Vertical deep hole falling mine sublevel caving mining method typical plan - mining work

The mining work mainly includes mining and mining work.

(1) Mining work

1) Falling ore generally adopts medium or deep holes or deep holes (multiple use of medium and deep hole falling ore). The YG-80 rock drill is often used, and the rock drilling work is carried out with the FJY-24 type garden snow truss. If deep holes are used, use the YQ-100 DTH drill .

2) This mining method is widely used for extrusion blasting.

1 The essence of extrusion blasting—Extrusion blasting is a blasting method in which the ore is not fully loose during the process of caving, and it is necessary to use blasting to squeeze adjacent loose bodies to obtain compensation space.

2 Classification of extrusion blasting

According to the method of obtaining the compensation space, it can be divided into the following two types: the side extrusion blasting and the small compensation space extrusion blasting.

(1) Lateral extrusion blasting - it is to compensate the space by squeezing the loose layer by the impact force during blasting. Its looseness coefficient is generally less than 1.2. (K _p <1.2).

(2) Small compensation space extrusion blasting - it is to pre-cut a certain number of roadways or diverticulum in the ore body to be blasted as the compensation space for extrusion and blasting. The looseness coefficient of the caving ore is generally not more than 1.2 to 1.3 (i.e., K _p < 1.2 to 1.3).

Compared with free space blasting, squeeze blasting reduces the amount of compensation and improves the blasting effect.

3 Main parameters and process of extrusion blasting
(1) Parameters and processes during lateral extrusion blasting

(a) Loose ore

The purpose of loosening ore-mining--loose ore is one of the important prerequisites for lateral extrusion blasting. The purpose of loosening the ore is to loosen the ore, so that the extruded ore is brought to a normal loose state, so as to create conditions for the next extrusion.

The amount of loose ore-mining - loose ore can not be too large or too small. Too small will cause "over-squeezing". When too large, the blasting effect cannot be fully exerted.

According to the experience of mine production in China, it is known that the amount of loose ore is generally controlled at 15-20%. E.g

The loose ore deposit of the Zhuzigou Mine is 20%, the Huxiang Mine is 18%, and the Yimen Mine Shishan Pit is 15%.

When the amount of minerals carried by each funnel is different, it should be noted that the funnel with more ore is placed more, and the funnel with less or less minerals is less. It is better to achieve loose parts.

(b) First row of blastholes

When multiple rows of holes are subjected to differential blasting, the blasting of the first row of holes is extremely important. In addition to the collapse of the ore in this layer, it is necessary to compensate for the blasting of the subsequent rows of blastholes. . That is to say, the compensation space is mainly caused by the blasting of the first row of holes. Therefore, the first row of holes is an important factor affecting the effect of extrusion blasting. The first row requires a large amount of blasting energy to compensate for the energy absorbed by the loose ore and to squeeze out the necessary compensation space for the loose ore.

In order to strengthen the first row of holes, "strengthening rows" are often used. That is, at the 0.4 to 0.6 meters after the first row of holes, a row of holes having the same parameters is added, and the first row of holes is detonated.

[Reference] Some mines will increase the minimum resistance line W value of the first row of holes from 1.8 meters to 2.0 meters, and some to 2.5 meters.

(c) a layer of collapse (ie, the step size of the collapse)

Increasing the thickness of a collapsed layer, that is, increasing the amount of blasting, can reduce the number of blasting and the corresponding auxiliary workload, make full use of the squeezing effect during blasting, and improve the blasting quality.

However, increasing the thickness of a collapse layer is limited. If the thickness of a collapsed layer is too large, it will produce "over-squeezing", and in severe cases, it may cause the consequences of refusal. If the thickness of a collapsed layer is too small, the number of blasting will increase.

The thickness of a collapsed layer is related to various factors such as the thickness of the ore body, the structure of the mining method, and the organization and management. According to experience, the thickness of a collapsed layer is 10-20 meters.

[Reference]: When the lateral extrusion blasting, the example of the mine from the collapse of the mine, the Zhuzigou Mine: 15 to 18 meters; the Huxiang Mine: 6 to 13 meters, the Yimen Mine Lion Mountain Pit is 20 meters.

(2) Small compensation space extrusion blasting

Small compensation space extrusion blasting is also called restricted space extrusion blasting. Small compensation space extrusion blasting is relative to free space extrusion blasting. The small compensation space is squeezed, and the blasting method is artificially provided with 10 to 20% of the compensation space. (And free space blasting is artificially providing 30% of the compensation space). It does not allow the caving ore to be loose enough to be squeezed. This type of blasting is to cut one or several cutting vertical grooves in advance, usually formed in the same stage as the falling mine.

The advantages of small compensation space extrusion blasting are:

1 is not subject to the constraints of adjacent stopes;

2 The amount of blasting can be large, small and flexible;

3 This method is highly independent and can be applied in addition to ore with high cohesiveness.

Advantages: The small compensation space extrusion blasting is less than the free space extrusion blasting, and the mining quality can be improved.

Disadvantages: 1 The amount of mining and cutting engineering is large (15 ~ 22 m / thousand tons); 2 the complex structure of the stope is poor.

Applicable conditions for small compensation space extrusion blasting:

Most of the ore used is relatively broken, loose and difficult to form compensation space, or the conditions of the initial return to the mining block during lateral extrusion and blasting.

(2) Mining work

It is usually mined with electricity. (Now some mines have the tendency to use high-power electric shovel to shorten the transportation distance. Use 50~100KW electric 耙)