A stress coordination method for mine goaf

Abstract

The present invention discloses a kind of mine goaf stress coordination method, relate to the field of mine operation technology, comprise the following steps: step 1: construct rectangular enclosure along ore rock mining direction in the mining goaf; step 2: fill the filling work unit layer by layer reciprocatingly and uniformly with high-strength filling aggregate; step 3: repeat step 1 close to the high-strength strip in step 2, fill the filling work unit layer by layer reciprocatingly and uniformly with high-strength filling aggregate; step 4: alternately carry out step 2 and step 3 in the goaf, until the goaf is fully filled, pre-fill high-strength filling aggregate at the bottom of low-strength filling body, if the low-strength filling body and the high-strength bottom material at its bottom are regarded as a whole, the equivalent elastic modulus of the low-strength strip as a whole is improved, can provide stronger support effect to the roof, mobilize its own bearing capacity, and unload the high-strength filling body. This method can improve the uneven bearing state of the composite support body.

Description

Technical Field

[0001] The present invention relates to the technical field of mining operations, and in particular to a stress coordination method for a mine goaf. Background Art

[0002] Non-ferrous metal mines generate large quantities of tailings during the mining process. Mining companies typically treat these tailings by building tailings ponds and storing the waste. To foster green mines, most mines choose to backfill the tailings into mined-out areas. However, due to the fluctuating tailings grade during actual production and the complex underground conditions, it is difficult to determine the actual compressive strength of low-strength materials.

[0003] In the existing technology, especially in large-scale and high-intensity combined mining, high-strength filling media and low-strength filling media with large strength differences are used to alternately fill the goaf. The core idea is to use the high strength of the high-strength filling body to support the goaf roof to prevent the roof from collapsing; and use low-strength filling bodies to fill the goaf at low cost and in large volume to ensure the filling efficiency of the goaf.

[0004] However, this technology still has defects. The relatively flexible low-strength filling body exerts a smaller load on the bearing roof, while the relatively rigid high-strength filling body exerts a larger load on the bearing roof. The composite support body shows a significant uneven load, and most of the supporting load is concentrated on the rigid support body. The load borne by each support body does not match the ultimate load it can withstand. The low-strength filling body does not fully utilize its supporting capacity, and there is a waste of power. The long-term high-strength load of the high-strength filling body causes damage and continues to develop, even to support failure, the supporting force of the composite support body is reduced, and even the overall instability of the mining field is caused. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for stress coordination in mine goafs, so as to solve the defects raised in the above-mentioned background technology but still existing in the technology. The relatively flexible low-strength filling body bears a smaller load on the top plate, and the relatively rigid high-strength filling body bears a larger load on the top plate. The composite support body shows a significant uneven load, and most of the support load is concentrated on the rigid support body. The load borne by each support body does not match the ultimate load it can withstand. The low-strength filling body does not give full play to its supporting capacity, and there is a waste phenomenon. The long-term high-strength load of the high-strength filling body leads to damage and continuous development, and even support failure, reduced supporting force of the composite support body, and even causes the problem of overall instability of the mining field.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for coordinating stress in a mine goaf, comprising the following steps:

[0007] Step 1: Construct a rectangular wall along the mining direction of the ore rock in the goaf. The rectangular space enclosed by the four walls of the wall is the filling work unit. Filling aggregate is poured inside the wall. The wall of the wall is made of steel baffles. The baffles are gradually raised as the filling body is poured, and finally reach the top plate of the mining area to form a closed space;

[0008] Step 2: The filling work unit is uniformly filled with high-strength filling aggregate in a reciprocating manner layer by layer. During this period, the filled high-strength filling aggregate is compacted layer by layer. The above filling and compacting steps of the high-strength filling aggregate are repeated layer by layer until the filling reaches 0.5m from the top plate of the mining area. Then, low-strength filling aggregate is used to fill the remaining unfilled area to ensure contact between the high-strength filling body and the top plate of the mining area. After the high-strength strip is poured and waited for solidification and formation, the support device is removed to form a high-strength strip;

[0009] Step 3: Repeat step 1 close to the high-strength strip in step 2, and fill the filling work unit with high-strength filling aggregate in a reciprocating manner layer by layer. During this period, the filled high-strength filling aggregate is compacted layer by layer. Repeat the above high-strength filling and compaction steps layer by layer. Stop filling after filling 0.5-1.2m, and then use low-strength filling aggregate to fill the high-strength filling body just filled to the top plate of the goaf. After the low-strength strip is poured, wait for it to solidify and form, remove the support device, and form a low-strength strip;

[0010] Step 4: Alternately perform steps 2 and 3 in the goaf until the goaf is completely filled.

