A High-Efficiency, Low-Damage Mining Method for Hard Stone

Abstract

This invention relates to the field of decorative stone mining technology, and more particularly to a high-efficiency, low-damage mining method for hard stone. The invention provides a high-efficiency, low-damage mining method for hard stone, comprising the following steps: dividing the hard stone mining area into zones and then drilling holes; sequentially applying microwave radiation excitation, high-pressure jet cutting, and carbon dioxide blasting to the hard rock mass in a predetermined fracturing direction. This mining method overcomes the problems of traditional rock explosive blasting, such as difficulty in controlling energy, high risk, large vibration effects, and significant damage to the internal structure of the stone, as well as the severe wear and low production efficiency of wire saws in hard stone mining, thus achieving high-efficiency, low-damage mining of hard stone.

Description

Technical Field

[0001] This invention relates to the field of decorative stone mining technology, and in particular to a method for efficient and low-damage mining of hard stone. Background Technology

[0002] my country boasts abundant and widely distributed stone resources, and is home to the world's largest construction market. Domestic stone consumption has been increasing annually, particularly in recent years, with my country's total stone exports and actual stone content ranking among the world's top. In some regions, stone has become a pillar industry. The first step in stone quarrying is separating the stone from the large rock blocks—a process known as block separation. To ensure the value of the extracted stone is not diminished, the integrity of the blocks must be preserved as much as possible during block separation, avoiding or minimizing the formation of new cracks and damage within the blocks. Therefore, block separation is the first and crucial step in stone quarrying.

[0003] Traditional methods for separating raw stone blocks include blasting and non-blasting. Blasting involves using the powerful energy generated by the explosion of explosives installed in a borehole to separate the raw stone blocks. However, for rocks with high hardness coefficients, blasting often requires high-density, high-velocity explosives to enhance the stress wave effect and ensure the formation of initial fractures. High-density, high-velocity explosives inevitably increase internal damage to the rock in non-mining areas, compromising the integrity of the raw blocks and reducing their value. Furthermore, blasting generates significant dust and noise pollution; therefore, traditional blasting methods have been banned in stone mining. Non-blasting methods primarily utilize the internal disintegration of the rock itself and employ techniques such as wedge cutting and flame cutting to extract the stone. However, due to the demanding application conditions and extremely low efficiency, this method is unsuitable for mining hard stones. Mechanical mining refers to the use of mechanical equipment to extract raw stone blocks. This is currently the main method for extracting raw stone blocks, and there is a wide variety of related equipment available. For example, Chinese patent CN205154156U discloses a stone mining device that uses a cutting unit rotating around a substrate to create kerfs in the rock, while a grinding unit simultaneously grinds the stone surface on the sides of the kerf to smooth it, thereby reducing the number of mining steps and improving mining efficiency. However, this method is also inefficient for mining hard stone and has certain limitations on the cutting direction. Therefore, developing a green and efficient method for mining hard stone has significant theoretical and practical implications. Summary of the Invention

[0004] The purpose of this invention is to provide a method for mining hard stone, which overcomes the problems of traditional explosive blasting, such as difficulty in controlling energy, high risk, large vibration effect, and significant damage to the interior of the stone, as well as the problems of severe wear and low production efficiency of wire saw mining in hard stone mining, thereby achieving efficient and low-damage mining of hard stone.

[0005] To achieve the above-mentioned objectives, this invention provides a method for efficiently and with low damage to hard stone, comprising the following steps: Drilling is performed after dividing the hard stone quarry area into zones.

[0006] Microwave radiation excitation, high-pressure jet cleaving, and carbon dioxide blasting were sequentially applied to the hard rock mass in the predetermined fracturing direction.

[0007] Preferably, the partitioning is determined based on the relationship between microwave radiation excitation and distance on the degree of rock mass damage and the predetermined effective damage to the rock mass.

[0008] Preferably, determining the relationship between microwave radiation excitation and the degree of rock mass damage as a function of distance includes the following steps: Select an area that represents the rock mass properties of the hard stone quarry as the production test area; A fixed measure hole is determined in the production test area, and after a series of test holes are set in the measure hole, holes are drilled to obtain the measure hole and a series of test holes; Microwave radiation excitation is applied to the measured hole, and the damage of the test hole is detected in the test hole to obtain the radius of influence of microwave radiation.

