A method of mining an open pit mine

Abstract

The application discloses a mining method for open-pit mine, which comprises the following steps: performing overall perforation on the blasting pile of open-pit mining, performing secondary ore circle on the blasting pile after the test result is obtained, optimizing the blasting sequence according to different types of ores or waste rocks and the free surface of blasting, performing regional blasting according to the blasting sequence, achieving the purpose of sub-blasting, creating conditions for sub-shovel and sub-loading, and reducing the loss and dilution rate of mining.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of open-pit mining, in particular to a mining method for open-pit mine. BACKGROUND

[0002] Open-pit mining is a process of removing the covering on the ore body to obtain the desired minerals, generally including perforation, blasting, mining and loading, transportation, and earth removal operation processes. The open-pit mining has the advantages of full resource utilization, high recovery rate, low dilution rate, and suitability for large-scale mechanical construction.

[0003] A certain super large gold-copper mine is a typical high-sulfide type epithermal deposit, which presents the distribution characteristics of "upper gold and lower copper". The upper gold ore body occurs in the oxidation zone and is composed of a main ore body and several small ore bodies. After years of mining, the gold ore body has been basically exhausted. The copper ore body occurs in the primary zone and is composed of a main ore body and several small ore bodies. The main ore body is an irregular large lens with low-grade ore bodies and waste rock inclusions, poor mineralization continuity, and complex morphology. The overall trend is 320°, the inclination is northeast, the inclination angle is 10°-20° in the middle and shallow part, and 15°-30° in the middle and deep part. In the profile, it presents a right-shaped lateral column distribution with a lateral inclination angle of about 15°-35°, distributed in the 27th line to the 16th line, 1200m long, 1100m wide, and 1.40km2 in area. The main part of the ore body is distributed in the 19th line to the 8th line, 750m long, 850m wide, and distributed in the interval of 650-50m elevation, presenting an irregular "columnar body" with a southwest inclination and a narrow upper part. Some small ore bodies appear in the high-elevation oxidation zone or the edge of the main ore body. The overall distribution of the copper ore body is complex.

[0004] The engineering grid of the mine production resource reserve model has reached 25m (trend) x 50m (inclination), and the local grid has reached 25m (trend) x 25m (inclination). However, due to the complex occurrence of the ore body, the proven resource reserve level engineering grid cannot control the ore body. In addition, the production demand divides the ore types into many categories, the use of whole-penetration whole-blasting technology (that is, penetrating one blast pile for whole-blasting) brings certain difficulties to the loss and dilution management, and may lead to an increase in loss and dilution rate.

[0005] If the parallel to the working slope advancement direction is adopted, different rock types of ore bodies are blasted and loaded separately, and small cutting is used. This method is prone to cause loss of ore resources during mining, and always mixes ore and rock into the crushing production system to some extent, resulting in unqualified products, especially in the position of narrow strip ore body, which is not conducive to the quality matching utilization of resources. Secondly, it is easy to appear root at the ore-rock boundary position, and the loading equipment needs to be frequently moved, which has a great influence on the efficiency of the equipment. Thirdly, the step flatness is not easy to control by using the method of separate blasting and separate mining.

[0006] Therefore, in order to reduce the loss of the dilution rate and improve the mining management level, a more reasonable technical solution needs to be proposed to solve the above technical problems. SUMMARY

[0007] In order to solve the above problems, the application provides a mining method suitable for a complex ore body which is not well identified and a strip mine which is divided into various ore types.

[0008] The mining method of the strip mine of the application comprises the following steps:

[0009] S1, designing hole grid parameters of a mine area according to a mine type and a mine grade, and forming designed blast hole coordinates;

[0010] S2, performing lofting and constructing a down-the-hole drill according to the designed blast hole coordinates;

[0011] S3, sampling rock powder in all blast holes and drawing a blast hole sketch;

[0012] S4, testing the sampled rock powder and filling test results near blast hole positions of the blast hole sketch;

[0013] S5, performing secondary ore delineation on the blast hole sketch according to the test results and performing resource estimation;

[0014] S6, dividing a mine rock boundary line of a mine area on site according to the blast hole sketch;

[0015] S7, optimizing a blasting sequence according to a direction of a free surface of the mine area, performing regional blasting according to the blasting sequence, and respectively performing shovel loading and transportation to different grade ore storage areas or spoil grounds.

[0016] Preferably, hole grid parameters of a gold mine and waste rock area in the S1 step are 6m (hole spacing) x 5m (row spacing), hole grid parameters of a copper mine area are 5.5m (hole spacing) x 4.5m (row spacing), and hole grid parameters of a hard rock mine area which is difficult to blast are 4.8m (hole spacing) x 3.8m (row spacing).

[0017] Preferably, the cross-cutting ditch scraping surface sampling method is used to sample the blast holes in the S3 step.