[0011] Preferably, the preparation of the filling aggregate in the goaf is as follows: for preparing low-strength filling aggregate, 32.5 composite silicate cement is used, and the ash-sand ratio calculated by mass is between 1:12 and 1:15, and the slurry concentration is between 70% and 80%; for preparing high-strength filling aggregate, 32.5 composite silicate cement is used, and the ash-sand ratio calculated by mass is between 1:6 and 1:8. The two filling aggregates are mixed and stirred in the mine filling station according to the above proportions, and the obtained mixture is transported to the goaf through different pipelines for distribution and filling.

[0012] Preferably, the steel baffles are 0.5m high, 2m long, and 5cm thick, and can be tightly assembled with each other. The steel baffles have steel support devices to ensure safe filling of the filling unit, and can be dismantled and reused in subsequent operations after filling.

[0013] Preferably, the layer-by-layer reciprocating pouring pours 20 cm of filling aggregate each time, and a vibrating rod is used to expel the internal air to ensure that the filling aggregate is dense and free of bubbles.

[0014] Preferably, the completion of filling the goaf refers to the completion of filling the goaf of a panel.

[0015] Compared with existing technologies, the present invention offers the following advantages: by pre-filling the bottom of the low-strength filler with high-strength filler aggregate, if the low-strength filler and the high-strength filler material at its base are considered as a whole, the equivalent elastic modulus of the low-strength strips is increased, providing stronger support for the roof, mobilizing their own load-bearing capacity, and relieving pressure on the high-strength filler. This method can improve the uneven load-bearing state of the composite support. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the actual operation section of the goaf area of ​​the present invention;

[0017] Figure 2 This is a top view of the actual operation of the goaf area of ​​the present invention.

[0018] In the figure: 1-high-strength filling body, 2-low-strength filling body, 3-high-strength pre-cast body, 4-ore pile, 5-roof, 6-broken roof, 7-unmined body, 8-bottom plate, 9-ventilation uphill, 10-pillar, 11-ventilation uphill, 12-high-strength strip, 13-low-strength strip, 14-goaf, 15-upper segmented scraper road, 16-lower segmented scraper road, 17-air shaft, 18-chute. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] See also Figure 1-2 The present invention provides a method for coordinating stress in a mine goaf, comprising the following steps:

[0021] Step 1: Construct a rectangular wall along the mining direction of the ore rock in the goaf. The rectangular space enclosed by the four walls of the wall is the filling work unit. Filling aggregate is poured inside the wall. The wall of the wall is made of steel baffles. The baffles are gradually raised as the filling body is poured, and finally reach the top plate of the mining area to form a closed space;

[0022] Step 2: The filling work unit is uniformly filled with high-strength filling aggregate in a reciprocating manner layer by layer. During this period, the filled high-strength filling aggregate is compacted layer by layer. The above filling and compacting steps of the high-strength filling aggregate are repeated layer by layer until the filling reaches 0.5m from the top plate of the mining area. Then, low-strength filling aggregate is used to fill the remaining unfilled area to ensure contact between the high-strength filling body and the top plate of the mining area. After the high-strength strip is poured and waited for solidification and formation, the support device is removed to form a high-strength strip;

[0023] Step 3: Repeat step 1 close to the high-strength strip in step 2, and fill the filling work unit with high-strength filling aggregate in a reciprocating manner layer by layer. During this period, the filled high-strength filling aggregate is compacted layer by layer. Repeat the above high-strength filling and compaction steps layer by layer. Stop filling after filling 0.5-1.2m, and then use low-strength filling aggregate to fill the high-strength filling body just filled to the top plate of the goaf. After the low-strength strip is poured, wait for it to solidify and form, remove the support device, and form a low-strength strip;

[0024] Step 4: Alternately perform steps 2 and 3 in the goaf until the goaf is completely filled.