[0009] Preferably, the standard that represents the rock mass properties of the hard stone mining area is that the lithology, rock physical and mechanical parameters, and the development of rock mass joints and fissures are consistent with those of the hard stone mining area. The series of detection boreholes are preferably set at different positions along an extension line in the radial direction centered on the detection borehole.

[0010] Preferably, the key parameters of the microwave radiation excitation include: excitation frequency ≥ 3 GHz, power ≥ 10 kWm, and time ≥ 10 min.

[0011] Preferably, the predetermined effective damage to the rock mass is ≥80% of the rock mass.

[0012] Preferably, the appropriate length of the mining area is determined based on the mining plan and the size requirements of the mineral products. L and the width of the mining area W Length of mining area L and the width of the mining area WIt is an integer multiple of the required length and width dimensions of the mineral product.

[0013] Preferably, the horizontal distance between two adjacent boreholes is... a for: ; in, d The diameter of the borehole. D m This refers to the range of influence of microwave radiation.

[0014] Preferably, the direction of the microwave radiation excitation and the direction of the guide groove formed by the high-pressure jet cutting are consistent with the axial direction of the borehole.

[0015] Preferably, the length of the guide groove in the carbon dioxide blasting fracturing borehole is 0.6 to 0.8 times the borehole diameter, and the width is 0.10 to 0.12 times the borehole diameter; The length of the guide slot in the jet-cut guide borehole is 0.4 to 0.6 times the borehole diameter, and the width is 0.12 to 0.18 times the borehole diameter. The installation of the carbon dioxide blasting fracturing equipment involves placing the carbon dioxide blasting fracturing device into the borehole, adjusting the fracturing direction so that the cutting direction of the release pipe of the carbon dioxide blasting fracturing device coincides with the predetermined direction of stone mining and the direction of the guide groove formed by the jet cutting.

[0016] This invention provides a method for efficient and low-damage mining of hard stone, comprising the following steps: dividing the mining area of ​​the hard stone mine into zones and then drilling holes; sequentially applying microwave radiation excitation, high-pressure jet cutting, and carbon dioxide blasting to the hard rock mass in the predetermined fracturing direction.

[0017] Compared with existing technologies, the stone mining method of the present invention has the following advantages: 1) This invention fully utilizes the advantages of microwave radiation technology, such as selective heating, volumetric heating, directional penetration, and cleanliness without pollution, as well as the advantages of high-pressure abrasive water jet, such as non-destructive, cleanliness, and directional cutting, to pre-emptively weaken hard rock mass in the direction of stone mining and form guide grooves. Secondly, the "heat-cold alternation" effect brought about by the simultaneous action of microwave radiation and high-pressure abrasive water jet cutting on the surrounding rock mass inside the borehole further weakens the dynamic properties of the rock mass, reducing the rock mass crack initiation pressure under subsequent carbon dioxide blasting. At the same time, the guiding effect of the jet cutting pores and the stress concentration effect guide the carbon dioxide blasting cracks to expand along the predetermined mining direction, while reducing the pressure acting on the retained rock mass, thereby weakening the internal damage of the stone blocks and ensuring the quality of stone block mining. 2) This invention uses carbon dioxide blasting to induce fracturing, which overcomes the problems of traditional rock explosives, such as difficulty in controlling blasting energy, high risk, large vibration effect, large damage to the inside of the stone, low efficiency of wire saw mining, and severe wear in hard rock, and provides a new approach for the mining of hard stone. Attached Figure Description

[0018] Figure 1 These are the implementation steps of the efficient and low-damage mining method for hard stone described in this invention; Figure 2 This is a schematic diagram of the zoning of the high-efficiency, low-damage mining method for hard stone described in this invention; Figure 3 This is a schematic diagram of the microwave radiation excitation direction and high-pressure water jet cutting in the efficient and low-damage mining method for hard stone described in this invention. Figure 4 This is a schematic diagram of the drilling structure for the efficient and low-damage mining method for hard stone described in this invention. Wherein: 1 is the boundary of the mining zone, 2 is the mining zone number, 3 is the area affected by microwave radiation, 4 is the predetermined fracturing direction of carbon dioxide blasting, 5 is the fracturing borehole of carbon dioxide blasting, 6 is the guide groove formed by high-pressure abrasive jet cutting, 7 is the guide hole of the jet cutting, 8 is the fracturing lead wire of carbon dioxide blasting, 9 is the borehole plug, and 10 is the carbon dioxide blasting fracturing device. Detailed Implementation

