Non-cutting free surface blasting device for complex ore body and mining method

Abstract

The invention discloses a cutting-free-surface-free blasting device for a complex ore body and a mining method, and relates to the technical field of blasting engineering and mining. The invention provides a blasting device and a mining method using the same in order to solve the problem that a preset free surface is difficult to form on an ore body in complex geology. The blasting device comprises shaped charge units of a specific structure or combination, such as an axial shaped charge unit and an annular / radial shaped charge unit, and part of the units can be integrated into a multi-point detonating structure. According to the mining method, the device is utilized, three-dimensional blast hole arrangement is adopted, energy gathering units with different functions are arranged at specific blast hole positions, and in-hole multi-point detonation and inter-hole millisecond detonation technologies are combined, so that efficient and directional crushing of ore rocks under the condition of no preset free surface is achieved. The device is matched with the method, the difficulty, the cost and the risk of complex ore body mining are reduced, and the efficiency and the safety are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of blasting engineering and mining, and in particular to a blasting device for blasting without a preset free surface and a mining method using the device, which is particularly suitable for ore body mining under complex geological conditions. Background Art

[0002] In underground mining or rock engineering, blasting is the most commonly used means of rock breaking. Traditional blasting theory and practice usually rely on pre-excavated free faces (such as cutting shafts and horizontal tunnels) to provide compensation space and energy release direction for rock crushing. However, when encountering complex geological structures (such as dense joints and developed faults), irregular ore bodies, and poor rock stability, excavating free faces is not only costly, time-consuming, and difficult, but may even be impossible to implement due to safety accidents.

[0003] Conventional blasting methods and devices often have poor results when blasting under such conditions without a preset free surface. Energy is difficult to release and utilize effectively, resulting in problems such as insufficient fragmentation, high rate of large blocks, residual roots, irregular blasting boundaries, and possible excessive damage to the surrounding disorderly damaged rock mass. Although shaped charge technology (ShapedCharge) can focus energy in a directional manner, most of the existing shaped charges are standard designs, lacking specific devices or optimized combinations that can both force the opening of the initial fracture surface and finely control the blasting range requirements under conditions without a free surface. At the same time, the corresponding blasting methodology also needs to be innovated in conjunction with special devices.

[0004] Therefore, developing a blasting device that can work effectively under free surface conditions and combining it with a set of efficient and safe mining methods is of great significance for solving the mining problems of complex ore bodies. Summary of the invention

[0005] The present invention aims to overcome the difficulties of prior art in blasting mining without a preset free surface under complex geological ore bodies, and to provide a blasting device (system or unit) that can effectively generate a blasting free surface and control the blasting range, as well as a method for efficient and safe mining using the device.

[0006] In order to solve the above problems, the present invention provides a blasting device system for complex ore body without cutting free surface blasting. The core of the system includes at least two shaped charge units with different functional focuses: Axial shaped charge unit: Its structure (especially the liner design) is optimized to generate strong impact energy (such as high-speed jet or shock wave) focused along the axis of the device when detonated, in order to force the formation of an initial rupture area, i.e., "explosion free surface", inside the dense target medium (rock). The specific type of specific geometric shape can be conical, arc-shaped, etc.

[0007] Boundary controlled shaped charge unit: Its structure is designed to make the explosive energy propagate mainly in radial direction (such as circumferential, semi-circular, fan-shaped) or in a specific angle direction, which is used to accurately control the boundary of the blasting, cut the contour or protect the stability of the top plate / bottom plate / side wall. These units can be designed to be modular for easy combination. Some units can also integrate structures that allow multiple detonating elements to be connected to support multi-point in-hole detonation technology. Circumferential shaped charge belongs to boundary controlled shaped charge. The detonating element can be a detonator, detonating cord, etc.

[0008] Another aspect of the present invention provides a method for mining a complex ore body without cutting free face using the above-mentioned blasting device system or unit. The method comprises the following key steps: Three-dimensional blasthole arrangement: According to the specific conditions of the ore body and surrounding rock, a three-dimensional blasthole network is designed and drilled to distinguish between main blastholes (which undertake the main crushing or first detonation tasks) and auxiliary blastholes (used to expand the range, assist in crushing and control the boundaries).

