A method for treating the collapse of an ore pass

Abstract

The present invention relates to the technical field of underground mining of metal ores, and particularly relates to a method for treating the collapse of an ore pass, which includes the following steps: S1: Empty the original ore bin; conduct remote blasting and air shock on the collapsed objects in the original ore bin, manually cut off the ore discharge port to expose the steel bars, and gradually dredge the ore pass; S2: Fill the original ore bin with high concentration; pour yellow sand with a height equal to the forehead wall into the emptied original ore bin, and fill the slurry on top of the yellow sand. The slurry is prepared from 40% tailings, 60% gobi material, 70% slag micro-powder, and 30% cement in a ratio of 1:3; S3: Construct blasting holes in the filling body; after the filling is completed, cure for 6 - 10 days. After the curing is completed, pour a cement floor; let the cement harden for 3 - 5 days; drill blasting holes at intervals of 20 - 40 mm on the cement floor; S4: Pre-splitting control in the filling body; by strengthening the ventilation of the blasting holes, reduce the temperature of the blasting holes to below 28°C; S5: VCR blasting to form a well; S6: Clean the filling body. The treatment efficiency after the collapse of the original ore bin is improved, and the impact on production is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of underground mining of metal mines, and particularly relates to a method for treating the collapse of an ore pass. Background Art

[0002] In the underground metal mine mining system, the raw ore bin is one of the important ore transfer facilities. Its collapse will cause deformation and dislocation of the shafts and roadways around the ore bin, resulting in the suspension of mining in some mining areas of the mine. In severe cases, it will affect the overall production of the mine and bring many impacts to the mine.

[0003] At present, the mining depth of Ashile reaches 900 m, and the production capacity reaches 6000 t / d. Below the elevation of 350 - 0 m, two ore passes are respectively arranged near the 9# and 11# exploration lines in the footwall of the ore body. In the 1st ore pass, inverted sections are set at the 200 m and 0 m levels respectively, and in the 2nd ore pass, inverted sections are set at the 250 m and 100 m levels respectively. Vibration ore draw machines are installed at each inverted section. The ore from the 2nd ore pass is transported by the belt at the 0 m level and enters the raw ore bin through the branch chute of the 1st ore pass. The net diameter of the raw ore bin is Φ4.0 m, and it is about 280 m away from the main shaft. Branch chutes and ore unloading chambers are set at each production level. Grizzlies (mesh size 630 mm × 630 mm) are set on the branch chutes. The ore mined from each level is loaded by a load-haul-dump machine into the branch ore pass of this level, and then unloaded from the branch chute into the ore pass, and finally converges at the deep crushing chamber. The deep crushing chamber is located near the 9# exploration line at the -50 m level. The crushed ore is transported by the transfer belt at the -50 m level to the finished ore bin, and then metered and loaded through the loading belt at the -100 m level and 2 metering funnels, and unloaded into the skip of the 2# main shaft to be hoisted to the surface ore bin.

[0004] In the early morning of June 7, 2022, a large-area collapse occurred at the ore outlet of the 00 m raw ore bin. The collapse area formed an empty area with a length of 22 m, a width of 16 m, and a depth of 20 m in the 00 level. After scanning the empty area, the collapsed volume reached 2500 m³. The collapse of the raw ore bin led to the paralysis of the operation of the deep ore pass and crushing system. The 2# main shaft could not hoist ore. The underground production organization could only transport the ore in the lower mining area to the ore pass and crushing system in the upper mining area by trucks, and hoist the ore to the surface through the 1# main shaft. The production capacity was reduced to 4000 t / d, which had a huge impact on the production efficiency of the company. Moreover, the long-term ore hauling by trucks imposed a huge pressure on the underground safety management.

[0005] Nonferrous Metals Engineering (No. 07, 2019) published the stability analysis and evaluation of the repair and treatment of a large-collapse raw ore bin. The overall repair and treatment plan generally considered the control of large-range rock mass movement by double-control anchor cables outside the shaft and the control of local rock mass movement by bolt-mesh-shotcrete support inside the shaft. The main construction procedures and parameters are as follows:

[0006] (1) Gravel filling: Fill the raw ore bin with unbonded 4-6mm gravel to prevent the "hanging top" phenomenon from occurring during the lowering of the gravel.

