The temperature of the mining face shall not exceed 30℃, and the temperature below the inlet wellhead (dry bulb temperature, the same below) must be above 2℃. Each excavation point must be equipped with a cavern, which is a horizontal tunnel with large cross section and short length without passing through the surface exit. Its function is to install all kinds of equipment and machines, store materials and tools, or use them for other special purposes.

Such as machine repair room, explosive magazine, lounge, etc. The shapes, specifications and structures of various chambers vary widely, and the properties of the rocks they pass through are also different, so the construction methods are also varied. These construction methods can be divided into the following three categories: full-face one-time excavation method, step surface construction method and pilot tunnel construction method.

Temperature is a physical quantity that indicates the degree of heat and cold of an object, and it is the intensity of molecular thermal motion of the object at the microscopic level. Temperature can only be measured indirectly through some characteristics of an object that changes with temperature. The scale used to measure the temperature value of an object is called a temperature scale. It specifies the reading starting point (zero point) of temperature and the basic unit for measuring temperature. The international unit is the thermodynamic temperature scale (K).

From the point of view of molecular motion theory, temperature is a sign of the average kinetic energy of an object's molecular motion. Temperature is the collective expression of a large number of molecular thermal movements, which has statistical significance. For a single molecule, temperature is meaningless. According to an observable phenomenon (such as the expansion of mercury column), the degree of heat and cold is measured by one of several arbitrary scales.