Research and Application of Cementing Filling Technology of Xulou Iron Mine Tailings
China's mineral resources are relatively complete, but there are many poor ore, co-contained ore and refractory smelting, which will produce a large number of tailings, and it is increasing year by year [1]. Not only can make full use of tailings comprehensive utilization of mineral resources, mineral expand the scope of use, to extend the mine life, reduce environmental pollution, but also save a lot of land and capital, resulting in huge economic and social benefits, sustainable development of mining The inevitable choice [2]. Filling of mine goaf is one of the effective ways to directly use tailings. Mine filling technology innovation is the main driving force for green, safe and sustainable mining. Tailings filling technology is of great significance in protecting the environment, improving resource recovery and ensuring safety.
In recent years, the filling technology with tailings sand as the main filling material has developed rapidly, such as water sand filling [3], full tail sand cementing filling [4], graded tailings cement filling [5], high concentration full tailings cement filling [6] -7], paste pumping filling [8], paste-like cement filling [9], (super) high water speed filling [9-10] and so on. Scholars at home and abroad have carried out a large number of basic theories and experimental research, and have achieved rich results [11].
Xu Anhui iron ore is a floor-contact type account skarn magnetite ore depth of 48 ~ 385m, using underground backfill mining. The total resource of the 56 district of Xulou Mine is about 30 million tons. According to the 80% recovery rate, it is estimated that about 24 million tons of ore will be produced, and the total tailings will be about 6.2 million tons (3.3 million m3). The first phase of the iron ore mine will be used to mine the Shilou deposit, and the ore body with a level above 100m will have a total reserve of 5.39 million tons, a production capacity of 400,000 t/a, and an annual output of 100,000 tons (50,000 m3) of tailings. . In order to ensure safe, efficient and environmentally friendly mining, tailings must be disposed of properly.
1 tail sand disposal plan selection The design scale of Xulou Iron Ore Building No. 1 Mine Belt is 400,000 t/a, the ore grade is 48%, the concentrate grade is 65%, and the annual output of tailings is 103,600 tons. The composition of the first ore belt in the Xulou Iron Ore Building Mine Area is shown in Table 1.
China's mineral resources are relatively complete, but there are many poor ore, co-contained ore and refractory smelting, which will produce a large number of tailings, and it is increasing year by year [1]. The comprehensive utilization of tailings can not only make full use of mineral resources, expand the scope of mineral utilization, extend the service life of mines, reduce pollution to the environment, but also save a lot of land and funds, generate huge economic and social benefits, and be a sustainable development of mining industry. Inevitably choose [2]. Filling of mine goaf is one of the effective ways to directly use tailings. Mine filling technology innovation is the main driving force for green, safe and sustainable mining. Tailings filling technology is of great significance in protecting the environment, improving resource recovery and ensuring safety.
In recent years, the filling technology with tailings sand as the main filling material has developed rapidly, such as water sand filling [3], full tail sand cementing filling [4], graded tailings cement filling [5], high concentration full tailings cement filling [6] -7], paste pumping filling [8], paste-like cement filling [9], (super) high water speed filling [9-10] and so on. Scholars at home and abroad have carried out a large number of basic theories and experimental research, and have achieved rich results [11].
The Xulou Iron Mine in Anhui Province is a contact-type skarn magnetite mine with a depth of 48-385m and underground mining. The total resource of the 56 district of Xulou Mine is about 30 million tons. According to the 80% recovery rate, it is estimated that about 24 million tons of ore will be produced, and the total tailings will be about 6.2 million tons (3.3 million m3). The first phase of the iron ore mine will be used to mine the Shilou deposit, and the ore body with a level above 100m will have a total reserve of 5.39 million tons, a production capacity of 400,000 t/a, and an annual output of 100,000 tons (50,000 m3) of tailings. . In order to ensure safe, efficient and environmentally friendly mining, tailings must be disposed of properly.
1 tail sand disposal plan selection The design scale of Xulou Iron Ore Building No. 1 Mine Belt is 400,000 t/a, the ore grade is 48%, the concentrate grade is 65%, and the annual output of tailings is 103,600 tons. The composition of the first ore belt in the Xulou Iron Ore Building Mine Area is shown in Table 1.
In the formula, Va is the volume of the average filling goaf, m3/a; Gk is the ore output by the filling method, 400,000 t/a; Z is the charging ratio, taking 1; rk is the ore density, 4.39 t/m3 . The average filling gob volume Va=9.11 million m3/a is calculated.
According to the formula, the amount of tailings is
In the formula, mso is the amount of tailings, 1.35t/m3.
