A stage open stope subsequent filling mining method with cooperation of phosphorite deposit pillar and ore block

Abstract

The present application belongs to the field of phosphate ore filling mining, and particularly relates to a phosphate ore deposit bottom pillar and ore block coordinated stage empty field subsequent filling mining method, which comprises the following steps: dividing the ore bed into a plurality of ore blocks along the strike of the ore bed, wherein the ore block comprises an ore room and a bottom pillar; constructing a roadway for transportation and ventilation; first mining the ore bed with a smaller rock mass strength coefficient and filling; retaining or blasting the interlayer; mining the ore bed with a larger rock mass strength coefficient and filling; and mining the ore bed in the bottom pillar of the previous middle section. The present application does not need to fill the empty area formed by the bottom pillar recovery, can reduce the filling process and filling material, reduce the filling cost and construction process, and improve the mining efficiency. The present application can realize the full mining of the ore bed, does not leave the top pillar, and recovers the bottom pillar without filling, so that the ore recovery rate is close to 100%, and good economic benefits can be achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of phosphate ore filling mining, and particularly relates to a stage empty field subsequent filling mining method of phosphate ore bed bottom column and ore block cooperation. BACKGROUND

[0002] The Dangtang ore section of Wengfu phosphate ore mainly includes two ore layers, namely, an a ore layer and a b ore layer, with an inclination of 85 degrees; the two ore layers are respectively hosted in the second section (Z1d 2 ) and the fourth section (Z1d 4 ) of the Lower Sinian Doushantuo Formation, and a relatively stable dolomite interlayer (Z1d 3 ) is interbedded between the two ore layers, with a total thickness of 1.38-5.25 m and an average thickness of 2.59 m. The a ore layer is generally 7.6-12.4 m thick, with an average thickness of 11.48 m, and mainly composed of gray green, gray black thin plate-shaped sandy phosphorite; the bottom plate of the a ore layer is light gray, gray medium-thick layer-shaped fine-crystal dolomite, and the upper part of the a ore layer is a Z1d 3 light gray, gray white thick layer to block-shaped fine to powder-crystal dolomite interlayer; the b ore layer is generally 7.29-31.63 m thick, with an average thickness of 17.35 m, and mainly composed of banded dolomitic phosphorite, siliceous lump dolomitic phosphorite, striped dolomitic phosphorite, lump dolomitic phosphorite, pseudo-oolitic dolomitic phosphorite, dense blocky phosphorite and argillaceous phosphorite; the lower part of the b ore layer is a Z1d 3 dolomite interlayer, and the top plate of the b ore layer is light gray, gray white layer-shaped fine to medium-crystal phosphorus-containing dolomite and dolomite.

[0003] For the above-mentioned double ore layers with interlayers at close distances, combined with the thickness and inclination of the ore layers, it is determined that the deep hole ore falling stage empty field subsequent filling mining method is more suitable. However, how to optimize the mining sequence of the a ore layer and the b ore layer, how to determine a suitable interlayer treatment method to improve the stability and safety of the ore layer mining, and how to optimize the setting (and recovery) method of the inter-column and bottom column between the middle sections to improve the recovery rate and efficiency become important research topics. SUMMARY

[0004] In order to solve the above technical problems, the application provides a stage empty field subsequent filling mining method of phosphate ore bed bottom column and ore block cooperation, which comprises the following steps:

[0005] S1: in the range of the middle section, the ore layer is divided into a plurality of ore blocks along the strike of the ore layer; for each ore block, the ore block is divided into a mine house and a bottom column along the height direction, and the thickness of the ore block is the total thickness of the ore layer and the interlayer; the upper part of the mine house is the bottom column left after the mine house of the ore block of the previous middle section is subsequently filled;

[0006] S2: a middle section transportation roadway is constructed at the bottom of the middle section on the side of the floor of the roof of the bottom pillar along the strike of the ore body, an ore drawing connecting roadway is constructed at the bottom of the middle section on the side of the floor of the roof along the strike of the ore body, a middle section return air roadway is constructed at the bottom of the middle section on the side of the floor of the bottom pillar along the strike of the ore body, and an ore drawing return air roadway is constructed at the bottom of the middle section on the side of the floor of the bottom pillar along the strike of the ore body;

