GATE Surface Environment, Mine Ventilation and Underground Hazards: Surface Environment – Previous Year Questions
18 GATE previous year questions on Surface Environment (Surface Environment, Mine Ventilation and Underground Hazards, Mining Engineering) with answers and explanations, from every paper.
- GATE 2021 MN Q32 – The lower and upper frequencies of a 1/1 octave band are 710 Hz and 1420 Hz. Find its centre frequency in Hz, to the nearest integer.
- GATE 2021 MN Q33 – In the Battelle Environmental Evaluation System, air pollution has PIU 52. Environmental quality falls from 0.8 before the project to 0.6 after it.…
- GATE 2021 MN Q41 – A 10 mL wastewater sample is diluted to 300 mL with BOD-free water. Initial dissolved oxygen is 9.0 mg/L and the original wastewater’s BOD₅ is 60…
- GATE 2021 MN Q51 – CO is emitted at ground level at 25 g/s. Wind speed is 5 m/s; horizontal and vertical Gaussian dispersion coefficients are 150 m and 200 m. Find…
- GATE 2022 MN Q25 – The ambient lapse rate exceeds the dry adiabatic lapse rate. Classify the atmosphere.
- GATE 2022 MN Q35 – AQI subindices for PM₂.₅, NO₂ and O₃ at a station are 180, 96 and 84. Find station AQI as an integer.
- GATE 2022 MN Q56 – A 20×40 km city has an inversion lid 100 m high. Wind enters perpendicular to the 20 km side at 4 m/s. PM₁ emission is 1 kg/s. Under a steady…
- GATE 2023 MN Q17 – Which products result when calcium hydroxide reacts with acidic ferruginous mine water?
- GATE 2023 MN Q55 – Groundwater contains Ca²⁺ at 200 mg/L. Find calcium carbonate equivalent hardness in mg/L, to one decimal.
- GATE 2024 MN Q29 – A washery discharges 300 m³/day of water at DO 4 mg/L into a stream flowing 0.04 m³/s at DO 8.5 mg/L. Ignoring temperature effects, find immediate…
- GATE 2024 MN Q30 – Dumper and shovel together produce 95 dB(A) at a point. The shovel alone produces 90 dB(A). Find the dumper-only level in dB(A) to two decimals.
- GATE 2024 MN Q47 – A 50 μm dust particle enters a dry settling chamber 0.5 m above the floor at horizontal speed 1 m/s. Density is 2000 kg/m³, air viscosity 1.8×10⁻⁵…
- GATE 2025 MN Q21 – The environmental lapse-rate profiles are shown. Dry adiabatic lapse rate is−10°C/km. Which profile gives the most unstable atmosphere?
- GATE 2025 MN Q57 – Noise is80 dB(A) for10 min and60 dB(A) for30 min. Find the40-min energy-equivalent level in dB(A) to two decimals.
- GATE 2025 MN Q62 – A10×10 km airshed emits20 kg SO₂/s. Wind speed is4 m/s and mixing height1200 m. Incoming concentration is zero and SO₂ is conservative. Find steady…
- GATE 2025 MN Q64 – Ultimate BOD is300 mg/L. The20°C rate constant is0.22/day and temperature coefficient1.05. Find5-day BOD at25°C in mg/L to two decimals.
- GATE 2026 MN Q53 – A2.5 μm dust particle of density3600 kg/m³ settles500 m through still air of viscosity1.80×10⁻⁵ kg/(m s). Neglect air density and turbulence. Find…
- GATE 2026 MN Q54 – A15 mL wastewater sample is diluted to300 mL and incubated for5 days at20°C. Dissolved oxygen drops from9.2 to4.4 mg/L. Find sample BOD in mg/L as an…