1 Overview
The mine is located in the northwest high altitude, complex geological structure mining, ore unstable, there are two different types of mine ore: Pb Zn Ag-Cu lead-zinc ore and independent mine mining method of choice to Sublevel Method and shallow hole retention method. Due to the different annual processing volume, the status quo of the ore body descending is caused. With the increase of the service life of the mine, the ground pressure activity begins to appear: the roadway extrusion deformation, the patchwork, the roofing phenomenon frequently occur, and the stope loss depletion index Increase.
2 Mine status
The mine uses Pingyi+main chute (lead-zinc chute)+auxiliary inclined well to develop, silver-copper-lead-zinc ore and independent lead-zinc ore. The mine production has been nearly 10a, and the development and transportation system of silver-copper-lead-zinc ore has been The lead-zinc slip well system that forms the independent lead-zinc ore has not yet been fully formed. After the main downhole slip into the middle of each main adit 3886m produced silver in copper ore beneficiation plant to transport by rail; independently after the lead-zinc ore in the middle of the pit before stacking adit port, the car was shipped to the dressing with the road surface plant. The mine has formed 3,886m main transport flats, as well as 4250, 4200, 4160, 4100, 4050m and 4000m stages, and is currently preparing for the 3950m middle section.
The silver-copper-lead-zinc ore body above the middle of 4100m, except for the middle part of the 4100m part, the Cu6 mine is about to be harvested in vitro. The remaining part is basically the pillar. Cu7～Cu12 is mostly narrow and low grade ore body, which is difficult to meet the recovery conditions, above the middle of 4200m. The mining method using a bottomless column and the like has also been basically finished. The Cu1 ore body of the 8-50 line in the middle of the 4050m is currently being harvested. The independent lead-zinc ore body above the middle section of 4160m has basically recovered, and most of the Pz1-Pz3 independent lead-zinc ore bodies of the 6-3m middle section of the 4100m section have been recovered, and the remaining lead-zinc ore bodies have not yet been mined.
3 The necessity of using the filling mining method
The production practice shows that with the implementation of open field mining, the exposed area of ​​surrounding rock is getting larger and larger, and the amount of surrounding rock is getting larger and larger, especially in the middle and late mining of the stope, the local stope even produces large The large scale pieces help to make the ore and surrounding rock mix during the mining process, causing the ore loss to become more and more dilute. After the mining of the mine, some of the mines fell due to the surrounding rock gangs, and the mining conditions of the pillars were severely damaged. It was difficult to recover normally and only the residuals could be carried out. When some mining houses are mining, the amount of surrounding rock is less and the integrity of the pillar is better. However, after the middle and deep hole collapses, the exposed area of ​​the upper and lower discs is further enlarged, and the stress changes in the goaf are intensified, which makes the upper and lower discs larger. The scale fell, and the top column of the ore and the bottom column of the upper stage also fell.
In addition, with the development of the open field method, there are more and more multi-level goafs, and the phenomenon of falling is becoming more and more serious. According to the survey, the current ground pressure problem of mines has been very prominent, and the safety pressure of mine production is also growing.
At present, the proportion of mining methods used in the mine is 60% for shallow hole retention and 40% for segmented empty field method. The segmentation empty field method design loss rate is 15%, the shallow hole retention method design loss rate is 12%, and the comprehensive loss depletion rate is 13.5%. However, it is difficult to reach the design index in actual production. According to the on-site investigation, the depletion rate of the pillar recovery is more than 50%, and the comprehensive mining depletion rate is at least 22%. In order to fully recover the ore resources and meet the production demand, The situation of simultaneous operation in multiple middle sections has been formed; the mine urgently needs to use the filling method to solve the above problems.
According to the investigation of the mine site, the ore body above 4250m should not be recycled, and the 4200, 4160m middle pillar is recovered by caving method. The 4100m middle section of the independent lead-zinc ore body is mined by the upward horizontal stratified filling method. The 4100m middle section of the silver-copper ore body is only suitable for the recovery of the pillar due to the collapse of the pillar and most of the empty area. The survey results show that: 4106, 4206 The 4207 mine can be filled, so it is pumped to fill the three mines. The silver-copper ore body below 4100m and the independent lead-zinc ore body are all mined by the upward horizontal layered filling method.
4 filling plan
4.1 filling system
The filling system mainly includes the ground filling filling preparation station, the tailings conveying system of the concentrating plant to the filling preparation station, the filling well and the pipeline laid in the well lane. After the ground mixing station is prepared to meet the filling process requirements, the filling slurry is transported through the filling pipeline to the designated place in the well to fill the gob.
The filling line of the ore body below 4100m is: the filling port of the filling pump of the filling preparation station→4100m flatness→filling well→the middle section of the roadway below 4100m→filling the contact roadway→filling the stope. The filling material is transported by a filling pump, and is transported to the filling stop by self-flow after each middle section.
The 4100～4160m ore body filling line is: filling filling station of the filling filling station→4100m flat ç¡â†’filling the contact roadway→filling the stope. This filling line is determined according to the stability of the mining area in the middle section of 4100m. If the mine has collapsed, there is no possibility of filling.
