MineSafety煤矿安全大学毕业论文英文文献翻译及原文

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　　文献、资料中文题目：煤矿安全

　　文献、资料英文题目：Mine safety

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　　翻译日期： 2017.02.14

　　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. Today's 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 not

　　necessarily, located on

　　surface, either exhausting

　　air through the system as

　　shown on Figure 1 or,

　　alternatively, connected to

　　downcast shafts or main

　　intakes and forcing air into and through the system. Because of the additional hazards of gases and dust that may both be explosive, legislation governing the ventilation of coal mines is stricter than for most other underground facilities. In many countries, the main ventilation fans for coal mines

　　are Figure 1. Typical elements of a main ventilation system

　　required, by law, to be placed on surface and may also be subject to other restrictions such as being located out of line with the connected shaft or drift and equipped with blow-out panels to help protect the fan in case of a mine explosion.

　　Stoppings and Seals:In developing a mine, connections are necessarily made between intakes and returns. When these are no longer required for access or ventilation, they should be blocked by stoppings in order to prevent short-circuiting of the airflow. Stoppings can be constructed from masonry, concrete blocks or fireproofed timber blocks. Prefabricated steel stoppings may also be employed. Stoppings should be well keyed into the roof, floor and sides, particularly if the strata are weak or in coal mines liable to spontaneous combustion. Leakage can be reduced by coating the high pressure face of the stopping with a sealant material and particular attention paid to the perimeter. Here again, in weak or chemically active strata, such coatings may be extended to the rock surfaces for a few metres back from the stopping. In cases where the airways are liable to convergence, precautions should be taken to protect stoppings against premature failure or cracking. These measures can vary from crush pads located at the top of the stopping to sliding or deformable panels on prefabricated stoppings. In all cases, components of stoppings should be fireproof and should not produce toxic fumes when heated.

　　As a short term measure, fire-resistant brattice curtains may be tacked to roof, sides and floor to provide temporary stoppings where pressure differentials are low such as in locations close to the working areas.

　　Where abandoned areas of a mine are to be isolated from the current

　　ventilation infrastructure, seals should be constructed at the entrances of the connecting airways. If required to be explosion-proof, these consist of two or more stoppings, 5 to 10 metres apart, with the intervening space occupied by sand, stone dust, compacted non-flammable rock waste, cement-based fill or other manufactured material. Steel girders, laced between roof and floor add structural strength. Grouting the surrounding strata adds to the integrity of the seal in weak ground. In coal mines, mining law or prudent regard for safety may require seals to be explosion-proof.

　　Doors and airlocks：Where access must remain available between an intake and a return airway, a stopping may be fitted with a ventilation door. In its simplest form, this is merely a wooden or steel door hinged such that it opens towards the higher air pressure. This self-closing feature is supplemented by angling the hinges so that the door lifts slightly when opened and closes under its own weight. It is also advisable to fit doors with latches to prevent their opening in cases of emergency when the direction of pressure differentials may be reversed. Contoured flexible strips attached along the bottom of the door assist in reducing leakage, particularly when the airway is fitted with rail track.

　　Ventilation doors located between main intakes and returns are usually built as a set of two or more to form an airlock. This prevents short-circuiting when one door is opened for passage of vehicles or personnel. The distance between doors should be capable of accommodating the longest train of vehicles required to pass through the airlock. For higher pressure differentials, multiple doors also allow the pressure break to be shared between doors.

　　Mechanized doors, opened by pneumatic or electrical means are particularly

　　Cfd applied to ventilation sys tems：Due to recent advances in computer processing power CFD has been used to solve a wide range of large and complex flow problems across many branches of engineering (Moloney et. al. 1997/98/99). The increase in processor speed has also enabled the development of improved post processing and graphical techniques with which to visualize the results produced by these models. Recent research work has employed CFD models, validated by scale and full-scale experiments, to represent the ventilation flows and pollutant dispersion patterns within underground mine networks. In particular, studies by Moloney (1997) demonstrated that validated CFD models were able to successfully replicate the ventilation flows and gaseous pollutant dispersion patterns observed within auxiliary ventilated rapid development drivages. CFD has proven a capable method by which to identify detailed characteristics of the flow within critical areas such as the cutting face. The results produced by the CFD models were able to demonstrate the relative