Network — Equivalent Orifice of a Mine
Equivalent Orifice of a Mine for ventilation network design and surveying.
The equivalent orifice imagines the whole mine as a single hole in a wall — a 19th-century metric that still benchmarks mines instantly: above 2 m² is generous, below 1 m² is a hard mine that will fight every expansion. Track it yearly; a shrinking orifice is workings outpacing infrastructure.
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.
Equivalent Orifice of a Mine for ventilation network design and surveying. A free mine ventilation & air quality tool — no sign-up, no upload, instant results in your browser.
About Network — Equivalent Orifice of a Mine
Network — Equivalent Orifice of a Mine computes the governing relationship A = 1.19·Q/√p [Murgue's equivalent orifice] live as you type. The equivalent orifice imagines the whole mine as a single hole in a wall — a 19th-century metric that still benchmarks mines instantly: above 2 m² is generous, below 1 m² is a hard mine that will fight every expansion. Track it yearly; a shrinking orifice is workings outpacing infrastructure. 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 Network — Equivalent Orifice of a Mine
- 1Enter your values — Mine total quantity, Fan pressure (sensible defaults are pre-filled).
- 2Read the live results: Equivalent orifice.
- 3Check the "with your numbers" line to see A = 1.19·Q/√p [Murgue's equivalent orifice] substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Network — Equivalent Orifice of a Mine?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula A = 1.19·Q/√p [Murgue's equivalent orifice] with authoritative sources cited on the page (McPherson, M.J., Subsurface Ventilation and Environmental Engineering; Hartman et al., Mine Ventilation and Air Conditioning, 3rd ed.)
- ✓The equivalent orifice imagines the whole mine as a single hole in a wall — a 19th-century metric that still benchmarks mines instantly: above 2 m² is generous, below 1 m² is a hard mine that will fight every expansion.
- ✓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 network — equivalent orifice of a mine use?+
It evaluates A = 1.19·Q/√p [Murgue's equivalent orifice], exactly as published. Sources: McPherson, M.J., Subsurface Ventilation and Environmental Engineering; Hartman et al., Mine Ventilation and Air Conditioning, 3rd ed.. 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?+
The equivalent orifice imagines the whole mine as a single hole in a wall — a 19th-century metric that still benchmarks mines instantly: above 2 m² is generous, below 1 m² is a hard mine that will fight every expansion. 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?+
Equivalent Orifice of a Mine for ventilation network design and surveying. A free mine ventilation & air quality tool. Track it yearly; a shrinking orifice is workings outpacing infrastructure. 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.
Related tools
- Network — Anemometer Traverse Quantity
- Network — Gauge-and-Tube Pressure Leg
- Network — Air Changes per Hour
- Network — Stopping/Seal Leakage
- Network — Ventilation-on-Demand Saving
- Network — District Flush/Recharge Time
- Network — Controlled Recirculation Fraction
- Plant Ops — Cold-Feed Proportioning
- Decking — Composite Stud Count
Related Manufacturing tools
Spindle Speed Calculator — Aluminum 6061
Carbide starting RPM for milling Aluminum 6061: n = 1000·Vc/(π·D) with a handbook cutting speed preset.
● LiveSpindle Speed Calculator — Mild Steel 1018
Carbide starting RPM for milling Mild Steel 1018: n = 1000·Vc/(π·D) with a handbook cutting speed preset.
● LiveSpindle Speed Calculator — Stainless 304
Carbide starting RPM for milling Stainless 304: n = 1000·Vc/(π·D) with a handbook cutting speed preset.
● Live