Daxigou iron ore in 2010 by a private enterprise integration from mining iron ore and iron ore products for the main body of TiO2 associated weight compounds and associated P2O5 weight compounds from mining state and provincial roads close, convenient transportation. The deposit is a sedimentary metamorphic super-poor magnetite. In addition to the thin Quaternary coverage of the vegetation in the mining area, there are almost no Quaternary topsoil covering. According to the natural geography of the mining area and the occurrence conditions of the ore body, in order to reduce the mining cost, it is determined that the shallow ore body of the Daxigou super-poor magnetite is open-pit mining. According to the regional rock mass conditions and the previous scientific research results, it is determined that the vertical height of the open slope is about 200m, the step height is 10m, the step slope angle is 65°, and the final slope angle of the open pit is not more than 51°. Article source: Mining Technology; 2017.17(3) Author: Luli Song; Poly Mining Investment Co., Ltd., Beijing 010010 Copyright: Pontoon Salvage,Boat Salvage Airbags,Ship Salvage Airbags,Salvage Pontoons For Ship Shandong Nanhai Airbag Engineering Co., Ltd. , https://www.nanhaimarine.com
1 Overview
The geological block method is used to estimate the ore resources in the mining area. Within its mining license (+811m to +471m), the iron ore resource (332+333) is 68,813,900 tons, the TFe grade is 13.02%, and the mFe grade is 4.54%. The amount of TiO2 compound (332+333) in the iron ore is 2.0273 million tons, the grade of TiO2 is 2.95%, the amount of P2O5 compound (332+333) is 653,900 tons, and the grade of P2O5 is 0.95%. This paper only analyzes and discusses the comprehensive development and utilization of the open pit mining in Daxigou Mine.
2 mining area geological environment
2.1 Regional strata
The exposed strata in the area are mainly from old to new: the Taimiaojie single tower subgroup Baimiao Formation, Fenghuangzui Formation, Liuying Formation, Nandianzi Formation and Taipingzhuang Formation, and the Mesozoic Jurassic Zhongtong Tucheng subgroup. the Commission and gold just Zhangjiakou mountain group, Mesozoic Cretaceous Yixian Formation and under the EC Jiufotang, Cenozoic Quaternary. The stratum of the Baimiao Formation in the Taitao Group of Taikoojie is closely related to the mineralization of the super-poor magnetite in the mining area.
2.2 Regional structure
The fault structure is more common in the area, especially near the east-west fault. The Changge-Fengshan fault in the northern part of the area is the most representative. The fault is more than 10 kilometers long and slopes southward, showing a tensile characteristic. The second is the NE-trending fault, which is mainly found in the southern part of the region. The fault is mostly south-eastward and also shows the characteristics of tensile faults. The North-East East and North-South fault structures are also seen in the area. The near east-west and north-east faults have obvious control effects on the overall orientation of the regional strata. The fold structure in the area is mainly the Xiaogukou anticline, which is developed in the strata of the Baimiao Formation of the Taitazi Group in the Archean. The anticline axis is near east-west and more than 2km long. It has strong control over the production characteristics of the strata and the ore layer. effect.
There is no large fault tectonic activity in the mining area, but small faults, joints, and fold structures are relatively developed. The scale is small, and it is mostly filled by later veins. The pulse thickness is generally about 0.20~1.70m. It is more than ten meters thick, and its veins have different appearances and have no destructive effect on the ore body. Joints and fissures can be divided into two groups according to the trend, that is, NW direction and NE or near EW direction, and are more developed in the NW direction. The small folds are more developed, and the local body has tensile and thickening effects on the ore body, but its scale is small, and the whole has no effect on the ore body.
2.3 Magmatic rock
The regional magmatic activity is strong, the scale is large, the distribution area is wide, the rock type is more complex, and it is produced from ultrabasic, basic, neutral and acidic. The magmatic activity is mainly intrusion, followed by ejector.