[0007] (2) Double-control tension anchor cable drilling and installation construction: Double-control tension anchor cable drilling is carried out along the north and south sides of the original ore bin toward the inner wall of the shaft. After all the drilling is completed, the steel strands are installed. After the staggered piers are completed, the sub-project construction in the shaft can be started. After the anchor cable ends at the same elevation in the shaft are fixed, the pre-tightening force is applied to the anchor cables on the ground according to the design requirements. After all the anchor cables are constructed, the entire length of the hole is anchored with mortar. The anchor cable adopts 750kN grade, and a single bundle anchor cable is made of 6 15.24mm steel wires tied together. (3) Staggered spraying net support in the shaft: This sub-project is carried out layer by layer in the original ore bin gravel pile as the ore is placed, and the height of each ore placement is 2m. Mortar anchor rods are constructed layer by layer as the ore is placed. The anchor rod specifications are medium 20mm*2.5m, and the spacing between rows is 1m*1m. After the anchor rod construction is completed, a 6mm steel bar is used to weave a steel mesh with a mesh size of 100m*100mm to make it fit closely with the rock wall. (4) Construction of long anchor cables in the shaft: anchor cable holes are constructed in the shaft around the original ore bin, with a drilling depth of 8m, a spacing of 2m, a single anchor cable diameter of 15.24mm, a resin anchor length of 2m, and an initial tension of 10t. The rest of the space in the borehole is then filled with grout. The staggered rods and cables must be applied vertically to the rock wall and structural surface.

[0008] The above technology is used to repair the original ore bin. Due to the conditions of the original ore bin, the various repair and management steps are subject to time constraints, including but not limited to the drilling - installation of steel strands - anchor pier production - anchor cable pre-tightening - mortar anchoring mentioned in step (2), and the layer-by-layer construction mentioned in step (3). Since there are many construction processes and many processes in a progressive relationship (the next process can only be started after the previous process meets the conditions), such as pouring mortar in layers, it is necessary to wait for the previous layer to solidify before constructing the next layer. During this period, too much time will be wasted.

[0009] The Ashele deep ore crushing system crushes and transports 5,000-6,000 tons of ore every day, and is the throat of Ashele's production. The collapse of the original ore bin will cause inconvenience to subsequent mining construction, which will cause huge economic losses. The management of the collapse of the original ore bin requires efficient disposal methods. Summary of the invention

[0010] The present invention provides a method for treating ore chute collapse, which can improve the treatment efficiency after the original ore bin collapses and reduce the impact on production.

[0011] In order to solve the above technical problems, this application provides the following technical solutions:

[0012] A method for treating ore chute collapse comprises the following steps:

[0013] S1: Empty the raw ore bin; conduct remote blasting and air shock on the collapsed materials in the raw ore bin, manually cut to expose the steel bars at the ore discharge opening, and gradually dredge the chute.

[0014] S2: Fill the raw ore bin with high-concentration filling material; pour yellow sand up to the height of the forehead wall into the emptied raw ore bin, and fill the slurry above the yellow sand. The slurry is prepared by mixing 40% tailings, 60% gobi material, 70% slag micro-powder, and 30% cement in a ratio of 1:3.

[0015] S3: Drill blasting holes in the filling body; after the filling is completed, cure for 6 - 10 days. After the curing is completed, pour a cement floor; let the cement harden for 3 - 5 days; drill blasting holes at intervals of 20 - 40 mm on the cement floor.

[0016] S4: Pre-splitting control in the filling body; by strengthening the ventilation of the blasting holes, reduce the temperature of the blasting holes to below 28°C; select 3 blasting holes, load 4 kg of explosive, and the height of each cut is 1 m each time.

[0017] S5: VCR blasting to form a shaft; when the empty roof height at the bottom of the raw ore bin reaches 9 m, use 6 - 9 holes for a single blasting, with 4 kg of explosive loaded in each hole, and continue cut blasting until the cut height reaches above the inclined chute of the raw ore bin.