It is calculated that the annual amount of tailings in the Xulou Iron Ore Building No. 1 Mine is 122,800 tons, which is greater than the annual tailings output of 103,600 tons, all of which are backfilled in the goaf, and there are 19,200 tons of gaps. Therefore, the tailings of the Xulou Iron Mine can be fully recharged underground, and there is no need to build a tailings pond on the surface.
3 filling slurry strength test
3.1 Test materials The aggregates were made of Xulou Iron Mine's full tailings, and the cementing material was ordinary 425# Portland cement. A total of 48 test pieces with different ratios of sand to sand, concentration and solidification period were produced.
3.2 Xu F characteristic sand iron deposit metallic minerals mainly magnetite, hematite times, maghemite, pyrite, pyrrhotite trace, marcasite, yellow copper ore, Hui copper; main gangue minerals and carbonate minerals like calcium magnesium silicate minerals. The tailings are mainly composed of carbonate minerals such as calcite and dolomite, and calcium-magnesium silicate minerals such as actinolite , diopside and tremolite , followed by CaO, MgO, SO3, P2O5, etc., and a small amount. Chemical elements such as Au, Ag, Pb, As, Ni, and Co. According to the wet sieving method, the fractional composition of the tailings of the Xulou iron ore was measured and sampled by the bottom tail of the plant. See Table 2. The cumulative distribution curve of tailings particle size is shown in Figure 1.
As can be seen from Table 2 and Figure 1, d10 = 4.35 μm, d50 = 28.78 μm, d90 = 190.23 μm; unevenness coefficient a = 43.69. That is, the median diameter d50 of tailings in Xulou Iron Mine is 28.78μm; according to the distribution of tailings particle size, the fine particle content of -28.78μm is about 50%, which belongs to fine tailings.
3.3 Test methods
The test firstly dries the tailings, and then according to the measured mass, the ratio is 70%, 71.5%, 73%, 75%, and the different ratios are 70.7mm×70.7mm× 70.7mm test block. Among them, the density of cement and tailings are 2.81 and 2.76 g/m3, respectively. The test piece was placed under the well for maintenance. After 24 hours, the compressive strength of 1, 3, 7, and 28d was measured according to the design requirements. The filling ratio of the filling slurry is shown in Table 3.
3.4 test results
The test results of the compressive strength test of the filling block are shown in Table 4. It can be seen that the mass concentration of 75% filler slurry has the highest compressive strength, but its fluidity is poor, and the transportation is extremely difficult; the concentration of 70% filler slurry is good, the transport is easy, but the strength is low, and it is not suitable for this project. Concentration 71.5% ~ 73% filling slurry can meet the requirements from all aspects, suitable for this project. Therefore, the main technical parameters of the actual filling project are the mass concentration of the filling slurry of 71.5% to 73%, the preparation capacity of the filling station is 30 to 40 m3/h, and the ratio of the filling sand to sand is 1:4, 1:6.
4 filling process
According to the test selection, the proportion of the strength requirements is designed, and a new and fully automated filling system suitable for filling the goaf is designed. The process flow is shown in Figure 2.
(1) After the tailings of the plant is pressurized by the high-head slurry pump, the concentration is 30%-55%, the flow rate is about 50m3/h, and it is transported to the filling station by the polymer wear-resistant pipe to two vertical stands of about 500m3. Sand bin. The tailings plus natural sedimentation of the medicament, the overflow water is pressurized by the pipeline pump and then transported to the plant for recycling through the return pipe.
(2) After the natural sedimentation and dehydration of the tailings in the silo, open the inlet pipe to pressurize and grout. After the tailings in the silo are evenly ground, open the sanding valve and the electric control valve, and supply the tailing mortar to the mixer through the sanding pipe.
(3) Arrange the auxiliary slurry water valve on the lower side of the sand release valve. When the sand release valve is opened but the tail sand is not released, the auxiliary slurry water valve can be opened. After the tailings is released, the valve is closed. In order to detect and adjust the sand discharge flow, an electromagnetic flowmeter and an electric control valve are arranged on the sand discharge pipe.
(4) The bulk cement is transported from the tanker to the filling station and blown into the 250t cemented silo through the soot blowing pipe. There is also an exhaust device and a heavy hammer level gauge at the top, and a gate valve, a double pipe screw feeder and a nuclear scale at the bottom of the warehouse. The rubber compound is fed according to the design ratio through the double pipe screw feeder, and is metered by the nuclear scale and sent to the mixer.