2.4 ore body characteristics
Three magnetite-bearing black mica oblique long-horned flash gneiss belts were found in the mining area. There are two industrial values, FeI and FeII, respectively. See Table 1 for details. The surrounding rock and stone composition of the ore body are the same, mainly including magnetite ore hornblende gneiss or slanted amphibolite and weak magnetic oblique hornblende gneiss. 
3 mining conditions
(1) Engineering geological conditions. There is no large-scale fault-fracture zone structure in the area, and the small fault structure is mostly filled with quartz veins, monzonite veins, diorite veins, fault breccia, etc. The rocks are dense and hard, and are massive. The iron ore in the area is mainly composed of magnetic amphibolites and magnetized oblique long-horned flash gneiss. The top and bottom plates are mainly slanted long-horned flash gneiss. The type of engineering geological exploration in the mining area belongs to the second type, the first type, which is a simple deposit mainly composed of massive rock such as hard and semi-hard crystalline metamorphic rocks.
(2) Environmental geological conditions. In the middle and low mountain areas of the mining area, the erosion and cutting effect is strong, the neotectonic movement is not developed, and there is no active fault. The type of geological environment in the mining area belongs to the second category, and the mining area with medium geological environment quality.
(3) Hydrogeological conditions. Most of the ore bodies in the mining area are located above the local erosion datum, and the topography is conducive to natural drainage. It is a fissure-filled deposit with simple hydrogeological conditions.
(4) The natural environment of the mining area. The regional climate of the mining area is continental, with short summers, more southeast winds, long winters and more northwest winds. It is rainy season from July to August, with an average annual rainfall of 343.3-705.9 mm. It begins to freeze in November, the next year. Thawed in the month, the maximum depth of frozen soil is 1.31m, and the lowest temperature is -28.3°C.
(5) External transportation conditions. The G112 national highway passes through 10.5km in the northern part of the mining area, and the S244 provincial road passes through the southeast 10km. The Shirengou Township to the G112 National Road and the S244 Provincial Road are connected by township highways, and the traffic is convenient.
(6) Power supply and water supply. The power supply (10kV) comes from the dry selection workshop near the stope. There is no industrial site and domestic water facilities. The original living facilities are located in the northeast direction of the broken dry selection plant, with a distance of about 100-400m. The water system is considered by the living area. .
(7) Mining and stripping construction. The main project of the mine infrastructure is to expand and exfoliate the open pit, and the enterprise can construct it by itself and the construction conditions are good. For the circled symbiotic phosphorus, and titanium in the ore realm, by utilizing design considerations; ultra-lean associated magnetite and phosphorus titanium ore, all designed to use.
4 mining
According to the principle that the stripping ratio of the boundary is less than or equal to the economically reasonable stripping ratio, the final slope angle is not greater than the recommended value, the 332 and 333 resources are used, and the symbiotic phosphorus and titanium ore resources in the surrounding rock are comprehensively utilized, the floating cone is adopted. The law delineates the open-air boundary and defines two stopries. Among them, the north stope is located between 13~7 exploration lines, with a surface length of 670m and a width of about 500m. The minimum elevation of the stope is 580m, the highest elevation is 820m, and the height of the closed circle is 670m. The total access and exit is located near the exploration line No. 9 in the east of the stope. The South Stope is located between 5 and 12 exploration lines with a surface length of 1600m and a width of 320m. The minimum elevation of the stope is 470m, the highest elevation is 660m, and the closed circle is 550m. The total access and exit is located near the No. 8 exploration line in the east of the stope.
The height of the mining step is 10m, and the mining is to the final boundary position every 2 steps, the height of the section is 20m; the slope angle of the stage is 65° (the surface weathering part is 46°); the width of the safety platform of the stope is 5.5~8m; The width of the stope transport platform is 12m (cycle line 9.5m); the stop slope angle is 46°~51°.
The ore volume in the realm is 38.204 million tons, the rock volume is 51.205 million tons, and the average stripping ratio is 1.34t/t. The ore volume in the northern stope is 16.92428 million tons, and the rock mass is 2109.41 million tons. The average stripping ratio is 1.25t/t, the amount of ore in the boundary of the South Stope is 2,217,500 tons, the rock volume is 30,106,400 tons, and the average stripping ratio is 1.41t/t.
