Application of no-mineral horizontal stratified continuous mining method in medium-thick ore mining

Shihu gold ore mining area 101 is a thin original ore, ore mining shallow hole mining method. Due to the poor stability of the surrounding rock of the ore body, when the large amount of ore is mined in the late stage of the ore-retaining method, the surrounding rock is easy to collapse and the depletion loss index is too large. According to statistics from relevant departments, the mining depletion rate is nearly 50%, and the loss is taken. Up to 20%. The gold grade of the 101 mining area is relatively high. According to the data provided by the geological department, the average gold grade of the middle section of 180m is 6.5g/t. The mining method of high loss and depletion rate seriously restricts the improvement of the company's economic benefits and the company. sustainable development. With the downward extension of the mining depth, the thin ore body in the upper part of the mining area is about to end, and the ore body in the middle section of the 180m middle section is mainly medium-thick ore body; due to the change of the thickness of the ore body and the limitation of mining technical conditions, the ore remains The mining method is no longer suitable for the mining of medium-thick ore bodies in the 101 mining area. Therefore, mining methods with low loss and depletion must be sought.
1 mining technical conditions
The ore body in the middle section of 180m is mainly distributed between 19 and 31 exploration lines. The ore body is about 315m long and has an inclination of 73°. The average thickness of the ore body is 6.3m, the maximum thickness is more than 10m, and the average grade is 6.5g/t.

The ore body lithology is silicified rock and chlorite petrified siliceous rock. The ore body RQD is generally 70%-90%; the f coefficient is 5-7, the crack is not developed, the average compressive strength is 58.44MPa, and the shear strength is 13. 3MPa, tensile strength is 1.72MPa, and the stability is good. The lower part of the ore body is black cloud slanted gneiss , the rock is stable; the upper plate rock is a potassic black cloud slant gneiss, medium stable ~ unstable, localized kaolin soiling phenomenon, when the exit area is too large In the process of mining, it is easy to fall off. The ore has a body weight of 2.85 t/m3 and a rock loosening coefficient of 1.54.
2 mining method selection
According to the mining technical conditions of the ore body and the current mining situation, several feasible mining methods are proposed for this type of ore body: the non-mineral column horizontally layered full tailings cemented filling continuous mining method, after the retention method Filling and up-stratification filling combined mining method, segmented medium-bore deep-hole filling and upward stratified filling combined mining method. Through comprehensive comparative analysis of the three mining methods, the final mining method is selected from the non-mineral column to the horizontal layered full tailings cementing filling continuous mining method. The mining method is shown in Figure 1.

3 Non-mineral column horizontally layered full tailings cemented filling continuous mining method
3.1 mining engineering layout
The stope is arranged along the direction of the ore body. The length of the stope is 60m, the width is the thickness of the ore body, and the height of the middle section is 40m. There is no column and top column between the stope and the stope.
3.2 Acquisition and cutting
A total of 5 stopries were arranged in the middle section of 180m. The main mining projects include ramps, sectioned alleys, chutes, stopway links, and chute corridors. The section height is 10m, and the middle section of 180m is the middle section of 220m. Therefore, the three sections of 190, 200, 210m are arranged between the middle sections of the two sections, and all of the sections are arranged. From the middle of the 180m middle transport lane, the sloping ramp is connected to the 190m section of the alley, and the 190m section roadway is used to connect the 200m section roadway and the 210m section roadway. In order to save the cutting capacity, 210m There is no ramp connection between the segment and the middle level of 220m. Through the construction of the stopway of each section of the roadway, the construction of the stopway is first carried out, and the maximum slope is 20%. After each upward recovery and filling of a stratification, the top of the stopway is raised upwards to the previous stratified height position, the waste rock is filled to fill the stopway, and the excess waste rock is transported to the stope by the scraper. The tailings cemented backfill together form a backfill.