4.2 filling system process
The tailings are conveyed to the sand bin by a concentration of 55% tailings. The tailings are injected into the silo from the center of the silo, and the overflow water is discharged from the annular overflow trough in the silo. After the tailings in the silo are homogenized by pressing gas (pressure water), the sand discharging pipe is opened to supply the tail mortar to the mixer. In order to detect and adjust the sand discharge flow, an electromagnetic flow meter, a manual regulating valve and a flow valve are arranged on the sand discharging pipe. The bulk cement is transported from the tanker to the filling station, and is blown into the cement silo through the soot blowing pipe. The bottom of the cement silo is provided with a gate valve, a double pipe screw feeder and a spiral electronic scale, and the cement is metered and conveyed into the mixing drum. The tail mortar and cement enter the twin-shaft mixer through their respective feeding lines, and the filling slurry is initially stirred by the double-shaft mixer, and then enters the high-speed activated mixer through the tapered connecting member to perform strong activation and stirring. After the above-mentioned two sections are uniformly stirred, the filling slurry is pumped through the filling well and the underground pipe network to the underground mining site for filling.
4.3 Filling preparation station
The filling station has a pulping capacity of 100m3/h. The tailings are transported through the pipeline to the tail silo (two Φ8.0m sand silos, each with a geometric volume of 737m3 and an effective volume of 583m3). The cement is transported to the vicinity of the mixing station by tanker, and the cement is blown into the cement silo (1 seat, Φ8.0m, height 26m, cement silo capacity 693t) with its own compressed gas.
When filling, the tailings are transported into the agitation tank through the sand-discharging pipe at the bottom of the warehouse, and the concentration of the slurry and the flow of the tailings are controlled by a concentration meter and a flow meter; the cement is conveyed into the agitation tank through the double-tube screw feeder at the bottom of the tank. The cement is metered by the punching flowmeter, and the double-tube screw feeder is adjusted by the frequency conversion speed regulation; the water is metered by the electromagnetic flowmeter, and is adjusted by the electric valve. The tail mortar, cement and appropriate amount of water with a concentration of about 68% enter the feed hopper through the respective feed lines and are supplied to the mixer. The mixer is a two-stage continuous stirring with a two-shaft mixer + a high-speed activated mixer. The two-stage mixer is continuous with a connecting bucket. The filling material is uniformly stirred in two stages to prepare a filling slurry with moderate concentration and good fluidity, and enters the measuring tube, and is transported by the filling industrial pump, and the concentration meter, the flow meter and the electric motor are sequentially installed on the slurry tank outlet line of the stirring tank. Pipe clamp valve for detecting and controlling the concentration and flow rate of the filling slurry.
The prepared filling material is placed in the middle section through the filling well, and the filling slurry conveying pipeline is formed by the horizontal pipeline and the vertical pipeline, and the filling slurry prepared by the filling station is transported to the filling place. The main pipe of the filling pipeline adopts Φ180mm×10mm composite wear-resistant steel pipe, the horizontal horizontal pipe adopts Φ180mm composite wear-resistant steel pipe, and the inner diameter of the mining site is 110mm polyethylene reinforced plastic pipe.
4.4 Stope filling process requirements
The mine uses an upward horizontal layered cementation filling mining method. In order to fully recover ore resources, achieve low-cost, low-cost and efficient recovery, reduce filling costs, reduce downhole pollution, and accelerate the speed of the stope, the filling system's process and conveying performance must meet the upward horizontal layered cementing filling method for filling. Claim.
(1) In order to ensure the strength of the filling body, the concentration of the filling slurry must be >68%, and the filling slurry is filled into the mining field without substantially dehydrating.
(2) The filling station must be able to achieve automatic control of each filling material, including its flow rate and concentration, and perform inspection before entering the filling pipeline and achieve feed adjustment of each filling material.
(3) According to the requirements of the upward horizontal layered cementation filling mining method, the filling body is divided into a false bottom layer, an intermediate layer and a pouring layer. The ratio of the pseudo-bottom filling slurry to sand is 1:4, the concentration is >68%, the ratio of the intermediate layer filling slurry to sand is 1:12, the concentration is >68%, and the ratio of the filling layer to the filling slurry is 1:4. Concentration >68%.
(4) After filling the retaining wall for 2d, it can resist side pressure above 4MPa.
(5) The end of the main filling pipe must have an accident pool and a flushing pipe valve to ensure that the flushing water of the pipe before and after filling does not enter the stope.
5 Conclusion
According to the current situation of the mine and the stope conditions with filling conditions, in the early stage of the completion of the filling station, the mine plans to select some 4050m silver-copper-lead-zinc mining yard and 4100m independent lead-zinc mining yard for the initial filling. According to the field test, the main The technical and economic indicators are superior, the production capacity of the stope has been greatly improved, and the needs of the ore blending of the plant have been met. The use of medium-deep hole caving ore has greatly reduced the direct cost of mining, which is reduced by about 37%; The environment has greatly improved in terms of safe work. In addition, from the construction process of 1900m segmented cutting patio and the degree of differentiation and fragmentation of 1900m sublevel caving ore, the maximum exposed area of ​​the broken ore vein group is about 100m2. It is safe and reliable to use the segmental ore-remaining caving method to exploit the broken vein group. of.
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Source: Mining Technology: 2016, 16(2);
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