[0007] The roof of the bottom pillar of the previous middle section is left with the transportation roadway of the previous middle section as an auxiliary transportation roadway of the present middle section, the floor of the bottom pillar of the previous middle section is left with the return air roadway of the previous middle section as a drilling return air roadway of the present middle section, and the previous middle section has a through-vein roadway constructed horizontally in each ore block to connect the transportation roadway of the previous middle section and the return air roadway of the previous middle section as a drilling roadway of the present middle section, and a drilling chamber is constructed along the strike in each ore block of the a ore layer and the b ore layer;

[0008] The return air shaft is extended to the bottom of the present middle section, and a horizontal roadway is constructed to connect the return air shaft with the drilling return air roadway, the ore drawing return air roadway, and the middle section return air roadway, in the present middle section, for each ore block, an ore drawing roadway is horizontally constructed from the ore drawing connecting roadway to the ore drawing return air roadway, and a stope chute is horizontally constructed from the side of the ore drawing connecting roadway away from the ore body to connect with the middle section transportation roadway;

[0009] S3: the a ore layer with a smaller rock stratum solidity coefficient is mined first, a large-diameter deep hole is constructed from the drilling chamber to the a ore layer in the mine chamber, after charging, the layers are blasted from bottom to top, the ore produced by blasting is discharged to the ore drawing roadway, and then is transported to the stope chute and then to the middle section transportation roadway;

[0010] S4: based on the ratio of the plastic zone and the thickness of the non-plastic zone of the interlayer after the a ore layer in the mine chamber is mined, the interlayer is determined to be retained or to be blasted, when the interlayer is retained, tailings filling material is used to fill the empty space produced by the mining of the a ore layer in the mine chamber, and if the interlayer is blasted, the interlayer in the mine chamber is broken and the rock is dropped while the tailings filling material is used to fill the empty space produced by the mining of the a ore layer in the mine chamber and the interlayer;

[0011] S5: a large-diameter deep hole is constructed from the drilling chamber to the b ore layer, after charging, the layers are blasted from bottom to top, the ore produced by blasting is discharged to the ore drawing roadway, and then is transported to the stope chute and then to the middle section transportation roadway;

[0012] S6: tailings filling material is used to fill the empty space produced by the mining of the b ore layer;

[0013] S7: blasting drill holes are constructed from the drilling chamber to the a ore layer and the b ore layer of the bottom pillar of the previous middle section, after charging, the layers are blasted from bottom to top, and the ore produced by blasting is transported to the auxiliary transportation roadway through the drilling roadway.

[0014] Preferably, while steps S3-S6 are being performed, for each ore block, a through-vein roadway is horizontally constructed from the middle section transportation roadway to the middle section return air roadway, and a drilling chamber is constructed from the through-vein roadway along the strike in the a ore layer and the b ore layer.

[0015] Preferably, in step S4, when the plastic zone thickness accounts for less than the first threshold of the interlayer thickness and the non-plastic zone thickness is greater than the second threshold, the interlayer is retained; when the plastic zone thickness accounts for less than the first threshold of the interlayer thickness and the non-plastic zone thickness is less than the second threshold, the goaf generated by the room mining of the a-mineral layer is filled with the tailings filling material, and the grouting drill hole is constructed between the tailings filling body and the interlayer to grout and reinforce the plastic zone of the interlayer.

[0016] Preferably, in step S4, when the plastic zone thickness accounts for greater than the first threshold of the interlayer thickness and the non-plastic zone thickness is greater than the second threshold, the goaf generated by the room mining of the a-mineral layer is filled with the tailings filling material, and the grouting drill hole is constructed between the tailings filling body and the interlayer to grout and reinforce the plastic zone of the interlayer, and if the non-plastic zone thickness is greater than the third threshold, only the goaf generated by the room mining of the a-mineral layer is filled with the tailings filling material.

