a) Minefield development
1. The coal field is divided into Ida
The coal-bearing rock series with continuous development formed in the same geological development process, whose distribution is regularly ruled and basically connected into one piece, is called coal field. Among the coal seam occurrence conditions, the influence on coal development is the thickness and inclination of the coal seam. Therefore, coal seams are often classified by thickness and inclination.
Coal fields have a large range and abundant reserves, some of which cover hundreds of square kilometers and have reserves of tens of billions of tons. The coal seams contain more than ten layers or even dozens of layers. Therefore, the coal field must be divided into several parts, each part being mined by a mine. The part of the coal field that is divided into a mine is called a mine field.
2. Pioneering method of minefield After the coalfield is divided into minefields, the range of the minefield is generally large, and the length of the strike can reach several kilometers to more than 10,000 meters; the length of the slope can reach several kilometers. For such a wide range of well fields, under the current technical conditions, it must be subdivided into smaller parts suitable for mining, and planned and sequential mining, to meet technically and economically reasonable requirements.
3. Ways of mine development
According to the different types of wells entering the coal seam, the mine development methods are divided into four types: inclined shaft development, vertical shaft development, flat development and comprehensive development.
(2) Wellbore
The wellbore is a project that is excavated from the surface into the ground. It is usually used as a main well or auxiliary ventilation (transportation personnel, materials, equipment, meteorites, etc.) for the transportation of coal. The wellbore mainly consists of vertical shafts, inclined shafts and flat shafts.
(3) Mainly develop roadways
The main development laneway refers to the basic roadway excavated for the development of the minefield, including the wellbore, the bottom hole yard, the transportation lane, the Shimen, and the total return airway.
(4) Principles for determining the shape and size of the cross section of the roadway
The shape of the section of the roadway is mainly determined by the nature of the surrounding rock, the service life of the shaft and the supporting materials.
1. Principle of determining the shape and size of the wellbore
The cross-section shape of the vertical shaft is generally circular, and the section of the vertical shaft drilled in the early stage adopts a rectangular shape and an elliptical shape (currently rarely used); the cross section of the inclined well shaft has an arch shape and a trapezoidal shape.
The principle of determining the size of the wellbore section is related to its function. Arrange the lifting equipment required for production, meet the requirements for personnel access, meet the requirements of ventilation air volume, meet the requirements of laying pipelines, and meet the requirements of the Coal Mine Safety Regulations.
2. Lane section shape and selection principle
The cross-section shape of the roadway used in coal mines in China is rectangular, trapezoidal, polygonal, arched, round, horseshoe, elliptical and so on.
The principle of selection of the section shape of the roadway: the magnitude and direction of the surrounding rock of the roadway, that is, the nature of the surrounding rock passing through the roadway; the use and service life of the roadway; the materials and support methods used for the roadway; the tunneling method and rock formation Buried.
3. The principle of determining the size of the roadway
The smaller the section of the roadway, the better the stability. The final determination of the reasonable section size should take into account the construction technology, the purpose of the roadway and the utilization of the section. The net section of the roadway in the coal mine shall meet the needs of pedestrians, transportation, ventilation, equipment installation and maintenance as well as construction.
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