Microsecond blasting structure for limestone mine blasting

Abstract

The utility model discloses a millisecond blasting structure for limestone mine blasting, which belongs to the technical field of mine blasting, and comprises a production step, a plurality of rows of blast holes are arranged on the production step, the plurality of rows of blast holes are distributed in a quincunx shape along the production step, a charging structure is arranged in the blast holes, and the charging structure comprises explosives. According to the utility model, the blasting quality is improved and the yield of over-crushed raw ore is reduced by redesigning the parameters of the blasting hole net and the charging structure.

Description

Technical Field

[0001] The utility model relates to the technical field of mine blasting, in particular to a micro-difference blasting structure for limestone mine blasting. Background Art

[0002] Uneven ore size distribution and high fines rates are major challenges in mining blasting operations. These factors not only increase the cost of aggregate crushing but also lead to the permanent waste of significant ore resources. Therefore, improving ore size distribution during blasting is a key issue that needs to be addressed.

[0003] At present, the production of raw ore has the following problems: (1) The undersize material accounts for a large proportion, which is 11% of the raw ore. There is a lot of ore powder in the undersize material, which wastes a lot of mineral resources; (2) There are many broken materials in the raw ore. In the first crushing production, the proportion of materials screened by the roller screen is very large, and the load is large, which restricts the crusher from fully utilizing its production capacity, resulting in low production efficiency. The main reason for the above problems is that there are too many broken materials in the raw ore, so reducing the broken materials in the raw ore and increasing the large block rate are the key to solving the problem.

[0004] Substandard ore yields significantly impact production and operational indicators such as quality, efficiency, and cost, placing significant pressure on mining and stripping, stope balance, and the supply of finished aggregates. Chronically substandard ore recovery rates not only hinder production and economic efficiency, but also waste resources and reduce the effective service life of a mine. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the utility model provides a micro-difference blasting structure for limestone mine blasting; the micro-difference blasting structure for limestone mine blasting improves the blasting quality and reduces the yield of over-crushed ore by redesigning the parameters of the blasting hole network and the charging structure.

[0006] In order to solve the above technical problems, the utility model provides a micro-difference blasting structure for limestone mine blasting, including a production step, on which a plurality of rows of blast holes are arranged in a plum blossom shape along the production step, and a charging structure is provided in the blast hole, which includes explosives.

[0007] In a further improvement of the present invention, the height of the production step is 15 meters.

[0008] In a further improvement of the present invention, the blasthole is drilled at 75 degrees, the blasthole depth is 2m, and the blasthole diameter is 115mm.

[0009] In a further improvement of the present invention, the multiple rows of blast holes are arranged in 3 rows close to the free surface area on the production step, with a total of 24 blast holes.

[0010] In a further improvement of the present invention, the hole spacing range of the blast holes is 6.3m-6.9m, and the row spacing range of the blast holes is 3.5m-4.1m.

[0011] In the further improvement of the present invention, the hole network adopts a blasthole spacing of 6.7m*blasthole row spacing of 3.7m.

[0012] In a further improvement of the present invention, the charge structure adopts an axially uncoupled charge structure with air intervals in the middle of the hole and staged blasting.

[0013] In a further improvement of the present invention, the range of the intermediate air spacing in the hole is 0.6m-2.5m.

[0014] In a further improvement of the utility model, the explosive includes expanded explosive and emulsion explosive.

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

[0016] The utility model improves blasting quality and reduces the yield of over-crushed ore by redesigning the parameters of the blasting hole network and the charging structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the background technology or the technical solution of the present invention, the following is a brief introduction to the drawings used in conjunction with the prior art or specific implementation methods; obviously, the structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention, so they have no technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0018] Figure 1 This is a schematic diagram of the blasthole arrangement of a specific implementation method of the present utility model. DETAILED DESCRIPTION

[0019] In order to enable people skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work should fall within the scope of protection of the present invention.

[0020] At the same time, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like cited in this specification indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0021] At the same time, in the description of this specification, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the internal parts of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0022] At present, the company's raw ore production has the following problems: (1) The proportion of undersize material is large. According to the production statistics in 2022, the proportion of undersize material in the raw ore is 11%. There is a lot of ore powder in the undersize material, which wastes a lot of mineral resources; (2) There are many crushed materials in the raw ore. In the primary crushing production, the proportion of materials screened by the roller screen is large, and the load is large, which restricts the crusher from fully utilizing its production capacity, resulting in low production efficiency. The main reason for the above problems is that there are too many crushed materials in the raw ore, so reducing the crushed materials in the raw ore and increasing the large block rate are the key to solving the problem.