[0017] Preferably, in step S4, when the plastic zone thickness accounts for greater than the first threshold of the interlayer thickness and the non-plastic zone thickness is less than the second threshold, the rock breaking and rock falling of the interlayer in the room are performed while the goaf formed by the room of the a-mineral layer and the interlayer is filled with the tailings filling material.

[0018] Preferably, in steps S4 and S6, when the room is filled with the tailings filling material, the ratio of the cementing material to the tailings in the tailings filling material is 1:4 in the lower part and 1:6-1:10 in the upper part.

[0019] Preferably, in step S7, if the plastic zone thickness formed after the interlayer is subjected to the mining of the two side mineral layers is greater than the fourth threshold and the non-plastic zone thickness is greater than the fifth threshold, the interlayer is retained; if the plastic zone thickness formed after the interlayer is subjected to the mining of the two side mineral layers is less than the fourth threshold and the non-plastic zone thickness is greater than the sixth threshold, the interlayer is retained; otherwise, the interlayer is blasted together with the mineral layer, and the interlayer is not transported out during the ore drawing.

[0020] Preferably, each ore block is constructed in sequence along the strike or each ore block is constructed at intervals.

[0021] Preferably, the ore drawing connecting roadway, the middle section transportation roadway, and the auxiliary transportation roadway are the air intake roadways.

[0022] Preferably, the auxiliary transportation roadway is used as the transportation path of the tailings filling material, and the previous middle section pillar is mined in the later period as the ore transportation path.

[0023] Beneficial technical effects: 1. The present application is aimed at near-vertical ore layer, and the ore layer mining sequence is determined based on the strength of the ore layer, the ore layer with lower strength is mined first, which is beneficial to mining and can reduce the disturbance to the interlayer. Then the treatment method of the interlayer is determined based on the thickness of the interlayer and the influence of the mining of the ore layer, so as to ensure that the interlayer has sufficient strength or is directly treated before the mining of another ore layer, so as to prevent the instability of the interlayer during the mining of another ore layer with higher strength, and to prevent the damage, danger and large amount of ore and gangue.

[0024] 2. In the present application, since the upper and lower parts of the bottom pillar are tailings filling bodies during the mining of the previous middle section bottom pillar, it is not necessary to fill the empty area formed by the mining of the bottom pillar, thereby reducing the filling process and filling materials, reducing the filling cost, reducing the construction process, and improving the mining efficiency. The present application can realize the full mining of the ore layer without setting a top pillar, and the bottom pillar is recovered without filling, the ore recovery rate is close to 100%, and good economic benefits can be achieved.

[0025] 3. The present application adopts a three-in and three-out air inlet mode, and the air inlet roadway includes a ore outlet connecting roadway, a middle section transportation roadway and an auxiliary transportation roadway, which can ensure the health of workers and reduce the harm of mine dust to workers. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the inclined section during the mining of the ore layer of the stage empty field subsequent filling mining method a of the present application;

[0027] Figure 2 is a schematic diagram of the inclined section during the mining of the ore layer of the stage empty field subsequent filling mining method b of the present application;

[0028] Figure 3 is a schematic diagram of the inclined section during the mining of the bottom pillar of the stage empty field subsequent filling mining method of the present application;

[0029] In the figure, the middle section transportation roadway 1, the stope chute 2, the ore-rock boundary line 3, the blast hole 4, the bottom pillar 5, the upper middle section transportation roadway (auxiliary transportation roadway) 6, the air return shaft 7, the middle section air return roadway 81, the ore outlet air return roadway 82, the upper middle section air return roadway (rock drilling air return roadway) 83; the interlayer 9; the ore 10; the upper middle section cross-vein roadway (rock drilling roadway) 11; the rock drilling chamber 12; the tailings filling body 13; the cross-vein roadway 14; the ore outlet roadway 15; the ore outlet connecting roadway 16; the ore room 17. DETAILED DESCRIPTION

[0030] The present application will be further described below in combination with the accompanying drawings. Figures 1-3 Based on the 1060 middle section of Datang ore section of Wengfu phosphate mine, the present application is further described.

