A low-loss mining method for thick ore bodies by eliminating broken zones

Abstract

The present invention discloses a low-loss mining method for thick ore bodies that excludes broken zones, comprising the following steps: reserving a bottom layer of the broken zone lower wall and a top layer of the broken zone upper wall in the broken zone lower wall and upper wall, respectively; constructing a rock drilling chamber at the top of the stope, and constructing downward parallel large-diameter blastholes in the rock drilling chamber, wherein the downward parallel large-diameter blastholes pass through the top layer of the broken zone upper wall, the broken zone, and the bottom layer of the broken zone lower wall, so that the downward parallel large-diameter blastholes can be charged and blasted in layers according to the inclination angle of the broken zone interpenetrating surface, thereby eliminating the broken zone and the ore body above the top layer of the broken zone upper wall, and blasting and ore removal in layers from bottom to top. The method of the present invention can separately remove ore and slag, realizing low-loss mining with separate mining of the ore body and the broken zone with interbedded rocks.

Description

Technical Field

[0001] The invention relates to the technical field of mining, and in particular to a low-loss mining method for eliminating broken zones in thick ore bodies. Background Art

[0002] The low-depletion loss mining of thick ore bodies under the condition of interpenetration of broken zones has obvious technical complexity and particularity: (1) The ore blocks are affected by the interpenetration of broken zones, which can easily lead to large-scale roof collapse and slab spalling in the mining area. In serious cases, the mining area will be scrapped and a large amount of geological resources will be lost; (2) The stability of the ore rock is poor, the boundary of the mining area is difficult to control, the amount of mixed broken zones and surrounding rocks is large, and the ore depletion rate is high; (3) The blastholes in the broken zones are easily deformed and blocked, making charging difficult and the ore block rate is high.

[0003] While reducing stope structural parameters can mitigate stope caving, it cannot effectively reduce the extensive dilution caused by caving in the fracture zone. This significantly reduces stope production capacity and increases mining costs. Therefore, a low-dilution mining method that eliminates fracture zones in thick ore bodies is urgently needed to address these mining technical challenges. Summary of the Invention

[0004] In order to solve the problem in the prior art that fracture zones easily lead to large-scale roof collapse, slab spalling, and even scrapping of the stope, the present invention provides a low-loss mining method for thick ore bodies by eliminating fracture zones. The method comprises the following steps:

[0005] (1) Construct the mine-exit tunnel and the cutting tunnel along the stage transport tunnel at the bottom of the stope, then construct the ore loading road and connect the mine-exit tunnel and the cutting tunnel;

[0006] (2) Construct a cutting cross tunnel in the cutting bottom tunnel, use the cutting cross tunnel as the free surface for charging and blasting, and form a stope ore-dropping space after the ore is mined;

[0007] (3) Reserve the bottom layer of the broken zone and the top layer of the broken zone in the broken zone footwall and the broken zone upper wall respectively;

[0008] (4) A rock drilling chamber is constructed at the top of the stope, and a number of downward parallel large-diameter blastholes are constructed in the rock drilling chamber. The downward parallel large-diameter blastholes pass through the top layer of the upper wall protection of the broken zone, the broken zone, and the bottom layer of the lower wall protection of the broken zone. The downward parallel large-diameter blastholes can be used to charge and blast the slag in layers according to the inclination angle of the broken zone interlaced surface, and remove the broken zone;

[0009] (5) The upper wall of the broken zone and the lower wall of the broken zone and the lower wall of the broken zone are collapsed by natural collapse or induced collapse. No explosives are charged in natural collapse, and the amount of explosives charged in induced collapse is less than that of conventional blasting.

[0010] (6) The ore body above the top layer of the upper plate of the crushed zone is blasted and discharged in layers from bottom to top;

[0011] (7) After the entire mining area is mined, the goaf is filled.

[0012] Preferably, the diameter of the downward parallel large-diameter blastholes is 100mm to 125mm, the row spacing is 2.8m to 3.6m, and the hole spacing is 2.8m to 3.6m. The thickness of the bottom wall of the broken zone is 1.0m to 2.0m, and the thickness of the top wall of the broken zone is 0.8m to 1.5m, which is used to eliminate broken zones with a thickness of 4m to 40m. The charge used in the step (5) of inducing caving is 10% to 20% of the conventional blasting charge.

[0013] For safe construction, step (4) further includes supporting the drilling chamber 8 with a shotcrete mesh. The drilling chamber uses a shotcrete mesh and anchor cables to jointly support its roof. The stage transport tunnel, the mine roadway, the cutting bottom tunnel, and the ore loading access roadway use shotcrete mesh support. Anchor cables are installed in the mine roadway, the cutting bottom tunnel, or the ore loading access roadway to pre-support the broken zone.

