JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II MINE ENVIRONMENTAL ENGINEERING – I Previous Question Paper (August/September - 2022 - R16)
Answer any five questions
All questions carry equal marks
Main
Explain the following underground mine gases and their occurrence, properties, detection and physiological effects.
O2
Answer
Oxygen (O2) is essential for human life and combustion. In underground mines, it occurs in the normal atmosphere at approximately 20.9% concentration. It is consumed by human respiration, oxidation of coal and timber, and combustion. Properties include being colorless, odorless, and tasteless. Detection is performed using oxygen deficiency detectors or electrochemical sensors. Physiological effects include hypoxia, dizziness, and unconsciousness when levels drop below 17%, and death occurs rapidly below 10%.
CO2
Answer
Carbon Dioxide (CO2) is a colorless, odorless gas with a slightly acidic taste. It occurs in mines due to respiration, blasting, oxidation of organic matter, and strata emission. It is heavier than air (specific gravity 1.53). Detection is via infrared gas analyzers or chemical absorption methods. Physiological effects include increased breathing rate at 2-3% concentration, headaches and panting at 5%, and potential suffocation or death at concentrations exceeding 10%.
CO
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Methane
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Discuss in detail the methane drainage in the coal mine with a neat sketch.
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Write a short note on Cowords diagram and its significance.
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What are the potential effects of heat and humidity on the mines?
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Explain the methods of improving of cooling power of mine air in underground mines.
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What is meant by Geothermic Gradient and how do we calculate it ?
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What is the purpose, mode of action and inference from readings of a hygrometer used in mines?
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Write a short note on Mechanical ventilation.
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How natural ventilation produced? Give its advantages and disadvantages?
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What are the factors to be considered in selection of mine fans?
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Give a neat sketch of an axial-flow main ventilating fan, showing plan and elevation with casing and evasee chimney.
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Describe the advantages and disadvantages of forcing fan and exhaust fan.
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Define i) Ascensional Ventilation ii) Descensional Ventilation iii)Homotropal Ventilation iv) Anti-tropal Ventilation.
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What are the instruments required for ventilation survey?
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Discuss the procedure of pressure survey.
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Define i) Ventilation stopping ii)Brattice Partition iii) Air Crossing iv) Regulator.
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