Three-dimensional cutting blasting method suitable for boulder mining

Abstract

The invention relates to the technical field of stone mining, and particularly discloses a three-dimensional cutting blasting method suitable for boulder mining, which comprises the following steps: (1) drilling: drilling blast holes, including horizontal cutting blast holes, longitudinal cutting blast holes and transverse cutting blast holes, in a regular step surface in a mining area, a three-dimensional cutting network formed by the blast holes divides the rock mass to be cut into a plurality of cuboid-shaped or cube-shaped cutting blocks. (2) charging: charging a cartridge at the center of the blast hole to ensure that the axis of the cartridge coincides with the axis of the blast hole; and (3) blasting: after the blast holes are blocked, detonating according to a specific detonating sequence. According to the method, through combination of three-dimensional multidirectional collaborative cutting blast hole arrangement and a prefabricated directional cutting blast hole structure, low-unit-consumption accurate cutting can be conducted on the rock mass, the blasting energy requirement is remarkably reduced, and therefore directional blasting cutting mining of regular boulders is achieved; the mining quality of the boulder is improved, the mining cost is reduced, and harmful effects such as blasting vibration are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stone mining, in particular to a three-dimensional cutting blasting method suitable for large block stone mining. BACKGROUND

[0002] In the field of water conservancy and hydropower, mining, etc., the traditional technology faces significant bottlenecks: mechanical cutting method (such as diamond wire saw) can achieve acceptable accuracy, but has low efficiency and high energy consumption, and cannot realize three-dimensional separation of deep rock mass. High-strength rock mass leads to rapid tool wear and significant cost increase. Conventional blasting methods, especially traditional bench blasting, cause uncontrollable release of blasting energy and low utilization rate due to the arrangement of blast holes in the vertical plane, the use of coupled charge (leading to high-pressure crushing of hole wall), and the simultaneous or differential blasting of single or multiple rows of blast holes. The random expansion of blast-induced cracks is disturbed by geological weak planes, especially the lack of horizontal pre-splitting holes, resulting in uneven bottom fracture surface. Ultimately, the shape and size of the mined stone blocks are irregular.

[0003] This irregularity not only significantly increases the difficulty and cost of subsequent stone shaping and processing, causing serious waste of high-quality resources, but also poses high construction safety risks (such as flying stones and vibrations). The traditional method cannot meet the needs of large-scale and fine mining in terms of efficiency, accuracy, energy consumption, and safety. Therefore, there is an urgent need to develop a new block stone mining technology that can achieve efficient and accurate three-dimensional separation of rock mass, significantly improve the regularity of block stones, and reduce energy consumption and safety risks. SUMMARY

[0004] To improve the quality of large block stone mining while reducing energy consumption and safety risks, the present application provides a three-dimensional cutting blasting method suitable for large block stone mining.

[0005] The three-dimensional cutting blasting method suitable for large block stone mining provided by the present application adopts the following technical solution: A three-dimensional cutting blasting method suitable for large block stone mining, comprising the following steps: Drilling: drilling blast holes on a regular bench surface in the mining area, the bench surface including a horizontal surface and a vertical surface, the blast holes including vertical cutting blast holes drilled on the horizontal surface and a plurality of rows of horizontal cutting blast holes drilled on the vertical surface, the vertical cutting blast holes including a plurality of rows of longitudinal cutting blast holes and a plurality of rows of transverse cutting blast holes; the plurality of rows of horizontal cutting blast holes form a plurality of horizontal cutting surfaces, the plurality of rows of longitudinal cutting blast holes form a plurality of vertical longitudinal cutting surfaces, and the plurality of rows of transverse cutting blast holes form a plurality of vertical transverse cutting surfaces; the horizontal cutting surfaces, longitudinal cutting surfaces, and transverse cutting surfaces together form a three-dimensional cutting network, separating the rock mass to be cut into a plurality of cuboid or square cutting blocks; Charging: Charge the cartridge at the center of the blast hole, ensuring that the cartridge axis coincides with the blast hole axis; Blasting: After the blast hole is plugged, it is initiated according to a specific initiation sequence.