[0018] Preferably, the number of ore delineation in the S5 step is as follows: (gold containing) high copper (-1, Cu grade ≥ 0.40%), (gold containing) medium copper (-2, 0.40% > Cu grade ≥ 0.30%), (gold containing) low copper (-3, 0.30% > Cu grade ≥ 0.20%), low low copper (-4, 0.20% > Cu grade ≥ 0.15%), waste rock or gold ore (Au grade ≥ 0.15g / t).

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. effectively reduce the loss of dilution rate, improve economic efficiency: loss rate from 1.96% to 1.76%, a decrease of 0.3%; dilution rate from 3.88% to 3.34%, a decrease of 0.54%. According to the plan of 2021, the amount of ore is 1550 million tons, the grade of copper is 0.401%, the loss rate is reduced, and the amount of copper metal recovered is 186.46 tons, which produces economic benefits of about 1212 million yuan (copper price is 65000 yuan / t); the dilution rate is reduced, and 8.37 million tons of waste rock is reduced, which can reduce the cost of 435 million yuan after entering the flotation plant, and the total economic benefit is about 1647 million yuan per year.

[0021] 2. effectively improve the operation efficiency. The efficiency of the whole drilling and blasting technology is improved compared with the drilling and blasting technology, which avoids the back and forth movement of the drilling machine, saves the drilling time and improves the drilling efficiency.

[0022] 3. reduce exploration costs. For the branch complex ore body, the existing engineering network is 25m (towards) x 50m (tendency), and the local 25m (towards) x 25m (tendency) still cannot find out the distribution of the ore body, if the ore body needs to be completely controlled, a large amount of exploration costs should be invested, the whole drilling and blasting technology is adopted, the blast hole is sampled and tested, and the second ore body is circled, which can make up for the insufficient drilling engineering network. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the flow chart of the mining method of the present application;

[0024] Figure 2 is the blast hole design drawing of the present embodiment;

[0025] Figure 3 is the blast hole sketch of the present embodiment;

[0026] Figure 4 is Figure 3 add test results;

[0027] Figure 5 is Figure 4 add ore body, resource reserve estimation and ore-rock boundary;

[0028] Figure 6 is Figure 5 digital map. DETAILED DESCRIPTION

[0029] The present application will be further described in detail below in combination with the drawings and specific embodiments:

[0030] Please refer to Figure 1 , the mining method of the open pit mine of the present embodiment, comprising the following steps:

[0031] Based on the latest grade status map and bench grade distribution map, and considering the spatial distribution patterns of the ore body, the S1 blasting management personnel implemented separate blasting and drilling in areas where the planned blasting area consisted entirely of ore or waste rock. In areas with complex ore and rock distribution that did not meet the requirements for separate blasting and drilling, whole blasting and separate blasting were implemented. The mine adopted different borehole parameters for blasting based on the approximate gold, copper, and waste rock areas. For example, the borehole parameters for gold and waste rock areas were 6m (hole spacing) × 5m (row spacing), while the general borehole parameters for copper ore areas were 5.5m (hole spacing) × 4.5m (row spacing). In areas with hard, difficult-to-blast rock and ore, the borehole parameters were adjusted to 4.8m (hole spacing) × 3.8m (row spacing). For example, the 556B2027 blast pile was a medium-to-low grade copper ore body before the borehole design, with proven reserves. The drilling control grid reached 25m (strike) × 25m (dip). Therefore, the borehole grid parameters were designed according to 5.5m (hole spacing) × 4.5m (row spacing), see... Figure 2 .

[0032] S2 surveyors laid out the borehole coordinates according to the design; drilling personnel drilled down-the-hole drills according to the borehole locations, preserving the rock powder intact to avoid contamination between samples.

[0033] S3 geological sampling personnel used the "cross-groove scraping sampling method" to sample the blast holes, taking one sample per hole. During sampling, a triangular pickaxe was used to evenly create a cross-shaped groove in the rock powder pile within the blast hole, ensuring the groove reached the surface. Rock powder was then evenly scraped from the groove wall using a sample spoon, 3-5 spoonfuls from each side of the groove, for a total of 8 sides. The scraping order was from the bottom of the groove upwards and from the inside out. The scraped rock powder was placed in a clean sample bag, labeled with the sample number, and the bag was secured to prevent sample contamination. Single-sided and double-sided sampling were compared for each groove, and the sample weight should be greater than 4 kg. Simultaneously, a blast hole sketch was drawn based on the blast hole location, such as... Figure 3 Please fill in relevant information such as sampling time, borehole time, sampling personnel, engineering company, sampling location, borehole number, blast pile number, hole depth, hole direction, and number of designed holes.

[0034] S4 will send the collected samples from the blast borehole to the testing company for analysis. The sampling personnel will record the test results below the borehole location. Numbers with a percentage indicate copper ore grade, while numbers only indicate gold ore grade. If the gold grade is less than 0.10 g / t, the test results do not need to be copied onto the graph; instead, use color coding to distinguish the grade. See [link / reference]. Figure 4 .

