An open-pit mining method for a multi-vein complex rare earth ore section

Abstract

The present application relates to the technical field of open-pit mining, in particular to an open-pit mining method for a multi-vein complex rare earth ore section, which determines the ore body strike and working bank advancing direction, sets out the mining steps along the advancing direction of the working bank, and sets a strip on the mining steps and sequentially cycles the stripping according to the strip; a slag zone is reserved on the strip free face, a blasting area is arranged vertically to the strip strike, and the perforation, sampling and blasting operations are sequentially completed; the sampling material in the blast hole is tested, and several sections along the strip strike are divided and marked; the mining and transportation scheme of the ore quality is determined and the mining and transportation are performed. The method solves the problems of frequent changes in the nature of the working face ore rock, unstable ore quality, and difficulty in blasting and mining, and achieves the purpose of stabilizing the target raw ore quality for selection, providing protection for the downstream beneficiation process. The method can effectively reduce the ore dilution rate and improve the ore resource recovery rate. Through the ore blending scheme feedback, the stable production and operation of the mine can be ensured.

Description

Technical Field

[0001] This invention relates to the field of open-pit mining technology, and specifically to an open-pit mining method for complex rare earth ore sections with multiple veins. Background Technology

[0002] Open-pit mining is a process of stripping overburden from an ore body to obtain ore. Currently, common mining methods often involve arranging the mining strip perpendicular to the working face's advance direction and advancing along the strip. However, this method is highly prone to problems such as frequent changes in the properties of the ore face, unstable ore quality, and difficulties in separate blasting and mining when mining multi-vein sections with thin ore bodies, uneven ore grade distribution, and complex ore body morphology. This hinders the blending and utilization of ores of different qualities and the control of dilution and loss rates, affecting the stability of the quality of the raw ore entering the beneficiation process and negatively impacting downstream beneficiation processes.

[0003] Therefore, existing multi-vein combined mining schemes need to be optimized. Corresponding mining plans should be proposed for different vein combination conditions to facilitate ore blending and improve ore resource recovery. Thus, more reasonable technical solutions are needed to address the technical problems existing in current technologies. Summary of the Invention

[0004] To overcome at least one of the aforementioned defects, this invention proposes an open-pit mining method for complex rare earth ore sections with multiple veins. By combining the distribution of the veins, the sections are adaptively divided and mining and stripping are carried out accordingly, thereby ensuring the stability of the quality of the mined ore and reducing the ore dilution rate and loss rate.

[0005] To achieve the above objectives, the mining method disclosed in this invention can adopt the following technical solution:

[0006] An open-pit mining method for complex rare earth ore sections with multiple veins includes the following processes:

[0007] Determine the strike of the ore body and the direction of the working face advance. Set up several ore-extraction benches along the direction of the working face advance, and set up several strips on the ore-extraction benches. Then, mine and strip in sequence according to the strips, with each strip constituting one mining and stripping cycle.

[0008] A slag strip of a predetermined width is reserved on the free face of the strip. The blasting area is arranged in the direction perpendicular to the direction of the strip. Drilling, sampling and blasting operations are completed in sequence within the blasting area.

[0009] The samples taken from the boreholes were tested to determine the properties of the rock and the quality of the ore. The strips were divided into several sections and marked along their direction.

[0010] Determining the mining and transportation scheme based on ore quality: Using each ore section in each strip as the ore source for the blending process, the optimal blending scheme is determined through linear programming to achieve refined blending. This not only ensures the full and comprehensive utilization of ores of different qualities and stabilizes the quality of the blended ore, but also effectively reflects the overall changes in the ore by showing the trend of the blending scheme. This helps guide the research direction of the beneficiation of ores of different qualities in the mine, and provides a basis for the development of mineral processing technology and the preparation of mining and stripping plans.

[0011] The ore is excavated and transported from one end of the strip to the other end, while simultaneously excavating and transporting ore in a direction perpendicular to the strip according to the determined excavation and transport plan.

[0012] The aforementioned mining method, which employs blasting mining for different ore body distributions in open-pit mines, is adaptable to various ore body distributions. It can ensure the purity of the ore during excavation as much as possible, reduce the frequent changes in ore and rock properties during excavation, thereby reducing the ore dilution rate, improving ore quality, and facilitating ore blending and resource recovery.

[0013] Furthermore, the present invention can be applied to complex multi-vein situations, including various scenarios. Here, we optimize and propose one feasible option: the ore body strike can be perpendicular to the working face's advance direction, parallel to the working face's advance direction, or scattered. The above describes the actual distribution of the ore body after the working face's advance direction has been basically determined, encompassing all distribution scenarios of complex ore bodies.