[0031] The geological conditions of the 1060-section of the Datang mining section of the Wengfu phosphate mine are basically the same as those of its upper and lower middle sections. The ore layers include ore layer A and ore layer B, with a dip angle of 85° and thicknesses of approximately 12m and 18m respectively. The thickness of interlayer 9 between the two ore layers is approximately 3m. The top plate, interlayer, and bottom plate are all composed of dolomite. The rock firmness coefficients f of the top plate, ore layer B, interlayer, ore layer A, and bottom plate are 14.37, 12.45, 7.29, 8.44, and 9.86 respectively.

[0032] Based on the thickness and strength of the two ore layers, and the strength and thickness of the interlayer 9, this invention proposes a mining sequence of mining ore layer A first, followed by ore layer B, and a technical solution for retaining the interlayer; simultaneously, no top pillar is set, only a bottom pillar is set, and the bottom pillar of the previous intermediate section (e.g., intermediate section 1130) is used as the top pillar of the next intermediate section (e.g., intermediate section 1060), and the stope of the previous intermediate section (e.g., intermediate section 1130) and the next intermediate section (e.g., intermediate section 1060) are mined simultaneously. Specifically, the staged open-stope subsequent backfilling mining method of the present invention, which coordinates the bottom pillar and the ore block in phosphate deposit mining, includes the following steps:

[0033] S1: As Figure 1 As shown, within this section (section 1060, the lowest elevation of which is 1060m), the ore layer is divided into several blocks along the strike. The length of each block along the strike is 15-20m, and it is recommended to set the length of the block along the strike in an alternating pattern of 15m and 20m. For each block, it is divided into a stope 17 and a pillar 5 along the height direction. The vertical height of the stope 17 is 55m, and the vertical height of the pillar 5 is 15m, that is, the vertical height of the block is 70m. The thickness of the block is the total thickness of the ore layer and interlayer. The upper part of the stope 17 is the bottom pillar 5 left after the stope of the previous section (section 1130, the lowest elevation of which is 1130m) is mined using the staged open-stope and subsequent backfilling mining method.

[0034] S2: As Figure 1 As shown, the intermediate transport roadway 1 is constructed at the bottom of the top plate side of the intermediate column 5 along the ore layer. The elevation of the intermediate transport roadway 1 is consistent with the bottom elevation of the intermediate column 5. Above the intermediate transport roadway 1, the ore extraction connecting roadway 16 is constructed at the bottom of the top plate side of the intermediate stope 17 along the ore layer.

[0035] At the bottom of the bottom plate side of the central column 5, the central return airway 81 is constructed along the ore layer. The elevation of the central return airway 81 is consistent with the bottom elevation of the central column 5. Above the central return airway 81, at the bottom of the bottom plate side of the central stope 17, the ore extraction return airway 82 is constructed along the ore layer.

[0036] The upper middle section has a transport roadway 6 on the top side of the bottom pillar 5 of the upper middle section, which serves as an auxiliary transport roadway 6 for this middle section; the upper middle section has a return air roadway 83 on the bottom side of the bottom pillar 5 of the upper middle section, which serves as a drilling return air roadway 83 for this middle section; in each block of the upper middle section, an upper middle section through-vein roadway 11 is also constructed horizontally to connect the upper middle section transport roadway 6 and the upper middle section return air roadway 83, which serves as a drilling roadway 11 for this middle section to connect the auxiliary transport roadway 6 and the drilling return air roadway 83 for this middle section; and drilling chambers 12 are also constructed along the strike in the a-seam and b-seam of each block.

[0037] Extend the return air shaft 7 to the bottom of this middle section, and construct a horizontal roadway to connect the return air shaft 7 with the rock drilling return airway 83, the ore extraction return airway 82, and the middle section return airway 81.

[0038] In this middle section, for each ore block, the ore outlet roadway 15 is constructed horizontally from the ore outlet connecting roadway 16 to the ore outlet return airway 82, and the stope pass 2 is constructed horizontally from the side of the ore outlet connecting roadway 16 away from the ore layer to connect the middle section transport roadway 1.