[0018] S6: Clean the filling body; after the cut height of the raw ore bin reaches above the inclined chute, organize manual tunneling of the filling body of the inclined chute.

[0019] Basic principle and beneficial effects of this solution: After adopting high-strength and rapid filling, use the pre-splitting control + VCR blasting to form a shaft solution to repair the raw ore bin. Through steps such as emptying the raw ore bin, filling the raw ore bin with high-proportion filling slurry, drilling blasting holes, forming the raw ore bin by VCR cut blasting, and connecting the inclined chute, the collapsed raw ore bin is repaired. Through an integrated operation process (that is, uniformly operating (filling) the entire collapsed raw ore bin, then blasting to form a shaft and connecting it with the inclined chute to form a new raw ore bin), the operation difficulty is reduced and the operation efficiency is improved. And there are also the following beneficial effects:

[0020] 1. High-concentration rapid filling technology: Use high-quality washed sand as the filling aggregate, add cement in a ratio of 1:3, and add slag micro-powder to increase the final setting strength of the filling body. The strength of the filling body measured before the final blasting cut can reach above 4 MPa.

[0021] 2. Pouring yellow sand at the bottom of the raw ore bin: It can not only reduce the damage of blasting vibration to the forehead wall, but also reduce the engineering quantity of blasting and shaft sinking in the raw ore bin, provide a compensation space for cut blasting, and increase the repair efficiency of the raw ore bin.

[0022] 3: Controlled blasting + VCR blasting for shaft sinking technology: The VCR blasting for shaft sinking technology is already very mature. However, there is no precedent for using VCR blasting for shaft sinking in backfill. Compared with the original rock, the backfill has low strength, and the drill holes are prone to blockage after blasting; the explosibility is poor, and it is difficult to determine the charging structure. To ensure the success of blasting, by excavating blasting holes at intervals and charging flexibly, difficulties such as high temperature in the hole and drill hole deformation are overcome.

[0023] 4: This solution saves construction time and reduces the impact on production.

[0024] Further, after excavating the blasting holes in step S3, it further includes step S31: Excavating pre-splitting shock-absorbing holes with a hole diameter of 70 - 80 mm and a distance of 20 - 40 mm between adjacent two pre-splitting shock-absorbing holes.

[0025] Beneficial effect: The pre-splitting shock-absorbing holes are constructed with a geological drill and are arranged around the blasting holes, reducing the damage of blasting vibration to the backfill.

[0026] Further, the diameter of the blasting hole is selected as 165 mm, and the diameter of the pre-splitting shock-absorbing hole is selected as 75 mm.

[0027] Beneficial effect: Facilitate the construction of the submersible drill.

[0028] Further, the distance between adjacent two blasting holes is 30 mm, and the distance between adjacent two pre-splitting shock-absorbing holes is 30 mm.

[0029] Further, when manually excavating the inclined chute backfill in step S6, first excavate through to the side of the raw ore bin with a rectangular section of 1.0 m × 1.0 m and a slope of 20%. After penetration, then brush and expand the bottom according to the design, and brush and expand the inclined chute to 1.4 m × 1.2 m with a slope of 65% to ensure smooth ore chuting of the inclined chute.

[0030] Further, in step S4, the internal temperature of the blasting hole is reduced to below 28°C by ventilating with a high-pressure air pipe installed at the bottom of the raw ore bin and increasing the return air efficiency by installing a fan in the top connecting roadway. Description of the Drawings

[0031] Figure 1 It is a step diagram in a method for treating the collapse of an ore pass;

[0032] Figure 2 It is a layout design plan view in a method for treating the collapse of an ore pass;

[0033] Figure 3 It is a blasting schematic diagram of the raw ore bin in a method for treating the collapse of an ore pass;

[0034] Figure 4 It is a blast hole layout diagram in a method for treating the collapse of an ore pass;

[0035] Figure 5 Schematic diagram of pre-buried precast pipes during the filling of the raw ore bin in Example 2;

[0036] Figure 6 It is Figure 5 Cross-sectional view of the precast pipe in

[0037] Reference signs in the specification drawings: precast pipe 1, pipe wall 2, solid nodules 2, hollow medicine-embedded area 3, slurry filling area 4, yellow sand filling area 5. Specific implementation manners