If the production task of the panel is small, there is sufficient remaining turnaround time between the exits of the panel, and the access road can be digged from the stope to the section roadway, and the waste rock can be used to break into the open space. Reduce the construction difficulty, improve the operation efficiency and reduce the cost of tunneling. During the test period, the contact roads of each stop are constructed according to this method. In order to maximize the efficiency of the electric scraper, a slippery mine is arranged outside the coil of each stop.
3.3 stoppage work
Starting from the stopway along the vein roadway, the shallow hole drilling machine is used to pull the bottom to the boundary of the ore body, and the height of the bottom is 2.5m. The bottomed ore is mined by artificial ore-loading or shipping machine. After the ore is loaded, the mine is transported from the tunnel to the middle section. The stope does not leave the top and bottom columns, and the lower middle section corresponding to the stope still has the ore body to be recovered. After the completion of the bottoming, the high-strength concrete false bottom is laid, with a thickness of 0.5m. Replacing concrete with a filling body, filling a thickness of 1 m, and adding steel bars and metal mesh to the bottom plate. The actual amount of cutting work in the test panel area is shown in Table 1.

3.4 recovery
(1) Rock drilling and blasting. After the bottom of the bottom is finished, it starts to stratify from the bottom to the top. Firstly, the first layer of ore body mining is started. Because the surrounding rock of the ore body is not stable, in order to reduce the ups and downs of the surrounding rock, in the mining, the upper ore body is recovered by pressing or topping. The 1.5m ore body will not be recovered for a while, and will be filled after the ore is discharged. The filling height is not higher than the bottom height of the upper ore body. After the strength of the filling body meets the requirements, the second layer of ore body mining is started. Similarly, the ore body is first recovered. After the ore is discharged, the 1.5m ore body reserved for the upper plate is recovered and the horizontal hole is used for mining. The part of the ore is small in quantity, and the ore-mining speed is fast. After the ore is exhausted, it is filled, and the surrounding rock fragments are reduced. And so on until the mining to the upper middle section. Rock drilling parameters: hole spacing 1 ~ 1.2m, row spacing 0.8 ~ 1m, hole depth 2 ~ 2.5m. The plum blossom type arranges the blasthole, and the detonating tube detonator blasts the explosive in the hole. The explosive consumption of single explosive is 0.4kg/t, and the large piece of secondary crushing, the comprehensive consumption of explosives is 0.45kg/t.
(2) mining. Due to the limitation of the main wellbore section, the large scraper cannot enter the underground. At the same time, in order to reduce the amount of cutting and production and the production cost, combined with the production capacity requirements of the stope, the mining equipment adopts 0.75m3 electric scraper and scraper tail. The effective length of the rope is 85m. Before the mining, the top stone is treated first, and the ore heap is sprinkled to reduce the dust. The scraper mining adopts the forward-type mining method, and the mining ore is transported from the stopway and the sectioned alley to the ore chute through the scraper. A 400mm×400mm sieve is installed at the wellhead of the chute, and it cannot be smashed by blasting or sledgehammer after passing through the large block of the sieve.
(3) Ventilation. The fresh air flow enters each section from the middle section of the transportation lane and the slope of the mining area, and then enters the stope through the sectioned roadway and the stopway of the stope. After flushing the working surface, the dirty wind is introduced into the upper and middle section of the transportation lane by the ventilation patio. Return air system, discharge the surface.
3.5 full tail sand cement filling
After the completion of the stratified mining, the filling process begins. Before the filling starts, the bottom of the contact road is kept at the same height by the topping, and all the entrances and exits of the entrance and exit are closed by the retaining wall, and the ventilated patio is filled from the upper part of the stop. The pipe is filled with full tailings. The filling aggregate is made of mine tailings and cement as gelling agent. According to the strength requirements of the filling body, in order to reduce the filling cost, the low-ash sand is used to fill the filling, and then the high-ash sand is used to fill the surface. According to the indoor test of the filling body strength, the strength of the filling body 7d with a sand-sand ratio of 1:4 can reach 1MPa or more, which satisfies the requirement of the scraper to walk on the filling body, and the strength of the cemented backing body is 28d when the ratio of sand to sand is 1:6. Up to 1MPa or more. Therefore, the design is generally filled with a 1:6 ratio of sand to sand, the filling height of the pouring surface is 0.5 m, and the cementing filling of the pouring surface is a ratio of 1:4.
