GATE Mining Engineering Surface Environment, Mine Ventilation and Underground Hazards Syllabus

Surface Environment, Mine Ventilation and Underground Hazards syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Surface Environment, Mine Ventilation and Underground Hazards in GATE Mining Engineering, not a summary of it.

1. 1

   Surface Environment

   1 topic

   • Air, Water, and Soil Pollution
     • Standards of quality, causes, and dispersion of contamination and control
     • Noise pollution and control
     • Land reclamation
     • EIA (Environmental Impact Assessment)
2. 2

   Mine Ventilation

   2 topics

   • Underground Atmosphere
     • Heat load sources and thermal environment
     • Air cooling
   • Mechanics of Airflow
     • Distribution, natural and mechanical ventilation
     • Mine fans and usage
     • Auxiliary ventilation
     • Ventilation survey and planning
     • Ventilation networks
3. 3

   Underground Hazards

   2 topics

   • Mine Gases
     • Methane drainage
   • Underground Hazards from Fires, Explosions, Dust, and Inundation
     • Rescue apparatus and practices
     • Safety management plan
     • Accident data analysis and assessment
     • Mine lighting
     • Mine legislation
     • Occupational health and safety

Surface Environment, Mine Ventilation and Underground Hazards flashcards for GATE Mining Engineering

20 of 51 cards from the Surface Environment, Mine Ventilation and Underground Hazards deck — real questions with worked answers.

1. What are the three primary categories of environmental pollution dealt with in mining surface environment, and give the main mining source of each?

   Air pollution (from blasting, haul-road dust, fugitive emissions and combustion), Water pollution (from acid mine drainage and tailings effluent), and Soil/Land pollution (from overburden dumps, spoil heaps and subsidence).

2. What is Acid Mine Drainage (AMD) and write the overall reaction for pyrite oxidation that produces it.

   AMD is acidic, sulphate-rich, metal-laden water formed when sulphide minerals (chiefly pyrite) oxidize on exposure to air and water. Overall: $$\ce{4FeS2 + 15O2 + 14H2O -> 4Fe(OH)3 + 8H2SO4}$$

3. In air-pollution dispersion modelling, what does the Gaussian plume model give and what is its standard concentration equation?

   It gives the ground-level pollutant concentration downwind of a continuous point source. $$C(x,y,z)=\frac{Q}{2\pi u\,\sigma_y\sigma_z}\exp\!\left(-\frac{y^{2}}{2\sigma_y^{2}}\right)\left[\exp\!\left(-\frac{(z-H)^{2}}{2\sigma_z^{2}}\right)+\exp\!\left(-\frac{(z+H)^{2}}{2\sigma_z^{2}}\right)\right]$$ where $Q$ is emission rate, $u$ wind speed, $\sigma_y,\sigma_z$ dispersion coefficients, and $H$ effective stack height.

4. Define 'effective stack height' in plume dispersion.

   $H=h_s+\Delta h$, the sum of the physical stack height $h_s$ and the plume rise $\Delta h$ (buoyancy plus momentum rise of the hot exhaust above the stack top).

5. What are the six Pasquill–Gifford atmospheric stability classes and what governs them?

   Classes A (extremely unstable) through F (moderately stable), with D being neutral. They are governed by surface wind speed, daytime incoming solar radiation, and nighttime cloud cover; they set the values of the dispersion coefficients $\sigma_y,\sigma_z$.

6. How is the decibel sound pressure level (SPL) defined?

   $$L_p=20\log_{10}\!\left(\frac{p}{p_0}\right)\ \text{dB}$$ where $p$ is the measured RMS sound pressure and $p_0=20\ \mu\text{Pa}$ is the reference threshold of hearing.

7. How do you combine two equal incoherent noise sources, e.g. two machines each at 90 dB?

   Adding two equal levels increases the total by $10\log_{10}2\approx 3$ dB, so two 90 dB sources give 93 dB. In general $L_{total}=10\log_{10}\sum 10^{L_i/10}$.

