Safety measures for non-coal mine stope and slope stability

February 04 10:08:13, 2024

To achieve the stope and the stability of the slope, first requires preliminary design of the selected technical parameters meet the requirements, according to the "open-air metal nonmetal mine safety regulations" and "small quarry production safety Interim Provisions" determine the parameters as follows:

1. The stage height should meet the requirements of Table 7-1.

If the stage height exceeds the requirements of Table 7-1, it must be technically demonstrated and approved by the competent authority on the premise of ensuring safety. When the excavator or front-loading machine is installed, the height of the explosion should not exceed 1.5 times the maximum excavation height of the machine. Mechanical mining, generally not more than 20m.

Table 7-1 Determination of stage height

Mineral rock properties
Mining operation
Stage height
Soft rock
Mechanical shovel
Not blasting
Not more than the maximum digging height of the machine
Hard and stable ore
blasting
Not more than 1.2 times the maximum digging height of the machine
Sandy ore
Artificial mining
Not more than 1.8m
Soft ore
Not more than 3.0m
Hard and stable ore
Not more than 6.0m

2. Minimum platform width regulations (Table 7-2)

Table 7-2 Minimum Platform Width Regulations

Mining use
Artificial mining (m)
Mechanical mining
Security platform
2
3 to 6
Work platform
3 (not including the explosion width)
According to equipment requirements
Transportation platform
4
According to equipment requirements
Cleaning platform
4
According to the cleaning method and equipment

3. Slope angle regulations (Table 7-3)

Table 7-3 Slope angle regulations

Mining height
(Meter)
Rock hardness
Coefficient (f)
Final slope angle (o)
Step slope angle (o)
Below 90 meters
Below 180 meters
Below 240 meters
300 meters or less
15~20
60～80
57-65
53~60
48~54
70-75
8~14
50~60
48～57
45～53
42~48
65~70
3~7
43～50
41~48
39～45
36~42
60～65

(1) Safety technical countermeasures

1. According to the requirements of “Safety Regulations for Metallic Non-Metal Open-pit Mines” and “Interim Provisions for Safety Production of Small Open-pit Quarry”, the height of the steps selected by the project is not more than 6 meters, and the width and slope angle meet the requirements of the regulations.

2, surface drainage

Drainage is provided on the surface to prevent surface water from seeping into the slope, thus preventing landslides and collapses along the fracture surface.

3. When approaching the final slope, the safety and transportation platform must be reserved according to the width determined by the design. To maintain the safe slope angle of the stage, the bottom of the slope must not be overtaken.

4. It is found that the slope angle becomes steep and the lithology and stability of the slope rock mass change. When the structural structure surface appears, measures should be taken in time to adjust the slope angle by using the method of slope reduction and load reduction to achieve safe production.

5. Controlled blasting technology is applied to the adjacent slope to reduce the impact of blasting on the slope.

(2) Safety management measures

1. Establish and improve the slope management and inspection system, and deal with key areas and potential landslide hazards.

2. The slope should be regularly observed at fixed points, and the danger should be dealt with in a timely manner.

3. Set up a special agency or assign a special person to carry out daily management of the slope.

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