A method for fine stripping of rocks in a super-large open-pit mine under complex restricted conditions

Abstract

The application discloses a fine stripping method for large open-pit mine rock under complex restricted conditions, which comprises the following steps: S1, making geological records on the upper flat disc and the step slope of a step, and preliminarily drawing a lithology sketch; S2, selecting rock samples according to lithology to analyze dam-constructing property and acid-producing capacity of the rock; S3, designing parameters of a mine area blast hole grid according to the types and the blastability of the rock; S4, tracking the construction condition of the blast hole to serve as a surrounding rock limit; S5, correcting the lithology sketch drawn in the early stage; S6, integrating the tailing pond damming, the dump site dumping and the acid waste rock discharging into the ore production, and reasonably planning the area and the sequence of large blasting; S7, optimizing the blasting sequence, and respectively carrying out shovel loading and transportation to the dump site or the tailing pond damming after blasting. The method is favorable for fine management of the mine, realizes accurate blasting and shovel loading, and effectively reduces negative influences on the environment.

Description

Technical Field

[0001] This invention relates to the field of non-coal open-pit mining technology, and in particular to a method for refined rock stripping in open-pit mines under complex and confined conditions, which is suitable for rock stripping management in open-pit mines. Background Technology

[0002] Open-pit mines require the stripping of large quantities of rock during ore extraction. This rock typically needs to be dumped into tailings dams or waste dumps. On the one hand, as societal concerns about tailings dam safety increase, the requirements for rock suitability for dam construction are becoming increasingly stringent. On the other hand, some rocks contain sulfides, which, under long-term natural oxidation and rainwater leaching, easily produce acidic water and dissolve large amounts of heavy metal ions, causing adverse environmental impacts. With increasingly stringent environmental pressures, the treatment of acidic rocks urgently needs to be addressed. Therefore, open-pit mines face higher demands for the safe, environmentally friendly, and rational handling of large quantities of rock. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a safe, efficient, simple, and easy-to-manage method for the fine stripping of rocks in open-pit mines. This method ensures that the daily output of waste rock is sufficient for dam construction and meets the requirements for waste rock disposal; it also ensures that the waste rock used for dam construction possesses sufficient dam-building properties (strength and mud content); and simultaneously considers environmental requirements (sulfur and acid content).

[0004] The technical solution adopted in this invention is:

[0005] A method for refined rock stripping in large open-pit mines under complex and confined conditions includes the following steps:

[0006] S1. Geological logging of the upper flat plate and slope of the steps, and preliminary lithological sketches;

[0007] S2, by sampling, analyzes the acidity and dam-building properties of the rocks;

[0008] S3, Design the borehole grid parameters and coordinates according to the type and blastability of the rock;

[0009] S4. Survey and set out the boreholes and carry out drilling. Track the construction of the boreholes and observe the color, composition and backflow color of the rock powder in the borehole. When a change in the rock powder composition or a significant change in the rock powder color or backflow color is found, record the depth of the borehole at this time as the boundary point of the rock mass. All planned boreholes are tracked and recorded in this way as the boundary of the surrounding rock.

[0010] S5. Based on the surrounding rock boundaries delineated by the blast holes, the previously drawn lithological sketches are revised.

[0011] S6, in 3D mining software such as Dimine / Surpac, updates the 3D solid models of rocks and ore bodies based on the corrected lithological sketches and adds new rock properties (dam-building and acidity) to the block models, refining and updating the block models, thus laying the data foundation for refined rock mining.

[0012] Then, the needs for tailings dam construction and tailings dump disposal are incorporated into the production schedule along with ore recovery. Using the open-pit planning function of 3D mining software such as Dimine / Surpac, the overall long / short-term recovery sequence and production plan that simultaneously meet the multiple objectives of ore recovery, tailings dam construction and tailings dump disposal are selected.

[0013] S7. Following the sequence of bench blasting, and based on the long / short-term plan, when blasting a specific individual bench, the blasting sequence within the bench is optimized according to the direction of the free face of the bench. After blasting, the waste is shoveled and transported to the spoil heap or tailings dam for dam construction.

[0014] As a further improvement of the present invention, in step S2, the rocks are divided into dam-constructable non-acidic rocks, dam-constructable acidic rocks, and non-dam-constructable rocks according to their dam-constructability and acidity. The non-dam-constructable rocks are all transported to the tailings dump. Among the dam-constructable rocks, acidic rocks are preferentially used for tailings dam construction, while non-acidic rocks are transported to the tailings dump, thereby reducing the generation of acidic water.

[0015] As a further improvement of the present invention, in step S2, the acidity of the rock and its dam-building capability are determined by NNP (Net Neutralization Capacity) test and compaction test, respectively.

[0016] As a further improvement of the present invention, in step S3, based on the hardness and blastability of the rock, the hole mesh parameters for general areas are 6.0m × 5.0m (hole spacing × row spacing), and the hole mesh parameters for hard and difficult-to-blast areas are 4.5m × 3.5m (hole spacing × row spacing).