[0014] Furthermore, to ensure excavation and transportation after blasting, the layout of the ore-excavating benches is adjusted and optimized. The following feasible option is proposed: the minimum horizontal distance between the surfaces of two adjacent ore-excavating benches is the width of the working platform, which is greater than 40m. With this scheme, after the slopes of the ore-excavating benches are blasted, the working platform still has sufficient distance for excavation and transportation. Simultaneously, the blasting and excavation of adjacent benches will not interfere with each other, thus ensuring overall mining efficiency.

[0015] Furthermore, in this invention, to balance mining efficiency and overall mine management, the number of ore-exiting steps is limited. One feasible option is to use 2 to 3 ore-exiting steps. With this approach, the mine infrastructure can meet mining requirements while also providing high mining efficiency and output. By reducing the size of the mining strip and the stripping sequence within it, the cycle time of the mining strip is shortened, the amount of ore of different qualities to be mined increases, and the types of ore used for blending are diversified. This provides a strong guarantee for the stability of the quality of the raw ore entering the beneficiation process and is of great significance to the stability of downstream beneficiation processes.

[0016] Furthermore, in this invention, the width of the slag zone is limited. One feasible option is that the width of the slag zone is at least 1m. When using this approach, the concentrated blasting pile, high crushing quality, and small blasting pile displacement of slag blasting are utilized to reduce blasting pile displacement. The degree of damage to the ore-rock boundary after blasting is controlled. Simultaneously, the width of the blasting strip is shortened, avoiding excessive variation in the ore body within a single strip. The blasting displacement direction is nearly parallel to the ore-rock boundary, effectively avoiding problems such as unclear mining boundaries and excessive working face depth during excavator operations, reducing ore dilution rate, and improving resource recovery rate.

[0017] Furthermore, based on the geological conditions of the mine and the height of the ore bench, a blasting scheme can be designed. Various forms can be adopted, and it is not limited to one. Here, we optimize and propose one feasible option: the blasting area is arranged with blast holes in a quincunx pattern. The hole network parameters include 4m×6m, hole depth of 13m (1m extra depth), and hole diameter of 140mm.

[0018] Furthermore, the strip division of the ore bench varies depending on the distribution of the ore body. Specifically, when setting strips, the width of the strip is less than 5 times the spacing between blast holes. The higher the parallelism between the extension direction of the ore body and the advancement direction of the working face, the wider the strip can be set. In particular, the strip width is divided according to the principle of reducing the complexity of ore body changes within a single strip and facilitating subsequent ore and rock separation mining.

[0019] Furthermore, the ore body's distribution varies within the ore bench, resulting in alternating distribution of blasted ore and rock. To improve ore quality, separate excavation and transportation are necessary. Here, we propose an optimization and a feasible option: when marking sections, mark the areas containing the ore sequentially along the direction of the strip's extension. With this approach, markers can be placed at the section boundaries for indication. The ore can be divided into several sections based on ore type and quality. Utilizing the flexibility and small size of excavators, each section can be mined separately, with the mining sequence determined by blending requirements. This technical solution achieves multi-level quality control of the ore to be mined, ensuring quality for subsequent blending. Simultaneously, refined, segmented mining reduces the possibility of ore-rock mixing, minimizing ore dilution and loss.

[0020] Furthermore, during excavation and transportation, various equipment and development schemes can be used. Here, we optimize and propose one feasible option: deploy several excavators to excavate and transport the blasted material. One excavator advances along one end of the strip to the other end for excavation and transportation, while another excavator operates perpendicular to the strip, carrying out ore excavation and transportation according to a predetermined scheme. Using this scheme, excavation along the strip allows for thorough clearing, while excavation perpendicular to the strip allows for selective excavation and transportation of different sections in a set sequence, aligning with the mine's operational schedule.

[0021] Furthermore, in order to improve the efficiency of excavation and transportation, several excavators were set up to strip and excavate the rock within the strip.

[0022] Compared with the prior art, some of the beneficial effects of the technical solution disclosed in this invention include:

[0023] 1. In response to the challenges of frequent changes in the properties of ore and rock at the working face, unstable ore quality, and difficulty in separate blasting and mining during the mining process of complex rare earth ore sections with multiple ore bodies, improvements and integration in aspects such as mining zone layout, blasting technology, and production organization have been made to achieve the goal of stabilizing the quality of the target raw ore for beneficiation, thus providing a guarantee for the stability of downstream beneficiation processes.

