Zhaoyuan gold ore deposits in accordance with its conditions, with a shrinkage stoping method.
First, mining technical conditions
Zhaoyuan gold deposit was allowed to warm to fill gold in quartz veins and altered rock deposit, by a plurality of ore body. The phenomenon of compounding, expanding, pinching, and lateral appearance of vein branches is very common. Most of the veins are extremely thin and extremely thin ore bodies, with a strike of 30 to 50°, a length of more than 1000 m, an inclination of more than 65°, an average thickness of the ore body of less than 1.5 m and a depth of more than 300 m. The type of ore is quartz vein type and altered rock type, and the surrounding rock is altered granite . The ore rock is relatively stable, and the boundary of the ore is obvious, but the mineralization is uneven.
Second, the basic situation of the application of the retention method in Zhaoyuan Gold Mine
The retention method is the basic mining method that has been used since the 1958 production of the Linglong Gold Mine and the Jiuqu Mining Area. The production practice in the past 40 years has made this mining method more perfect in terms of structural parameters, and the scope of use has also been expanding. The amount of ore mined by the method of retention of minerals accounts for 80% of the total ore produced by such veins in the whole mine.
(1) Main schemes and structural parameters
The main schemes and structural parameters of the retention method are listed in Table 1.
Table 1 Main schemes and structural parameters of the retention method
Main plan | Structural parameter /m |
Stage high | Nugget length | Top column thickness | Bottom column height | Column width | Funnel spacing |
Retaining column, top column and bottom column | 40 | 40~60 | 2 to 3 | 3 to 5 | 4~6 | 5~5 |
No column, top column | 40 | 40~60 | 2 to 3 | 3 to 5 | | 5~6 |
No column and bottom column, no top column | 40 | 40~60 | 2 to 3 | | | 4~5 |
No column and top column, no bottom column | 40 | 40~60 | | 3 to 5 | | 5~6 |
No pillars | 40 | 40~60 | | | | 4~5 |
Sloping patio | 40 | 50~60 | | 3 to 5 | | 5~6 |
Low stage | 40 | 40~60 | | 3 to 5 | | 5~6 |
(2) Approved work
The electric roadway or the rock loading ore loading roadway is arranged in the surrounding rock of the lower plate. The flat bottom mining outlet is set every 4~6m, and the ore discharging well and the pedestrian ventilation well are arranged on the side of the mining house. Excavate the ore and nugget patio, and connect the upper and lower stages to transport the roadway. Dig the contact roads (with the column scheme) to the mining houses on both sides every 3 to 3.5 m in the patio, and cut the work from the flat bottom.
(3) Mining process
The YSP-45 type rock drilling machine is used to drill rock with a hole depth of 1.5 to 1.8 m, a hole spacing of 0.6 to 0.8 m, and a diameter of 38 to 42 mm. The No. 2 rock explosive is detonated by a detonating tube and a fire detonator.
Use ore or rock loader for ore transport. During the recovery period of the mining house, one-third of the ore is released after each collapse, so as to maintain a certain space for the stope. After the mining is completed, a large amount of ore is released and all the ore is released.
Use the main wind flow of the mine to carry out ventilation and dust removal in the stope. The fresh air flows from the transportation lane through the patio into the stope and the electric ramp, and the dirty wind is discharged to the return airway through the return air patio.
After the mine is harvested, after the ore is completely released, the YGZ-90 rock drill is used to drill the deep hole, and the intermediate column, the top column and the upper stage bottom column are recovered. After the ore is recovered, the goaf is treated.
The main technical and economic indicators obtained by the Zhaoyuan Gold Mine application method are as follows (average indicators from January to September 1991):
Production capacity of ore block /t·d - 1 35～45
Mining ergonomics / t·Working class - 1 9
Acquisition coefficient /m·kt - 1 25～40
Ore loss rate /% 8 ~ 15
Ore depletion rate /% 20～40
Explosive consumption / kg·t - 1 0.32
Wood consumption / m 3 · 10,000 t - 1 0.003
Direct mining cost / yuan · t - 1 6.25
3. Practical experience of applying the ore retention method in Zhaoyuan Gold Mine
(1) Intra-pulse slope retention method
No. 210 vein of Jiuqu Mining Area of ​​Zhaoyuan Gold Mine is a steeply inclined ore body with an average thickness of 0.8m and a grade of 30g/t. The ore is relatively stable and the ore body is continuously 80m long. According to the specific conditions of the ore body, a mining block is used to recover the mining method by using the in-pulse slope section of the mine (Fig. 1), which reduces the amount of mining and cutting time and shortens the mining time.
Figure 1 Intra-pulse slope retention method
1—surrounding rock; 2—mine body; 3—slope track; 4—patio; 5—ore; 6—funnel
At the end of the nugget, the inner courtyard of the vein is excavated, and the roadway for excavation is transported at the bottom. The mine crossing and the ore discharge are excavated every 5~6m, and the ladder is retracted from the patio. The length of the first mine is L is obtained by the following formula:
Where H-stage height, m;
L—mine length, m;
A—the angle between the slope of the pulse and the horizontal, (°).
