controlled mining section is 1,600 meters long and 1,300-1,650 meters wide.
The mineral deposits are produced in the Nanlinghu Formation of the Lower Triassic.
The bottom is mainly gray and gray-black thin to medium-thick layers of micrite limestone, interspersed with several layers of nodular limestone or muddy striped limestone, with an average thickness of 47.05 meters (the same below). There is an 8.31-meter mezzanine on the top. The mineral layer contains 50.67% calcium oxide and 0.47% magnesium oxide.
The lower part is light gray, gray medium-thick to extremely thick layer of micrite limestone, pure in quality, with developed sutures, and 3.60 meters of nodular limestone or muddy strips interlayered below, with a thickness of 153.47 meters. The mineral layer contains 53.89% calcium oxide and 0.49% magnesium oxide.
The middle part is light gray, gray, red gray thin to thick layers of micrite limestone, argillaceous limestone, and worm-like plastic conglomerate limestone, with two layers of 0.08 meters and 4.90 meters thick at the bottom and middle The mezzanine layer has a total thickness of 68.41 meters. The mineral layer contains 51.20% calcium oxide and 1.15% magnesium oxide.
The upper part consists of gray thin to very thick layers of micrite limestone and worm-like plastic gravel limestone, and there is a layer of rigid gravel limestone at the bottom, 1.32-19.38 meters thick. A few sections have no gravel and phase change. It is micritic limestone. The total thickness is 113.68 meters, and the mineral layer contains 50.97% calcium oxide and 1.14% magnesium oxide.
The top is light gray, medium gray to very thick micritic limestone, and some layers contain foraminifera. It has not reached its peak, and its thickness is >207.10 meters. The mineral layer contains 52.45% calcium oxide and 0.96% magnesium oxide.
All interlayer calcium oxides are grade II. If they exceed the standard, they will be downgraded to interlayers.
The weighted average thickness of all ore layers contains 52.28% calcium oxide and 0.86% magnesium oxide. Sulfur dioxide, chloride ions, phosphorus pentoxide and other oxides all meet the requirements of dry production. Due to the influence of structure and erosion, the lower part accounts for 60.85% of the total reserves, of which the Grade I product contains 53.02% calcium oxide and 0.72% magnesium oxide.
The anticline is open, with an axial direction of 234°-54°, an inclination angle of 15°-35° on the northwest limb, and an inclination angle of 45°-65° on the southeast limb. The faults are mainly transverse faults with staggered layers, but have no effect on the quality of the ore. Only fissures and caves develop near the faults, especially in the footwall of normal faults.
The deposit is a large chemical-clastic sedimentary deposit. Produced in the late Early Triassic. Due to the uplift of the Jiangnan Ancient Continent, the Lower Yangtze Sea transformed into an open sea platform, which is in the subtidal low-energy zone, has smooth access to the outer sea, and has normal salinity. In the later period, the salinity increased slightly, and the seafloor was weakly agitated by seawater, forming gravel limestone.
After exploration, it was found that the cement limestone mineral reserves amount to 610 million tons, divided into grade I products of 580 million tons and grade II products of 33.014 million tons. In 1984, exploration was conducted in the Cishan mining section on the southwest side, and reserves of 158 million tons were found.
A mine preparation headquarters was established at the end of 1982, but construction failed to start due to lack of funding. It was not until the beginning of 1992 that the state officially approved the construction. The first phase of the project is 1.5 million tons, and the second phase is to build another 1.5 million tons. It is possible to expand to 4.5-6 million tons.