[0024] 2. Refined strip and section mining can effectively reduce ore dilution rate and improve ore resource recovery rate.

[0025] 3. When the overall quality of ore declines, timely feedback can be provided through the ore blending plan, thereby ensuring the stable production and operation of mining enterprises by adjusting the mining and stripping plan or tackling key ore beneficiation technologies. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the plan layout for the strip-type gentle slope mining of the present invention.

[0028] Figure 2 for Figure 1 A cross-sectional view of the mining area at point AA.

[0029] Figure 3 This is a schematic diagram of the layout of the ore body's strike parallel to the direction of the working slope's advance.

[0030] Figure 4 This is a schematic diagram of the layout of the ore body's strike perpendicular to the direction of the working face's advance.

[0031] In the above attached figures, the meanings of each label are as follows:

[0032] 1. Working platform; 5. Strip division; 9. Ore section;

[0033] 2. Mining bench; 6. Safety platform; 10. Rock section;

[0034] 3. Slope crest line; 7. Cleaning platform; 11. Excavator;

[0035] 4. Slope bottom line; 8. Work assistance direction; 12. Work strip. Detailed Implementation

[0036] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0037] In response to the challenges of frequent changes in the properties of ore and rock at the working face, unstable ore quality, and difficulty in separate blasting and mining in complex multi-vein mining sections, the following embodiments are adjusted and optimized to overcome the defects in the existing technology.

[0038] Example

[0039] Based on the characteristics of the Yaoniuping rare earth deposit, its ore sections generally consist of a few or more relatively thick veins of one or two types, along with numerous parallel fine veinlets or fine network veinlets. Some sections are almost entirely composed of parallel fine veinlets or fine network veinlets. There is no clear boundary between the ore body and the surrounding rock. The ore body morphology is diverse, primarily branched vein-like, lenticular, and banded, followed by irregular lenticular, pocket-like, and dendritic shapes. It often exhibits branching and compounding, pinch-out and reappearance, and pinch-out and lateral appearance. The ore body size varies, with thicknesses ranging from tens of centimeters to tens of meters. The degree of rare earth mineralization within a single ore body varies greatly, with a rare earth grade variation coefficient reaching 130%.

[0040] like Figures 1-4 As shown, this embodiment provides an open-pit mining method for complex rare earth ore sections with multiple veins, including the following process:

[0041] S01: Determine the ore body strike and working slope advance direction 8, set several ore extraction benches 2 along the working slope advance direction, and set several strips on the ore extraction benches 2, and mine and strip in sequence according to the strips, with each strip being one mining and stripping cycle.

[0042] This embodiment is applicable to complex multi-vein situations, including various scenarios. Optimizations are presented here, and feasible options are offered: For example... Figure 3 , Figure 4As shown, the orebody strikes include those perpendicular to the working face advance direction 8, those parallel to the working face advance direction 8, and scattered distributions. The above is the actual distribution of the orebody as determined after the working face advance direction 8 was basically determined, including all distributions of complex orebody types.

[0043] To ensure proper excavation and transportation after blasting, the design of the ore extraction bench 2 has been adjusted and optimized. This embodiment adopts the following feasible option: Figure 1 As shown, the minimum horizontal distance between the surfaces of two adjacent mining benches 2 is the width of the working platform 1, which is greater than 40m. With this scheme, after the slope of the mining bench 2 is blasted, the working platform 1 still has sufficient distance for excavation and transportation. Simultaneously, the blasting and excavation of adjacent benches will not cause any impact, thus ensuring overall mining efficiency.

[0044] Preferably, the width of the working platform 1 here is the shortest distance between the top line 3 of this mining step 2 and the bottom line 4 of the previous mining step 2.

[0045] In this embodiment, to balance mining efficiency and overall mine management, the number of ore-exit benches 2 is limited. This embodiment adopts one feasible option: such as... Figure 1 As shown, the number of ore-exit steps 2 is 2 to 3. When this scheme is adopted, the mine construction foundation can meet the mining needs, while also providing high mining efficiency and output. By reducing the size of the mining strip and the stripping sequence within the strip, the cycle of the mining strip is shortened, the amount of ore of different qualities to be mined increases, and the types of ore used for blending are diversified. This provides a strong guarantee for the stability of the quality of the raw ore entering the beneficiation process and is of great significance to the stability of downstream beneficiation processes.

