Application Practice of "Four Matching" Mining Method in Sijiaying Iron Mine

Szechiaying which iron ore mine strata is covered by the fourth area, the coverage area of more than 70% of the total area of the mine, generally a thickness of 20 ~ 30m. The base rock outcrop is distributed in a random distribution except for the continuous distribution of the eastern part of the mining area and the Shangshan-Tieshishan. The pre-Sinian strata in the area are mainly composed of granulite, schist and quartzite with relatively shallow metamorphism, fine grain size and simple lithology [1]. The ore mineral composition of the mining area is relatively simple, mainly magnetite, imaginary hematite, and sub-hematite. The gangue minerals are mainly quartz , followed by actinolite , tremolite , a small amount of amphibole and pyroxene.
At the beginning of the production, Sijiaying Iron Mine mainly carried out the mining of the upper oxidized ore body in the open pit. With the further advancement of the stope, the working surface gradually expanded, the upper oxidized ore decreased gradually, and the lower magnetite increased. The ore body has also changed from a single single ore body to three main ore bodies, and the shape of each ore body is not the same, and the ore properties are quite different.
Since the difference between the nature of the ore stope large and frequent changes, so that the quality fluctuations mineral stone, wherein, w (TFe) 23% ~ 29%, w (FeO) 0.1% ~ 8%, plus beneficiation process Complex, resulting in unstable tailings grade, resulting in reduced ore dressing recovery, increased ore dressing costs and waste of iron ore resources. The Sijiaying iron ore mine is affected by factors such as complex changes in ore rock properties, slower dip angles of the ore body, and large-scale mining equipment, which makes it difficult to select the rock, which inevitably leads to an increase in the depletion rate and loss rate. In order to ensure the stability of the ore grade in production, ultra-low grade ore and ultra-thin ore bodies have to be lost. In operation, each ore mining location determines the loss of ore and the removal of the rock according to the actual situation, which is easy to cause the ore grade to be unstable, and the mineral processing technical index is difficult to control. To this end, it is necessary to optimize the mining and supply management procedures to ensure the quality of the selected ore is stable.
1 "four matching" ore method
According to the on-site analysis, with the downward movement of the working surface and the opening of the working face, the ore grade distribution is uneven, the FeO content of different ore bodies is different, and the distribution of useful minerals in the ore is uneven. The phenomenon that the ore grinding degree differs greatly between different parts of the ore body and between different layers, which leads to large fluctuations in the mining quality of the stope and unstable ore processing. In this regard, on the one hand, it should be targeted to prepare the mining and stripping plan; on the other hand, it should strengthen the application of the ore-producing production organization and the sub-explosive detonation technology in production, and strengthen the advantages of small equipment in the selection of ore. To achieve the purpose of stable selection of ore quality, control of loss rate and depletion rate [2].
(1) TFe grade. The design grade of Sijiaying Iron Mine is 30.44%, but with the gradual development of the development, the quality grade of the mining site is decreasing year by year. The difference in grades of different ore blocks is increased, and the inclusions of minerals become more complicated, resulting in nearly 2a. The average grade of the ore is only about 26%.
In order to ensure the high quality completion of the production and operation tasks, and reduce the ore loss rate and the depletion rate to a reasonable range, the method of multi-point mining and other methods will control the total iron grade of the ore into 24%. ~28%, the total iron grade fluctuation within 7d is controlled within ±1%, achieving the purpose of stable beneficiation process.
(2) FeO grade. At present, the iron ore exposed in the open-pit mining site of Sijiaying is mainly oxidized ore, and some magnetite. From the distribution of FeO content, the central part of the 1# ore body in the stope is mainly magnetite, and the north and south are mainly oxidized ore and semi-oxidized ore, w(FeO) 2%~10%, and the highest is up to 15%; The FeO content of 3# and 4# ore bodies is generally low, mostly 0.1% to 5%. The uneven distribution of FeO content has become an important factor restricting the ore dressing production. To this end, in the actual production process, while ensuring the normal production of magnetite ore dressing, according to the actual situation of the stope, the semi-oxidized ore and a small part of magnetite are used as the ore source of the oxidized ore series to supplement the FeO content of the oxidized ore. Insufficient, so as to achieve the purpose of improving mineral processing technical indicators. In the process of ore blending, according to the distribution characteristics of FeO content in the stope, the FeO content of the oxidized ore series into the grinding ore is controlled as much as possible from 4% to 6%.