[0014] Preferably, the filling of the goaf in step (7) is performed by using full tailings paste filling, graded tailings cement filling, or crushed stone cement filling. The filling of the goaf in step (7) has a filling strength of 1.0 MPa to 2.5 MPa.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The method of the present invention removes ore before the crushing zone collapses, and then constructs downward parallel large-diameter blastholes in the rock drilling chamber. The downward parallel large-diameter blastholes can be charged and blasted in layers according to the inclination angle of the crushing zone intersecting surface, and the crushing zone is gradually eliminated, thereby improving the integrity and stability of the crushing zone during the stope recovery process. The ore body above the top layer of the upper plate of the crushing zone is charged and blasted in layers from bottom to top; the ore discharge and slag discharge are carried out separately, realizing the separate mining of the ore body and the crushing zone with rocks, improving mining efficiency, and achieving low-loss mining. At the same time, because the crushing zone lower plate protection bottom layer and the crushing zone upper plate protection top layer are reserved in the lower plate and upper plate of the crushing zone respectively, and the diameter of the downward parallel large-diameter blastholes is large enough, it is ensured that the blastholes in the crushing zone will not be blocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a front view of a low-loss mining method for removing broken zones from thick ore bodies;

[0018] Figure 2 yes Figure 1 A magnified view of part A;

[0019] Figure 3 This is a schematic diagram of the stope cutting bottom;

[0020] Figure 4 is relative to Figure 1 Top view of .

[0021] Figure numerals: bottom layer of the lower plate of the crushed zone 1, crushed zone 2, top layer of the upper plate of the crushed zone 3, blasthole 4, loading access road 5, stage transportation tunnel 6, mining tunnel 7, drilling chamber 8, collapsed ore 9, filling body 10, cutting bottom tunnel 11, cutting cross tunnel 12. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] This is an example of mining a thick ore body with a thickness of 35m, a crushing zone thickness of 10m, and a crushing zone inclination of 15°. Figures 1 to 4 , the specific implementation steps are as follows:

[0024] (1) The stope structure parameters are set as follows: stope length 35m, width 10m, and stage height 50m. The ore body is divided into two steps of mining: chamber and pillar. No pillars are left between the first and second step stopes.

[0025] (2) constructing the ore-exit tunnel 7 and the cutting-pull bottom tunnel 11 along the stage transport tunnel 6 at the bottom of the stope, and then constructing several ore-loading access roads 5 to connect the ore-exit tunnel 7 and the cutting-pull bottom tunnel 11;

[0026] (3) A 1.5m thick bottom layer 1 for the broken zone lower wall and a 1.0m thick top layer 3 for the broken zone upper wall are reserved on the lower wall and upper wall of the broken zone 2 respectively;

[0027] (4) Anchor cables are constructed in the ore loading access road to provide pre-support for the broken zone 2;

[0028] (5) constructing a cutting cross tunnel 12 in the cutting bottom tunnel 11, using the cutting cross tunnel 12 as the free surface for blasting, forming a stope ore drop space after the ore is mined, and emptying the ore in the stope when mining reaches the bottom layer 1 of the crushed zone footwall;

[0029] (6) A rock drilling chamber 8 is constructed above the top layer 3 of the upper plate protection in the broken zone, and the rock drilling chamber 8 is supported by a combination of shotcrete nets and anchor cables;

[0030] (7) constructing downward parallel large diameter blastholes 4 in the rock drilling chamber 8, with a diameter of 120 mm, a row spacing of 3.0 m, and a hole spacing of 3.2 m. The ore is dropped and discharged by layered charging and blasting according to a 15° inclined surface, i.e., the blasting surface formed is parallel to the inclination direction of the intersecting surface of the crushing zone, and the layer height is 8 m;

[0031] (8) The charge of the downward parallel large-diameter blastholes 4 in the crushed zone 2 and the crushed zone lower wall protection top layer 1 and the crushed zone upper wall protection top layer 3 is 8% of the conventional blasting charge;

[0032] (9) The broken zone 2 is charged and blasted to remove the slag, and the broken zone 2 is removed;

[0033] (10) Continue to blast the ore body above the top 3 of the broken zone in layers from bottom to top;

[0034] (11) After the entire stope is mined, the goaf is cemented and filled with graded tailings and cementitious materials, and the strength of the filling is 1.2 MPa.

[0035] The present invention is particularly effective for ore bodies with a crushing zone of 4 to 40 meters. In this case, the thickness of the lower wall protection layer of the crushing zone is selected to be 1.0 to 2.0 meters, and the thickness of the upper wall protection layer of the crushing zone is selected to be 0.8 to 1.5 meters. The diameter of the downward parallel large-diameter blastholes is 100 to 125 mm, the row spacing is 2.8 to 3.6 meters, and the hole spacing is 2.8 to 3.6 meters. When the crushing zone is thicker, the upper and lower wall protection layers or the protective layers of the crushing zone can be thicker, the blasthole diameter can be larger, and the hole spacing and row spacing can be closer.