[0006] The present application realizes three-dimensional directional separation of rock mass through a three-dimensional cutting network formed by longitudinal, transverse and horizontal cutting blast holes, improves the problem of incomplete cutting surface in traditional bench blasting, and ensures uniform release of explosive energy along the blast hole axis through a central charging structure, avoiding excessive crushing of the hole wall. The specific initiation sequence controls the crack propagation path, and the three work together to ensure the regularity and integrity of large stone cutting.

[0007] Further, the horizontal cutting blast hole and the vertical cutting blast hole are arranged alternately, the axis of the horizontal cutting blast hole is perpendicular to the line connecting the two adjacent longitudinal cutting blast holes, and the axis of the horizontal cutting blast hole intersects the midline of the line connecting the two adjacent longitudinal cutting blast holes.

[0008] The horizontal cutting blast hole and the vertical cutting blast hole are arranged alternately to form a spatial mechanical balance system, which precisely controls the intersection of horizontal and vertical cracks, avoids uneven fracture of rock mass, and significantly improves the flatness of the stone.

[0009] Further, the height of the bench face is 4-6m, and the longitudinal length of the bench face is 30-50m.

[0010] Limiting the height and length of the bench, optimizing the spatial scale adaptability of the three-dimensional blast hole network, ensures efficient transmission of blasting energy to the deep layer of rock mass, while considering the safety of construction and the feasibility of equipment operation.

[0011] Further, the blast hole is a pre-splitting blast hole; in the scene where the flatness of the cutting surface needs to be strictly controlled, a special blast hole with a prefabricated wedge-shaped slot hole or a prefabricated hole wall notch structure is used.

[0012] The prefabricated wedge-shaped slot hole or notch direction guides the blast gas pressure to convert into symmetric tensile stress, guides the blast crack to extend along the predetermined direction, and makes the flatness of the cutting surface meet the requirements of high-value stone raw material mining, reducing subsequent processing loss.

[0013] Further, the prefabricated wedge-shaped slot hole or prefabricated hole wall notch is a V-shaped or U-shaped slot hole or notch along the depth direction of the blast hole, and the tip thereof faces the predetermined cutting direction.

[0014] The tip of the V / U-shaped slot faces the cutting direction, uses the stress concentration effect to guide the crack to extend along the tip, and makes the crack extend along the slot line direction, improving the cutting accuracy.

[0015] Further, the depth of the vertical cutting blast hole is 3-7m, the hole diameter is 50-90mm, the hole spacing is 8-15 times the hole diameter, and the blast hole density coefficient is 0.4-0.7.

[0016] The low specific charge, small hole spacing and small dense coefficient are adopted: the low specific charge can reduce the hole wall load and reduce the damage to the rock mass; the small hole spacing forms a dense weakening zone, so that the cracks develop along the hole connecting line; the small dense coefficient increases the resistance line by reducing the hole spacing, reduces the reflection effect of the free surface, and the cracks between the holes are also formed quickly, which can reduce the blasting time, so as to produce large blocks.

[0017] Further, the longitudinal cutting blast hole is arranged in 2-4 rows, and the last row of longitudinal cutting blast hole is arranged with an overdeep of 0.5-1.0 m.

[0018] The overdeep of 0.5-1.0 m of the last row of longitudinal cutting blast hole helps to compensate the constraint force of the bottom rock mass, ensures the cutting seam to penetrate to the bottom of the step, solves the problem of uneven bottom fracture surface, and avoids the need for secondary treatment of residual rock ridge.

[0019] Further, the horizontal cutting blast hole is arranged in 1-3 rows, the hole depth does not exceed the last edge longitudinal cutting surface, the hole diameter is 45-90 mm, and the hole spacing is 8-15 times of the hole diameter.

[0020] The depth of the horizontal cutting blast hole does not exceed the last edge longitudinal surface, the hole diameter / hole spacing is matched with the vertical cutting blast hole, a closed cutting body is formed, and the lateral leakage of blasting energy is prevented.

[0021] Further, in the charging step, the cartridge is adopted with low blast speed explosive, the cutting blasting specific charge is 1 / 2-1 / 4 of the traditional step blasting, the linear charge density is 230-480 g / m, and the uncoupling coefficient of the charge is 1.5-5.

