Coal mine knowledge training materials - Minefield development section

The first section of minefield and minefield subdivision

First, the coal field is divided into minefield

In the process of geological history development, a substantially continuous large-area coal-bearing zone formed by the deposition of carbonaceous materials is called a coal field. There are large and small coal fields. The large coal fields can reach hundreds to tens of thousands of square kilometers, and the coal reserves range from hundreds of millions of tons to tens of billions of tons. This large coal field with abundant reserves is called “rich coal fields”. For a "rich coal field", if it is mined by a mine, it is not only economically unreasonable, but also technically difficult to achieve. Therefore, it is necessary to divide the coal field into several areas suitable for mining by one mining area (or one mine).

Develop a social area formed by coal fields and become a mining area. Large coal fields are often divided into several mining areas for development, and coal fields with smaller areas and reserves can also be developed by one mining area.

The scope of the mining area is still very large and needs to be further divided into minefields according to the coal reserves and the conditions of occurrence. In the mining area, the part of the coal field that is assigned to a mine is called the mine field (mine field).

(1) Principles of well field division

When the coalfield is divided into minefields, it is necessary to ensure that each minefield has a reasonable size and realm, so that all parts of the coalfield can be reasonably developed.

1. Make full use of natural conditions

Possible use of large faults and other natural conditions as Ida boundary, or the use of rivers, railways, safety coal pillar leaving in the following cities and towns as Ida boundary. This will not only reduce the loss of coal pillars, increase the coal mining rate, but also reduce the difficulties caused by mining work, and also help protect the ground facilities, as shown in Figure 2-1.

Figure 2-1 Using natural conditions as a well boundary

1-river; 2-coal outcrop; 3-town; 4-rail; 5-large fault; 6-small coal mine; one to nine-divided mine

2. Have a reasonable length

The well field range must be compatible with the mine production capacity to ensure that the mine has sufficient reserves and reasonable well field parameters, especially to have a reasonable strike length. In general, the length of the field should be greater than the length of the slope. If the length of the mine field is too short, it is difficult to ensure that the mine has sufficient reserves and reasonable service life for each mining level, resulting in tight production success of the mine; or in this case, sufficient service life to ensure the mining level to make the stage (horizontal) height Increased will bring difficulties to mine production. The length of the mine field is too long, which will bring difficulties to the ventilation and underground transportation of the mine. Therefore, in the case of a certain mine production capacity, the length of the mine field is too long or too short, which will reduce the economic benefits of the mine. The reasonable length of mine field in China at present is generally: small mine is not less than 1500m; medium mine is not less than 4000m; large mine is not less than 7000m.

3. To handle the relationship between adjacent well fields

When dividing the boundary of the well field, the coal seam is usually not inclined, and the coal field extending along the slope is divided into two parts: the shallow part and the deep part. Generally, it should be shallow and deep, first easy and difficult, and separately develop wells to save initial investment, while avoiding complex pressure relationships in shallow and deep mines. The shallow mine well type and range can be smaller than the deep mine.

When it is necessary to increase the development intensity, it is necessary to build wells at the same time in the shallow and deep parts or to develop the existing mines in the shallow part. When a new well is to be built in the deep, it should be considered to leave room for the development of the shallow mine, and the shallow mine should not be prematurely scrapped.

4. There is room for development of the mine

After the mine is put into operation, the production capacity of the mine is often increasing during the service period of several decades. Therefore, when dividing the mine field, factors such as coal seam occurrence conditions and technological development trends should be fully considered, and the well field should be properly drawn. Larger or reserved for the mine, leaving ample room for the development of the mine.

5. Have a good safety and economic effect

When dividing the mine field, we must strive to make the mine have a reasonable development method and coal mining method, which is convenient for selecting the wellhead location and the ground industrial site, which is conducive to the protection of the ecological environment, the small amount of wells and lanes, the investment, the short construction period, and the production. The working environment is good, safe and reliable, laying a good foundation for the coal mine enterprises to obtain the maximum economic and social benefits.

