Investigation and disposal of hidden danger of open-pit mine slope and dump

In order to achieve the desired effect, it is necessary to accurately understand the depth and shape of the main sliding surface of slope deformation and failure before grouting, so that the grouting pipe can go down to a favorable position below the sliding surface. The grouting pipe can be installed in the grouting hole or directly driven.

(5) Control blasting method

At present, high step, large diameter hole and high explosive are widely used in mines, which effectively reduces the mining cost. But these measures also cause the energy concentration in the blasting area, which leads to the serious back-thrust rupture of the final slope.

The controlled blasting methods commonly used in open-pit mines include shock absorbing blasting, buffer blasting, pre-cracking blasting and linear hole row. These methods are designed to produce a low explosive energy concentration per square meter of the slope surrounding the open pit, while controlling the energy concentration of the production blasting so as not to destroy the final slope.

1. Damping blasting

Damping blasting is the simplest method of controlled blasting. This method is often used in conjunction with some other controlled blasting technique, such as pre-split blasting.

2. Buffer blasting

Buffer blasting is blasting along pre-designed excavation limits, but these buffer blasting holes are detonated after the main production blasting holes are blasted. The purpose of buffer blasting is to trim or trim excess rock from the side to improve the stability of the slope.

In order to achieve the best buffer effect, all buffer holes should be detonated at the same time. In the hard rock, the exposed slope surface after blasting is smooth and clean, and the residual hole marks are clearly visible.

3. Presplitting blasting

Presplitting is one of the most successful and widely used controlled blasting methods to protect the presplitting line from the effects of production blasting. A row of densely spaced blasting holes with a small charge is detonated prior to the production blasting so that a continuous open crack is formed along the design excavation limit to escape the expanding gas produced by the production blasting.

The purpose of pre-cracking blasting is to charge specific rocks and hole spacing in a special way, so that the pressure of the hole wall can burst rocks, but still does not exceed their in-situ dynamic compressive strength, and the rock around the blasting hole does not crush. Reducing the burst pressure can be achieved by using uncoupled charges, spaced charges or low density explosives.

5. Safety inspection of waste dump

(1) Safety inspection of the dump

The discharge parameters include: the height of each type of dump, the length of the discharge line, the reverse slope of each type of dump, the bottom width, top width and height of the safety retaining wall of the automobile dump, the slope and curvature radius of the railway dump line, the distance between the excavator and the top line of the standing step slope, and the distance between the outside track of the dump machine and the top line of the step slope. In accordance with the "metal and non-metal mine dump safety production rules".

Check the dump for landslides. The position, scope, shape, dynamic trend and cause of landslide should be checked when the landslide occurs in the dump.

(2) Inspection of drainage structures and flood control safety of waste dumps

1. The main contents of the safety inspection of the drainage structure include: whether the structure is deformed, displaced, damaged, silting, and whether the drainage capacity meets the requirements.

2. The inspection contents of the section of the flood interception ditch include: the section size of the flood interception ditch, the landslide and collapse along the hillside, the deformation, damage, fracture and abrasion of the protective wall, and the blockage of the material in the ditch.