[0036] After the downward parallel large-diameter blastholes penetrate the top layer of the upper wall of the broken zone and the underlying broken zone and lower wall of the broken zone, the broken zone can be collapsed by natural or induced caving. Natural caving requires no explosive charge, while induced caving uses a charge less than that used in conventional blasting, typically 10% to 20% of the conventional blasting charge. Whether to use natural or induced caving depends on the specific conditions of the broken zone. After the entire stope is mined, the goaf is backfilled, with a fill strength of 1.0 MPa to 2.5 MPa. Filling can be done with either full tailings paste, graded tailings cemented fill, or crushed stone cemented fill.

[0037] It can be clearly seen from the above specific embodiments that the method of the present invention has the following characteristics:

[0038] (1) The ore can be removed before the broken zone collapses, and the ore and slag can be removed separately, so as to realize the separate mining of the ore body and the broken zone interbedded rocks;

[0039] (2) Downward parallel large-diameter blastholes are constructed in the rock drilling chamber, and the bottom layer and top layer of the broken zone are reserved in the lower plate and upper plate of the broken zone respectively. The blastholes in the broken zone will not be blocked, and the ore is blasted and discharged in layers according to the inclination of the intersecting surface of the broken zone, thereby improving the integrity and stability of the broken zone during the mining process;

[0040] (3) When mining reaches the bottom layer of the crushed zone, the downward parallel large-diameter blastholes in the crushed zone and the upper and lower wall protection layers of the crushed zone can be loaded with less explosives or no explosives, and the crushed zone can be collapsed by natural collapse or induced collapse, effectively saving explosives.

Claims

1. A low-loss mining method for thick ore bodies by eliminating broken zones, comprising the following steps: (1) Construct the mine-exit tunnel and the cutting tunnel along the stage transport tunnel at the bottom of the stope, then construct the ore loading road and connect the mine-exit tunnel and the cutting tunnel; (2) Construct a cutting cross tunnel in the cutting bottom tunnel, use the cutting cross tunnel as the free surface for charging and blasting, and form a stope ore drop space after the ore is unearthed; (3) Reserve the bottom layer of the broken zone and the top layer of the broken zone in the broken zone footwall and hanging wall respectively; (4) A rock drilling chamber is constructed at the top of the stope, and a number of downward parallel large-diameter blastholes are constructed in the rock drilling chamber. The downward parallel large-diameter blastholes pass through the top layer of the upper wall protection of the broken zone, the broken zone, and the bottom layer of the lower wall protection of the broken zone. The downward parallel large-diameter blastholes can be used to charge and blast the slag in layers according to the inclination angle of the broken zone intersecting surface, and remove the broken zone; (5) The upper wall of the broken zone and the lower wall of the broken zone and the lower wall of the broken zone are collapsed by natural collapse or induced collapse. No explosives are charged in natural collapse, and the amount of explosives charged in induced collapse is less than that in conventional blasting. (6) The ore body above the top layer of the upper wall of the crushed zone is blasted and discharged in layers from bottom to top; (7) After the entire stope is mined, the goaf is filled; The charge amount in the step (5) of inducing caving is 10% to 20% of the charge amount in conventional blasting.

2. The low-loss mining method for removing broken zones from thick ore bodies according to claim 1 is characterized by: The diameter of the downward parallel large-diameter blastholes is 100mm-125mm, the row spacing is 2.8m-3.6m, and the hole spacing is 2.8m-3.6m.

3. The low-loss mining method for removing broken zones from thick ore bodies according to claim 1 is characterized by: The bottom layer of the broken zone lower plate protection has a thickness of 1.0m to 2.0m, and the top layer of the broken zone upper plate protection has a thickness of 0.8m to 1.5m, and is used to remove the broken zone with a thickness of 4m to 40m.

4. The low-loss mining method for removing broken zones from thick ore bodies according to claim 1 is characterized by: The step (4) further comprises supporting the rock drilling chamber (8) with a sprayed anchor net.

5. The low-loss mining method for removing broken zones from thick ore bodies according to claim 1 is characterized by: The rock drilling chamber adopts a shotcrete mesh and an anchor cable to jointly support the top plate of the rock drilling chamber.

6. The low-loss mining method for removing broken zones from thick ore bodies according to claim 1 is characterized by: During the above stage, the transport tunnel, mine exit tunnel, cutting bottom tunnel and loading access road are supported by shotcrete mesh.

7. The low-loss mining method for thick ore bodies with the broken zone removed according to claim 1 is characterized by: Anchor cables are constructed in the mine exit tunnel, cutting bottom tunnel or loading access road to pre-support the broken zone.

8. The low-loss mining method for thick ore bodies with the broken zone removed according to claim 1 is characterized by: In step (7), the goaf is filled with full tailings paste filling, graded tailings cement filling, or crushed stone cement filling.

9. The low-loss mining method for removing broken zones from thick ore bodies according to claim 1 is characterized by: In step (7), the goaf is filled, and the filling body strength is 1.0 MPa to 2.5 MPa.

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