[0009] Functional charge arrangement: The above-mentioned shaped charge units with different functions are arranged in different blast holes or different positions of blast holes in a targeted manner. For example, axial shaped charge units are arranged in the main blast hole or the first row of holes to form a blast free surface; circumferential and semi-circular boundary control units are arranged in the top plate holes and side holes.

[0010] Precise detonation control: Comprehensive use of multi-point detonation in the hole (such as time-sharing detonation of device units in a single long hole) and micro-difference detonation between holes (accurately set the millisecond delay time between different blast holes). Through the carefully designed detonation sequence (usually giving priority to detonating the blast holes that form the blasting free surface) and delay time, the superposition and propagation direction of stress waves are controlled, the blasting energy is guided to be effectively released to the blasting free surface, and the final blasting effect (such as blockiness and contour) is controlled.

[0011] The present invention can produce the following beneficial effects: (1) Synergy between device and method: The specific function blasting device provided is closely combined with the specialized mining method, solving the core problem of blasting without free surface.

[0012] (2) No need to preset free face: The device can force the generation of explosive free face, avoiding the difficult and dangerous free face excavation project and reducing costs and risks.

[0013] (3) Good blasting effect: Directed energy concentration and precise timing control improve energy utilization and rock crushing effect, reduce the rate of large blocks, and control the blasting boundary.

[0014] (4) Strong adaptability: It is particularly suitable for mining in ore bodies with complex geological conditions where conventional operations are not possible.

[0015] (5) High safety: It reduces the risks associated with free face excavation and improves operation safety through controlled blasting. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the application scenario of the fan-shaped blasthole arrangement.

[0018] Figure 2 It is a side view schematic diagram of the blasthole arrangement.

[0019] Figure 3 It is a top view schematic diagram of the blasthole arrangement.

[0020] Figure 4 It is a schematic diagram of the charge structure and detonation sequence in the blast hole.

[0021] Figure 5a It is a schematic diagram of the energy-gathering tube structure for annular energy gathering at the bottom of the hole.

[0022] Figure 5b It is a schematic diagram of the energy-gathering tube structure for semi-annular energy gathering at the bottom of the hole.

[0023] Figure 5c It is a schematic diagram of the energy-focusing tube structure of axial energy focusing and semi-annular energy focusing.

[0024] Figure 5d It is a schematic diagram of an energy-focusing tube with 1 / 4 axial energy focusing and 1 / 4 annular energy focusing. DETAILED DESCRIPTION

[0025] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The specific embodiments described here are only used to explain the present invention and are not used to limit the present invention. Example 1: Non-cutting free face blasting mining method

[0026] This embodiment takes the mining of a complex ore body in an underground metal mine as an example. The ore body has developed joints and fissures, irregular shapes, poor stability, and is not suitable for excavating traditional cutting shafts or cutting lanes. The non-cutting free face blasting mining method of the present invention is adopted.

[0027] Blasthole arrangement (see Figure 1 , Figure 2 , Figure 3 ): A fan-shaped three-dimensional blasthole arrangement is adopted. The main blasthole is arranged in the central area of ​​the working face, along the expected collapse direction of the ore body, with the hole depth set to 12 meters and the hole spacing set to 2.0 meters according to the ore and rock conditions in the central area. Auxiliary blastholes are arranged in a fan-shaped or radial shape on both sides and above the main blasthole. The hole spacing of the auxiliary blastholes is adjusted to 1.5 meters according to their position and function, and the hole depth is set to 10 meters according to the ore body boundary and control requirements. For example, the auxiliary holes close to the free face direction can be shallower to assist in crushing; the side holes and roof holes are controlled according to the contour and stability as needed.

[0028] Charge structure and detonation (see Figure 4 , Figure 5a , Figure 5b , Figure 5c , Figure 5d ): Charge: The main gun ports in the first row or center area (such as Figure 4 The blastholes marked as 1d-4d in the figure): an axial shaped charge structure, such as an axial shaped charge tube, is used to force the formation of an initial blast free surface. At the same time, semi-circular shaped charges can be used in the orifice section (near the top) of these blastholes for pre-splitting or controlling the top ore rock.

