Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation · 2 marks · Numerical answer
An intake shaft 400 m deep has resistance 0.05 N s²/m⁸ and flow 100 m³/s. Average density is 1.2 kg/m³. Surface barometer reads 99.375 kPa; g=9.81 m/s². Find the barometer reading at 400 m depth in kPa, to two decimals.
Descending hydrostatic pressure gain isρgH=1.2×9.81×400=4708.8 Pa. Flow losesRQ²=0.05×100²=500 Pa to resistance. Bottom pressure is 99.375+(4708.8−500)/1000=103.5838 kPa, or 103.58 kPa. The friction loss opposes the hydrostatic increase along the intake flow.
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