[0022] The low blast speed explosive and the uncoupling charge are adopted, the peak pressure of the hole wall is reduced to below the dynamic compressive strength of the rock mass, and the formation of the crushing zone is avoided; the specific charge is reduced to 1 / 2-1 / 4 of the traditional one, which directly reduces the amount of explosive, and at the same time, the linear charge density is 230-480 g / m, which balances the cutting force and the vibration control requirement.

[0023] Further, in the blasting step, the specific initiation sequence satisfies: In the same cutting block, the horizontal cutting blast hole and the longitudinal cutting blast hole are initiated at the same time, and the initiation time interval between the horizontal cutting blast hole and the vertical cutting blast hole is 0-30 ms; The initiation time interval between different cutting blocks is 25-50 ms.

[0024] Delay blasting can control the amount of single initiation explosive, reduce the harmful effects of blasting vibration; at the same time, a certain delay can provide new free surface for subsequent blasting, improve the blasting effect. Specifically, the same cutting block is simultaneously initiated to form an initial through joint; the horizontal / vertical cutting hole is initiated with millisecond delay to guide the three-dimensional intersection of the cracks; the delay between different cutting blocks can isolate the vibration superposition, and the three work together to realize the ordered control of "crack expansion-three-dimensional closure-energy isolation".

[0025] In summary, the present application includes the following beneficial technical effects: The present application combines the arrangement of three-dimensional multi-directional collaborative cutting holes with the structure of prefabricated directional cutting holes to accurately cut the rock mass with low specific energy consumption, significantly reducing the demand for blasting energy and improving the flatness of stone, specifically including: 1. Form vertical cutting surfaces inside the rock mass by longitudinal and transverse cutting holes, and form horizontal cutting surfaces at the bottom of the rock mass by horizontal cutting holes to avoid uneven bottom surface, and the three-dimensional cutting network composed of vertical and horizontal cutting surfaces for three-dimensional directional separation of rock mass; 2. Small hole spacing forms a dense weakening zone, which cooperates with the directional cracking effect of prefabricated wedge-shaped slot holes or notches to make the cracks develop along the hole connecting line, thereby improving the flatness of stone; low specific energy consumption only provides the energy required for crack propagation to avoid excessive fragmentation of rock mass; 3. By millisecond delay initiation, each cutting surface expands and intersects in the designed order, forcing the cracks to develop along the predetermined path. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the three-dimensional cutting hole arrangement of the embodiment of the present application; Figure 2 is a schematic diagram of the pre-splitting blasting hole structure of the embodiment of the present application, wherein (a) is a pre-splitting blasting hole structure, (b) is a prefabricated wedge-shaped slot hole structure with backfilling concrete, and (c) is a prefabricated hole wall notch structure.

[0027] Reference signs: 1, rock mass to be cut; 2, longitudinal cutting hole; 3, transverse cutting hole; 4, horizontal cutting hole; 5, cutting block; 6, cutting line; 7, cartridge; 8, concrete; 9, hole wall; 10, prefabricated directional splitting inducing slot; 11, prefabricated hole wall notch; 12, hole axis. DETAILED DESCRIPTION

[0028] The following will be described in detail in combination with the accompanying Figures 1-2 The present application will be further described in detail.

[0029] The embodiment of the present application discloses a three-dimensional cutting blasting method suitable for large block stone mining, including the following steps: Step 1, drilling: Referring toFigure 1 The blasting holes are drilled on the regular bench face in the mining area, the bench face includes a horizontal face and a vertical face, the height of the bench face is 4-6m, and the longitudinal length of the bench face is 30-50m. The blasting holes include vertical cutting blasting holes drilled on the horizontal face and 1-3 rows of horizontal cutting blasting holes 4 drilled on the vertical face; the vertical cutting blasting holes include 2-4 rows of longitudinal cutting blasting holes 2 and several rows of transverse cutting blasting holes 3, the number of the rows of the transverse cutting blasting holes 3 is adjusted according to the longitudinal length of the bench face. The axis 12 of the vertical cutting blasting hole is perpendicular to the horizontal face, and the axis 12 of the horizontal cutting blasting hole 4 is perpendicular to the vertical face.