[0038] The following is a further detailed description through specific implementation manners:

[0039] In Example 1, as shown in the Figure 1 drawing,

[0040] A method for treating the collapse of an ore pass includes the following steps:

[0041] S1: Empty the raw ore bin

[0042] The elevation of the raw ore bin wellhead is 0 m, the elevation of the crushing chamber is -45 m, the elevation of the ore discharge port is -39 m, the depth of the raw ore bin is 39 m, and the ore storage height in the well is 20 m. The raw ore bin was originally supported by 400 mm concrete lining, with double-layer steel bars inside, and the impact section was also lined with steel rails. After the collapse of the raw ore bin, there are a large amount of ores, concrete, steel bars, etc. in the shaft. It is necessary to empty the raw ore bin and then organize the filling of the collapsed raw ore bin with high-concentration filling slurry. The method of using bamboo poles to support explosive blasting and air shock is adopted. The steel bars are exposed by manually cutting the ore discharge port, and the ore pass is gradually dredged. During the high-risk operation period, Ashile arranges technical personnel to follow the class throughout the process, controls the amount of explosive charge per single blast, tries to avoid damaging the shaft, and ensures the operation safety at the same time.

[0043] S2: Fill the raw ore bin with high concentration

[0044] After the raw ore bin is emptied, the height of yellow sand perfusion is 6 m: this height is from the ore discharge port to the top of the crushing chamber, that is, the height of the forehead wall. During the filling process, the bottom yellow sand section can play a good role in filtering water and accelerate the solidification of the filling body. Before the blasting of the raw ore bin, the yellow sand filling section is emptied, which can ensure that the slotting blasting section is above the forehead wall, prevent the situation of blasting damage to the forehead wall, and at the same time provide a certain free surface for the slotting blasting.

[0045] The filling slurry above 6m is washed sand + cement + stones, prepared with 40% tailings, 60% gobi material: 70% slag micro-powder and 30% cement in a ratio of 1:3. Adding tailings not only reduces costs but also increases the fluidity of the slurry; adding slag micro-powder can improve the final setting strength of the filling body. The gobi material is washed and desanded, with low mud content, which improves the strength of the filling body. Finally, the entire collapsed original ore bin was filled on June 28. After statistics, the filling volume in the collapsed area of the original ore bin was 2455.80m³. In order to fully filter water and ensure the filling quality, the filling was carried out in 5 times, and the filling took 8 days. After the filling was completed, the bottom of the well was emptied and filled with yellow sand, and the measured height was 6m, achieving the expected effect.

[0046] S3: Construction of blasting holes in the filling body

[0047] After the filling is completed, cure for 7 days and pour a cement floor. 3 days after the completion of the cement floor pouring, the T-150 blasting hole drilling rig enters the site and starts the construction of blasting holes and pre-splitting shock-absorbing holes, as shown in the appendix Figure 2 and the appendix Figure 4 As shown, for the construction of blasting holes, a total of 11 φ165mm blasting holes were constructed, with a total length of 330m. In order to reduce the damage of blasting vibration to the filling body, pre-splitting shock-absorbing holes were constructed around the blasting holes using a geological drill. A total of 21 φ75mm pre-splitting holes were constructed, with a total length of 630m. During the drilling construction, the filling body dissipated heat severely, and the temperature in the hole was as high as over 40°. An exhaust fan was erected at the operation site and high-pressure air was introduced for ventilation to cool down the operation site and ensure the safety of construction personnel.

[0048] S4: Pre-splitting control in the filling body

[0049] In order to ensure blasting safety, it was decided not to organize blasting temporarily and strengthen ventilation. A high-pressure air pipe was erected at the bottom of the original ore bin for ventilation, and a fan was erected at the top connection roadway to increase the return air efficiency, so that the temperature in the hole could be reduced as soon as possible. When the temperature was reduced to 27°C, blasting began. Since the early blasting was close to the forehead wall, in order to prevent the blasting vibration from damaging the forehead wall, 3 holes were first used, with a single-hole charge of 4Kg, and the slotting height was 1m each time, trying to use as little charge as possible to reduce the damage of blasting vibration to the forehead wall. Due to the relatively soft filling body, plugging occurred immediately after blasting, and it was necessary to organize hole cleaning after each blasting, which greatly affected the blasting efficiency.