[0029] Side holes (such as Figure 4 The blasthole marked as 5d in the figure): A combination of shaped charges at specific angles can be used, such as 90° axial shaped charges (energy directed to the lateral free surface) and top annular / semi-annular shaped charges (to control the roof and boundary).

[0030] The second row and subsequent blast holes (such as Figure 4The second and third rows in the middle: ordinary ammonium oil charges can be used as needed, but annular shaped charges (such as the second row) or semi-annular shaped charges (such as the third row) are used at the bottom of the hole or the hole mouth to solve the possible root residue or top hanging problem. Combined shaped charges can also be used for side holes.

[0031] Detonation: In-hole detonation: For some deep holes or holes that are expected to be difficult to break, two-point detonation is used. For example, a detonator is placed at about 1 / 2 of the length of the blasthole and at the bottom of the hole. When detonating, the middle detonator is detonated first (if a 200ms delay is used), and then the bottom detonator is detonated (if a 400ms delay is used), so that the ore and rock begin to break from the middle and lower parts, and then collapse as a whole.

[0032] Inter-hole detonation: millisecond micro-difference detonation technology is used. The detonating caps of the first row (or main gun holes) are set to a lower millisecond segment (such as MS5 segment, about 100ms delay, assuming the benchmark is 25ms per segment, then the 4th segment or according to the actual detonator number). The surrounding auxiliary gun holes use higher millisecond segments (such as MS6 segment, MS7 segment..., that is, about 125ms, 150ms...) in turn according to the distance and fragmentation order to ensure step-by-step and directional fragmentation. For example, the delay time of the main gun hole is set to 25 milliseconds (as a relative benchmark or the first batch), and the delay time of the adjacent auxiliary gun holes is set to 35 milliseconds or higher, and the peripheral ones are increased to ensure effective energy superposition and propagation.

[0033] Energy control and effect: By precisely adjusting the charge amount, energy type, detonation point position and micro-difference detonation time of each blasthole, the distribution and release path of the blasting energy in the ore body are effectively controlled, achieving directional and efficient crushing without a preset free surface.

[0034] Example 2: Blasting device system configuration This embodiment provides a blasting device system for implementing the mining method of the present invention. The system is configured to meet the requirements of both forcing the generation of a blasting free surface and effectively controlling the blasting range under the condition of no preset free surface.

[0035] Reference Figure 5a , Figure 5b , Figure 5c , Figure 5d , the blasting device system usually includes the following types of shaped charge units: Axial shaped charge unit: e.g. Figure 5c The unit shown in the figure contains an "axial energy focusing" part (such as an "axial energy focusing-semi-annular energy focusing" structure). This type of unit has a structure that can focus the explosive energy mainly along the axial direction of the device (such as a conical or specific arc liner), and its main function is to produce deep penetration or strong impact in dense rock mass, forcing the formation of an initial explosion free surface.

[0036] Boundary Control Shaped Charge Units: These units are used to control the final contour of the blast, protect the roof or boundaries. Depending on the control requirements, they may include: Annular energy focusing unit (such as Figure 5a "Annular energy focusing at the bottom of the hole"): Generates energy that is evenly or substantially evenly distributed along the entire radial circumference, which is used to form an annular cut at the bottom or top of the blasthole to control the root or hanging top.

[0037] Semi-circular energy-gathering unit (such as Figure 5b "Hole bottom semi-circular energy focusing" Figure 5c The semi-annular part of “axial energy focusing-semi-annular energy focusing”): generates energy mainly concentrated in a radial range of about 180°, which is used for single-side boundary control or roof pre-splitting.

[0038] Specific angle focusing unit (such as Figure 5d The annular part of "1 / 4 axial energy focusing - 1 / 4 annular energy focusing", or the 90° axial energy focusing in the text description): produces energy focusing in a smaller angle range (such as 90°, 45°) or a specific direction (such as lateral) for fine contour control or corner cutting.

