一、The Features of Mining Equipment
In general, there are two types of quarry opening. One is the underground mining and the other is the opencast working.
1）Because the space of the mine is limited, the mechanism of the mining machinery should be compact and the volume of it should be small. Thus, the pressure and load that the bearing and the wheel gear are under are quite big.
2) The mining machinery should be moved usually flexibly. It is because the working conditions are various and the load is of changes in load.
3) Most of the mining machines are in operation at middle speed or at low speed. Most of them are of heavy load.
4) The environmental condition in the mine is bad. It is humid and there are rock dust, coal dust, and gas, the main component of which is methane in the the mine. In some mines, there is harmful gas with sulfur, such as sulfur dioxide, hydrogen sulfide. Therefore, as for lots of mining machinery, all of them will suffer from some problems like fire prevention, anti-explosion, anti-corrosion.
5) The air-open mining machinery selected can be exposed to the weather,which means that it should bear different climate changes like wind, rain, isolation, and different seasons.
6) Because the space in the mine is narrow, the machinery maintenance in the mine is more difficult than that on the ground. Thus, the mining machinery should be endurable and be convenient for maintenance.
二、Some Requirements of the Lubricant:
1) The volume of the mining machinery and the fuel tank’s volume are small, the amount of the lubricant of which is also small. At the working time, the oil temperature is high. Therefore, the lubricant should be of good stability and oxidation resistance.
2) Because the environmental condition of the mine is bad, which is of lot of coal dust, rock dust, and moisture, the lubricant can not get rid of the pollution of these impurities. Therefore, the lubricant should be of some properties like rust protection, anti-corrosion, emulsion resistance. It is required that, when the lubricant has been polluted, the properties of it do not change a lot. In other words, its sensitivity to pollution should be small.
3) There are obvious changes of the air-open mining machinery in summer and in winter. In some places, the temperature difference day and night is large so that the viscosity of the lubricant should decrease with the changes of the temperature. It should be avoided that, at high temperature, the viscosity of the lubricant becomes too low, which will cause that it can not form the lubricating film. Then it can not lubricate the machine. Meanwhile, at the low temperature, the viscosity of the lubricant is so high that it is hard to start or operate the machine.
4) As for some mining machinery, especially the machines used in the mine, where fire disaster and explosion accident occur probably, it should adopt the lubricant of good combustion resistance. The combustible mineral oil must not be adopted.
5) The lubricant should adapt to the sealing elements well, in case of the damage of the sealing elements.