[0023] By optimizing and adjusting the blasting process parameters, the unevenness index Cu and the average fine ore rate can be reduced, the curvature coefficient Cc and the average block size can be increased, and the blasting fine ore rate can be gradually reduced to the target of 7.5%. At the same time, the ore grading can reach a good level to meet the production requirements of aggregate mines.

[0024] 1. Under the condition that the improved functions of crushing and screening equipment are relatively stable, the particle size distribution of the ore after the first-level crushing is compared and measured. Starting from the perforation blasting process, the blasting software design and the micro-difference blasting technology between holes are optimized. By improving the parameters of the perforation network and the charging structure, the blasting process technology is studied to improve the blasting quality and reduce the yield of over-crushed ore.

[0025] Basic parameters: a 15m mining bench height, 75-degree drilling, approximately 2m over-depth, a plum blossom pattern, and primary explosives consisting of expanded and emulsion explosives. Explosive consumption varies based on joints, fissures, and weathering. By studying the ore bed's occurrence, the team optimized parameters in three areas: hole pattern, charge structure, and detonation differential time, seeking the optimal combination.

[0026] like Figure 1 As shown, the present application provides a micro-difference blasting structure for limestone mine blasting, including a production step, on which a plurality of rows of blast holes are arranged in a plum blossom shape along the production step, and a charging structure is provided in the blast hole, which includes explosives; wherein the explosives include expanded explosives and emulsion explosives.

[0027] Among them, the step height of the production step is 15 meters.

[0028] The blasthole is drilled at a 75-degree angle, has a depth of 2 meters, and a diameter of 115 mm.

[0029] The multiple rows of blast holes are arranged in 3 rows on the production bench near the free surface area, with a total of 24 blast holes.

[0030] The blasthole spacing ranges from 6.3m to 6.9m, and the blasthole row spacing ranges from 3.5m to 4.1m; and the hole network adopts a blasthole spacing of 6.7m and a blasthole row spacing of 3.7m.

[0031] The charge structure adopts an axially uncoupled charge structure with an air gap in the middle of the hole and segmented blasting; the range of the air gap in the middle of the hole is 0.6m-2.5m.

[0032] The specific plan is as follows:

[0033] On-site blasting test

[0034] Test 1: When conducting on-site blasting tests, the fixed-row delay detonators were 5-stage millisecond delay detonators (delay time was 110ms), and the delay time between holes was changed. Two-stage, three-stage, and four-stage millisecond delay nonel detonators with delays of 25ms, 50ms, and 75ms were used respectively. Three groups of tests were conducted under each working condition. During the test, three rows of 24 blast holes were arranged on the production bench close to the free surface area each time.

[0035] Test 2: Six parameter combinations were designed for testing. The blasthole diameter was 115 mm, the blasthole filling form was an axially uncoupled charge structure with air space in the middle of the hole and staged blasting.

[0036]

[0037] Experiment 3: The blasthole filling form with a hole grid of 6.7m×3.7m and a hole diameter of 115mm is an axial uncoupled charging structure with an air gap in the middle of the hole and staged blasting. Four combinations of blasthole filling forms are designed for testing: ① The air gap length is set to 0.6m; ② The air gap length is set to 1m; ③ The air gap length is set to 1.5m; ④ The air gap length is set to 2m; ⑤ The air gap length is set to 2.5m.

[0038] Results and Analysis

[0039] After blasting, a layered sampling method was adopted; according to the test requirements of "GB / T14685-2011 Pebbles and Crushed Stones for Construction", ore particles with a particle size of less than 75 mm were counted; a sampling point was set up above, in the middle, at the bottom, on the left, in the middle, and on the right side of the blast pile surface (a total of 9 points), and 2 kg of post-blast rock samples were sampled at each sampling point, and sieved and analyzed using a national standard sieve; when the blast pile was excavated along the step direction, the above method was repeated for sampling and analysis every time it advanced to 5 m.

[0040] The ore distribution data of each test group was counted, and after calculating the average value, the blasting measured screening test data was statistically analyzed.

