Stope structure parameter optimization method

Abstract

The invention discloses a stope structure parameter optimization method which comprises the following steps: under the condition that a two-step stope roof in an abnormal region IV is supported by a long anchor cable system, the stope length can be 40m; under the condition that local support measures are taken, the length of the stope can be 22 m; iII, under the span of 15m and 13m, supporting the stope roof by adopting a long anchor cable system, and enabling the stope length to be 40m; the method has the advantages of being better in safety, improving efficiency and the like.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing, and in particular to a method for optimizing stope structure parameters. Background Art

[0002] The Secretary Gou Iron Mine is located in Zhangerkouzi Village, two kilometers west of Xiaoshetai Town, Urad Front Banner, Bayannur City, Inner Mongolia Autonomous Region. The geographical coordinates of the center of the mining area are: longitude: 109°28′30″, latitude: 41°09′46″; the iron ore bodies in the mining area are located in the gneiss section of the Serteng Mountain Group, and the main lithology is plagioclase amphibolite gneiss and mixed rock plagioclase. The mining area is divided into four abnormal areas, Ⅰ, Ⅱ, Ⅲ, and Ⅳ. Among them, the mining of ore bodies in abnormal areas Ⅰ and Ⅱ shares a production system, numbered as mining area 1; the mining of ore bodies in abnormal areas Ⅲ and Ⅳ shares a production system, numbered as mining area 2. The production systems of mining areas 1 and 2 are relatively independent. All are being mined, with ore bodies ranging in elevation from 1360m to 780m. The ore bodies in abnormal areas III and IV are nearly east-west in direction, with a total east-west length of about 1270m and a north-south width of about 530m. The second mining area is dominated by thick ore bodies, with medium-thick and thin ore bodies accounting for a smaller proportion, and are steeply inclined ore bodies. The mine design determines that thick ore bodies (thickness > 15m) will adopt the segmented rock drilling and segmented empty site subsequent filling mining method perpendicular to the ore body direction, and medium-thick ore bodies (thickness <15m) will adopt the segmented rock drilling and segmented empty site subsequent filling mining method along the ore body direction.

[0003] The design of stope structure parameters lacks theoretical basis. The stope structure is designed based on "empirical method" and "engineering analogy method", which leads to the current stope structure parameters of the mine being unable to ensure the balance of ground pressure caused by mining. There are problems such as poor stability of the stope and strong ground pressure. The stope roof collapses seriously. The unreasonableness of the stope structure parameters in abnormal areas III and IV is mainly manifested in the following aspects:

[0004] (1) When designing the stope structure parameters, the design concept of the approach-type backfill mining method was followed. The main focus was on the stope span, and the effect of the stope length on the stability of the stope surrounding rock was ignored. Therefore, the stope length of the mine is generally determined according to the thickness of the ore body, which lacks a theoretical basis. In addition, after the first-step mine room is mined, the second-step pillar will change from a three-way stress state to a two-way stress state, and the destructive strength of the rock mass itself will decrease. In addition, due to the damage induced by blasting disturbance and the concentration of mining stress, the two sides of the first-step stope (the second-step pillar) are extremely easy to become unstable, causing a large-scale collapse of the two sides of the stope. The collapse of the two sides will lead to an increase in the span of the goaf, which will in turn cause the stope roof to collapse.

[0005] (2) The impact of factors such as the deterioration of rock mass quality caused by excavation disturbance in the second-step stope (including mining stress concentration, rock mass damage caused by blasting damage), changes in the stress environment, and changes in surrounding rock conditions were ignored. The structural parameters of the first-step stope were still used, resulting in serious roof collapse in the stope. Although the mine appropriately reduced the stope size in subsequent production practice, there was a lack of theoretical basis. Summary of the invention

[0006] The invention discloses a method for optimizing stope structure parameters to solve the defects of the prior art mentioned in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for optimizing stope structure parameters, comprising the following steps:

[0008] (1) Conduct on-site engineering geological surveys of the mining areas and tunnels: Conduct rock mass structural surface information surveys and core surveys at 1200m, 1140m, 1120m, 1080m, and 1030m in abnormal mining areas III and IV, and analyze the investigated joints using DIPS5.1 software;

[0009] (2) Rock mechanics test: The physical and mechanical properties of the surrounding rocks and ore bodies in the upper and lower plates of the anomaly zones III and IV were tested and analyzed. The rock samples used in the test were chlorite schist blocks and magnetite quartzite blocks collected from the anomaly zones III and IV. The rock blocks had no obvious joints and cracks and had good integrity. The samples were subjected to uniaxial compression tests, Brazilian splitting tests, and shear tests using a hydraulic universal testing machine.