[0017] As a further improvement of the present invention, in step S7, the blasting method for a single step is as follows: under the condition of satisfying the blasting free surface, priority is given to blasting non-acidic waste rock that cannot be used for damming, then blasting non-acidic waste rock that can be used for damming, and finally blasting acidic waste rock that can be used for damming. This ensures that non-acidic waste rock discharged into the tailings dump is not contaminated by acidic waste rock, and also reduces the mixing of muddy and low-strength waste rock into the tailings dump, thus reducing sources of environmental pollution and improving the safety of tailings dam construction.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] (1) It is conducive to the multi-objective refined management of mines. By incorporating different types of rocks and ores into the mine production schedule, the mine can improve the reliability of ore production and rock waste disposal, and reduce the amount of acidic rock emissions, thus achieving multi-objective optimization.

[0020] (2) Achieve precise blasting and loading. By blasting different types of rock in different areas within a single bench, the efficiency and accuracy of loading are improved to a certain extent.

[0021] (3) Effectively reduce negative environmental impacts. By classifying rocks, different types of rocks can be discharged separately in the spoil heap, reducing the entry of acidic waste rock into the spoil heap and creating conditions for the enclosure and isolation of acidic rocks.

[0022] (4) It effectively reduced the mixing rate of acidic waste rock in the spoil heap and the mixing rate of waste rock that cannot be dammed in the tailings pond, thereby reducing the source of acidic waste rock that pollutes the environment from the root, and also improving the safety of tailings dam construction, thus ensuring safe, environmentally friendly and green mining. Attached Figure Description

[0023] Figure 1 This is a planar schematic diagram of the present invention.

[0024] Figure 2 This is a schematic diagram of the lithology of the boreholes.

[0025] Figure 3 This is a schematic diagram of the lithology of the cross section under existing technology.

[0026] Figure 4 This is a schematic diagram of the lithology of the cross section of this invention. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Please see Figures 1-4 Take a super-large copper mine as an example.

[0029] S1. Geologists conduct geological logging on the upper flat plate and slope of the steps. They classify and determine the grade according to the degree of mudification, weathering and hardness by visual inspection and geological hammering, and make preliminary lithological sketches.

[0030] S2. Representative surrounding rock samples were selected to analyze the acid-producing capacity and dam-construction suitability of the rocks.

[0031] The acid production capacity was determined by the NNP (Net Neutralization Capacity) test, and the dam-building capacity was determined by the compaction test.

[0032] S3. Based on the preliminary classification of lithology, and according to the type and blastability of the rock, design the borehole mesh parameters for the mining area. Specifically: the mesh parameters are determined based on the hardness and blastability of the rock; for general areas, the mesh parameters are 6.0m × 5.0m (hole spacing × row spacing), and for hard, difficult-to-blast areas, the mesh parameters are 4.5m × 3.5m (hole spacing × row spacing). See [link / reference]. Figure 1 .

[0033] S4. Based on the designed borehole coordinates, measure and lay out the boreholes and construct the boreholes. According to the preliminary lithological sketch, track the construction of the boreholes and observe the color, composition and backflow color of the rock powder in the borehole. When changes in rock powder composition or significant changes in rock powder color or backflow color are found, record the depth of the borehole at this time as the boundary point of the rock mass. All planned boreholes are tracked and recorded in this way as the boundary of the surrounding rock.

[0034] S5, based on the surrounding rock boundaries delineated by the blast holes, revise the previously drawn lithological sketches. For example... Figure 3 For example, based on the surrounding rock of different blast holes, the different surrounding rocks were re-delineated.

[0035] S6, in 3D mining software such as Dimine / Surpac, updates the 3D solid models of rocks and ore bodies based on the corrected lithological sketches and adds new rock properties (dam-building and acidity) to the block models, refining and updating the block models, thus laying the data foundation for refined rock mining.

[0036] Using 3D mining software such as Dimine / Surpac, production scheduling is carried out for different types of rocks / ores in long-term and short-term plans. Under the premise of meeting mine production requirements, multiple objectives such as tailings dam construction, tailings dump disposal, and acid waste rock discharge are incorporated into the production scheduling. The overall long-term and short-term mining sequence and production plan that simultaneously meet the multiple objectives of ore recovery, tailings dam construction, and tailings dump disposal are optimized.

[0037] S7. Following the bench blasting sequence and based on long-term / short-term plans, at a specific bench blasting stage, the blasting sequence is optimized according to the free face direction of the bench. After blasting, the waste rock is shoveled and transported to the tailings dump or tailings dam for construction. Specifically, under the condition of satisfying the free face blasting requirements, non-acidic waste rock unsuitable for damming is blasted first, followed by non-acidic waste rock suitable for damming, and finally acidic waste rock suitable for damming. This ensures that non-acidic waste rock discharged into the tailings dump is not contaminated by acidic waste rock, and also reduces the mixing of muddy and low-strength waste rock into the tailings dump, thus reducing sources of environmental pollution and improving the safety of tailings dam construction.

