0 preface
The mining problem in the process of gently inclined medium-thick to thick orebody mining has always been the focus of research and optimization of this type of ore body mining. The reasonable bottom structure of the stope is very important for safe and efficient mining and obtaining good technical and economic indicators. The meaning.
The average thickness of the copper ore Eastern YONGPING 42m ore, ore average tilt angle 30 °, dipping thick metal ore, ore consistent coefficient f = 8 ~ 10, the ore body weight 3.12t / m3, surrounding rocks and ores loose The coefficient is 1.46, the natural angle of repose is 38°, and the ore is generally stable. For this type of ore body, after continuous optimization of the mining method, the mine is finally determined to use the staged rock drilling stage, the empty field, the post-filling mining method for mining, and the mining body is divided into a panel every 90m, and the vertical ore body orientation in the panel The stope is arranged and the mining is carried out in two steps. The width of the stope is 12m in one step and the width of the stope in the second step is 18m. The length of the stope is the horizontal thickness of the ore body.
With the continuous advancement of mining, the first-stage mining site of the panel has been harvested by flat-bottom structure, and the post-mortem cementation filling has been carried out. When the second-stage mining of the panel is carried out, the original design scheme is to fill the tunnel in the body, but Since the actual filling strength of the partial one-step stop does not meet the design requirements, there are certain problems in the roadway filling the body, and the cost of support is high. Therefore, the bottom structure of the two-step stope needs to be optimized.
1 stop floor structure scheme
In view of the problems existing in the mining structure of the bottom structure of the second-step mining area, combined with the current status of mining, and meeting the needs of large-scale scraper and mining trucks, three technically feasible bottom structure schemes are proposed: One: filling the structure of the bottom of the trench in the roadway; scheme 2: the bottom structure of the sulcus; scheme 3: the bottom structure of the bucket.
In each plan, the horizontal thickness of the ore body is 42m, and the average inclination angle is 30°. All the cutting roadways are calculated according to the designed sectional area. Each scheme is divided into a panel along the direction of the ore body every 90m. The vertical ore body in the panel is arranged to adopt the stope. The length of the stope is the horizontal thickness of the ore body. Each panel contains three completed steps. And three two-step stopries to be recovered, the width of the first and second steps is 12,18m. The height of the middle section is 37m, and the middle section is divided into two sections. The height of the section is 17,20m from bottom to top. The total mine volume of the panel is 519,000 tons, of which the total amount of mining in the second step of the panel is 311,000 tons. This project quantity and loss depletion index only compares the contents of the bottom structure.
1.1 Filling the body to tunnel the roadway trench bottom structure plan (Scheme 1)
After the strength of the filling body in the first step of the plan is reached, the rock-sparing roadway along the original one-step mining road is used to excavate the ore-penetrating roadway in the filling body, and the ore-passing roadway is used to construct the loading and unloading roadway in the two-step rocking roadway. The loading distance is 10m, and the angle of intersection with the mining roadway is 60°.
In the second-step mining stop mining, rock blasting is carried out in each section roadway. The caving ore is mainly mined in -87m section, and part of the ore is segmented in -70m. After the mining is completed, it can be filled. The bottom structure scheme is shown in Figure 1.
1.2 The structure of the bottom side of the sulcus (Scheme 2)
The one-step stope of the panel adopts the segmental empty field method to recover, the bottom bottom structure, and the post-clay cementation filling. In this scheme, the excavation roadway, the loading and unloading road and the rock drilling roadway are excavated in the second-step mining site. That is to say, in the stope, the two sides of the original ore roadway are excavated with a vein roadway, one is used as a rock tunnel and the other is used as a mine roadway. The two roadways are connected by a loading tunnel.
The second-step stope adopts segmented medium-deep hole recovery, and the caving ore is mainly mined in -87m section, and part of the ore is segmented in -70m. After the second step of the mining site is completed, the filling is completed. There are many roadways in the bottom structure, and the columns are small. It is recommended that the roadway be supported by spray Anchor nets. In addition, considering that the -87m horizontal triangular pillar has a large loss, a medium-deep hole receding type can be used to recover part of the pillar. The bottom structure scheme is shown in Figure 2.
1.3 The scheme of the bottom of the bucket is worn (Scheme 3)
The mining level of this project is -95m level, the roadway height is 3m, and the absolute height of the roadway roof to the -87m filling body floor should be greater than 5m. Firstly, the slope is drilled from the middle section of -100m to the level of -95m, and then the roadway along the outer vein of the lower vein is drilled at -95m level. Then, the mine tunnel and the loading tunnel (bottle neck) are excavated from the vein road to the second. In the middle of the stope, the bucket neck and the -87m rock-boring road are connected from the end of the loading tunnel, and the upper part of the bucket neck is properly leaked to reduce the chance of card leakage.
Most of the ore that collapsed slipped down to the -95m level through the neck and was mined to the ore chute at a level of -95m using a 2m3 scraper. This scheme is shown in Figure 3.
2 qualitative and quantitative comparison analysis of each program
2.1 Comparison of advantages and disadvantages of the program and indicators
Through the detailed description of the bottom structure scheme of the two-step two-step stope above, the advantages and disadvantages of each scheme are as follows:
(1) Filling the internal tunnel roadway trench structure plan (Scheme 1) The double-sided mining area has large production capacity, high recovery intensity and low loss; the original project can be fully utilized, and the engineering quantity is relatively low. However, it is necessary to dig the roadway in the filling body, the construction is difficult, and the strength of the filling body is not up to the requirement that the support cost is high.