[0035] S5 The geologist circles the ore according to the blast hole test results, and divides it into high copper (-1, Cu grade >= 0.40%), medium copper (-2, 0.40%> Cu grade >= 0.30%), low copper (-3, 0.30%> Cu grade >= 0.20%), low-low copper (-4, 0.20%> Cu grade >= 0.15%), waste rock or gold ore (Au grade >= 0.15g / t). Figure 5 , 556B2027 blast pile divides three areas, one high copper, one rock, and one low-low copper. After the circle is completed, the blast hole sketch is digitized, and resource estimation is performed for different types of ore, and waste rock is not estimated (see Figure 6 ), and the resource reserve estimation results are filled into the IDS reserve calculation results of Figure 5 .

[0036] S6 The geologist divides the ore and rock boundary of the blast pile on site according to the blast hole sketch.

[0037] S7 According to the direction of the free surface of the blast pile, the blasting sequence is reasonably arranged, such as Figure 5 It can be seen that the high copper area is preferentially blasted, and the shovel loading and transportation are transported to the draw well or the plant; then the waste rock area is blasted, and the shovel loading and transportation are transported to the dump; and then the low-low copper area is blasted, and the shovel loading and transportation are transported to the low-low copper stacking area.

[0038] The present application provides a mining method suitable for complex ore bodies that have not been thoroughly investigated, and divides various ore types in open-pit mines. The application has the following advantages:

[0039] 1. Effectively reduce the loss and dilution rate, and improve economic benefits: the loss rate is reduced from 1.96% to 1.76%, a decrease of 0.3%; the dilution rate is reduced from 3.88% to 3.34%, a decrease of 0.54%. According to the 2021 annual plan, 15.5 million tons of ore with a copper grade of 0.401% are mined, the reduction of loss rate can recover 186.46 tons of copper metal, and generate economic benefits of about 12.12 million yuan (copper price is calculated at 65,000 yuan / t); the reduction of dilution rate can reduce the mixing of waste rock by 83,700 tons, and after entering the flotation plant, the treatment cost per ton of ore is 52 yuan / t, which can reduce the cost by about 4.35 million yuan, a total of about 16.47 million yuan per year.

[0040] 2. Effectively improve the operation efficiency. The whole drilling and blasting technology has certain improvement in efficiency compared with the split drilling and blasting technology, avoids the back and forth movement of the drilling machine, saves the drilling time, and improves the drilling efficiency.

[0041] 3. Reduce exploration costs. For branch complex serious ore body, the existing engineering network degree 25m (towards) x 50m (tendency), local 25m (towards) x 25m (tendency) still can not detailedly find out the ore body distribution, if want to completely control the ore body, should need to invest huge exploration costs, using the whole wear branch blasting technology, sampling and testing of blast hole, then secondary ore exploration, can make up the shortage of drilling engineering network.

[0042] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A mining method for an open-pit mine, characterized in that, Includes the following steps: Based on the latest grade status map and bench grade distribution map, and combined with the spatial distribution pattern of the ore body, the S1 drilling and blasting management personnel will carry out separate drilling and blasting in areas where the planned advancement area consists entirely of ore or waste rock, and carry out whole drilling and separate blasting in areas where the ore and rock distribution is complex and does not meet the requirements for separate drilling and blasting; based on the type and grade of ore, the borehole network parameters of the mining area will be designed to form the design borehole coordinates. S2 performs layout and down-the-hole drilling based on the designed borehole coordinates; S3 samples rock powder from all boreholes and draws a sketch of the boreholes; S4 will test the rock powder and fill in the test results near the location of the blast hole on the blast hole sketch. The test results include the copper ore grade and the gold ore grade. S5 performs secondary delineation of the borehole sketch based on the test results. The delineation values ​​are as follows: high copper gold content - Cu grade ≥ 0.40%, medium copper gold content - 0.40% > Cu grade ≥ 0.30%, low copper gold content - 0.30% > Cu grade ≥ 0.20%, very low copper gold content - 0.20% > Cu grade ≥ 0.15%, waste rock or gold ore - Au grade ≥ 0.15 g / t. Resource estimation is then performed, and the resource reserve estimation results are filled into the IDS reserve calculation results. S6. Based on the aforementioned blast hole sketch, the mining area is demarcated on-site to define the ore-rock boundary. S7 optimizes the blasting sequence based on the direction of the free face of the mining area, and performs blasting in different areas according to the blasting sequence, and then loads and transports the ore to storage areas or spoil heaps of different grades.

2. The mining method for open-pit mines according to claim 1, characterized in that, In step S1, the aperture parameters for the gold mine and waste rock areas are 6m (aperture spacing) × 5m (row spacing), the aperture parameters for the copper mine area are 5.5m (aperture spacing) × 4.5m (row spacing), and the aperture parameters for the rock and ore areas that are hard and difficult to blast are 4.8m (aperture spacing) × 3.8m (row spacing).

3. The mining method for open-pit mines according to claim 1, characterized in that, In step S3, the "cross-grooving and scraping sampling method" is used to sample the blast holes.

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