[0019] This invention provides a method for efficient and low-damage mining of hard stone, comprising the following steps: Drilling was performed after dividing the hard stone quarry area into zones; Microwave radiation excitation, high-pressure jet cleaving, and carbon dioxide blasting were sequentially applied to the hard rock mass in the predetermined fracturing direction.

[0020] This invention involves drilling holes after dividing the mining area of ​​hard stone quarries into zones.

[0021] In this invention, the mining area is preferably determined based on the geological conditions of the mine. Preferably, the criteria for determining the mining area based on the geological conditions are consistent with the lithology, rock physical and mechanical parameters, and the development of rock mass joints and fissures in the hard stone quarry.

[0022] In this invention, the partitioning is preferably determined based on the relationship between microwave radiation excitation and distance on the degree of rock mass damage and the predetermined effective damage to the rock mass.

[0023] In this invention, the drilling is preferably performed by arranging a jet slit guide hole between every two carbon dioxide blasting fracturing drilling holes.

[0024] In this invention, the predetermined effective damage to the rock mass is preferably ≥80% of the degree of damage to the rock mass.

[0025] In this invention, determining the relationship between microwave radiation excitation and the degree of rock mass damage as a function of distance preferably includes the following steps: Select an area that represents the rock mass properties of the hard stone quarry as the production test area; A fixed measure hole is determined in the production test area, and after a series of test holes are set in the measure hole, holes are drilled to obtain the measure hole and a series of test holes; Microwave radiation excitation is applied to the measured hole, and the damage of the test hole is detected in the test hole to obtain the radius of influence of microwave radiation.

[0026] This invention selects an area that represents the rock mass properties of a hard stone mining area as the production test area.

[0027] In this invention, the preferred standard for representing the rock mass properties of the mining area of ​​hard stone is lithology, rock physical and mechanical parameters, and the development of rock mass joints and fissures.

[0028] After obtaining the production test area, the present invention determines a fixed measure hole in the production test area, and drills a series of test holes after setting a series of test holes in the measure hole to obtain the measure hole and a series of test holes.

[0029] The present invention does not impose any special limitation on the position of the measuring hole; any position is acceptable, but the center position is more preferred.

[0030] In this invention, the series of detection boreholes are preferably set at different positions along an extension line in the radial direction centered on the detection borehole.

[0031] The present invention does not impose any special limitations on the drilling process; any process known to those skilled in the art can be used.

[0032] After drilling is completed, the present invention preferably includes hole washing. The present invention does not have any special limitations on the hole washing process, and any process known to those skilled in the art can be used.

[0033] After obtaining the measure hole and a series of test holes, the present invention applies microwave radiation excitation to the measure hole and detects the damage of the test holes to obtain the radius of influence of microwave radiation.

[0034] In this invention, the key parameters of the microwave radiation excitation preferably include: excitation frequency preferably ≥3GHz, more preferably ≥4GHz; power preferably ≥10kWm, more preferably ≥12kWm; and time preferably ≥10min, more preferably 5~10min.

[0035] In this invention, the preferred method for detecting the damage of the borehole is the acoustic method. This invention does not impose any special limitations on the process of the acoustic method, and any process well known to those skilled in the art can be used.

[0036] In this invention, the preferred zoning is to determine the appropriate mining area length based on the mining plan and the size requirements of the mineral products. L and the width of the mining area W Length of mining area L and the width of the mining area W It is an integer multiple of the required length and width dimensions of the mineral product.

[0037] In this invention, the horizontal distance between two adjacent boreholes is... a Preferred options are: ; in, d The diameter of the borehole. D m The range of influence of microwave radiation (i.e., the range within which the predetermined effective damage to the rock mass is ≥80% of the damage to the rock mass).