The slope of the slope depends on its use and construction method. When used for pedestrians, ventilation and erecting of feng shui pipelines, the natural accumulation slope of ore is 25~35°, and the inclination angle can be increased when artificially constructing the slope.
As the mining room picks up upwards, the lower part of the patio is gradually filled with caving ore, which is scrapped, with the upper part serving as a safe exit and return air; the other end of the stope is using a ramp constructed on the ore pile as a pedestrian, wind inlet and erection pipeline. The passage and the feng shui pipe are fixed to the top plate of the slope by anchors. Before the blasting of the mine, the slope of the slope should be sealed with wooden boards, leaving only 0.3m 2 of air inlets to facilitate ventilation after the blasting.
Compared with the ordinary retention method, the slope-retaining method saves 120m of cutting and cutting work, and saves 15m 3 of pit wood. Since more than 1,000 tons of high-grade ore is recovered without leaving the column, the economic benefit is 200,000 yuan.
(2) Local ore discharge and well retention method
In the local mining section of Zhaoyuan Gold Mine, the ore body is developed with cracks, and the surrounding rock has a fault mud of 5 to 50 cm thick, and the stability is very poor.
When applying the ordinary retention method, the mine adopts the method of shortening the length of the mine to 20m, leaving the triangular pillars to support the surrounding rock in the stope, and after the technical measures such as the use of the bolts for the disk, the mining house is 16 ～20m high, a large area of ​​the surrounding rock will fall off and be forced to stop mining.
According to the analysis and research, the main reason for the interruption of the production of the surrounding rock fragments is due to frequent local ore-boring, resulting in intermittent gaps near the upper plate; creating favorable conditions for its movement and fragmentation.
The local ore-draining method (Fig. 2) is used in the mining process of the mining house, and the mining mine is constructed with steel plates in the center of the mining house. The crushed ore after each blasting is released from the well. The ore remaining in the stope is always in a static state, which can provide a stable supporting effect on the surrounding rock, prevent the surrounding rock from moving and destroying, and ensure the mining house is smoothly harvested. When the mine is harvested, the ore deposit is quickly and evenly released by the 2DPJ-13 electric winch, so that the ore loss rate is less than 10%, the depletion rate is less than 20%, and the partial ore deposit accounts for about one-third of the caving. The ore amount is the ore with a higher depletion rate and a higher grade of ore.
Figure 2 Local ore mining and well retention method
(3) Low-stage retention method
The low-stage retention method divides the stage into two low-level stages of equal height or height, and then picks, cuts and recovers according to the ordinary retention method (Fig. 3).
Figure 3 Low-stage retention method
The boundary line between the two low stages is generally at the inclination of the ore body (for example, the inclination angle is changed from more than 65° to 60° or less), or the surrounding rock is less stable, and is divided into two equal parts from the middle of the stage. Low-stage mining room.
Firstly, the lower stage low-level mining house is firstly collected. After the mining, the blind stage and the funnel are opened, and the upper mining room is cut and recovered. The ore is collected, transferred to the lower mine through the funnel, and then loaded by the funnel. export.
This scheme is suitable for conditions in which the up and down inclination of the ore body is changed or the stability of the surrounding rock is poor.
(4) Inclined electric raft retention method
There is a triangular ore at the end of the steeply inclined thin vein of the mine. The ore grade is relatively high. It is recovered by the ordinary method of retaining ore, and the high funnel is required to be mined. This not only has a large amount of mining, but also causes the phenomenon of ore mining. .
According to the shape of the ore body, adopting the method according to local conditions to create a method of retaining ore for the mining of inclined electric rafts (Figure 4)
Figure 4 inclined electric rail retention method
When applying this scheme, firstly, the ore body shape should be explored, and the location of the contact line of the ore rock should be grasped. On this basis, the inclined electric roadway should be arranged and the inclination angle should be no more than 30° to ensure the normal antimony operation and prevent A rolling stone accident occurred.
(5) Mining branching and compound veins by using the method of retaining ore
In the long-term production practice, the mine summarizes the corresponding layout method and mining plan of the retention method (see Table 2) for the various cases of vein branching and compounding.
Table 2 Branching compound ore vein retention method
Branching phenomenon | Upper and lower stage vein morphology | Open and layout | Mining method |
Branching along the way | Both the upper and lower stages are branching | There is a patio on the side of the compound vein and a patio on the edge of the branch vein. | Two mining houses at the same time |
Branching down | One vein in the upper stage and two veins in the lower stage | A patio is set up at the intersection of the veins, and a patio is provided on the same section of the branch veins. | When two mining houses are first combined and compounded, they are combined into one mining room. |
Branching along the top | Two veins in the upper stage and one vein in the lower stage | Set a patio at the compound vein, cross the main vein to the branch vein, or branch the vein and hit the patio. | First mining |
Along the way Tendency | One or two veins in the upper stage and multiple veins in the next stage | According to the branching of the veins, the above method is used to set up the patio. | Mining or mining |
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