Research and Practice on Mining Technology of Difficult Small Ore Body in Lushan Copper Mine
Langya Mountain copper mine is located next to the National Forest Park in the western suburbs of Langyashan Chuzhou City, Anhui Province, Anhui Province is the core subsidiary of the Langyashan Mining Corporation. The Langyashan copper mine was founded in 1958, it has become the total annual mining more than 30 million t, beneficiation daily processing capacity of nearly 1000t, annual output of copper concentrate 4000t of medium-sized underground mines. In recent years, the production of mines is stable and the safety situation is good. However, there are many middle-stage operations, and it is difficult for small ore bodies to recover. The problem of system mismatch is gradually emerging. Therefore, strengthening the recovery of difficult ore bodies and gradually closing the upper middle section is a relatively urgent task for the mines in recent years. For this purpose, the company set up a difficult mining ore mining project group to focus on the technical research of the upper middle section of the difficult ore body, encourage engineering and technical personnel to boldly innovate, select safe and reliable technical solutions, and recover the upper middle section of the difficult ore body as soon as possible. Prepare for the next step in optimizing each system. From the floor transport lane design location construction funnel and 1# sidewalk, communicate the two patios at the 6m elevation from the floor of the roadway, and then construct the electric raft room and other related projects. Use the funnel and sidewalk rock sideways direction to cut the construction specifications 2m × 2m uphill, reach the design position and then construct the 2# ventilation pedestrian patio to communicate with the upper middle section. Form a ventilation, pedestrian filling system, and then carry out mining and filling work. During the next layer mining, the funnel sidewalk is extended to the next layer to pull the bottom layer height, and the first layer of construction is cut to cut the mountain and the subsequent mining and filling work. Article source: Mining Technology; 2017.17(2) Author: Qiao Xiaoming, Li Yongming; Anhui Langya Mountain Mining Corporation, Chuzhou, Anhui 239000 Copyright:
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1 ore body mining technical conditions and mining plan comparison 25#1 ore body is located between the 815 line and the 816 line in the west belt of the deposit, which belongs to the positive contact zone mineralization. The ore type is mainly copper-bearing skarn, and the ore mineral is mainly chalcopyrite. The shape of the 25#1 ore body is lenticular, and the boundaries between the ore body and the surrounding rock are clear. 25#1 has a proven area of ​​70m2 in the middle section of -245m, an average thickness of 3.5m, and an average grade of 1.21%. It does not reach the mid-plane of -185, and its highest elevation is -193m.
Ore body occurrence: 25#1 ore body is northeast, tending to the south, and the inclination is 60°. The side direction is northeast, and the side angle is about 30°. 25#1 ore body from the plane prospecting roadway and the hole exposure, the ore body of the ore body is relatively fractured, and the phenomenon of the porphyry vein interspersed with the ore body, affecting the safe mining, the limestone rock under the plate More complete.
The horizontal area of ​​the 25#1 ore body is too small, the thickness is not large, and the shape is complex. The filling method or the method of retaining ore in the mine can not achieve good benefits.
After careful study of the 25#1 ore body, two sets of mining plans were developed for comparative analysis. Option 1: The ore body is recovered using the stratified comprehensive method [1-2]. The cutting roadway is constructed along the side of the ore body, and the stratification is divided according to the vertical height of the ore body. Depending on the stability of the ore rock, the number of stratification and the stratification height are determined: when the stability of the ore is good, the layer is divided into two layers, and the stratification height It is 5m; when the stability of the ore is not good, it is divided into 3 layers and the stratification height is 3.5m. Two pedestrian ventilated patios, one funnel. Option 2: The horizontally stratified filling mining method [3-4] is used to recover the ore body, and three pedestrian patios, two funnels, and one filling well are arranged. Through economic and technical comparison, it was decided to use Scheme 1 to recover the 25#1 ore body. Option 1 has the following advantages:
(1) The amount of mining work is small, and the mining process is simple.
(2) Low material consumption and low mining cost.
(3) Construction of cutting roadway along the side of the ore body, stratification according to the vertical height of the ore body, changing the conventional method. For the 25#1 ore body, the horizontal direction is short, the lateral distance is long, and the ore body thickness is not large. Many disadvantages and low utilization.
(4) This method fills the empty area, which is conducive to improving mining recovery rate and mining safety management. It is a combination of the empty field method and the filling method.