[0039] These units with different functions can be selected as finished products or modularly combined according to the specific blasting design and loaded into the corresponding blasthole positions.

[0040] In addition, some (especially longer) charge units in the system can be designed or equipped with a structure that supports multiple-point detonation in the hole, for example, multiple independent detonating cap installation interfaces (such as Figure 4 Schematic diagram), allowing segmented and time-divided detonation in the same blasthole.

[0041] Example 3: Comparison of blasting effects In the application of Gongchangling underground iron ore of Anshan Iron and Steel Group, the blasting device system as described in Example 2 was used. Only the blasting method was different, and the blasting effect of the traditional single-point detonation scheme at the bottom of the hole was compared with the blasting effect of the method of the present invention (including two-point detonation, shaped charge, and optimized micro-difference): The original plan: single-point detonation at the bottom of the hole, the large block rate is about 4.7%, the ore discharge in a single blast is about 2112 tons, and there is a relatively obvious hanging roof after the blast, with a measured height of about 3.6 meters.

[0042] The solution of the present invention adopts two-point detonation in the hole (first explosion in the middle and then explosion at the bottom of the hole), combined with axial and annular shaped charges, and the ore discharge capacity of a single blasting is increased to 3456 tons.

[0043] After blasting, the large block rate was reduced to 3.8%, which was about 19% lower than the original plan ((4.7-3.8) / 4.7≈19%). The ore discharge in a single blasting increased by about 63.6% ((3456-2112) / 2112≈63.6%), nearly 1.6 times, compared with the original plan. After blasting, the height of the suspended roof was significantly reduced to only 0.16 meters, indicating that the roof control effect was good and the ore collapse was sufficient.

[0044] These data intuitively prove that the method of the present invention can effectively improve the ore crushing effect (reduce the large block rate), significantly increase the ore output of a single blasting, and effectively control the roof overhang under the condition of no cutting free surface, thereby improving mining efficiency and safety. Example 4: Application process of the free-face mining method without cutting in complex ore bodies

[0045] This embodiment describes the specific method steps for mining using the blasting device system described in Example 2 in an underground ore body with complex geological conditions (such as developed joints and irregular shapes) and where free surfaces cannot be excavated and cut.

[0046] Blast hole arrangement: Reference Figure 1 (Arrangement of fan-shaped blast holes), Figure 2 (side view) and Figure 3 (Top view). A three-dimensional blasthole arrangement is used.

[0047] Main blast hole: arranged along the main strike of the ore body or the predetermined advancement direction, it plays a core role in generating the initial blast free surface. According to the stability of the ore rock and the blasting requirements, the hole spacing is set to 1.5 meters and the hole depth is set to 10-15 meters.

[0048] Auxiliary blastholes: arranged in a fan-shaped or radial pattern around the main blasthole (on both sides, above, below), used to expand the crushing range, assist in forming a free surface and control the final contour. The hole spacing is adjusted to 1.0-2.0 meters according to the location, and the hole depth is set to 4-10 meters according to the ore body boundary and control requirements.

[0049] Charge arrangement: According to the function of the blasthole, different shaped charge units described in Example 1 are selected for filling. The specific strategy can be referred to Figure 4 (Charge structure diagram): The first row of holes (e.g. Figure 4 Marked as 1d-4d in the figure): These blastholes undertake the key task of forming the initial blast free surface. They are mainly loaded with axial shaped charge units. In order to control the top plate of the orifice at the same time, semi-circular shaped charge units can be installed on the top of the blasthole (orifice section).

[0050] Side holes (e.g. Figure 4Marked as 5d): Used to control the blasting boundary. It can be loaded with a specific combination of units, such as a 90° axial energy-focusing unit (energy pointing to the side) combined with a top annular / semi-annular energy-focusing unit.

[0051] Subsequent blastholes (e.g. Figure 4 Middle second and third rows): Second row: Ordinary explosives or units with moderate power can be used, but annular energy-gathering units are loaded at the bottom of the hole to prevent the root residue and improve the ore recovery rate. The side holes can use axial energy-gathering units to assist in lateral rock breaking.