[0038] The present invention does not impose any special limitations on the drilling process after the partitioning is completed; any process well known to those skilled in the art can be used. After drilling, the present invention preferably includes hole washing; the hole washing process is not particularly limited and any process well known to those skilled in the art can be used. In the present invention, the drilling results in a carbon dioxide explosion-induced fracturing borehole.

[0039] After the drilling is completed, the present invention preferably includes drilling a jet slit guide hole at the midpoint between every two adjacent boreholes and at the edge of the mining free face.

[0040] After obtaining a carbon dioxide film-induced fracturing borehole, the present invention sequentially applies microwave radiation excitation, high-pressure jet cutting, and carbon dioxide blasting fracturing to the hard rock mass in the predetermined fracturing direction.

[0041] In this invention, the direction of the guide groove formed by the microwave radiation excitation and high-pressure jet cutting is preferably consistent with the axial direction of the borehole.

[0042] In this invention, the parameters of the microwave radiation excitation are preferably the same as those of the microwave radiation excitation described above.

[0043] In this invention, the microwave radiation excitation is preferably applied to the hard rock mass of the mine along a predetermined blasting direction.

[0044] In this invention, the microwave radiation excitation can change the internal intercrystalline structure of the rock mass and induce the development and expansion of initial microcracks within it, thereby enhancing the dynamic strength of the hard rock mass.

[0045] In this invention, the abrasive used in the high-pressure jet is preferably quartz sand slurry, and the concentration of the quartz sand slurry is preferably 15%; the nozzle pressure of the high-pressure jet is preferably 40~70MPa, more preferably 50MPa; the nozzle moving speed is preferably 0.5~0.8m / min; and the number of reciprocating cuts is preferably 1~3 times.

[0046] In this invention, the high-pressure jet preferably cuts the hard rock mass on both sides of the carbon dioxide film fracturing borehole along the predetermined fracturing direction to form a guide groove.

[0047] In this invention, the length of the guide slot in the carbon dioxide blasting fracturing borehole is preferably 0.6 to 0.8 times the borehole diameter, and the width is preferably 0.10 to 0.12 times the borehole diameter. The length of the guide slot in the jet cutting guide borehole is preferably 0.4 to 0.6 times the borehole diameter, and the width is preferably 0.12 to 0.18 times the borehole diameter.

[0048] After the high-pressure jet cutting is completed, the present invention preferably includes sequential hole washing and cooling. The present invention does not impose any special limitations on the hole washing process; any process well-known to those skilled in the art can be used. Similarly, the present invention does not impose any special limitations on the cooling process; any process well-known to those skilled in the art can be used to reduce the temperature to below 35°C.

[0049] In this invention, the carbon dioxide blasting preferably includes the sequential installation of the fracturing device, sealing the borehole, and initiation. This invention does not impose any special limitations on the process of installing the fracturing device, as long as the fracturing direction is adjusted so that the cutting direction of the carbon dioxide blasting fracturing device release tube is consistent with the predetermined fracturing direction and the direction of the guide groove. In this invention, the sealing of the borehole is preferably performed using a carbon dioxide blasting sealing device to seal the carbon dioxide film fracturing borehole. The minimum plugging length is preferably 5 times the borehole diameter, and the plugging quality is strictly guaranteed. In this invention, the initiation is preferably performed by connecting a carbon dioxide blasting initiation line between two boreholes, ensuring the power supply is intact; the power is turned on to start the carbon dioxide blasting electric heater and carry out the carbon dioxide blasting operation. In this invention, the predetermined fracturing direction is preferably the direction of microwave radiation excitation. In this invention, the initiation of the carbon dioxide blasting boreholes preferably ensures simultaneous initiation.

