Tunnel Ventilation — Decline Portal Drive
Construction ventilation check for a decline portal drive: velocity, air age and duct delivery.
Declines accumulate truck traffic as they deepen: the fleet that fit the airflow at 500 m exceeds it at 2,000 m of drive. Re-running this check at every extension and matching it against the diesel-fleet tools earlier in this category is the planned version of what otherwise becomes a DPM violation.
Formula
Note: Mine ventilation is statutory and life-safety territory: airflow quantities, gas limits and re-entry times must be set by the registered ventilation engineer/manager under your jurisdiction's mining regulations — this calculator is a planning and training aid.
Construction ventilation check for a decline portal drive: velocity, air age and duct delivery. A free mine ventilation & air quality tool — no sign-up, no upload, instant results in your browser.
About Tunnel Ventilation — Decline Portal Drive
Tunnel Ventilation — Decline Portal Drive computes the governing relationship v = Q/A · air age = V_tunnel/Q live as you type. Declines accumulate truck traffic as they deepen: the fleet that fit the airflow at 500 m exceeds it at 2,000 m of drive. Re-running this check at every extension and matching it against the diesel-fleet tools earlier in this category is the planned version of what otherwise becomes a DPM violation. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Tunnel Ventilation — Decline Portal Drive
- 1Enter your values — Drive length, Tunnel cross-section, Airflow delivered at face, Minimum velocity required (sensible defaults are pre-filled).
- 2Read the live results: Mean return velocity, Nominal air age.
- 3Check the "with your numbers" line to see v = Q/A · air age = V_tunnel/Q substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Tunnel Ventilation — Decline Portal Drive?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula v = Q/A · air age = V_tunnel/Q with authoritative sources cited on the page (McPherson, M.J., Subsurface Ventilation and Environmental Engineering; BS 6164 — Health & safety in tunnelling)
- ✓Declines accumulate truck traffic as they deepen: the fleet that fit the airflow at 500 m exceeds it at 2,000 m of drive.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the tunnel ventilation — decline portal drive use?+
It evaluates v = Q/A · air age = V_tunnel/Q, exactly as published. Sources: McPherson, M.J., Subsurface Ventilation and Environmental Engineering; BS 6164 — Health & safety in tunnelling. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Declines accumulate truck traffic as they deepen: the fleet that fit the airflow at 500 m exceeds it at 2,000 m of drive. Mine ventilation is statutory and life-safety territory: airflow quantities, gas limits and re-entry times must be set by the registered ventilation engineer/manager under your jurisdiction's mining regulations — this calculator is a planning and training aid.
When is this calculator the right tool for the job?+
Construction ventilation check for a decline portal drive: velocity, air age and duct delivery. A free mine ventilation & air quality tool. Re-running this check at every extension and matching it against the diesel-fleet tools earlier in this category is the planned version of what otherwise becomes a DPM violation. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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