[0030] Referring to Figure 1 , the connecting line of the same row of horizontal cutting blasting holes 4, the connecting line of the same row of longitudinal cutting blasting holes 2, and the connecting line of the same row of transverse cutting blasting holes 3 are the to-be-cut lines 6. The multiple rows of horizontal cutting blasting holes 4 form several horizontal cutting faces, the multiple rows of longitudinal cutting blasting holes 2 form several vertical longitudinal cutting faces, and the multiple rows of transverse cutting blasting holes 3 form several vertical transverse cutting faces; the horizontal cutting faces, the longitudinal cutting faces, and the transverse cutting faces jointly form a three-dimensional cutting network, which separates the to-be-cut rock mass 1 into multiple cuboid or square cutting blocks 5.

[0031] The depth of the vertical cutting blasting hole is 3-7m, the hole diameter is 50-90mm, the hole spacing is 8-15 times of the hole diameter, and the blasting hole density coefficient is 0.4-0.7; the last row (the row farthest from the vertical face of the bench face) of the longitudinal cutting blasting holes 2 is provided with an over-depth of 0.5-1.0m. The hole depth of the horizontal cutting blasting hole 4 does not exceed the last edge longitudinal cutting face, the hole diameter is 45-90mm, and the hole spacing is 8-15 times of the hole diameter.

[0032] The hole spacing of the horizontal cutting blasting hole 4 is the same as the hole spacing of the longitudinal cutting blasting hole 2. Further, the horizontal cutting blasting hole 4 is arranged alternately with the vertical cutting blasting hole, the axis of the horizontal cutting blasting hole 4 is perpendicular to the connecting line of the adjacent two longitudinal cutting blasting holes 2, and the axis 12 of the horizontal cutting blasting hole 4 intersects the middle line of the connecting line of the adjacent two longitudinal cutting blasting holes 2.

[0033] Referring to Figure 2 , the blasting hole is a pre-split blasting hole, and in the scene where the flatness of the cutting face needs to be strictly controlled, a special blasting hole with a prefabricated wedge-shaped slot hole or a prefabricated hole wall notch structure is used. The prefabricated wedge-shaped slot hole or the prefabricated hole wall notch is a V-shaped or U-shaped slot hole or notch along the depth direction of the blasting hole, and the tip thereof faces the predetermined cutting direction.

[0034] Specifically, as shown in (a) of Figure 2 , the profile of the blasting hole wall 9 of the pre-split blasting hole is circular, and the cartridge 7 is filled in the center of the blasting hole. As shown in Figure 2As shown in (b) of FIG. 1, the borehole with the prefabricated wedge-shaped slot is prepared by the method of backfilling concrete after drilling, the borehole wall 9 is circular in profile, the cartridge 7 is loaded in the center of the borehole, the inner circumferential side of the borehole is backfilled with concrete 8, the prefabricated directional splitting inducing slot 10 is arranged in the borehole, and the slot opening of the prefabricated directional splitting inducing slot 10 faces the predetermined cutting direction, i.e. the borehole connecting direction. As shown in (c) of FIG. 1, the borehole with the prefabricated borehole wall notch is prepared by the method of synchronous slotting of mechanical cutting tools and high-pressure water jet during drilling, the borehole wall 9 is circular in profile, the cartridge 7 is loaded in the center of the borehole, and the prefabricated borehole wall notch 11 is arranged on the outer circumferential side of the borehole, and the prefabricated borehole wall notch 11 faces the predetermined cutting direction, i.e. the borehole connecting direction. Figure 2

[0035] Step 2, charging: The cartridge 7 is loaded at the center of the borehole, and it is ensured that the axis of the cartridge 7 coincides with the axis 12 of the borehole; the cartridge 7 adopts low-blast-velocity explosives, the cutting blasting unit consumption is 1 / 2-1 / 4 of that of traditional bench blasting, the linear charge density is 230-480 g / m, and the uncoupling coefficient of the charge is 1.5-5.