(5) Compared with the conventional horizontal layered filling method, the recovery speed is fast and the efficiency is high.
2 stratified comprehensive mining law example
2.1 The quasi-structural parameters According to the characteristics of the 25#1 ore body, combined with the requirements of the comprehensive mining method and the filling method design, the pavement is equipped with two pedestrian patios, one of which is the -245m mid-section construction connected stope, one for The stope construction is connected to the upper part of the upper -185m section (also used as filling and ventilation shaft); a funnel is arranged; a transport lane is arranged in the middle section of -245m, and a return airway is arranged in the middle section of -185m. The ore blocks are divided into stratification along the lateral direction of the ore body. Depending on the stability of the ore, the stratification number and stratification height are determined, as shown in Figure 1. 
2.2 mining cutting
2.3 mining work
(1) Rock drilling and blasting. The 7555 or YT-28 rock drill is used to drill the eye, and the non-electric detonator is detonated. Use the cutting up the mountain brush to help the ore body boundary. In the recovery process because of better security situation after the top slate stone uncovered, so take two slicing, height 5m per stratification. The inclined shallow hole is used for ore mining, according to the hole spacing of 1.0-1.3m, the row spacing is 0.7-1.0m plum-shaped drilling, the blasthole is inclined upwards; after the blasting, the smooth surface layer is controlled to control the roof. The inclined hole drilling and smooth blasting construction directions are all from top to bottom.
(2) Ore transport. After the end of the mining, the electric slag is used to go to the funnel, and the funnel is transported into the mine through the funnel to the ore. At the elevated level, the mine is discharged to the mine by the sluice, transported to the main well, and lifted to the surface through the main well cage.
2.4 Top board management The ore body is divided into two layers of mining. The top layer is made of copper-bearing skarn during the first layer of mining. The top plate is dense, and the top plate is controlled by smooth blasting to achieve good results. However, the rock on the upper part of the ore body is relatively broken. The safety of the roof is prominent when the last layer is recovered. When the last layer is recovered, the roof is mainly controlled from the following aspects.
(1) Strictly control the mining height not exceeding 5m, smooth blasting control roof, eye distance 450~500mm, and the roof is slightly arched after construction.
(2) Technical personnel and construction personnel strengthen technical communication and communication, adjust mining design parameters and blasting parameters according to the exposed geological changes, and adopt measures such as multi-hole and less charge to reduce the impact of blasting vibration on surrounding rock.
(3) Reduce the construction time of construction workers in the stope, do a good job in construction preparation and coordination of various processes, and adopt measures of “strong mining, grabbing, fast charging†[5-6].
(4) Measures such as bolt support and anchor net support for the weak side of the top and the fault or slip surface to improve the strength of the top and ensure the safety of the workers.
2.5 Filling work After the first layer of mining, the cement filling is timely. After the filling is completed, the next layer of mining will be carried out. After the end of the last layer, the tailings will be used to enrich the goaf in the goaf.
3 Economic effect analysis After several years of research, the Shaoshan copper mine difficult small ore body project team has achieved good results. Safe recovery of ore 110,000 t, the amount of copper metal 1540t, creating economic benefits of nearly 70 million yuan. Among them, the 25#1 ore body recovered a total of 13555t of ore, the amount of copper metal was 199t, and the output value was nearly 7.5 million yuan. It took only 8 months from the time of picking to the end of the recovery.
It has been shortened by nearly one year than the conventional stratified filling mining method.
4 Conclusion
(1) Using the comprehensive mining method, the cutting roadway is constructed along the side of the ore body, and the stratification according to the vertical height of the ore body has achieved good economic benefits in the 25#1 ore body. It has been proved by practice that this mining method is applicable in ore bodies where the horizontal area of ​​the ore body is too small, the thickness is not large, and the shape is complex and the side angle is slow.
(2) Special attention should be paid to the ventilation work during the construction. Due to the construction of the single-head roadway when the construction is cut in the early stage, special attention should be paid to strengthening the ventilation work.
(3) The difficult ore bodies of the Lushan Copper Mine have different shapes and complex geological conditions. They are often unable to be harvested by conventional methods. When selecting mining methods, specific conditions should be analyzed and mining methods should be used flexibly. Through flexible layout and selection of mining methods, it is possible to speed up the recovery of difficult ore bodies and achieve safe, efficient and economical mining of difficult ore bodies, which is of great significance for similar mines.
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