(3) Grindability optional. At present, the Sijiaying iron ore has entered a stage of rapid development, and various technical research work with the core utilization coefficient of the ball mill is being further advanced. In order to further improve the utilization coefficient of the ball mill and the amount of treatment during the stabilization stage, the grindability and useful mineral inlay size of different ore areas in the stope were tested and analyzed in the process of ore blending. The results show that: 11# ore body north and middle The grindability is relatively good, the useful mineral inlay has a coarser grain size, the southern grindability is poorer, and the useful mineral inlay has a finer grain size; the 23# ore body has a relatively better grindability in the south, and the useful mineral inlay has a coarser grain size. The northern part can be worn to a lesser degree, the useful mineral inlay is finer in size, the middle part can be ground and the useful mineral inlay size is general; the 34# ore body has a relatively poor overall grinding degree, and the useful mineral inlay has a finer grain size. Therefore, the ore needs can be met by matching the ore bodies with different ore bodies, different steps and different grindability options.
(4) gangue minerals. Various non-quartz-like silicate-like gangue minerals such as mica and chlorite are abundantly contained in the ore body. Since most of these gangue layers are thin (0.1 to 1 m), it is difficult to It is effectively eliminated. If the silicate-like gangue minerals enter the oxidizing ore beneficiation process, it will affect the flotation operation. In severe cases, the flotation operation will not be divided, and the flotation concentrate grade is only about 50%, which seriously affects the gold. Recycling rate and concentrate quality. To this end, in the process of blending, the gangue minerals that are difficult to remove are planned to be fed into the beneficiation process. While ensuring the quality of the concentrate and the metal recovery rate, the utilization of ore resources and the loss rate of the ore in the stope are achieved. purpose.
2 for ore production organization
(1) Shovel arrangement. Strictly in accordance with the daily supply and distribution plan, each time the distribution of mines should not exceed 3 electric shovel at most, the proportion of ore blending should not exceed 3, avoiding the phenomenon of simultaneous supply of ore by mining ore and rock shovel at the same time. Otherwise, Difficult to operate and control, and multi-shovel mining is likely to cause production confusion.
(2) The arrangement of the car shovel. In the arrangement of the car shovel, try to ensure that the vehicle is running at full capacity. According to the proportion of the ore distribution, six 130t electric wheels are generally arranged to meet the ore blending requirements of the ore shovel, and the remaining vehicles are engaged in rock drilling.
(3) Arrangement of crushing discharge port. When the crushing discharge port is dumped, in order to ensure the balance of the selected grades, the mine production department arranges the discharge port management personnel to conduct on-site command and strictly proportionally match the mine. If 1# shovel: 3# shovel: 4# shovel = 1:1 2: The corresponding loading vehicles are also dumped in the order of 1:1:2, so reciprocating cycle, try to avoid the phenomenon of rolling and belt idling, and ensure the realization of the proportion of different shovel.
3 Discussion
In order to optimize the distribution management process of the Sijiaying open pit, and ensure the quality of the selected ore, a “four-match” ore blending method was proposed. The implementation of the method optimizes the number of ore shovel, the ratio of the shovel and the shovel time, reduces the randomness of the mining, improves the working efficiency of the vehicle and shortens the waiting time of the vehicle. The production practice of the past 1a shows that the grade and properties of the selected ore are effectively controlled. The ore quality in the 7d has basically no fluctuation, and the loss rate and depletion rate of the stope are well controlled. The technical and economic indicators of the mining and concentrating plant It also has a greater improvement than the first half of the year, and has certain reference value for the open mining mountain, especially the low grade and difficult mining mountain.
references
[1] Zeng Guanzhong. Preliminary study on geological characteristics and ore-controlling factors of Sijiaying iron deposit[J]. China Science and Technology Information, 2011 (16): 19-20.
[2] Guo Youqian, Ren Jianguo. Practice and research on ore mining of Jianshan Iron Mine [J]. Mining Engineering, 2003 (4): 29-31.
Author: Zhang Yang, Zhang end, Gongrui Jie; Luan County in Hebei Iron and Steel Group Co., Ltd. Sijiaying iron ore;
Article source: "Modern Mining"; 2016.8;
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