[0036] Step 3, blasting: After the borehole is plugged, it is initiated according to a specific initiation sequence, specifically: in the same cutting block 5, the horizontal cutting borehole 3 and the longitudinal cutting borehole 2 are initiated at the same time, and the initiation time interval between the horizontal cutting borehole 4 and the vertical cutting borehole is 0-30 ms; the initiation time interval between different cutting blocks 5 is 25-50 ms.

[0037] The following describes an embodiment of the three-dimensional cutting blasting method suitable for large stone mining according to specific examples: Example 1 In the large stone mining site of a certain water conservancy and hydropower project, regular large stones with high surface flatness are required to be mined out. After detailed investigation of the site geological conditions, including the lithology, structural plane, and joint fissure development of the rock mass, the regular bench face of the mining area is determined.

[0038] According to the mining requirements and the characteristics of the rock mass, a three-dimensional cutting borehole arrangement scheme is designed, and longitudinal cutting boreholes, horizontal cutting boreholes and horizontal cutting boreholes are arranged uniformly on the bench face.

[0039] ​The vertical cutting blast hole has a hole depth of 4 m, a hole diameter of 76 mm, a hole spacing of 13 times the hole diameter, and a blast hole density coefficient of 0.5; the horizontal cutting blast hole has a hole depth not exceeding the longitudinal cutting surface of the last edge, a hole diameter of 60 mm, and a hole spacing of 13 times the hole diameter. Three rows of longitudinal cutting blast holes are arranged with a row spacing of 2 m, and the last row of longitudinal cutting blast holes is provided with an over-depth of 0.5 m to ensure the integrity of the cutting. Two rows of horizontal cutting blast holes are arranged with a row spacing of 2 m. The horizontal cutting blast hole and the vertical cutting blast hole are arranged alternately, the axis of the horizontal cutting blast hole is perpendicular to the line connecting the two adjacent longitudinal cutting blast holes, and the axis of the horizontal cutting blast hole intersects the middle line of the line connecting the two adjacent longitudinal cutting blast holes.

[0040] The method of drilling backfilling concrete prefabricated wedge-shaped slot hole is used to make directional cutting blast hole with V-shaped slot hole, the tip of the V-shaped slot hole faces the predetermined cutting direction, the top angle of the front end slot hole is 45°, and the internal structure of the charging section blast hole is shown in Figure 2 (b) to ensure that the rock mass can be effectively guided to split during blasting.

[0041] A cartridge made of low-explosive is loaded at the center of the blast hole, the cutting blasting unit consumption is 1 / 3 of the traditional bench blasting unit consumption, the linear charge density in the hole is 280 g / m, and the cartridge axis is strictly ensured to coincide with the blast hole axis during the charging process.

[0042] The blast hole is plugged with required stemming as the plugging material, after the plugging is compacted, the blasting operation is carried out according to the specific initiation sequence. The horizontal cutting blast hole and the longitudinal cutting blast hole in the same cutting block are initiated at the same time, the initiation time interval between the horizontal cutting blast hole and the vertical cutting blast hole is 25 ms; the initiation time interval between different cutting blocks is 25 ms. Through this initiation sequence, the rock mass is cut in an orderly manner, the large stone obtained has a regular shape and a size meeting the design requirements, the blasting effect is good, and the expected mining purpose is achieved.

[0043] Example 2 In a certain stone mining project, the three-dimensional cutting blasting method suitable for large stone mining is implemented. According to the geological conditions on site, the blast hole arrangement parameters are appropriately adjusted. The vertical cutting blast hole has a hole depth of 3 m, a hole diameter of 50 mm, a hole spacing of 8 times the hole diameter, and a blast hole density coefficient of 0.4; the horizontal cutting blast hole has a hole diameter of 45 mm and a hole spacing of 8 times the hole diameter. Two rows of longitudinal cutting blast holes are arranged without over-depth treatment.

[0044] In the prefabricated splitting induced joint aspect, the method of synchronous slotting by mechanical cutting tool during drilling is used to make V-shaped splitting induced joint, and the internal structure of the charging section blast hole is shown in Figure 2 (c) to ensure that the rock mass can be effectively guided to split during blasting.