[0050] The mining method described in this invention integrates three major processes: microwave radiation excitation, high-pressure abrasive jet cutting, and carbon dioxide blasting fracturing, and is applicable to the mining of hard decorative stone. Its technical principle comprises three parts: First, according to the mine production design plan, microwave radiation excitation is applied to the hard stone rock mass in the predetermined mining direction, causing changes in the internal crystal structure of the rock mass, inducing the generation of micro-fractures and weakening their dynamic intensity. Second, within the fracturing borehole, a high-pressure abrasive jet cuts a guide groove in the predetermined mining direction. The cooling and contraction effect of the high-temperature rock mass upon encountering water exacerbates the internal damage of the hard rock mass in the predetermined mining direction, further weakening the dynamic intensity of the hard rock mass. Third, the carbon dioxide explosive gas generated by the guide groove in the fracturing borehole acts on the hard rock mass after microwave radiation, causing the explosive cracks in the rock mass to initiate and propagate along the predetermined mining direction. Simultaneously, the stress concentration effect formed by the jet groove in the guide borehole under the carbon dioxide blasting load further guides the explosive cracks to propagate along the predetermined mining direction, ultimately achieving safe, efficient, and low-damage mining of hard decorative stone.

[0051] The following detailed description of the method for mining hard stone provided by the present invention, with reference to specific implementation examples, should not be construed as limiting the scope of protection of the present invention.

[0052] Example 1 like Figure 1 As shown, the site is an open-pit mine in Southwest China. The mineral being mined is marble veneer stone, with a production scale of 200,000 tons / year. The ore lithology is marble (dense rock with weakly developed joints and fissures, and a degree of slight weathering). The saturated uniaxial compressive strength of the rock is 95 MPa, and the Protodyakonov hardness coefficient is 9~10, which is classified as hard rock. The production test area was determined based on microwave radiation excitation experiments: An area representing the rock mass properties of the mining area (rock lithology: marble, saturated uniaxial compressive strength 90-98 MPa, weakly developed joints and fissures, slightly weathered) was selected as the production test area. First, a fixed pilot borehole was drilled. Then, detection boreholes (numbered 1#, 2#, 3#, 4#, and 5#) were set at distances of 1.0m, 1.5m, 2.0m, 2.5m, and 3.0m from the pilot borehole. The boreholes were then washed. Microwave radiation excitation (frequency 5GHz, power 14kW, duration 8min) was applied to the pilot borehole. The damage at detection boreholes 1#, 2#, 3#, 4#, and 5# was assessed using acoustic methods, yielding a microwave radiation effect radius of 2.5m. Zoning: Based on the requirements of the client for hard-surface stone, the dimensions of the stone surface product are length × width = 6m × 4m. Therefore, the length of the single quarrying area is determined. L It is 12m long and has a width of 12m. W It is 8m, such as Figure 2 (As shown).

[0053] Hole Formation: Drilling (hole diameter 76mm, hole depth 2m, e.g.) Figure 2 As shown in 5 and 7 in the figure, the operation is based on the radius of influence of microwave radiation, according to the formula. Round down after calculation to determine. a =2m, meaning the distance between adjacent boreholes is 2m, and every two carbon dioxide blasting fractured boreholes (such as...) Figure 3 The sum of 5 in the middle Figure 4 Drill a jet slit guide hole between 5) and 6) (e.g.) Figure 3 The sum of 7 in the middle Figure 4 7). That is, three CO2 blasting fracturing boreholes and four jet cutting holes need to be arranged along the length of a single mining area, and two CO2 blasting fracturing boreholes and three jet cutting holes need to be arranged along the width, with the CO2 blasting fracturing boreholes and four jet cutting holes arranged at intervals. After drilling is completed, rock cuttings, water and other impurities in the boreholes should be cleaned. Microwave radiation excitation: Applying microwave radiation excitation to the hard rock mass of the mine along a predetermined blasting direction (microwave radiation area such as...). Figure 3 (As shown in 3) to change the internal intercrystalline structure of the rock mass and induce the development and expansion of initial microfractures within it, thereby weakening the dynamic strength of the hard rock mass; High-pressure jet slit cutting: High-pressure jet technology is used to cut along a predetermined slit direction (the predetermined blasting direction is as follows). Figure 3 As shown in Figure 4, guide slots are formed by cutting the hard rock mass on both sides of the axial direction of the carbon dioxide blasting fracturing borehole and the jet cutting guide borehole (e.g., as shown in Figure 4). Figure 4 As shown in Figure 6), the high-pressure jet technology uses quartz sand slurry as the abrasive, with a concentration of 15wt%. The nozzle pressure is 50 MPa, the nozzle moving speed is 0.65 m / min, and the number of reciprocating cuts is 2. The length of the guide groove in the carbon dioxide blasting fracturing borehole is 0.65 times the borehole diameter, approximately 50 mm, and the width is 0.15 times the borehole diameter, approximately 11 mm. The length of the guide groove in the jet cutting guide borehole is 0.5 times the borehole diameter, approximately 38 mm, and the width is 0.1 times the borehole diameter, approximately 8 mm. Hole cleaning: After the high-pressure jet cutting is completed, the rock cuttings, water and other impurities in the borehole are cleaned and the borehole temperature is reduced to below 35°C; Install the fracturing device: Place the carbon dioxide blasting fracturing device into the carbon dioxide blasting fracturing borehole, and adjust the fracturing direction so that the cutting direction of the release tube of the blasting fracturing device is consistent with the predetermined fracturing direction and the direction of the guide groove. Sealing and detonation: The borehole is sealed using a carbon dioxide blasting sealing device; the borehole is sealed using a carbon dioxide blasting sealing device; the carbon dioxide blasting initiation line between the two boreholes is connected, and the power supply is ensured to be intact; the power supply is turned on to start the carbon dioxide blasting electric heater, and the blasting operation is carried out, ensuring that the carbon dioxide blasting fracturing boreholes are detonated simultaneously.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for efficiently and with low damage to hard stone, characterized in that, Includes the following steps: Drilling was performed after dividing the hard stone quarry area into zones; Microwave radiation excitation, high-pressure jet cleaving, and carbon dioxide blasting were sequentially applied to the hard rock mass in the predetermined fracturing direction.