[0038] like Figure 1It is known that the blasting delineated three areas: early porphyry, late porphyry, and breccia. The early porphyry area was blasted first, and the blasted material was transported to the tailings dam to ensure the dam construction needs. Next, the late porphyry area was blasted. If the blasted material was insufficient for the dam construction, it was transported to the tailings dam. If the dam construction volume was sufficient, it was shoveled and transported to the spoil heap. Finally, all the breccia was dumped to the spoil heap.

[0039] The advantages of using the refined rock stripping method for large open-pit mines under complex and confined conditions according to the present invention are as follows:

[0040] (1) It is conducive to the multi-objective refined management of mines. By incorporating different types of rocks and ores into the mine production schedule, the mine can improve the reliability of ore production and rock waste disposal, and reduce the amount of acidic rock emissions, thus achieving multi-objective optimization.

[0041] (2) Achieve precise blasting and loading. By blasting different types of rock in different areas within a single bench, the efficiency and accuracy of loading are improved to a certain extent.

[0042] (3) Effectively reduce negative environmental impacts. By classifying rocks, different types of rocks can be discharged separately in the spoil heap, reducing the entry of acidic waste rock into the spoil heap and creating conditions for the enclosure and isolation of acidic rocks.

[0043] (4) It effectively reduced the mixing rate of acidic waste rock in the spoil heap and the mixing rate of waste rock that cannot be dammed in the tailings dam. The ratios before and after optimization are shown in the table below. It basically reduced the source of acidic waste rock that pollutes the environment from the root, and also improved the safety of tailings dam construction, ensuring safe, environmentally friendly and green mining.

[0044]

[0045] Those skilled in the art should understand that the protection scheme of the present invention is not limited to the above embodiments, and various arrangements, combinations and transformations can be made on the basis of the above embodiments. All transformations made to the present invention without departing from the spirit of the present invention fall within the protection scope of the present invention.

Claims

1. A method for refined rock stripping in a large open-pit mine under complex and confined conditions, comprising the following steps: S1. Geological logging of the upper flat plate and slope of the steps, and preliminary lithological sketches; S2. Representative rock samples were selected for analysis and experimentation on acidity and damability. The rocks were classified into three categories based on their acidity and damability: non-acidic rocks suitable for damming, acidic rocks suitable for damming, and rocks unsuitable for damming. Rocks unsuitable for damming were transported to the tailings dump. Among the rocks suitable for damming, acidic rocks were prioritized for tailings dam construction, while non-acidic rocks were transported to the tailings dump to reduce the generation of acidic water. S3, Design the borehole mesh parameters and coordinates according to the type and blastability of the rock; S4. Survey and set out the boreholes and carry out drilling. Track the construction of the boreholes. Observe the color, composition and backwater color of the rock powder in the borehole. When a change in rock powder composition or a significant change in rock powder color or backwater color is found, record the depth of the borehole at this time as the boundary point of the rock mass. All planned boreholes are tracked and recorded in this way as the boundary of the surrounding rock. S5. Based on the surrounding rock boundaries delineated by the blast holes, the previously drawn lithological sketches are revised. S6. In Dimine and Surpac 3D mining software, based on the revised lithology sketch, the 3D solid model of the rock and ore body is updated and new rock properties are added to the block model. The new rock properties are dam-building and acidity. The block model is refined and updated to lay a data foundation for refined rock mining. The needs for tailings dam construction and tailings dump disposal are incorporated into production planning along with ore recovery. Using the open-pit short-term planning function of Dimine and Surpac 3D mining software, monthly plans for different bench blasting that simultaneously meet the multiple objectives of ore recovery, tailings dam construction and tailings dump disposal are developed, and reasonable production areas and the order of bench blasting are selected. S7. Following the sequence of bench blasting, and based on long-term and short-term plans, for each bench, optimize the blasting sequence within the bench according to the direction of the free face of the bench. After blasting, the waste rock is shoveled and transported to the spoil heap or tailings dam for dam construction. The blasting sequence method for a single bench is as follows: under the condition of satisfying the free face of blasting, prioritize blasting waste rock that is not acidic and cannot be dammed, then blast waste rock that is not acidic and can be dammed, and finally blast acidic waste rock that can be dammed.

2. The method for refined rock stripping in open-pit mines under complex and confined conditions according to claim 1, characterized in that, In step S1, geological logging classifies and grades rocks according to their degree of weathering, degree of mudification, and degree of hardness by means of visual inspection and geological hammering.

3. The method for refined rock stripping in open-pit mines under complex and confined conditions according to claim 1, characterized in that, In step S2, the acidity and damability of the rock are determined by net neutralization capacity test and compaction test, respectively.

4. The method for refined stripping of rock in open-pit mines under complex and confined conditions according to claim 1, characterized in that, In step S2, based on the hardness and blastability of the rock, the hole spacing × row spacing parameters for general areas are 6.0m × 5.0m, and the hole spacing × row spacing parameters for hard and difficult-to-blast areas are 4.5m × 3.5m.

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