[0046] Preferably, 2-3 ore extraction steps 2 are arranged perpendicular to the working side advance direction 8; a dividing strip 5 is set on the upper platform of each ore extraction step 2, arranged parallel to the ore extraction step 2; the strip on the slope of the step adjacent to the ore extraction step 2 is the working strip 12.

[0047] S02: Reserve a slag strip area of ​​a set width on the free surface of the strip, arrange the blasting area along the direction perpendicular to the strip, and complete the drilling, sampling and blasting operations in sequence within the blasting area.

[0048] In this embodiment, the width of the slag zone is limited, and one feasible option is proposed: the width of the slag zone is at least 1m. When adopting this scheme, the characteristics of concentrated blasting piles, good crushing quality, and small blasting pile displacement of slag blasting are utilized to reduce blasting pile displacement, control the degree of damage to the ore-rock boundary after blasting, and shorten the width of the blasting strip to avoid excessive variation in the ore body within a single strip. The blasting displacement direction is nearly parallel to the ore-rock boundary, effectively avoiding problems such as unclear mining boundaries and excessive working face depth during excavator 11 operations, reducing ore dilution rate, and improving resource recovery rate.

[0049] Preferably, a blasting scheme is designed based on the geological conditions of the mine and the height of the ore bench 2. Various forms can be adopted, and there is no single limitation. Here, we optimize and propose one feasible option: blast holes are set at row and column intervals within the blasting area, with a hole grid interval of 4m × 6m. When using this scheme, the diameter of the blast holes is generally set to 140mm. When the bench height is 12m, the hole depth is 13 meters (with an extra 1 meter). Latex-based explosives are used for blasting, with a single hole charge of 120kg and a plug length of 5-6 meters.

[0050] Depending on the distribution of the ore body, the strip division of the ore bench 2 varies. Specifically, when setting the strips, the width of the strip is less than 5 times the spacing between blast holes. The greater the parallelism between the ore body extension direction and the working face advancement direction, the wider the strip can be set. Specifically, the strips are divided by width to reduce the complexity of ore body variations within a single strip and to facilitate subsequent ore-rock separation mining.

[0051] like Figure 3 As shown, when the ore body is perpendicular to the working slope advancement direction 8, the width of the strip is 4 to 5 times the borehole spacing; as Figure 4 As shown, when the ore body is parallel to the working slope advancement direction 8, the width of the strip is 3 to 4 times the borehole spacing; when the ore body is scattered, the width of the strip is 2 to 3 times the borehole spacing.

[0052] S03: Test the samples taken from the boreholes to determine the properties of the rock and the quality of the ore, and divide the strip into several sections and mark them.

[0053] Preferably, the ore body is distributed differently within the ore bench 2, resulting in alternating distribution of blasted ore and rock. To improve ore quality, separate excavation and transportation are necessary. Here, an optimization is proposed, suggesting one feasible option: when marking sections, the areas containing the ore are marked sequentially along the extension direction of the strip. With this approach, signs or marker poles can be placed at the boundaries of the sections for indication. The ore can be divided into several sections based on ore type and quality. Utilizing the flexibility and small size of the excavator 11, each section can be mined separately, with the mining sequence determined by blending requirements. By adopting the above technical solution, multi-level quality of the ore to be mined is achieved, providing a guarantee for subsequent blending work. Simultaneously, refined segmented mining reduces the possibility of ore-rock mixing, minimizing ore dilution and loss.

[0054] Preferably, according to the stratification of ore and rock, ore section 9 and rock section 10 are marked respectively, and each section of ore section 9 is marked as needed, such as 2850-① which means the 2850 ore-exit bench 2① section.

[0055] S04: Determining the mining and transportation scheme for ore quality: Taking each ore section 9 in each strip as the ore source for the blending process, the optimal blending scheme is determined through linear programming to achieve refined blending. This not only ensures the full and comprehensive utilization of ores of different qualities and stabilizes the quality of the blended ore, but also effectively reflects the overall changes in the ore by showing the trend of the blending scheme. This is beneficial for guiding the research direction of the beneficiation of ores of different qualities in the mine, and provides a basis for the research direction of mineral processing technology and the preparation of mining and stripping plans.