[0052] The third row: Similar to the second row, but the bottom of the hole can be controlled by a semi-circular energy-gathering unit. The side holes can also use a combination unit similar to the side holes in the first row. The charge is calculated and determined based on the diameter, length and ore properties of the blasthole.

[0053] Detonation implementation: Adopt precise detonation control technology: Multi-point detonation in the hole: This technology can be used for main blastholes or auxiliary blastholes with greater depth. For example, a detonating cap is placed in the middle of the blasthole (about 1 / 2 depth) and at the bottom of the hole. When detonating, the middle detonator is set to explode first (for example, using a detonator with a relative delay of T1) to break and loosen the rocks in the middle and lower parts of the blasthole first; after a short delay (for example, using a detonator with a relative delay of T2>T1), the bottom detonator is detonated to break the bottom and upper rocks of the hole. This helps to improve the crushing effect and the uniformity of the fragmentation.

[0054] Micro-difference detonation between holes: A millisecond (ms) micro-difference detonation network is used. The principle is that the main gun hole or the first row of gun holes that are responsible for forming the blast free surface should be detonated first, or set to a lower millisecond delay segment (for example, the reference time or 25ms segment). The surrounding auxiliary gun holes are set with increasing delay times in sequence according to their distance from the main gun hole and the expected fragmentation sequence (for example, adding a delay of 10ms-50ms per row or per circle, or using continuous higher millisecond detonators). Through reasonable micro-difference time design, the stress waves generated by subsequent explosions can be used to effectively superimpose and reflect and stretch the rupture zone or blast free surface formed by the previous explosion, thereby achieving optimal energy utilization and directional and efficient fragmentation of ore and rock.

[0055] Expansion processing (generally optional): As needed, in order to ensure that the blasted ore can fall smoothly to the lower mine exit channel, the relevant approach tunnels can be expanded to an appropriate width before blasting. At the same time, the stability of the tunnel surrounding rock after expansion needs to be evaluated and ensured.

[0056] Through the above steps, by using blasting device units with specific functions and precise arrangement and detonation methods, effective blasting mining can be achieved in complex ore bodies without preset cutting free surfaces.

[0057] Example 5: Application effect verification The blasting device and mining method described in Example 2 and Example 4 were applied to a complex ore body mining operation in Gongchangling underground iron ore mine of Anshan Iron and Steel Group. Compared with the blasting scheme of the mine area using the traditional single-point detonation at the bottom of the hole without special shaped charge, the effect is as follows: Large block rate: After applying the present invention, the large block rate of the blasted ore is reduced from 4.7% in the original scheme to 3.8%, a reduction of about 19%.

[0058] Ore output in a single blasting: After applying the present invention, the amount of ore that can be recovered in a single blasting is increased from 2112 tons in the original plan to 3456 tons, an increase of about 63.6% (nearly 1.6 times).

[0059] Overhanging roof control: After applying the present invention, the exposed height of the goaf roof formed by blasting is significantly reduced from an average of 3.6 meters in the original plan to 0.16 meters, indicating that the roof is effectively controlled, the ore collapses more fully, and the safety risks and additional costs of subsequent treatment of the hanging roof are reduced.

[0060] The comparative data of this embodiment strongly proves that the blasting device and mining method provided by the present invention have significant technical advantages and practical effects in solving the difficult problem of blasting complex ore bodies without cutting free surfaces, and can effectively improve blasting efficiency, increase ore recovery rate and improve operation safety.

[0061] It should be understood by those skilled in the art that the present invention is not limited to the details of the above-mentioned embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive.

[0062] The present invention provides a complex ore body non-cut free face blasting mining method, which successfully solves the technical bottleneck of being unable or difficult to set up pre-cut free faces under complex geological conditions through innovative three-dimensional blasthole arrangement, targeted application of shaped charge technology, multi-point initiation in the hole, and precise coordinated control of micro-difference initiation between holes, and realizes safe, efficient, and low-cost blasting mining operations. This method has achieved significant technical and economic benefits in practical applications and is suitable for various metal mines, non-metal mines, and other engineering blasting scenarios facing similar geological challenges.