[0039] S3: As Figure 1 As shown, comparing the rock strata firmness coefficients of ore layer a and ore layer b, the ore layer with the smaller rock strata firmness coefficient is mined first. In this embodiment, the rock strata firmness coefficients f of ore layer b and ore layer a are 12.45 and 8.44 respectively, so ore layer a is mined first. A large-diameter deep hole 4 is drilled from the rock-drilled chamber 12 into ore layer a in the stope. After loading the explosives, the ore is blasted layer by layer from bottom to top. The ore 10 produced by the blasting is discharged from the ore discharge funnel to the ore extraction roadway 15, and then transported from the ore extraction roadway 15 to the stope pass 2 and then to the intermediate transport roadway 1, and then transported out by the transport equipment in the intermediate transport roadway 1.

[0040] S4: As Figure 2 As shown, the proportion of the thickness of the plastic zone of interlayer 9 to the total thickness of the interlayer is determined after the mining of ore layer a in the mine, as well as the thickness of the non-plastic zone of the interlayer. When the proportion of the thickness of the plastic zone to the total thickness of the interlayer is less than the first threshold (set to 40% in this embodiment) and the thickness of the non-plastic zone is greater than the second threshold (set to 1.2m in this embodiment), the interlayer does not need to be reinforced and is retained, indicating that the interlayer thickness is large enough and the strength is high.

[0041] When the proportion of the thickness of the plastic zone to the thickness of the interlayer is less than the first threshold (set to 40% in this embodiment) and the thickness of the non-plastic zone is less than the second threshold (set to 1.2m in this embodiment), the void generated by the mining of the a-seam is filled with tailings backfill material, and grouting is carried out between the tailings backfill body 13 and the interlayer 9 to reinforce the plastic zone of the interlayer, indicating that the interlayer thickness is small but the strength is very high.

[0042] When the proportion of the plastic zone thickness to the interlayer thickness is greater than the first threshold (set to 40% in this embodiment) and the non-plastic zone thickness is greater than the second threshold (set to 1.2m in this embodiment), tailings backfill material is used to fill the voids generated by the mining of the A-series ore room. Grouting holes are drilled between the tailings backfill body 13 and the interlayer 9 to reinforce the plastic zone of the interlayer. This indicates that the interlayer thickness is moderate but the strength is weak. If the non-plastic zone thickness is greater than the third threshold (set to 3.5m in this embodiment), only tailings backfill material is used to fill the voids generated by the mining of the A-series ore room. Grouting holes are not required to reinforce the plastic zone of the interlayer. This indicates that the interlayer thickness is large but the strength is weak.

[0043] When the ratio of the thickness of the plastic zone to the thickness of the interlayer is greater than the first threshold (set to 40% in this embodiment) and the thickness of the non-plastic zone is less than the second threshold (set to 1.2m in this embodiment), while breaking and removing rock from the interlayer 9 in the ore chamber, tailings filling material is used to fill the ore chamber of the a ore layer and the void formed by the interlayer, indicating that the interlayer thickness is small and the strength is weak.

[0044] In this embodiment, the average thickness of interlayer 9 is 3m. Since the strength of the interlayer is only slightly less than that of ore layer A, the mining of ore layer A causes less disturbance to the interlayer. The plastic zone accounts for about 20%, and the thickness of the interlayer is moderate. The thickness of the non-plastic zone is about 2.4m. Therefore, in this embodiment, tailings backfill material is used to fill the void generated by the mining of ore layer A. Then, grouting boreholes are drilled between tailings backfill body 13 and interlayer 9 to reinforce the plastic zone of the interlayer.

[0045] In this embodiment, tailings backfill material is used to fill the voids created by mining (and interlayer rock breaking and falling) of the a-seam in the mine. The ratio of binder (such as cement) to tailings in the tailings backfill material is: 1:4 for the lower part (15m vertical height) and 1:6-1:10 for the upper part (15m vertical height).