[0056] Preferably, in this embodiment, the mining and transportation plan is specified in detail. For example, the mine currently has three types of ore: A, B, and C. Type A ore has a grade of 5%, is difficult to beneficiate, and can be mined 500 tons; Type B ore has a grade of 2%, is easily beneficiate, and can be mined 1000 tons; and Type C ore has a grade of 4%, is easily beneficiate, and can be mined 200 tons. When formulating the ore blending plan, it is assumed that x tons of Type A ore, y tons of Type B ore, and z tons of Type C ore are used. The final blending target is an ore grade of 3%-3.5%, and the proportion of difficult-to-beneficiate ore should not exceed 1 / 3. From this, the function can be listed as follows:

[0057] 0≤x≤500

[0058] 0≤y≤1000

[0059] 0≤z≤200

[0060] 3≤(5x+2y+4z) / (x+y+z)≤3.5

[0061] x / (y+z)≤1 / 3

[0062] The objective function g = x + y + z is maximized. Within the feasible region, g reaches its maximum value when x = 400, y = 1000, and z = 200. This determines the optimal blending ratio of the three types of ore while meeting the blending requirements.

[0063] This can be achieved using the ore blending function in mining software such as DMine and 3DMine.

[0064] S05: Advance from one end of the strip to the other end and carry out excavation and transportation operations, while simultaneously carrying out ore excavation and transportation operations in a direction perpendicular to the strip and in accordance with the determined excavation and transportation plan.

[0065] Preferably, during excavation and transportation, various equipment and development schemes can be used for processing. Here, we optimize and propose one feasible option: Several excavators 11 are set up to excavate and transport the blasted material. One excavator 11 advances along one end of the strip to the other end for excavation and transportation, while another excavator 11 performs ore excavation and transportation operations perpendicular to the strip direction according to a predetermined excavation and transportation scheme. Using this scheme, excavation and transportation along the strip extension direction allows for thorough clearing, while excavation and transportation perpendicular to the strip direction allows for selective excavation and transportation of different sections in a set sequence, which aligns with the mine's ore blending operations.

[0066] To improve excavation and transportation efficiency, when fewer than two excavators are operating at the ore extraction bench, one or two excavators are also set up to strip and excavate the rock within the strip.

[0067] The mining method disclosed in this embodiment is designed for blasting mining under different ore body distribution conditions in open-pit mines. It can adapt to the excavation of various ore body distribution conditions, and can ensure the purity of ore material as much as possible during the excavation process, reduce the frequent changes in ore quantity during the excavation process, thereby reducing the ore dilution rate, improving the ore quality, and facilitating ore blending and resource recycling.

[0068] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments under the guidance of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be defined in the claims.

Claims

1. A method for open-pit mining of complex rare earth ore sections with multiple veins, characterized in that, include: Determine the ore body strike and working slope advance direction (8), set several mining benches (2) along the working slope advance direction, and set several strips (5) on each mining bench (2), and mine and strip in sequence according to the strips, with each strip being one mining and stripping cycle; A slag strip of a predetermined width is reserved on the free face of the strip. The blasting area is arranged in the direction perpendicular to the direction of the strip. Drilling, sampling and blasting operations are completed in sequence within the blasting area. Within the blasting area, blast holes are arranged at row and column intervals, with a hole mesh interval of 4m × 6m; When setting up the strips, the width of the strips should be less than 5 times the spacing between the borehole rows; The samples taken from the boreholes were tested to determine the properties of the rock and ore and the quality of the ore. The strips were divided into several sections and marked along their direction. Determine the mining and transportation plan based on ore quality; The ore is excavated and transported from one end of the strip to the other end, while simultaneously excavating and transporting ore in a direction perpendicular to the strip according to the determined excavation and transport plan.

2. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 1, characterized in that: The ore bodies are distributed in several ways: perpendicular to the working slope advance direction (8), parallel to the working slope advance direction (8), and scattered.

3. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 1, characterized in that: The minimum horizontal distance between the steps of two adjacent mining steps (2) is the width of the working platform (1), and the width of the working platform (1) is greater than 40m.

4. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 1, characterized in that: The number of the ore-exiting steps (2) is 2 to 3.

5. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 1, characterized in that: The width of the slag zone is at least 1m.

6. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 1, characterized in that: When marking sections, the areas where the ore is located are marked sequentially along the direction of the strip extension.

7. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 1, characterized in that: Several excavators (11) are set up to excavate and transport the blasted material. One excavator (11) advances along one side of the strip to the other side, and another excavator (11) performs ore excavation and transportation operations in a direction perpendicular to the strip and in accordance with the determined excavation and transportation plan.

8. The open-pit mining method for complex rare earth ore sections with multiple veins according to claim 7, characterized in that: When fewer than two excavators are operating at the ore extraction bench, one or two more excavators are set up to strip and transport the rock within the strip.

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