5 piercing blasting and loading work
The mine selected KQ200 type down-the-hole drilling rig to drill deep holes with a diameter of 200mm. The deep hole blasting is carried out by the millisecond blasting method. According to the value of the chassis resistance line, the hole spacing of the ore blasthole is 5.5m and the row spacing is 4.5m. The hole spacing a of the rock is 6m and the row spacing b is 5m. . The number of blast holes per time is 45, and the average single hole explosive consumption is
203.3kg.
The rock and rock loading equipment is selected from the R964C hydraulic excavator with a bucket capacity of 3.5m3. There are 3 hydraulic excavators in the North Stope, 2 T220 bulldozers, 1 ZL-50D front loading machine for auxiliary work in the stope; 5 excavators in the South Stope, 3 T20 bulldozers, ZL-50D front loading machine 2 sets of stope assisted operations.
6 main technical and economic indicators
The main technical and economic indicators of the mine are 4.5 million tons of mines, 4.75 million tons of annual mining and stripping in the northern stope, 1.5t/t of production stripping ratio, and 6.89 million tons of annual stripping in the South Stope. 1.65t/t, the service life of the North Stope is 11a, and the service life of the South Stope is 10a. The development and transportation plan adopts road development, automobile transportation, mining from top to bottom, and the power consumption of mining unit products is 0.69kW·h/ t, labor quota is 318 people, the estimated total investment is 25,692,000 yuan, and the ore production cost is 28.9 yuan/t.
7 conclusions and recommendations
Through the analysis of the resources of Daxigou super-poor magnetite and the comprehensive mining technical conditions, the comprehensive development and utilization mode of the mine was determined, and the technical parameters of the mine were preliminarily determined by using the existing technical data. Provide guidance for the design and mining work. However, due to the limited technical data of the region, further investigation and verification are required, so the following suggestions are made:
(1) The ore body in the northwest of the mining area is thick, and the possibility of increasing the resources to the deep is very high. The mine should apply for expanding the scope of mining rights to scientifically and rationally use the mine ore resources;
(2) This paper only uses the existing data to make a rough estimate of the groundwater inflow in the mining area. It is recommended to carry out special hydrogeological work before the next step, to check the hydrogeological conditions of the mining area, and to further verify the groundwater inflow. And provide a detailed basis for production;
(3) Due to the limited experimental data of rock mechanics in the existing data, the safety factor of slope calculated in this paper may differ from the actual project. It only has certain reference value for the choice of design in the design. It is recommended to carry out slope engineering geology as soon as possible. Exploration work.
(4) In the production, the monitoring results of blasting vibration monitoring and other means can be used to continuously improve the blasting method and blasting parameters, reduce the blasting disturbance, reduce the surface water flow into the open pit, and ensure the stability of the open slope.
references:
[1] Yu Neng, Liu Zhengyu, et al. Sensitivity orthogonal range analysis of factors affecting slope stability [J]. Mining Research and Development, 2013 (5): 66-69.
[2] Zhang Zhihai, Pan Lixiang, Li Zhaohui, et al. Summary of development and utilization of super-poor magnetite resources [J]. Environmental Engineering, 2015(S1): 557-561.
[3] Wang Qing, Shi Weixiang. Mining science [M]. Beijing: Metallurgical Industry Press, 2006.
[4] Zhang Juwei, Gao Qian, et al. Research on rock movement and engineering stability of metal mines and dynamic prediction [J]. Geology and Exploration, 2006, 42(5): 98-102.
[5] Li Baoxiang. Open mining of metal deposits [M]. Beijing: Metallurgical Industry Press, 1992.
[6] Zheng Luzhen, Zheng Lulin, et al. Analysis of factors affecting the stability of open slope and prevention measures [J]. Metal Mine, 2014 (02): 131-136.
[7] Chang Chun, Zhou Depei, et al. The impact of open pit mining depth on slope stability [J]. Journal of Rock Mechanics and Engineering, 1998, 17(3): 247-249.