[0010] (3) Estimation of geostress in abnormal areas III and IV: Based on the measured vertical stress data, a scatter plot of the vertical stress and horizontal stress distribution with depth is made and estimated;

[0011] (4) Rock mass quality classification in abnormal areas III and IV: Based on the results of engineering geological survey and rock mechanics tests, the rock mass quality (Q) classification evaluation method of Barton rock mass, rock mass geomechanical classification index value (RMR), and geological strength index (GSI) are used to classify the rock mass quality of abnormal area IV.

[0012] (5) Estimation of rock mass mechanical parameters in abnormal areas III and IV: Based on the classification of engineering rock mass, empirical relationships are established to determine rock mass mechanical parameters, and rock mass mechanical characteristic indicators close to the actual ones are obtained for engineering rock mass calculations;

[0013] (6) Optimization method of stope structure parameters in IV abnormal area:

[0014] ①IV The process of solving the roof stability number N' of abnormal mining area is as follows: determination of rock mass quality index Q' value, stress coefficient A value, joint occurrence adjustment coefficient B, gravity adjustment coefficient C,;

[0015] ②Ⅳ Abnormal stope roof hydraulic radius: Under the conditions that the stope height H and stope span W are determined, the stability of the stope roof is determined in combination with the rock mass quality classification and the results of the on-site investigation, and the roof hydraulic radius is determined according to the improved stability diagram of Nickson and Hadjigeorgiou;

[0016] ③ Stability analysis of abnormal stope IV: According to the size of abnormal stope IV, a numerical calculation model is established, and the Hawke-Brown strength criterion is used as the failure criterion for judgment;

[0017] (7) Optimization method of stope structure parameters in abnormal area III:

[0018] ① Determine the maximum span of the stope based on the empirical chart method of rock mass quality classification;

[0019] ② Calculation of stope length in abnormal area III: Under the condition that stope height H and stope span w are determined, the stability of stope roof is determined in combination with rock mass quality classification and field investigation results, and the hydraulic radius of the roof is determined according to the improved stability diagram of Nickson and Hadjigeorgiou;

[0020] ③ Stability analysis of the stope in abnormal area III: According to the size of abnormal stope III, a numerical calculation model is established, and the Hawke-Brown strength criterion is used as the failure criterion for judgment.

[0021] The beneficial effects of adopting the above technical solution are:

[0022] In this application, the length of the second-step mining area in abnormal zone IV can be 40m under the condition of adopting a long anchor cable system to support the mining area roof; under the condition of taking local support measures, the length of the mining area can be 22m; in abnormal zone III, the mining area roof is supported by a long anchor cable system under spans of 15m and 13m, and the length of the mining area can be 40m; by optimizing the mining area parameters in the abnormal zone, the efficiency is improved while improving safety. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below:

[0024] A method for optimizing stope structure parameters comprises the following steps:

[0025] (1) Conduct on-site engineering geological surveys of the mining areas and tunnels: Conduct rock mass structural surface information surveys and core surveys at 1200m, 1140m, 1120m, 1080m, and 1030m in abnormal mining areas III and IV, and analyze the investigated joints using DIPS5.1 software;

[0026] (2) Rock mechanics test: The physical and mechanical properties of the surrounding rocks and ore bodies in the upper and lower plates of the anomaly zones III and IV were tested and analyzed. The rock samples used in the test were chlorite schist blocks and magnetite quartzite blocks collected from the anomaly zones III and IV. The rock blocks had no obvious joints and cracks and had good integrity. The samples were subjected to uniaxial compression tests, Brazilian splitting tests, and shear tests using a hydraulic universal testing machine.

[0027] (3) Estimation of geostress in abnormal areas III and IV: Based on the measured vertical stress data, a scatter plot of the vertical stress and horizontal stress distribution with depth is made and estimated;

[0028] (4) Rock mass quality classification in abnormal areas III and IV: Based on the results of engineering geological survey and rock mechanics tests, the rock mass quality (Q) classification evaluation method of Barton rock mass, rock mass geomechanical classification index value (RMR), and geological strength index (GSI) are used to classify the rock mass quality of abnormal area IV.