[0050] S5: VCR blasting to form a shaft

[0051] When the empty top height of the bottom of the ore bin reaches 9m, 6-9 holes are used for a single blast, with a charge of 4kg per hole, and slot blasting continues. Due to the good blastability of the filling body, the blasting effect is good after each blasting. The technicians flexibly determine the charge holes and the charge per hole according to the actual through-hole conditions and the hole depth after the hole is dug. It was originally planned that a small amount of charge was also required for the surrounding pre-splitting holes. However, according to the actual situation on site, it was found that the amount of slag falling from the filling body after blasting was better than expected. In the end, most of the surrounding φ75mm pre-splitting shock-absorbing holes were not charged, and only played a role in reducing the blasting vibration. Only a small number of pre-splitting shock-absorbing holes were charged with a small amount of charge in the case of poor blasting effect, which played the role of expanding the ore bin. The hole depth was measured to be 10m, and the slot height was above the inclined chute of the ore bin. In order to resume production as soon as possible, and at the same time, it played a good supporting effect on the I-beam support legs on the top of the ore bin, it was decided that the slot blasting would not be connected with the top of the ore bin. It was only necessary to connect the inclined chute and re-activate the ore bin. Finally, the VCR slot was blasted into a well. Figure 3 As shown in the figure, the crushing chamber is located at the bottom, and the ore bin is connected to it. The chute part of the ore bin goes straight upward ( Figure 3 The trough area in the middle is part of the chute area), the inclined part on the right is the inclined chute, and in the original rock area ( Figure 3 The white area in the middle of the upper part is the original rock, and the place where the collapse occurs is the lower part of the original rock. In order to prevent the original rock from being further explored and causing the original ore bin to be blocked, the original ore bin needs to be managed and repaired. When there is a collapse, the fallen original rock causes the original ore bin to collapse, and it is managed through steps S1-S5, where Figure 3 The lower end of the Zhongyuan ore bin is filled with yellow sand. Figure 3 The upper end of the inclined chute in the upper right corner is also filled with yellow sand to facilitate later cleaning and use. The area not covered by yellow sand will also be reinforced once in this governance, that is, the area except the collapsed area will also be reinforced.

[0052] S6: Cleaning the filling

[0053] The yellow sand poured into the inclined chute is cleaned out, and the height of the original ore bin is pulled to above the inclined chute. Manual excavation of the inclined chute filling body is started, with a 1.0m×1.0m rectangular section and a 20% slope to the side of the original ore bin. After penetration, the bottom is expanded according to the design, and the inclined chute is expanded to 1.4m×1.2m with a slope of 65% to ensure smooth ore flow in the inclined chute.

[0054] Embodiment 2

[0055] The difference between the second embodiment and the first embodiment is that, S2: filling the raw ore bin with high concentration; pouring yellow sand to the height of the wall in the emptied raw ore bin, that is, Figure 5The yellow sand filling area 5 shown in the figure. A precast pipe 1 is vertically fixed at intervals of 20 - 40 mm (40 mm is selected in this solution). The slurry is filled above the yellow sand. The slurry is prepared by mixing 40% tailings, 60% gobi material: 70% slag micro - powder, and 30% cement in a ratio of 1:3; The precast pipe 1 is as shown in Figure 6 the figure, which includes a pipe wall 2. The inside of the pipe is composed of solid nodules 2 and hollow explosive - embedding areas 3 arranged at intervals. Both the pipe wall 2 and the solid nodules 2 are made of concrete. After the slurry is poured and cooled to form, the hollow area of the precast pipe 1 serves as the explosive - embedding area. This eliminates the step of bringing in a drilling machine to drill holes, which can further improve efficiency, reduce the treatment time, and there is no heat generated by drilling. That is, the step of cooling the drill holes in subsequent S3 can also be omitted. After the shock - absorbing pre - splitting holes are opened, explosives can be directly placed in the hollow explosive - embedding area 3 of the precast pipe 1 for blasting operations.