[0046] This invention targets near-vertical ore layers. Based on the strength of the ore layer, the mining sequence is determined. The ore layer with lower strength is mined first, which is beneficial for mining and can reduce disturbance to interlayers. Then, based on the thickness of the interlayer and its impact on the ore layer mining (the proportion of the plastic zone), the treatment method of the interlayer is determined to ensure that the interlayer has sufficient strength or to directly treat the interlayer as a potential hazard before mining another ore layer. This prevents the interlayer from becoming unstable and damaged when mining another ore layer with higher strength, which would cause danger and result in a large amount of interbedded gangue in the ore.

[0047] S5: As Figure 2 As shown, a large-diameter deep hole 4 is drilled from the rock-drilling chamber 12 toward the b ore layer. After charging, the ore is blasted layer by layer from bottom to top. The ore 10 produced by the blasting is discharged from the ore discharge funnel to the ore extraction roadway 15, and then transported from the ore extraction roadway 15 to the stope pass 2 and then to the intermediate transport roadway 1, and then transported out by the transport equipment in the intermediate transport roadway 1.

[0048] S6: AsFigure 3 As shown, the mined-out area generated by mining the b ore layer is filled with tailings filling material, and the ratio of cement (as a cementing material) to tailings in the tailings filling material is 1:4 in the lower part (15 m in height) and 1:6-1:10 in the upper part (15 m in height);

[0049] While steps S3-S6 are performed, for each ore block, a crossheading 14 is horizontally constructed from the intermediate transportation roadway 1 to the intermediate return airway 81, and the crossheading 14 is constructed along the strike from the ore block to the a ore layer and the b ore layer.

[0050] S7: As shown, the a ore layer and the b ore layer in the floor pillar 5 of the upper intermediate section are constructed with blast holes from the rock drilling chamber 12, and after charging, the layers are sequentially blasted from bottom to top, and the ore 10 generated by blasting is transported to the auxiliary transportation roadway 6 through the rock drilling roadway 11 and then transported out. Figure 3

[0051] In step S7, if the thickness of the plastic zone formed after the interlayer 9 is mined by the two side ore layers is greater than the fourth threshold value (50% in this embodiment) and the thickness of the non-plastic zone is greater than 2 m, the interlayer is retained, indicating that the interlayer has general strength but large thickness; if the thickness of the plastic zone formed after the interlayer 9 is mined by the two side ore layers is less than the fourth threshold value (50% in this embodiment) and the thickness of the non-plastic zone is greater than 1.2 m, the interlayer is retained, indicating that the interlayer has large strength and moderate thickness; otherwise, the interlayer is blasted together with the ore layer, and the interlayer is not transported out during ore mining. In this embodiment, it is predicted that the plastic zone generated by the interlayer after mining the two side ore layers accounts for 40%, and the height of the floor pillar is relatively small, so the influence of mining the ore layer is small, the plastic zone range is small, the integrity is good, and the thickness of the non-plastic zone reaches 1.8 m, so the interlayer 9 can be retained.

[0052] In the present application, since the upper part and the lower part of the floor pillar are both tailings filling bodies when the floor pillar of the upper intermediate section is mined, it is not necessary to fill the mined-out area formed by mining the floor pillar, because when the present intermediate section is mined and filled, the upper part of the floor pillar of the upper intermediate section is a tailings filling body generated by mining the present intermediate section, and the proportion of the cementing material used is large, which ensures the strength of the tailings filling body, and can avoid the influence of the mined-out area generated after mining the floor pillar of the upper intermediate section on the mining of the present floor pillar, especially when the height of the present application is 55 m. In this way, the present application can reduce the filling process and the filling material, reduce the filling cost, reduce the construction process, and improve the mining efficiency. The present application can realize the full mining of the ore layer, without setting a roof pillar, and the floor pillar is mined without filling, and the ore recovery rate is close to 100%, which can produce good economic benefits.

[0053] In the present application, each ore block in the present intermediate section and the corresponding floor pillar of the upper intermediate section are sequentially constructed along the strike, or the odd ore blocks are constructed first and then the even ore blocks are constructed.

