Research on high-efficiency mining method for low-grade complex lead-zinc mine

0 Preface

Three of your mouth lead-zinc mine ore block south of Zijin Mining Co., Ltd. development and construction of Urad Rear Banner, lead and zinc ore industry resource of 87,667,200 t, Pb average grade of 0.53%, Zn average grade of 2.34 %, Pb metal amount is 46.16 million tons, Zn metal amount is 2.0506 million tons, and sulfur and silver elements are also associated.
The ore body in the mining area is distributed in the southwest--the northeast, 40 lines from the west to the west, 88 lines from the north to the east, with a length of 1400m, a width of 1300m from the north to the south, a buried elevation of 475-880m, and the deepest point is 665m below the surface. 360m from the surface. The deposit is jointly developed by the main and auxiliary shafts + ramps. The main mining objects of the deposit are 9-zn, 10-1-zn, 10-2-zn, 11-3-zn, 3-2-zn and 2-zn ore, which are produced according to the technical conditions of the mining. The ability to demonstrate that the mine construction will be completed in stages, the initial scale is 5000t/d, and the later scale is 10000t/d.
The ore resources in the mining area are large, the grade is low, the number of ore bodies is large, the shape is complex, and most of the ore bodies are gently inclined—the inclined medium-thick ore bodies, which are mostly superimposed and produced, and each ore body interacts during mining. Restriction, many mining and cutting projects, ore loss is difficult to control, belonging to the extremely difficult mining type of ore body, the choice of mining methods is complex and important, the mining method directly determines whether the mine can reach the design scale, but also determines the overall economy of the mine Benefits [1-2]. Therefore, it is necessary to find a high-strength mining method that is suitable for both mining technical conditions and mine production scale, and finally achieves stable production of mines and creates conditions for maximizing the comprehensive economic benefits of mining.
1 mining technical conditions
The mine first mines the 9-zn ore body, which is the largest zinc ore body in the region. The average grade of Zn is 2.30%, the average grade of Pb is 0.54%, and TS7.76%.
The ore body is gently distributed with the ground layer and continues to distribute on the 40-88 line. The strike length is 1020m, and the inclination is 1190 (56 lines) to 1250m (64 lines). The ore body thickness is 2-28m, and the inclination angle is 10°～90°.
Deep hole continuous recovery scheme in 2 section mining
According to the mining method requirements of the mining technical conditions of the Sanguikou South Mine Section, and the framework route of the mining method that has been determined by the mine, the mining method is technically feasible for the gently inclined, inclined and steeply inclined medium-thick ore bodies. There are: deep hole continuous mining method in segmental mining, medium-deep hole cutting roof column method [3], high-segment explosive force mining empty field method [4-6], chassis funnel continuous mining section mining house The method [7-8], through the technical and economic comparison, according to the particularity of the ore body, the deep hole continuous mining method in the section mining is selected as the gently inclined, inclined and steeply inclined medium ore body of the mine. Mining method.
2.1 stope structure parameters
Under normal circumstances, the length of the panel is less than 240m, and adjacent multi-layer or single-layer ore bodies can form a mining panel. Each layer of orebody in the panel is divided into ore blocks along the strike, and the ore blocks are arranged along the ore body. Three nuggets can be arranged for each panel. The middle section of the nugget is 50m high and 80m long, and the width is the thickness of the ore body. The first step is to return to the mining room. The parameters of the mine are about 42.5m high, 68m long and the thickness of the ore body. The 12m pillar between the mines in the middle section is used to arrange the mining project. A pillar with a horizontal width of 10 m between the middle sections is used to isolate the upper and lower middle sections from the mining room. In the middle section, the section height is determined according to the requirements of rock drilling and blasting, generally 13~15m.
2.2 Mining and cutting engineering
Considering the convenience of construction and the mutual utilization of the project, the ramps between the sections are straight through, and each section of the tunnel is used as the steering lane; the wide pillars between the stopes are arranged perpendicular to the pillars. The mine also explores the veins, which penetrate the layers of the ore body in the panel. The chute is arranged at a distance of 3 to 3.5 m from the outside of the segmented vein roadway. The chute specification is Φ2.5 m, and a small branch chute is used between the chute and the section. The stope adopts the bottom structure of the trench, and within the range of 12~18m from the lower plate boundary of the ore body, the lower plate is arranged along the vein transport roadway, and the ore loading route is arranged to the ore body every 10~14m from the vein transport roadway.
The horizontal rock drilling roadway is arranged along the veins of each section, and the rock drilling roadway needs to be increased according to the thickness of the ore body; the cutting roadway is arranged along the vertical ore body direction of the mining field, and the vertical cutting patio is arranged near the one side in the cutting roadway to penetrate the upper and lower sections.
2.3 mining process