[0063] It should be pointed out that the above specific embodiments are only exemplary descriptions of the present invention and are not limiting. For those skilled in the art, various forms of modification, combination or equivalent substitution can be made based on the understanding of the core idea of ​​the present invention, such as adjusting specific blasthole parameters, shaped charge type, detonation delay time, etc. These changes that do not deviate from the spirit and scope of the present invention should be included in the protection scope of the present invention.

Claims

1. A blasting device system for blasting complex ore bodies without cutting free surface, characterized in that: include: At least one axial shaped charge unit is configured to generate energy focused along its axis when detonated, so as to forcibly form an explosive free surface in a target medium without a preset free surface; as well as At least one boundary control shaped charge unit, configured to generate energy that propagates mainly in a radial direction or a specific angular direction when detonated, so as to control the blasting boundary or the roof stability; The axial shaped charge unit and the boundary-controlled shaped charge unit are designed to be used in coordination in a mining method to achieve blasting without a preset free surface.

2. The system according to claim 1, characterized in that The boundary-controlled shaped charge unit is a toroidal shaped charge unit or a semi-toroidal shaped charge unit.

3. The system according to claim 1 or 2, characterized in that: The axial shaped charge unit and / or the boundary-controlled shaped charge unit comprises a liner having a specific geometric shape designed to achieve the energy focusing or directional propagation.

4. The system according to claim 1, characterized in that The structure of at least part of the charge unit is configured to allow access to at least two detonating elements to achieve multi-point detonation in the hole.

5. A method for mining complex ore bodies without cutting free faces, characterized in that: The blasting device system according to any one of claims 1 to 4 comprises the following steps: (1) Blast hole arrangement: A three-dimensional blast hole arrangement method is adopted to arrange the main blast holes and auxiliary blast holes; the main blast holes are arranged roughly along the strike of the ore body or in a specific direction, and the auxiliary blast holes are distributed in a predetermined shape around the main blast holes; (2) Charging and detonation: A shaped charge structure is used in the blasthole, and multi-point detonation in the hole and micro-difference detonation between holes are adopted; the shaped charge structure includes an axial shaped charge for generating a blast free surface and an annular shaped charge for controlling the top plate or boundary; (3) Blasting: Detonate each blast hole in a preset sequence of micro-difference detonation between holes. The main blast hole is detonated before or in a specific sequence with other blast holes. The auxiliary blast holes are detonated in sequence with a delay time set according to their positions and functions. Axial focused energy blasting is used to first break part of the ore and rock to form a blasting free surface. The blasting energy of subsequent blast holes is propagated and released in the direction of the blasting free surface. The roof stability and blasting boundary are controlled by annular focused energy blasting.

6. The method according to claim 5, characterized in that In the step (1), the auxiliary blast holes are radially distributed around the main blast holes; the main blast holes have a hole spacing of 1.5-2.0 meters and a hole depth of 10-15 meters; the auxiliary blast holes have a hole spacing of 1.0-2.0 meters and a hole depth of 4-10 meters.

7. The method according to claim 5, characterized in that In the step (2), the first row of blast holes or some of the first detonated blast holes adopt an axial shaped charge structure to form an initial blasting free surface, and the hole mouths or hole bottoms of some of the later detonated blast holes adopt an annular shaped charge or a semi-annular shaped charge structure to control the roof overhang or form a clear blasting contour. Multi-point detonation in the hole refers to arranging at least two detonation points in a single blast hole, and detonating in a predetermined order and time interval.

8. The method according to claim 5, characterized in that In the step (3), the micro-difference detonation technology adopts a millisecond delay, the detonation delay time of the main blast hole is different from the detonation delay time of the auxiliary blast hole, and a delay time is also set between adjacent auxiliary blast holes.

9. The method according to claim 5, characterized in that It is used for mining of complex ore bodies with developed joints, many faults, irregular ore body shape, poor stability of surrounding rocks or ore bodies, where cutting wells or cutting tunnels are impossible or unsuitable.

10. The method according to claim 5, characterized in that Before blasting, the approach tunnel is expanded according to the ore body collapse requirements and surrounding rock stability conditions, and the reasonable expansion width is determined.

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