本科毕业论文--外文资料与中文翻译.doc
文本预览下载声明
附录:
外文资料与中文翻译
外文资料:
Mine safety
Coal mining historically has been a hazardous occupation but, in recent years, tremendous progress has been made in reducing accidental coal mine deaths and injuries.the main aspect is as following:
⑴ Safety of mine ventilation
? Purposes of Mine Ventilation
? Properly engineered control of the mine atmosphere is required to:
? provide fresh air (oxygen) for men to breathe
? provide a source of oxygen for internal combustion engines in machinery
? dilute atmospheric contaminants to acceptable levels
? maintain temperature and humidity within acceptable limits
? remove atmospheric contaminants from the mine.
Mine ventilation is twofold in purpose: first, it maintains life, and secondly it carries off dangerous gases. The historic role of ventilation was to provide a flow of fresh air sufficient to replace the oxygen consumed by the miners working underground. Todays mine ventilation primarily deals with noxious gases (mainly generated by trackless equipment underground).
Canaries are said to have been used to detect gas in coal mines in the early stages of coal mining. This sensitive bird would be taken into the workings and, if it perished, the colliers would immediately leave the mine.In the 1920s the hand-turned fans were replaced with air-powered small turbine fans. Large fans of the suction type were placed on the surface and gradually increased in size. Air from surface compressors was piped into the mine to power machinery and to assist in ventilation.
Unless the air is properly distributed to the face, the mine ventilation system is not performing its primary function [1]. While it has always been recognized that this last part of ventilation is the most import, it is also the most difficult to achieve.
The primary means of producing and controlling the airflow are also illustrated on Figure 1. Main fans, either singly or in combination, handle all of the air that passes through the entire system. These are usually, but
显示全部