(2) Method of dividing the realm of minefield

In addition to using natural conditions as the realm of the minefield, it is often necessary to use artificial methods to determine the realm of the well field when it is not subject to other conditions. The method of dividing the artificial boundary is usually divided into vertical division, horizontal division, division by coal group and division by natural condition.

Vertical division

Figure 2-2 Method of dividing the boundary of the well field

1-vertical division; 2-level division; 3-based on fault

Adjacent mines are bounded by a vertical plane, and the coal pillars at the boundary of each well along the boundary line are called vertical division. The well field is along the striker ends and is generally divided by vertical planes along inclined lines, exploration lines or parallel exploration lines. As shown in Figure 2-2, the boundary between the first and second mines and the left wing of the three mines is. Near-horizontal coal seam wells adopt vertical division method whether they are along the trend or along the trend.

2. Horizontal division

The coal seam floor contour line with a certain elevation is bounded, and the boundary coal pillar is placed along the coal seam floor contour line. This method is called horizontal division. In Figure 2-2, the upper and lower boundaries of the Minmetals field are bounded by the -300m and -600m contour lines respectively. This method is mostly used to divide the inclined and steep coal seams and the gently inclined coal seams with large dip angles. Upper and lower boundaries.

3. Classified by coal group

The mining boundary is divided according to the size of the coal seam (group) spacing, that is, the adjacent coal seams with smaller coal seam spacing are classified into one mine, and the coal seams (groups) with larger interlayer spacing are classified into another mine. This method is generally used in coal mines or coal groups with large spacing and shallow coal mining areas. In Figure 2-3, one mine and two mines divide the mine boundary by coal group and build well at the same time.

The mining industry can also be divided according to geological structural conditions. For example, faults are used as mining boundaries, and each mine retains coal pillars along the fault line. In Figure 2-3, the mining boundary between the three mines and the first and second mines is the right-wing boundary of the second and third mines in Figure 2-2.

It should be pointed out that no matter what method is used to divide the realm of the well field, it is necessary to make the realm of the well field tidy and avoid the difficulty of mining due to the staggered teeth.

Figure 2-3 Division of mining boundaries and grouping and centralized construction

1. 2, shallow part is set up to construct inclined well; 3 - deep is concentrated to establish well

Second, the subdivision of the mine field

(1) The well field is divided into stages or panels

The range of a mine field is quite large, and its strike length can range from several kilometers to more than 10,000 meters, and the length can reach several kilometers. Therefore, the well field must be divided into several smaller parts in order to carry out the mining in an orderly manner.

1. Division and characteristics of the stage

In the field of well fields, along the oblique direction of the coal seam, the coal seam is divided into a number of strips parallel to the strike at a certain elevation, each strip has an independent production system, called a stage. The length of the strike of the well is the length of the strike of the stage. The vertical distance between the upper boundary and the lower boundary of the mine is called the vertical height of the stage, generally 100-250 m. The length of the slope of the stage is the length of the stage, as shown in Figure 2-4.

Figure 2-4 Minefield is divided into stages and levels

J1, J2, J3-first, second, and third stages; h-stage oblique length

1-stage transportation lane; 2-stage return wind alley

There are separate transport and ventilation systems at each stage. For example, in the lower boundary of the stage, the transportation lanes (also used as the wind inlet lanes) will be used to return to the main road during the excavation stage of the upper boundary of the stage to serve the entire stage. After the last stage is completed, the transportation lane at this stage is used as the return airway in the next stage.

2. The concept of horizontal and auxiliary levels

The mining level is referred to as the level, which is the horizontal position of the mine transportation alley and the bottom hole and the mining range served. Mine production levels are often named in the order of their elevation or top-down order. As shown in Figures 2-4, the ±0 level, the -150 level, the -300 level, or the first level, the second level, and the third level. Dividing the mining level is to rationally arrange the wells and the rational and orderly mining of the whole wells. To correctly classify the mining level, it is necessary to analyze the reasonable stage length, the conditions of mining up and down the mountain, the application of the auxiliary level and the correct division principle.

According to the conditions of coal seam occurrence and the size of the mine field, one well field can be used.