(2) The structure of the bottom side of the sulcus (Scheme 2) The bottom structure of the structure is all in the ore body and can be used as a by-product. However, the original project cannot be used, and the amount of engineering is large; the loss of one-side mining is more; the bottom structure is more, and the cost of support is higher.
(3) The bottom structure of the bucket neck (Scheme 3) The bottom structure is all inside the ore body, and the stability is good; the production capacity of the two sides is large and the loss is small; the maintenance cost of the roadway is not affected by the quality of the one-step filling body. Low and safe. However, the amount of engineering is large. The main technical and economic indicators of each program are shown in Table 1.
2.2 Comprehensive evaluation based on Fuzzy theory
Through comparison and analysis of the advantages and disadvantages of the above three programs and the specific technical and economic indicators, the key points of each program comparison include safety, production capacity, roadway support cost, engineering quantity, loss rate and depletion rate. Each scheme has its own advantages and disadvantages, and it is difficult to directly analyze the optimal bottom structure scheme. Therefore, the fuzzy comprehensive evaluation with good decision-making function can be used to further quantitatively compare and analyze the advantages and disadvantages of each scheme.
According to the sensitivity of the bottom structure scheme to the above aspects and the weight matrix of each factor, the eigenvector 对应 corresponding to the largest eigenvalue λmax of the matrix is ​​calculated as the weight vector, and the calculation result is normalized to obtain the current fuzzy synthesis. The weight of the judgment is one-dimensional row vector:
F = [0.467, 0.194, 0.065, 0.045, 0.135, 0.094]. The qualitative indicators with no clear parameters among the above factors are evaluated by the grading method (between 0 and 1), and the quantitative indicators of each program are dimensionlessly processed to make the factors comparable.
Among them, the dimensionless treatment of quantitative indicators is as follows:
Where fjmax is the maximum value of the j factor indicator; fjmin is the minimum value of the j factor indicator; d is the grade difference and d=(fjmax-fjmin)/(1-0.1); fij is the index of the j factor of the i scheme value.
After evaluating, non-dimensionalizing and normalizing the factors of the above three bottom structure schemes, the final fuzzy comprehensive evaluation matrix R can be obtained:
The weighted average model is used to evaluate each scheme, and the final result is:
Based on the above multi-factor fuzzy comprehensive evaluation results, it can be seen that the scheme 3 (the bottom-of-the-bottom structure scheme) of the three kinds of bottom structure schemes has the greatest degree of membership required. The comprehensive qualitative and quantitative final analysis results show that scheme 3 is Yong The optimal scheme for the bottom structure of the second-step stope in the gently inclined thick ore body panel in the eastern part of Pingtong Mine.
3 conclusions
(1) Sectional rock drilling stage The empty field post-filling mining method is carried out in the bottom structure of the stope. The bottom structure of the stope greatly affects the efficiency of the mining method, labor productivity, and the amount of mining work. The depletion and loss of ore and the safety of mining production are necessary to optimize the arrangement of the bottom structure in combination with the occurrence conditions of the ore body.
(2) In view of the problems existing in the bottom structure of the second-step stope in the thick ore body of the eastern Yongping Copper Mine, three technically feasible schemes are proposed, and the scheme is qualitatively and quantitatively compared and analyzed according to fuzzy comprehensive evaluation. As a result of the analysis, it can be seen that the scheme 3 (the bottom-bottom structure scheme) is the preferred bottom structure scheme. This bottom structure has been in-situ industrial trials for more than half a year in the E3-6 stope in the eastern part of Yongping Copper Mine. It has been proved that the scheme can meet the demand for mining in the second-step mining area of ​​the panel. According to the site mining statistics, The actual loss rate of the stope is about 12%, and the depletion rate is about 17%, which meets the expected technical and economic indicators. Therefore, the bottom structure of the mine can be promoted and applied within the mining area.
references:
[1] Li Xiangdong, Wu Min, Wan Bing, et al. Comprehensive technology research on high-efficiency mining of gently inclined to medium-thick ore bodies in the southern Yongping Copper Mine (stage research report) [R]. Changsha: Changsha Mining Research Institute Co., Ltd., 2015: 20-51.
[2] Zeng Lingfang. Optimization of mining method for gently inclined thick ore body [J]. Modern Mining, 2015 (4): 17-19, 30.
[3] Feng Chunan. The application of the bottom structure segmentation empty field å…… filling method in Chuxiong Mining and Metallurgy Company [J]. Mining Technology, 2009, 9(1): 4-5, 10.
[4] Chen Faji, Zhao Guoyan, Jane Wanguo, et al. Application of fuzzy theory in the mining method of medium-thick and gently inclined ore body [J]. Mining Technology, 2006, 6(2): 1-3.
[5] Ge Wenjie. Comprehensive evaluation and selection of mining methods using fuzzy mathematics [J]. Mining Engineering, 2012, 10 (3): 14-17.
Author: Xiaohua; JCC Yongping Copper Mine, Jiangxi Shangrao City, 334,506;
Jiang Feifei, thousand men; Changsha Institute of Mining Research Co., Ltd., Changsha 410012; National Metal Mining Engineering Technology Research Center, Changsha 410012;
Source: Mining Technology 2015, 15(5);
Copyright:
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