The layered filling height is 2 to 2.5 m. When the top casting method is adopted, the top plate of the stope is not used in the form of a step, and the height of the empty top after filling is 1 to 1.5 m. If the top mining method is adopted, the top plate of the stopway is stepped in the upward direction, and the height of the empty roof after filling is 2 to 2.5 m. The height of the empty top of the stepped ore body near the surrounding rock of the upper plate is 0. 2 ~ 0.3m, the part of the ore body is harvested with horizontal blastholes.
In order to reduce the mutual restriction between recovery and filling, two alternate fields are used to ensure production tasks to improve production efficiency.
3.6 Main technical and economic indicators
According to the field test, a good technical and economic index was obtained by using the non-mineral column to horizontally layered full tailings cement filling and continuous mining method: the production capacity of the stope is 100-120t/d; the loss rate is 3%; the depletion rate It is 5%; the sampling ratio of kiloton is 9.47m/kt (standard meter).
4 conclusions and recommendations
For the mining of medium-thick ore bodies in the 101 mining area, the mining capacity has been greatly improved by using the non-mineral column to horizontally layered full tailings cement filling and continuous mining method, which greatly reduces the depletion loss index. No pillars are left between the stopes to effectively utilize underground mineral resources. The field test has advanced technical and economic indicators. It has been fully promoted in Shihu Mining Co., Ltd. and provides experience for other mines. It is suggested that the medium-thick ore body adopts the continuous mining method of no-mineral horizontal stratified full tailings cementing. In order to improve the degree of mechanization and production efficiency, rock drilling should be used to drill rock, and the bristle trolley and anchor rod should be installed. Advanced equipment such as trolleys and service vehicles.
references:
[1] Wang Li, Ming Shixiang, Zhang Yongda, et al. Mechanized upward horizontal stratification filling continuous mining method in a gold mine [J]. Mining Research and Development, 2015, 35 (07): 5-8.
[2] Mine Mining Design Manual [M]. Beijing: China Building Industry Press, 1986.
[3] Liu Shenglei. Application of cemented filling in Mountain Iron Mine [J]. Nonferrous Metal Mines, 2011, 63(1): 5-7.
[4] Zhang Zhaohui, Zhang Yougang, Wan Bing, et al. Application of horizontal stratified filling method without pillars in Shihu Gold Mine [J]. Mining Research and Development, 2013, 33 (05): 1-4, 76.
[5] Ouyang Wensheng. Application of up-horizontal layered filling mining method in sandstone mining [J]. Mining Technology, 2012, 12 (02): 1-2.
[6] Tian Changjin. Application of upward horizontal stratified cement filling mining method in a mine [J]. Nonferrous Metallurgy Design and Research, 2011(1): 1-3.
[7] Li Xingshang. Optimization study of upward horizontal stratified filling mining method [J]. Metal Mine, 2006 (4): 16-18.
[8] Han Zhi, Wang Ning, Tang Shaohui. Study on the structural parameters of the upper stratified filling in the non-column stope [J]. Mining Research and Development, 2005, 25 (05): 33-36.
[9] Yu Bin. Reasonable selection of the size of the mine room and the column in the upward and horizontal stratification filling step [J]. Hebei Metallurgy, 1997:03.
[10] Wang Dezhou. The filling method of Langyashan copper ore tailings and the horizontal slice optimization [J]. Mining Technology, 2011, 11 (05): 3-4, 11.