[0054] ​In the present application, during the ore falling and transportation of each ore block, the air inlet path is: the ore drawing connecting lane 16, the ore drawing lane 15, the ore drawing air return lane 82, and the air return raise 7. The ore dust generated by the ore room blasting is large, and the ore transportation workers are many, but the air freshness can be ensured by the ventilation through the ore drawing connecting lane 16, and the influence of the ore dust generated during the ore transportation is reduced. Since the ore is transported out through the stope shaft 2 and the middle section transportation lane 1, and the stope shaft 2 is located on the side of the ore drawing connecting lane 16 away from the ore layer, the air entering from the ore drawing connecting lane 16 is less affected by the ore transportation, the quality of the air in the ore drawing lane 15 can be improved, and the health of the workers can be ensured.

[0055] In the present application, during the construction of the ore drawing connecting lane 16 and the rock drilling chamber 12 of the middle section, the air inlet path is: the middle section transportation lane 1, the ore drawing connecting lane 16, the middle section air return lane 81, and the air return raise 7. Although the ore transportation will generate some ore dust, the influence is small due to the small number of workers.

[0056] In the present application, during the ore falling and filling of each ore block, the air inlet path is: the auxiliary transportation lane 6, the rock drilling lane 11, the rock drilling air return lane 83, and the air return raise 7. The auxiliary transportation lane 6 is used as the transportation path of the tailings filling material, the transportation path of the auxiliary material for construction, and the transportation path of the ore in the later stage of the bottom pillar stoping of the previous middle section (the transportation equipment of the auxiliary transportation can be used for transportation). The specific filling path is: the auxiliary transportation lane 6, the rock drilling lane 11 and the rock drilling chamber 12, the rock drilling air return lane 83, and the air return raise 7. The specific ore transportation path is: the rock drilling lane 11 and the auxiliary transportation lane 6.

[0057] The present application is not limited to the above-mentioned best embodiment, and anyone can derive other various forms of methods under the inspiration of the present application, as long as the technical solutions are the same or similar to the present application, they fall within the protection scope of the present application.

Claims

1. A combined pillar and block caving method for the extraction of phosphate ore deposits, characterized in that, The method comprises the following steps: S1: In the range of the present section, the ore body is divided into several ore blocks along the strike of the ore body; for each ore block, it is divided into ore rooms and pillars along the height direction, and the thickness of the ore block is the total thickness of the ore body and the interlayer; the upper part of the ore room is the pillar left after the backfilling of the ore room of the previous section; S2: A section transport roadway is constructed at the bottom of the present section on the side of the interlayer roof along the strike of the ore body, and an ore drawing connecting roadway is constructed at the bottom of the present section on the side of the ore room roof along the strike of the ore body; a section return airway is constructed at the bottom of the present section on the side of the interlayer floor along the strike of the ore body, and an ore drawing return airway is constructed at the bottom of the present section on the side of the ore room floor along the strike of the ore body; The pillar roof side of the previous section is left with a section transport roadway, which serves as an auxiliary transport roadway of the present section; the pillar floor side of the previous section is left with a section return airway, which serves as a drilling return airway of the present section; an upper section through roadway is horizontally constructed in each ore block of the previous section to connect the section transport roadway and the section return airway, which serves as a drilling roadway of the present section; a drilling chamber is constructed along the strike in each a ore layer and b ore layer of the ore block; An extension return air shaft is constructed to the bottom of the present section, and a horizontal roadway is constructed to connect the return air shaft with the drilling return airway, the ore drawing return airway and the section return airway; in the present section, for each ore block, an ore drawing roadway is horizontally constructed from the ore drawing connecting roadway to the ore drawing return airway, and a stope chute is horizontally constructed from the side of the ore drawing connecting roadway away from the ore body to connect the section transport roadway; S3: The a ore layer with a smaller rock mass strength coefficient is mined first, a large-diameter deep hole is constructed from the drilling chamber to the a ore layer in the ore room, after charging, the a ore layer is blasted layer by layer from bottom to top, the ore produced by blasting is discharged to the ore drawing roadway, and then is transported to the stope chute and then to the section transport roadway; S4: Based on the ratio of the plastic zone of the interlayer and the thickness of the non-plastic zone after the a ore layer in the ore room is mined, the interlayer is determined to be retained or blasted; when the interlayer is retained, tailings backfill material is used to fill the empty space generated by the a ore layer in the ore room; if the interlayer is blasted, the rock in the interlayer is broken and the tailings backfill material is used to fill the empty space formed by the a ore layer in the ore room and the interlayer; S5: A large-diameter deep hole is constructed from the drilling chamber to the b ore layer, after charging, the b ore layer is blasted layer by layer from bottom to top, the ore produced by blasting is discharged to the ore drawing roadway, and then is transported to the stope chute and then to the section transport roadway; S6: Tailings backfill material is used to fill the empty space generated by the b ore layer; S7: A blasting drill hole is constructed from the drilling chamber to the a ore layer and the b ore layer in the pillar of the previous section, after charging, the a ore layer and the b ore layer are blasted layer by layer from bottom to top, and the ore produced by blasting is transported to the auxiliary transport roadway through the drilling roadway and then is transported out; In step S4, when the thickness of the plastic zone accounts for less than a first threshold value of the thickness of the interlayer and the thickness of the non-plastic zone is greater than a second threshold value, the interlayer is retained; when the thickness of the plastic zone accounts for less than the first threshold value of the thickness of the interlayer and the thickness of the non-plastic zone is less than the second threshold value, tailings backfill material is used to fill the empty space generated by the a ore layer in the ore room, and a grouting drill hole is constructed between the tailings backfill body and the interlayer to grout and reinforce the plastic zone of the interlayer.