(5) After the filling slurry is evenly stirred by the vertical mixer, it enters the slurry conveying pump through the measuring tube, and finally is transported to the stope through the filling drilling hole and the underground pipe network.
(6) In order to adjust the preparation concentration of the filling slurry, a concentrated water supply line is set. A clean water pump and an electric control valve are provided on the water supply line. An electromagnetic flowmeter and a gamma ray concentration meter are arranged on the measuring tube to detect the flow rate and concentration of the filling slurry.
(7) When the sand bin needs to be thoroughly cleaned or repaired to replace the compressed gas slurry nozzle, the remaining slurry in the bin can be transported to the settling tank through the mixer.
5 Filling effect In order to verify the filling effect, the compressive strength test of the filling core samples was carried out at the patio of the second prospecting roadway in the No. 7 and No. 9 stop of the No. 0 mining area of ​​Shilou No. 1 Mine. The sampling position and test results are shown in Table 5. .
It can be seen from Table 5 that the compressive strength values ​​of the filling body samples all meet the test requirements, indicating that the cement and tailings are filled with a filling concentration of 71.5% to 73% and a water-cement ratio of 1:4 or 1:6. The slurry can meet the design requirements, and the ratio is the most economical and reasonable.
6 Conclusion
(1) Through comprehensive analysis, the tailings of Xulou Iron Mine can be fully recharged underground, and there is no need to build a tailings pond on the surface. It is most reasonable to use the gob filling scheme to dispose of tailings.
(2) Cement and tailings filling slurry with filling concentration of 71.5%~73% and water-cement ratio of 1:4 or 1:6 are suitable for underground filling of the mine, and the ratio is most economical and reasonable. Through the filling core core sampling test, the compressive strength can meet the design requirements (5MPa).
(3) Filling the sample in the downhole to maximize the simulation of the environment in which the filling body is located, and obtain more realistic and realistic test data. Xulou Iron Mine has designed a new set of fully automated filling system according to its filling requirements, which can simultaneously serve the goaf filling of underground mining in the second phase. The filling technology has a good reference for similar mines.
References [1] Xiao Liguang, Yi Jinhong, Cui Zhengxu. The status quo of comprehensive utilization of iron tailings at home and abroad [J]. Journal of Jilin Institute of Architecture and Engineering, 2010, 27(4): 22-26.
[2] Zhang Yuzhen. Utilization of recovery and beneficiation plant tailings [J]. Hunan Nonferrous Metals, 2002, 18(2): 7-9.
[3] Hu Hua, Sun Henghu. Development of mine filling technology and new technology like paste filling [J]. China Mining, 2001, 10 (6): 47-51.
[4] Benzaazoua M, Fall M, Belem T. A co ntribution to understanding the hardening process of cemented pastefill [J]. Minerals Engineering, 2004, 17( 2) : 141-152.
[5] Liu Zhixiang, Li Xibing. Chaos optimization of tailings grading [J]. Journal of Central South University: Natural Science Edition, 2005(4): 683-688.
[6] Wang Zhenpeng. Talking about the application of high concentration filling technology of full tailings in deep mines [J]. Modern Mining, 2010 (9): 76-77.
[7] He Binghong. The application of filling technology in iron ore mines in the past ten years [J]. Engineering Construction, 2011, 43(4): 28-32, 41.
[8]Fall M, Benzaazoua M, Ouelle S. Experimental characterization of the influence of tailings fineness and density on the quality of cemented paste backfill [J]. Minerals Engineering, 2005, 18( 1) : 41-44.
[9] Sunheng Hu, Prudential topaz, Yang Baogui. Contemporary cement filling technology [M]. Beijing: Metallurgical Industry Press, 2002.
[10] Feng Guangming, Wang Chengzhen. Super high water material goaf filling process system and application research [J]. Journal of Shandong University of Science and Technology: Natural Science Edition, 2011, 30( 4) : 1-8.
[11] Fu Jianxin, Du Cuicheng, Song Weidong. Strength sensitivity and failure mechanism of full tailings cemented backfill [J]. Journal of University of Science and Technology Beijing, 2014, 36( 9) : 1149-1157.
Article source: "Modern Mining"; 2017.2
Author: Teng Yongbo; Institute (Beijing) Engineering and Technology of China University of Geosciences; Huaibei Mining Co., Ltd. Xu floor;
Ma Junxue, Chen Jian; China University of Geosciences (Beijing) Engineering and Technology College Copyright:
Data Center Container,Telecom Container,Prefab Telecom Container,Data Container
Yangzhou Tonglee Reefer Container Co., Ltd. , https://www.cimctlc.com