[0025] During operation, when mining, high-strength filling body 1 and low-strength filling body 2 are used to form high-strength strips and low-strength strips respectively to alternately fill the goaf 14, and a high-strength pre-cast body 3 is set below the low-strength filling body 2. The upper end of the unmined body 7 is a broken roof 6, and the lower end of the unmined body 7 is a bottom plate 8. On the side of the bottom plate 8, the unmined body 7 close to the goaf 14 is an ore pile 4, and one side of the unmined body 7 is a No. 1 ventilation uphill 9. On one side of the high-strength filling body 1 is a spacer 10, and on the other side of the spacer 10 is a No. 2 ventilation uphill 11. On both sides of the broken roof 6 are an upper segmented scraper road 15 and a lower segmented scraper road 16, and an air shaft 17 and a chute 18 are respectively set on the outside of the lower segmented scraper road 16.

[0026] Therefore, this method proposes to use filling aggregates with an elastic modulus higher than that of the low-strength filling body 2 for bottom connection. This bottom connection material can bear part of the load applied by the top plate 5, and mobilize the bearing capacity of the ore rock and the low-strength filling body 2, improve the support strength of the low-strength filling body 2, and improve the uneven bearing state in the composite support. In view of the fact that it is more complicated to re-prepare new low-strength filling body 2 bottom connection materials in the actual production process, the filling cost also increases. Therefore, high-strength filling aggregates are used directly as the bottom connection materials for the low-strength filling body 2. In fact, if the high-strength bottom connection material and the low-strength filling body 2 are regarded as a whole, the equivalent elastic modulus of the low-strength strip 13 is increased, which is in line with the stress coordination idea of ​​increasing the elastic modulus of the low-strength filling body 2.

[0027] After the filling operation in the goaf 14 is completed, the filling body will produce a small deformation under the action of the surrounding rock. At this time, each filling strip is equivalent to a spring constraint, and the filling body plays a passive constraint role on the rock mass of the top plate 5 of the goaf 14. An equivalent mechanical model can be obtained by performing a force analysis on the interior of the composite support body. Under the action of the top plate 5 of the goaf, the filling body in the goaf 14 bears the load applied by the top plate 5. Because they are in the same goaf 14, the load applied by the top plate 5 of the goaf 14 will cause the strain of the two filling strips to be the same. However, since the elastic modulus of the high-strength filling body 1 is much greater than the elastic modulus of the low-strength filling body 2, the stress on the high-strength strip 12 filled with most of the high-strength filling aggregate is much greater than the stress on the low-strength strip 13. The presence of high-strength bottom material in the low-strength strip 13 increases its overall equivalent elastic modulus, thereby improving the support effect on the top plate 5, reducing the load of the top plate 5 on the high-strength filling body 1, and thereby improving the uneven load state of the composite support body.

[0028] Preparation of the filling aggregate in the goaf: low-strength filling aggregate is prepared by using 32.5 composite silicate cement, with a ash-sand ratio of 1:12 to 1:15 calculated by mass, and a slurry concentration of 70% to 80%; high-strength filling aggregate is prepared by using 32.5 composite silicate cement, with a ash-sand ratio of 1:6 to 1:8 calculated by mass, and the two filling aggregates are mixed and stirred in the mine filling station according to the above proportions, and the obtained mixture is transported to the goaf through different pipelines for distribution and filling, so as to prepare filling aggregates of different strengths to meet different strength requirements.

[0029] The steel baffle is 0.5m high, 2m long, and 5cm thick, and can be tightly assembled with each other. The steel baffle has a steel support device to ensure the safe filling of the filling unit. After the filling is completed, it can be dismantled and reused in subsequent operations. The standard steel baffle is used to ensure the strength of the steel baffle while achieving the uniformity of construction materials.

[0030] The layer-by-layer reciprocating pouring pours 20 cm of filling aggregate each time, and a vibrating rod is used to expel the internal air to ensure that the filling aggregate is dense and free of bubbles, thereby ensuring the construction strength of the filling aggregate.

[0031] The completion of filling the goaf refers to the completion of filling the goaf of a panel.