[0056] The solid nodules 2 can support the pipe wall 2 during the slurry pouring, preventing the force of the slurry on the pipe wall 2 from being too large and causing the pipe wall 2 to deform and rupture. During blasting, the solid nodules 2 can converge part of the force emitted by the explosion (when there is no nodule blocking, the explosion force spreads in the form of waves in all directions. After having the solid nodules 2, the propagation in the vertical direction is blocked, and part of the force will be converged and act on the pipe wall 2, that is, increasing the acting force on the pipe wall 2). Acting on the pipe wall 2 and then spreading to the filling body to complete the blasting. That is, the solid nodules 2 also play a role in storing force, improving the blasting effect. Each explosion can blast open the solid nodules 2 to ensure the normal placement of explosives next time.

[0057] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this embodiment. Common general knowledge such as specific structures and characteristics known in the art are not described in detail here. Those of ordinary skill in the art know all the common general knowledge in the technical field to which the invention belongs before the application date or the priority date, can know all the existing technologies in this field, and have the ability to apply conventional experimental means before this date. Those of ordinary skill in the art can, under the inspiration given in this application, combine their own abilities to improve and implement this solution. Some typical well - known structures or well - known methods should not become obstacles for those of ordinary skill in the art to implement this application. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. A method for treating the collapse of an ore pass, characterized in that, it includes the following steps: S1: Empty the original ore bin; conduct remote blasting and air shock on the collapsed materials in the original ore bin, manually cut the ore discharge opening to expose the steel bars, and gradually dredge the ore pass; S2: Fill the original ore bin with high concentration; pour yellow sand with a height equal to the forehead wall into the emptied original ore bin, and fill the slurry above the yellow sand. The slurry is prepared by mixing 40% tailings, 60% gobi material, 70% slag micro powder, and 30% cement in a ratio of 1:3; S3: Construct blasting holes in the filling body; after the filling is completed, cure for 6 - 10 days. After the curing is completed, pour a cement floor; the cement hardens for 3 - 5 days; blast holes are drilled every 20 - 40 mm on the cement floor; S4: Pre - crack control in the filling body; by strengthening the ventilation of the blast holes, reduce the temperature of the blast holes to below 28°C; select 3 blast holes, load 4 kg of explosive, and the slotting height is 1 m each time; S5: VCR blasting to form a well; when the empty roof height at the bottom of the original ore bin reaches 9 m, 6 - 9 holes are used for single - time blasting, and the charge per hole is 4 kg. Continue slotting blasting until the slotting height reaches above the inclined chute of the original ore bin; S6: Clean the filling body; after the slotting height of the original ore bin reaches above the inclined chute, organize manual tunneling of the inclined chute filling body. When manually tunneling the inclined chute filling body, first tunnel through to the original ore bin side with a rectangular section of 1.0 m × 1.0 m and a slope of 20%. After penetration, brush and expand the bottom according to the design, and expand the inclined chute to 1.4 m × 1.2 m with a slope of 65% to ensure smooth ore chuting in the inclined chute.

2. A method for treating the collapse of an ore pass according to claim 1, characterized in that: After drilling the blast holes in step S3, it further includes step S31: Drill pre - crack shock - absorbing holes with a hole diameter of 70 - 80 mm, and the distance between adjacent two pre - crack shock - absorbing holes is 20 - 40 mm.

3. A method for treating the collapse of an ore pass according to claim 2, characterized in that: The diameter of the blast holes is selected as 165 mm, and the diameter of the pre - crack shock - absorbing holes is selected as 75 mm.

4. A method for treating the collapse of an ore pass according to claim 3, characterized in that: The distance between adjacent two blast holes is 30 mm, and the distance between adjacent two pre - crack shock - absorbing holes is 30 mm.

5. A method for treating the collapse of an ore pass according to claim 1, characterized in that: In step S4, the internal temperature of the blast holes is reduced to below 28°C by means of installing a high - pressure air duct at the bottom of the original ore bin for ventilation and installing a fan at the top connecting passage to increase the return air efficiency.

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