[0041] In order to evaluate the grading characteristics of blasted ore, the unevenness coefficient Cu and curvature coefficient Cc are used to analyze the screening data. The calculation formula is as follows

[0042] Cu=d60 / d10

[0043] Cc=(d30)2 / (d60×d10)

[0044] Where: Cu is the uniformity coefficient; Cc is the curvature coefficient; d10 is the particle size at which 10% of the sieved weight is accounted for; d30 is the particle size at which 30% of the sieved weight is accounted for; d60 is the particle size at which 60% of the sieved weight is accounted for.

[0045] Implementation Effect

[0046] By analyzing the blast pile gradation unevenness coefficient Cu and curvature coefficient Cc of the blasted ore, we can preliminarily determine the particle size of the ore after blasting and, in turn, the corresponding ore fines ratio. A decrease in Cu indicates improved crushing uniformity, while an increase in Cc indicates an increase in particle size and a decrease in fines. The effectiveness of the implementation is also assessed through data such as the undersize ratio, first crushing time, and unit explosive consumption.

[0047] Direct benefit calculation

[0048] 1. After the blasting effect is improved, the output ratio of undersize material is expected to drop from the current 11% to 7.5%. Based on the annual output of 8.5 million tons, the output of undersize material will be reduced by 8.5 million tons * (11%-7.5%) = 297,500 tons. The price difference between undersize material and main product is calculated at 40 yuan / ton, and the profit is expected to increase by 11.9 million yuan.

[0049] 2. After the blasting effect is improved, the production line hours are greatly increased, and the electricity consumption cost can be saved each year: 2100kw / h (average energy consumption of the production line per hour) × 4h (time saved to complete the same amount of production tasks) × 250d / y (average annual production days) × 0.8 yuan / kw = 1.68 million yuan.

[0050] 3. After the blasting process parameters are adjusted, it is estimated that 168.6 tons of explosives can be saved annually through optimizing the technical parameters of the spacing between holes, segmented charging, millisecond difference initiation mode adjustment and other technical measures. Based on the current purchase price of 10,900 yuan per ton of explosives, the profit is expected to increase by 1.8377 million yuan.

[0051] 4. Due to the improvement in production efficiency and the shortening of daily start-up time, the labor intensity of workers and the difficulty of dispatchers in managing the site have been significantly reduced. The emergency response capability of the production line to deal with emergencies has been improved, bringing many potential economic benefits.

[0052] The utilization rate of ore resources increased by 3.5 percentage points. Based on the annual output of 8.5 million tons of construction aggregate products, the annual resource consumption was reduced by 297,500 tons, and the service life of the mine was extended. Due to the effective increase in the large ore rate, the amount of ore waste discharged was reduced, and the energy-saving and emission reduction effects were obvious.

[0053] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, ordinary technicians in this field can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention. Any technician familiar with this technical field can easily think of changes or substitutions within the technical scope disclosed in the present invention, and they should all be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A micro-difference blasting structure for limestone mine blasting, characterized in that: The production step comprises a plurality of rows of blastholes arranged on the production step, the plurality of rows of blastholes being arranged in a plum blossom shape along the production step, and a charge structure being arranged in the blastholes, the charge structure comprising explosives; The hole spacing range of the blastholes is 6.3m-6.9m, and the row spacing range of the blastholes is 3.5m-4.1m; the charging structure adopts an axially uncoupled charging structure with air intervals in the middle of the hole and staged blasting; the air intervals in the middle of the hole range from 0.6m to 2.5m; the explosives include expanded explosives and emulsion explosives.

2. The micro-difference blasting structure for limestone mine blasting according to claim 1, characterized in that: The step height of the production step is 15 meters.

3. The micro-difference blasting structure for limestone mine blasting according to claim 1, characterized in that: The blasthole is drilled at 75 degrees, has a depth of 2m and a diameter of 115mm.

4. The micro-difference blasting structure for limestone mine blasting according to claim 1, characterized in that: The multiple rows of blast holes are arranged in 3 rows on the production bench near the free surface area, with a total of 24 blast holes.

5. The micro-difference blasting structure for limestone mine blasting according to claim 1, characterized in that: The hole network adopts a blast hole spacing of 6.7m and a blast hole row spacing of 3.7m.

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