Mine Gas Monitoring Simulation (2D)

Ventilation & Source

Fan airflow velocity 1.20 m/s

Methane emission at face 3.0 m³/min

Safety Interlock

Alarm threshold 60 %LEL

Live Sensor Readout

⛏️ Face CH₄

0.00%

🔺 Roof layer CH₄

0.00%

📍 Mid-drift CH₄

0.00%

🌬️ Return CH₄

0.00%

O₂ at return

20.9%

Peak %LEL

Interlock status

MONITORING — OK

Ventilation quantity / model time

12.0 m³/s · 0.0 min

CH₄ at Mid-Drift Sensor

%LEL at sensor Alarm threshold

How it works

The drift is modelled as a 1D advection-diffusion field: ∂C/∂t = −v·∂C/∂x + D·∂²C/∂x² + S(x), integrated with an explicit upwind finite-difference scheme along 60 cells spanning 300 m from the coal face to the return airway. The fan sets the advection velocity v; the emission slider sets the source term S at the face, converted from m³/min into a %-by-volume injection rate using a 10 m² drift cross-section; turbulent diffusion D mixes gas between neighbouring cells.

Methane is lighter than air, so at low air velocities it stratifies near the roof instead of mixing into the bulk airflow — a real, well-documented hazard called methane layering. Below roughly 1.0 m/s the roof-layer sensor reads a multiplier on top of the bulk concentration that grows as velocity falls, so cutting ventilation both raises the average concentration and concentrates it exactly where a roof-mounted detector or ignition source would meet it first.

O₂ at the return airway is estimated from simple volumetric displacement: O₂% ≈ 20.9·(1 − CH₄/100). The %LEL readout expresses concentration as a fraction of methane's 5%-by-volume lower explosive limit. When any sensor's %LEL exceeds the alarm threshold, the interlock trips: airflow is automatically boosted (simulating powered ventilation doubling) until the reading falls 10 points below the threshold again — the same hysteresis logic used by real methanometer-controlled fan interlocks.

⚠ %LEL ALARM — VENTILATION INTERLOCK ENGAGED

⛏️ face → 🌬️ return airway — drag threshold/emission/fan sliders and watch the plume