(1) Rock blasting in the stope. The fan-shaped medium-deep hole rock blasting is used, and the rock drilling equipment is YGZ-90 machine. The diameter of the drill bit is 60-76 mm, and the depth of the blasthole is 10-18 m. In order to improve the height of the section and reduce the mining project, the blasthole with a 5° inclination angle is used on the upper plate. The blasthole spacing is 1.3 to 1.8 m, and the hole bottom distance is 1.3 to 2.8 m. The explosive consumption is 0.33~0.38kg/t. The detonator detonator is used to detonate. Each blasting is 2 to 3 rows, and multiple stages can be simultaneously blasted.
(2) Ventilation of the stope. Ventilation in the stope is relatively difficult, and ventilation is required by the air duct and the auxiliary fan. After the cutting of the cutting patio is opened, the venting of the stope is relatively easy after the blasting begins. The fresh air flow enters the working surface from the lower part of the stope and the lower plate, and passes through the vein. The dirty wind is discharged from the upper middle section.
(3) Mining in the stope. The bottom of the stope is mined by a 4m3 diesel scraper. The ore is loaded by the road. The ore loaded with the shovel is transported into a nearby chute or directly into the car. It is transported by the car to the central chute and decentralized to the crushing station of 537m. Each section is mined by a 2m3 diesel scraper. The scraper is directly shoveled on the working surface. The shovel loaded ore is transported into the nearby chute, and the chute is placed in the middle funnel and then loaded into the car by the funnel. When the method is harvested, there are many operating points and many mining points. The production capacity mainly depends on the management of production organization. Under normal circumstances, the mining capacity of 300-500t/d can be guaranteed.
2.4 empty area processing
Independent small goaf (within 50,000 m3 in goaf) or independent nugget with small ore body thickness. Under normal circumstances, the goaf does not need special treatment. After the end of mining, it is closed, and it will be filled with natural debris. Empty area is fine. A wide range of goafs can be designed according to the specific conditions, and the treatment method is mainly based on the surrounding rock of the caving area [9-11]. It can also be filled with tailings with suitable cement (50-80kg/m3). The purpose of adding cement is to prevent tailings from flowing downhole and cause major safety accidents.
2.5 Main technical and economic indicators
According to the designed stope structure parameters, rock drilling blasting parameters and equipment, the economic indicators calculated are: the production capacity of the stope is 300-500t/d, the depletion rate is ≤16%, the loss rate is ≤18%, and the cutting ratio is 43. 2m3/kt.
3 major problems and suggestions in production
The mine was put into operation in September 2014, and the production capacity reached the requirement of 5000t/d in the previous design. With the comprehensive promotion of mining methods in the mine, many problems have appeared in the production.
(1) The cutting ratio is large. Because the designed mining method is mainly used in medium-thick ore bodies, with the deepening of production, the exposed ore bodies are greatly different from the original geological data, and the thickness of the ore bodies is greatly reduced, which is caused by excessive mining ratio. The main reason.
(2) The depletion rate is large. The contact zone of the ore exposed by the 9-Zn ore body is relatively broken. After the blasting, a large number of surrounding rocks will enter the ore due to the impact of the blasting, resulting in an increase in the depletion rate of the ore.
In view of the above problems, after investigation and analysis, it is recommended to increase the intensity and density of prospecting on the one hand, accurately grasp the occurrence of ore bodies, and select suitable mining methods according to the occurrence (such as the shallow inclined ore-retaining method for steeply inclined thin ore bodies). On the other hand, the parameters of rock drilling and blasting are optimized, and the controlled blasting technology is adopted in the broken section of the rock to reduce the disturbance of the surrounding rock by the blasting, and to keep the surrounding rock stable, and the mining depletion rate can be controlled within the designed range.
4 Conclusion
The Sanguikou lead-zinc mine is a low-grade complex and difficult mining bed. Choosing a suitable mining method is the prerequisite for ensuring safe and efficient mining.
The deep hole continuous mining method in segmental mining has the advantages of strong applicability, combination of exploration and production, large production capacity, low mining cost, safe mining operation, strong regulation of mineralization and easy production management. More than one year of production practice has proved that the deep hole continuous mining method in segmental mining has good applicability to mining technical conditions. Through the preliminary production test, summing up the experience and optimizing the plan, it can guarantee the further improvement of the mine production capacity in the future.
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