2. The bench and fill mining method according to claim 1, characterized in that, While steps S3-S6 are performed, for each ore block, a crossheading is constructed horizontally from the middle section haulage roadway to the middle section return airway, and a crossheading is constructed from the crossheading in the a ore layer and the b ore layer along the strike.

3. The bench and fill mining method as claimed in claim 1, c h a r a c t e r i z e d in that In step S4, when the ratio of the thickness of the plastic zone to the thickness of the interlayer is greater than the first threshold value and the thickness of the non-plastic zone is greater than the second threshold value, tailings filling material is used to fill the mined-out area of the a ore layer, and a grouting drill hole is constructed between the tailings filling body and the interlayer to grout and reinforce the plastic zone of the interlayer, and if the thickness of the non-plastic zone is greater than the third threshold value, only tailings filling material is used to fill the mined-out area of the a ore layer.

4. The bench and fill mining method as claimed in claim 1, characterized in that, In step S4, when the ratio of the thickness of the plastic zone to the thickness of the interlayer is greater than the first threshold value and the thickness of the non-plastic zone is less than the second threshold value, the interlayer in the ore room is broken and the mined-out area of the a ore layer and the interlayer is filled with tailings filling material.

5. The bench and fill mining method defined in any one of claims 1 to 4, wherein, In steps S4 and S6, when the ore room is filled with tailings filling material, the ratio of the cementing material to the tailings in the tailings filling material is 1:4 in the lower part and 1:6-1:10 in the upper part.

6. The bench and fill mining method of any of claims 1 to 4, wherein, In step S7, if the thickness of the plastic zone formed by the interlayer after mining of the two adjacent ore layers is greater than the fourth threshold value and the thickness of the non-plastic zone is greater than the fifth threshold value, the interlayer is retained; if the thickness of the plastic zone formed by the interlayer after mining of the two adjacent ore layers is less than the fourth threshold value and the thickness of the non-plastic zone is greater than the sixth threshold value, the interlayer is retained; otherwise, the interlayer is blasted together with the ore layer, and the interlayer is not transported out during ore mining.

7. The bench and fill mining method as claimed in claim 1, c h a r a c t e r i z e d b y The ore blocks are constructed along the strike in sequence or at intervals.

8. The bench and fill mining method as claimed in claim 1, c h a r a c t e r i z e d b y The ore mining connection roadway, the middle section haulage roadway, and the auxiliary haulage roadway are air intake roadways.

9. The bench and fill mining method as claimed in claim 1, c h a r a c t e r i z e d b y The auxiliary haulage roadway is used as a transportation path for tailings filling material, and the bottom pillar of the previous middle section is mined in the later stage as a path for transporting ore.

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