8. What is the permissible occupational noise exposure limit (8-hour) commonly specified, and the exchange rate?

   90 dB(A) for an 8-hour shift, with a 5 dB exchange rate (permissible exposure halves for each 5 dB increase, e.g. 4 h at 95 dB, 2 h at 100 dB). Above 115 dB(A) no exposure is permitted.

9. List the three broad classes of noise-control measures with a mining example of each.

   Control at source (mufflers, balanced fans, vibration isolation), control along the path (enclosures, barriers, distance, acoustic lagging), and control at receiver (ear plugs/muffs, job rotation, soundproof cabins).

10. What is land reclamation in mining and name its two principal phases.

    Restoring mined-out land to a stable, productive, or near-natural condition. The two phases are technical (physical) reclamation — regrading, backfilling, soil/overburden placement — and biological (biotic) reclamation — soil amendment, revegetation and afforestation.

11. What is EIA (Environmental Impact Assessment) and what is its core output document?

    A systematic process to predict, evaluate and mitigate the environmental, social and economic effects of a proposed mining project before clearance. Its core output is the Environmental Impact Statement / EIA report, accompanied by an Environmental Management Plan (EMP).

12. State the main steps of an EIA process in order.

    Screening → Scoping → Baseline data collection → Impact prediction and assessment → Mitigation/Environmental Management Plan → Public hearing/consultation → Review and decision (clearance) → Post-project monitoring.

13. What is the normal volumetric composition of fresh surface air entering a mine?

    Approximately $20.93\%$ oxygen, $79.04\%$ nitrogen (plus inert gases), and $0.03\%$ carbon dioxide by volume, with variable water vapour.

14. What is the minimum oxygen content statutorily required in a working mine atmosphere, and what symptom appears below it?

    At least $19\%$ oxygen is required at working places. Below about $17\%$ the candle/flame is affected and rapid breathing begins; below $\sim12\%$ unconsciousness can occur.

15. Distinguish black damp, white damp, fire damp, stink damp and after damp.

    Black damp = $\ce{CO2}$ + excess $\ce{N2}$ (oxygen-deficient, irrespirable); White damp = carbon monoxide $\ce{CO}$; Fire damp = methane $\ce{CH4}$ (explosive); Stink damp = hydrogen sulphide $\ce{H2S}$; After damp = mixture of gases ($\ce{CO}$, $\ce{CO2}$, $\ce{N2}$) left after an explosion or fire.

16. What are the explosive limits of methane in air, and at what concentration is it most violently explosive?

    Methane is explosive between about $5\%$ (lower explosive limit) and $14\%$ (upper explosive limit) in air, and is most violent at approximately $9.8\%$ (near-stoichiometric).

17. Give the TLV/threshold limits commonly memorized for CO, CO2, H2S and NO2 in mine air.

    Carbon monoxide $\ce{CO}$: 50 ppm (0.005%); Carbon dioxide $\ce{CO2}$: 5000 ppm (0.5%); Hydrogen sulphide $\ce{H2S}$: 10 ppm; Nitrogen dioxide $\ce{NO2}$: 3–5 ppm (TLV ~3 ppm).

18. What instrument detects methane by combustion, and what instrument quantifies low oxygen?

    The flame safety lamp / methanometer (catalytic / interferometer type) detects methane (cap height on the flame); an oxygen meter or the flame safety lamp's flame extinction indicates oxygen deficiency.

19. Define the gradient of methane explosibility known as the 'coward triangle'. What does it represent?

    The Coward explosibility diagram plots combustible gas (CH4) against oxygen content; the triangular region defines mixtures that are explosive, with apexes/nose point showing the limiting conditions where the mixture can be made explosive by adding air — used to assess sealed-off fire atmospheres.

20. What is methane drainage and why is it carried out?

    Methane drainage (gas drainage) is the capture of methane via boreholes from coal seams and surrounding strata before or during mining, removing it through a pipe network. It reduces firedamp emission into ventilation air, lowers explosion risk, and the gas can be utilized as fuel.

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