In July 1977, the Provincial Construction Committee asked the Anhui Provincial Geological Exploration Team of the Geological Company of the Ministry of Building Materials to find a cement mine with an annual output of 3 million tons. The building materials team arranged for Li Zhongyan and Li Chengzheng to take on the task. Because the team came to Anhui in 1970 after being decentralized from the central public institutions, they were not familiar with the geological conditions of the province. Especially in the previous period, they had been involved in the work of non-metallic minerals such as gypsum and asbestos. They were unable to select a suitable mineral point and the time was very short. It is urgent to collect data comprehensively. It is impossible to conduct a systematic survey. We can only start with the characteristics of the cement plant with an annual output of 3 million tons and select key points. Such a large factory produces about 10,000 tons of cement every day, and requires 20,000 tons of transportation in and out. Without good transportation conditions, it is difficult to build a factory. The most ideal location is along the Yangtze River, the golden waterway. Although the quality of Carboniferous-Permian limestone is good, due to its thin thickness, it is impossible to form a large mine of 300 million tons.
Only the Triassic Nanlinghu Formation is thicker. However, because the Guishan limestone ore in Chaohu Cement Plant has high mud content, it cannot be used alone and needs to be matched with Carboniferous-Permian limestone. In the rainy season, mine shafts are often blocked, causing casualties. Therefore, everyone from the Provincial Construction Committee to the factory was opposed when they heard about the Triassic limestone. From the two 1:200,000 regional geological maps of Tongling and Anqing that were available at that time, it can be seen that large areas of the Nanling Lake Formation are distributed, but whether it is generally usable is not yet certain, and it must be confirmed by on-site surveys. On July 28, we first arrived in Tongling City. Deputy Director Zhou Zhiji of the Municipal Construction Committee, Section Chief Bu, and Li Zhongyan visited places such as Yifengling, Qingshan, and Changlong Mountain. They were all rejected because of the small amount of minerals and unsatisfactory transportation. Li Zhongyan and others proposed to explore the Umbrella Mountain. After field observations, they concluded that the limestone is of good quality, with low magnesium oxide content and few and thin muddy interlayers, making it a high-quality cement raw material. Then I learned about the traffic, power supply plant site, etc. and went to the site to inspect. The situation in all aspects was very ideal.
In order to give leaders a choice, Li Zhongyan and others went to Anqing and Guichi to explore Yueshan, Caoshan, Guankou and other places. Other mines have a certain scale, but transportation, ingredients, power supply, local industrial base, etc. are not as good as Umbrella Mountain.
The site selection began in early November 1977, the work started at the end of June 1978, and the field work was completed at the end of August. The design began in October 1979, and the detailed investigation work began in October 1980. By the end of 1982, 6 square kilometers of 1:2000 topographic and geological maps had been measured, 7 construction survey line sections, a total length of 7463 meters, 26 boreholes, and a footage of 4223.94 meters. , in September 1983, the "Geological Report on Umbrella Mountain Limestone Exploration in Tongling City, Anhui Province" was submitted. Li Zhongyan, head of engineering technology.
The Umbrella Mountain Cement Limestone Mine uses a 400×300 meter grid for exploration, with an investment of 489,300 yuan, and the exploration cost is 8.01 yuan/10,000 tons. If compared with the cement, flux, and chemical limestone mines that have been working in Anhui, Comparison (most of them use 200×200 meter mesh), at least two-thirds of the workload is saved. The work results confirmed that this kind of network can completely control the mineral layer, and it was unanimously approved at the report approval meeting held by the National Reserve Committee.
The degree of mineral exploration should be based on the principle of controlling the scale of mineral deposits and ascertaining the quality of ores. Anhui Province has limestone of different sizes, ages and grades. The exploration network should be sparse for large-scale, high-quality minerals with stable grade changes, such as the carboniferous, Permian, and Triassic limestones in the Yangtze stratigraphic division; for small-scale or poor-quality minerals with unstable grades and uneven distribution of harmful components Minerals should be properly intensified, such as the Sinian-Ordovician limestone in the Huaihe stratigraphic subdivision and the Jiangnan stratigraphic subdivision.
For large-scale cement plants, traffic conditions should be fully considered. Even if there are large mines, it is still impossible to build a plant if transportation is inconvenient. In addition, in addition to the main raw materials, other ingredients, energy, water sources, living facilities, etc. must also be considered. The advantageous factor of Umbrella Mountain is that it has convenient transportation and can keep up with other aspects.