[0032] Example

[0033] A ore seam is mined using the backfill method. The following mineral deposit conditions are available: the seam is 6 meters thick, has a dip of 10°, and is buried at a depth of 280 meters. The deposit is divided into panels, with a minor axis along the strike of the ore body and a width of 100 meters, and a major axis along the dip of the ore body and a length of 300 meters. 5-meter-wide interpanel pillars are reserved between panels along the dip of the ore body. The upper and lower sections of the scraper runway are 3 meters wide, and the ventilation runway is 3 meters wide. The mining height of the ore body is 6 meters.

[0034] According to the above conditions, a stress coordination method for filling the goaf of a mine is adopted in this patent for mining. The specific scheme is as follows:

[0035] The mining panel is divided into 10 strips along its short axis, each 10m wide and 300m long. Each strip is mined sequentially, with the mining direction aligned with the ore body's dip. Backfilling is performed after mining two strips. Each backfill unit is backfilled in the mining direction.

[0036] Each filling unit is 20m long, 10m wide, and 6m high. Steel baffles are spliced ​​together to form a structure for filling. First, a 0.5m high enclosure is built. The pouring equipment pours 0.2m of slurry. When the slurry reaches the top of the enclosure, another layer is added to ensure that the filling aggregate remains within the filling unit. During the pouring process, a vibrator is continuously used to expel air from the unit until the filling is complete.

[0037] After filling the entire panel along the long axis along the mining direction, the above filling operation is repeated again. Filling and mining are carried out simultaneously, and the reserved goaf in the middle is used as the filling operation space. Filling is carried out alternately according to steps 2 and 3 in sequence to form 10 filling strips. A composite support body is formed. The entire panel is mined and filled.

[0038] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A stress coordination method for a mine goaf, characterized by: The following steps are involved: Step 1: Construct a rectangular wall along the mining direction of the ore rock in the goaf. The rectangular space enclosed by the four walls of the wall is the filling work unit. Filling aggregate is poured inside the wall. The wall of the wall is made of steel baffles. The baffles are gradually raised as the filling body is poured, and finally reach the top plate of the mining area to form a closed space; Step 2: The filling work unit is uniformly filled with high-strength filling aggregate in a reciprocating manner layer by layer. During this period, the filled high-strength filling aggregate is compacted layer by layer. The above filling and compacting steps of the high-strength filling aggregate are repeated layer by layer until the filling reaches 0.5m from the top plate of the mining area. Then, low-strength filling aggregate is used to fill the remaining unfilled area to ensure contact between the high-strength filling body and the top plate of the mining area. After the high-strength strip is poured and waited for solidification and formation, the support device is removed to form a high-strength strip; Step 3: Repeat step 1 close to the high-strength strip in step 2, and fill the filling work unit with high-strength filling aggregate in a reciprocating manner layer by layer. During this period, the filled high-strength filling aggregate is compacted layer by layer. Repeat the above high-strength filling and compaction steps layer by layer. Stop filling after filling 0.5-1.2m, and then use low-strength filling aggregate to fill the high-strength filling body just filled to the top plate of the goaf. After the low-strength strip is poured, wait for it to solidify and form, remove the support device, and form a low-strength strip; Step 4: Alternately perform steps 2 and 3 in the goaf until the goaf is completely filled; Preparation of the filling aggregate for the goaf: low-strength filling aggregate is prepared, using 32.5 composite Portland cement, with a lime-sand ratio of 1:12 to 1:15 by mass and a slurry concentration of 70% to 80%; Prepare high-strength filling aggregates, using 32.5 composite Portland cement, with a lime-sand ratio of 1:6 to 1:8 by mass. Mix the two filling aggregates in the above ratio at the mine filling station, and transport the resulting mixture to the goaf through different pipelines for distribution and filling. The steel baffle is 0.5m high, 2m long, and 5cm thick, and can be tightly assembled with each other. The steel baffle has a steel support device to ensure the safe filling of the filling unit, and can be dismantled and reused in subsequent operations after the filling is completed.

2. A mine goaf stress coordination method according to claim 1, characterized in that: The layer-by-layer reciprocating pouring is performed to pour 20 cm of filling aggregate each time, and a vibrating rod is used to expel the internal air to ensure that the filling aggregate is dense and free of bubbles.

3. A mine goaf stress coordination method according to claim 1, characterized in that: The completion of filling the goaf refers to the completion of filling the goaf of a panel.

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