[0029] (5) Estimation of rock mass mechanical parameters in abnormal areas III and IV: Based on the classification of engineering rock mass, empirical relationships are established to determine rock mass mechanical parameters, and rock mass mechanical characteristic indicators close to the actual ones are obtained for engineering rock mass calculations;

[0030] (6) Optimization method of stope structure parameters in IV abnormal area:

[0031] ①IV The process of solving the roof stability number N' of abnormal mining area is as follows: determination of rock mass quality index Q' value, stress coefficient A value, joint occurrence adjustment coefficient B, gravity adjustment coefficient C,;

[0032] ②Ⅳ Abnormal stope roof hydraulic radius: Under the conditions that the stope height H and stope span W are determined, the stability of the stope roof is determined in combination with the rock mass quality classification and the results of the on-site investigation, and the roof hydraulic radius is determined according to the improved stability diagram of Nickson and Hadjigeorgiou;

[0033] ③ Stability analysis of abnormal stope IV: According to the size of abnormal stope IV, a numerical calculation model is established, and the Hawke-Brown strength criterion is used as the failure criterion for judgment;

[0034] (7) Optimization method of stope structure parameters in abnormal area III:

[0035] ① Determine the maximum span of the stope based on the empirical chart method of rock mass quality classification;

[0036] ② Calculation of stope length in abnormal area III: Under the condition that stope height H and stope span w are determined, the stability of stope roof is determined in combination with rock mass quality classification and field investigation results, and the hydraulic radius of the roof is determined according to the improved stability diagram of Nickson and Hadjigeorgiou;

[0037] ③ Stability analysis of the stope in abnormal area III: According to the size of abnormal stope III, a numerical calculation model is established, and the Hawke-Brown strength criterion is used as the failure criterion for judgment.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for optimizing stope structure parameters, characterized in that: The method comprises the following steps: (1) conducting on-site engineering geological surveys of the mining areas and tunnels: conducting investigations on the rock mass structural surface information and core investigations of the III and IV abnormal mining areas, and analyzing the investigated joints using the DIPS5.1 software; (2) rock mechanics tests: conducting physical and mechanical property parameter tests and analyses on the upper and lower wall surrounding rocks and ore bodies of the III and IV abnormal areas. The rock samples used in the tests are chlorite schist blocks and magnetite quartz blocks collected from the III and IV abnormal areas. The rock blocks have no obvious joints and fissures and have good integrity. A hydraulic universal testing machine is used to conduct uniaxial compression tests, Brazilian splitting tests and shear tests on the samples; (3) Estimation of geostress in abnormal areas III and IV: Based on the measured vertical stress data, a scatter plot of the vertical stress and horizontal stress distribution with depth is made and estimated; (4) Rock mass quality classification in abnormal areas III and IV: Based on the results of engineering geological survey and rock mechanics tests, the rock mass quality (Q) classification evaluation method of Barton rock mass, rock mass geomechanical classification index value (RMR), and geological strength index (GSI) are used to classify the rock mass quality of abnormal area IV. (5) Estimation of rock mass mechanical parameters in abnormal areas III and IV: Based on the classification of engineering rock mass, empirical relationships are established to determine rock mass mechanical parameters, and rock mass mechanical characteristic indicators close to the actual ones are obtained for engineering rock mass calculations; (6) Optimization method of stope structure parameters in abnormal area Ⅳ: ①IV The process of solving the roof stability number N' of abnormal mining area is as follows: determination of rock mass quality index Q' value, stress coefficient A value, joint occurrence adjustment coefficient B, gravity adjustment coefficient C,; ②Ⅳ Abnormal stope roof hydraulic radius: Under the conditions that the stope height H and stope span W are determined, the stability of the stope roof is determined in combination with the rock mass quality classification and the results of the on-site investigation, and the hydraulic radius of the roof is determined according to the stability diagram improved by Nickson and Hadjigeorgiou; ③ Stability analysis of abnormal stope IV: According to the size of abnormal stope IV, a numerical calculation model is established, and the Hawke-Brown strength criterion is used as the failure criterion for judgment; (7) Optimization method of stope structure parameters in abnormal area III: ① Determine the maximum span of the stope based on the empirical chart method of rock mass quality classification; ② Calculation of stope length in abnormal area III: Under the conditions that stope height H and stope span w are determined, the stability of stope roof is determined in combination with rock mass quality classification and field investigation results, and the hydraulic radius of the roof is determined according to the stability diagram improved by Nickson and Hadjigeorgiou; ③ Stability analysis of the stope in abnormal area III: According to the size of abnormal stope III, a numerical calculation model is established, and the Hawke-Brown strength criterion is used as the failure criterion for judgment.

2. A method for optimizing stope structure parameters according to claim 1, characterized in that: A rock mass structural surface information survey and core survey were conducted at 1200m, 1140m, 1120m, 1080m and 1030m in abnormal mining areas III and IV.