2. The mining method as described in claim 1, characterized in that, The partitioning is determined based on the relationship between microwave radiation excitation and distance on the degree of rock mass damage and the predetermined effective damage to the rock mass.

3. The mining method as described in claim 2, characterized in that, The determination of the relationship between microwave radiation excitation and the degree of rock mass damage as a function of distance includes the following steps: Select an area that represents the rock mass properties of the hard stone quarry as the production test area; A fixed measure hole is determined in the production test area, and after a series of test holes are set in the measure hole, holes are drilled to obtain the measure hole and a series of test holes; Microwave radiation excitation is applied to the measured hole, and the damage of the test hole is detected in the test hole to obtain the radius of influence of microwave radiation.

4. The mining method as described in claim 3, characterized in that, The standard that can represent the rock mass properties of the hard stone mining area is that the lithology, rock physical and mechanical parameters, and the development of rock mass joints and fissures are consistent with the hard stone mining area. The series of detection boreholes are preferably set at different positions along an extension line in the radial direction centered on the detection borehole.

5. The mining method as described in claim 3, characterized in that, The key parameters for microwave radiation excitation include: excitation frequency ≥ 3 GHz, power ≥ 10 kWm, and time ≥ 10 min.

6. The mining method as described in claim 2, characterized in that, The predetermined effective damage to the rock mass is defined as a damage degree of ≥80% to the rock mass.

7. The mining method as described in claim 1, characterized in that, Determine the appropriate length of the mining area based on the mining plan and the size requirements of the mineral products. L and the width of the mining area W Length of mining area L and the width of the mining area W It is an integer multiple of the required length and width dimensions of the mineral product.

8. The mining method as described in claim 1, characterized in that, The horizontal distance between two adjacent boreholes a for: ； in, d The diameter of the borehole. D m This refers to the range of influence of microwave radiation.

9. The mining method as described in claim 1, characterized in that, The direction of the microwave radiation excitation and the direction of the guide groove formed by the high-pressure jet cutting are consistent with the axial direction of the borehole.

10. The mining method as described in claim 9, characterized in that, The length of the guide slot in the carbon dioxide blasting fracturing borehole is 0.6 to 0.8 times the borehole diameter, and the width is 0.10 to 0.12 times the borehole diameter. The length of the guide slot in the jet-cut guide borehole is 0.4 to 0.6 times the borehole diameter, and the width is 0.12 to 0.18 times the borehole diameter. The installation of the carbon dioxide blasting fracturing equipment involves placing the carbon dioxide blasting fracturing device into the borehole, adjusting the fracturing direction so that the cutting direction of the release pipe of the carbon dioxide blasting fracturing device coincides with the predetermined direction of stone mining and the direction of the guide groove formed by the jet cutting.

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