[0045] The explosive column adopts low detonation velocity explosive, the linear charge density in the hole is 320 g / m, and the charge decoupling coefficient is 1.5. When charging, the explosive column is accurately placed at the center position of the blast hole, and it is ensured that the axis of the explosive column coincides with the axis of the blast hole.

[0046] After the blast hole is blocked, the horizontal cutting blast hole and the vertical cutting blast hole are simultaneously initiated according to the same cutting block, and the initiation time interval between the horizontal cutting blast hole and the vertical cutting blast hole is 25 ms; the initiation sequence of the initiation time interval of 25 ms between different cutting blocks is implemented for blasting. The results show that the mined valuable stone material large stone has good integrity, the cutting surface is flat, and the requirements of high-quality stone mining are met, and the blasting cost and the damage to the mine environment are effectively reduced.

[0047] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, so: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A three-dimensional cutting and blasting method suitable for mining large boulders, characterized in that: Includes the following steps: Drilling: Explosive holes are drilled on a regular stepped surface within the mining area. The stepped surface includes a horizontal plane and a vertical plane. The explosive holes include vertical cutting blast holes drilled on the horizontal plane and several rows of horizontal cutting blast holes drilled on the vertical plane. The vertical cutting blast holes include several rows of longitudinal cutting blast holes and several rows of transverse cutting blast holes. Several rows of horizontal cutting blast holes form several horizontal cutting surfaces, several rows of longitudinal cutting blast holes form several vertical longitudinal cutting surfaces, and several rows of transverse cutting blast holes form several vertical transverse cutting surfaces. The horizontal cutting surfaces, longitudinal cutting surfaces, and transverse cutting surfaces together form a three-dimensional cutting network, dividing the rock mass to be cut into multiple cuboid or cubic cutting blocks. Charging: Insert the propellant cartridge into the center of the borehole, ensuring that the axis of the propellant cartridge coincides with the axis of the borehole; Blasting: After the blast hole is blocked, it is detonated in a specific detonation sequence.

2. The three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: The horizontal and vertical cutting blast holes are arranged alternately. The axis of the horizontal cutting blast hole is perpendicular to the line connecting two adjacent vertical cutting blast holes, and the axis of the horizontal cutting blast hole intersects the centerline of the line connecting two adjacent vertical cutting blast holes.

3. The three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: The height of the step surface is 4-6m, and the longitudinal length of the step surface is 30-50m.

4. The three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: The blast hole is a pre-splitting blast hole; in scenarios where the flatness of the cut surface needs to be strictly controlled, a special blast hole with a pre-made wedge-shaped groove or a pre-made hole wall cut structure is used.

5. A three-dimensional cutting and blasting method suitable for mining large boulders according to claim 4, characterized in that: The prefabricated wedge-shaped slot or prefabricated hole wall cut is a V-shaped or U-shaped slot or cut along the depth direction of the borehole, and its tip faces the predetermined cutting direction.

6. The three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: The depth of the vertical cutting boreholes is 3-7m, the diameter is 50-90mm, the spacing between boreholes is 8-15 times the diameter, and the borehole density coefficient is 0.4-0.

7.

7. A three-dimensional cutting and blasting method suitable for mining large boulders according to claim 6, characterized in that: The longitudinal cutting blast holes are set in 2-4 rows, and the last row of longitudinal cutting blast holes is set to be 0.5-1.0m deeper.

8. A three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: The horizontal cutting boreholes are arranged in 1-3 rows, with the borehole depth not exceeding the longitudinal cutting surface of the last edge, the borehole diameter being 45-90mm, and the borehole spacing being 8-15 times the borehole diameter.

9. A three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: In the charging process, low-velocity explosives are used in the explosive cartridges, the unit consumption of cutting blasting is 1 / 2 to 1 / 4 of that of traditional step blasting, the linear charge density is 230-480 g / m, and the charge decoupling coefficient is 1.5-5.

10. A three-dimensional cutting and blasting method for mining large boulders according to claim 1, characterized in that: In the blasting process, the specific detonation sequence satisfies: In the same cutting block, the horizontal cutting holes and the vertical cutting holes are detonated simultaneously, and the detonation time interval between the horizontal cutting holes and the vertical cutting holes is 0-30ms. The detonation time interval between different cutting blocks is 25-50ms.

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