Birdi's Volumetric tool can now tell you what a stockpile weighs, not just how much space it takes up. Assign a Material to a volume and Birdi applies that material's density to give you Tonnage alongside the cubic metres.
That means the figure you hand to a client, a haulage contractor or a monthly production report is the one they asked for — no spreadsheet conversion in between.
Materials and tonnage support:
a built-in library of common site materials with industry-standard densities
custom materials with your own density, saved to your workspace for the whole team
bulk assignment across many volumes at once
Material, Density and Tonnage columns in table view, and in your PDF report exports
Note: Materials and tonnage are available on the Growth and Ultimate plans.
When to use materials and tonnage
You report stockpile quantities in tonnes because that's how the material is sold, hauled or invoiced.
You're reconciling survey volumes against weighbridge or truck-count records.
You're producing a monthly production or inventory report for a quarry, mine or landfill.
You need to quote or plan haulage, where truck capacity is set by weight rather than volume.
You're measuring several different materials on one site and want each reported at its own density.
If a volume doesn't need a weight — a cut/fill earthworks balance, a void, a water body — you can leave the material unset. Birdi will report volume only.
Step-by-step: assigning a material and reading tonnage
1. Calculate your volume first
Tonnage is derived from your calculated volume, so run the volume calculation before assigning a material.
Draw or select your volumetric annotation, choose your Volume DEM and Base method, then click Calculate.
If you need a refresher, see How to use the volumetric calculator.
2. Open the Volumetric Layer Toolbox
Select your volume in the Layer Panel to open the Volumetric Layer Toolbox. On the Details tab you'll see your calculated values — Total volume, Cut volume, Fill volume and Base area — with the Material selector below them.
3. Choose a material from the library
Click the Material dropdown and select a material. The library is organised into groups — Aggregates & quarry, Earth & fill, Construction & recycled, Mining & bulk, Organics and Other — and each option shows its density in t/m³ so you can see exactly what's being applied.
Pick one, and Material and Tonnage appear immediately in the values above. No need to recalculate.
Tip: Densities in the library are standard loose (bulk) densities. If your material is compacted, unusually wet, or you've had it tested, add a custom material instead — see the next step.
4. Or add your own material
If nothing in the library matches what's on site, scroll to Custom… in the dropdown. Then:
enter a Material name — something your team will recognise, like Screened topsoil — north pit
enter a Density (t/m³)
click Add material
Your custom material is saved to your workspace and appears at the top of the Material selector, so anyone on your team can reuse it on the next survey. Build the list once and your site's real densities are there for every future measurement.
Note: Custom materials can't be edited or removed in-app yet. If you need one changed or deleted, get in touch and we'll sort it out for you.
5. Apply a material to several volumes at once
At the end of a survey you've often measured a dozen piles of the same product. You don't need to set each one individually:
hold Shift and click each volume you want to include
open the Material selector in the Volumetric Layer Toolbox
choose a material
The material and density are applied to every selected volume, and tonnage is calculated for each.
Tip: This pairs well with AI Detect – Stockpile. Detect your piles, Shift-select them, calculate volumes in bulk, then apply the material in bulk. See How to turn your stockpile AI Detect results into a volumetric report.
6. Find your tonnage in table view and reports
Material, Density and Tonnage appear everywhere your volumes already do:
Table view — new columns alongside net, cut and fill volume. Select a single volume, or the Volumetric Layer Folder for the whole group, then click the Table Icon. Export to CSV from the Three Dots menu.
PDF report exports — material, density and tonnage carry through to your annotation report, so the deliverable you send out already has the weights in it.
If your workspace is set to imperial units, tonnage converts automatically. See How to change the measurement system and units for your annotations.
Ask Scout
Scout can set materials for you and talk through a volume assessment — useful when you're not sure which density is the right one for what you're looking at. Try:
"Set all the stockpiles in this folder to crushed rock"
"What's the tonnage of stockpile 7?"
"Help me work out which material to use for this pile"
Material library reference
Group | Material | Density (t/m³) |
Aggregates & quarry | Crushed rock / gravel | 1.60 |
| Blue metal / aggregate (10–20 mm) | 1.55 |
| Crusher dust / quarry fines | 1.60 |
| Sand, dry | 1.60 |
| Sand, wet | 1.90 |
| Sand & gravel mix | 1.70 |
| Crushed limestone | 1.55 |
| Road base (DGB), loose | 1.80 |
Earth & fill | Topsoil | 1.30 |
| Clay, dry | 1.40 |
| Clay, wet | 1.70 |
| Overburden / spoil | 1.60 |
Construction & recycled | Concrete, solid | 2.40 |
| Crushed concrete (recycled) | 1.40 |
| Asphalt millings (RAP) | 1.60 |
Mining & bulk | Coal, loose | 0.85 |
| Iron ore, loose | 2.40 |
| Broken hard-rock ore | 1.80 |
Organics | Mulch / wood chips | 0.50 |
| Compost | 0.60 |
| Sawdust | 0.25 |
Other | Water | 1.00 |
| Custom… | Your own name and density |
Best practice tips
Set the material once, then reuse it. Custom materials save to your workspace, so the densities your site actually uses are a click away on every future survey.
Use a tested density for anything commercial. Library densities are good estimates, but if the tonnage is going on an invoice or a royalty return, use a density measured from your own material.
Remember moisture. Wet sand is roughly 20% heavier than dry sand. If it's rained before the flight, pick the wet variant or set a custom density.
Name volumes by product, not just number. Sand 20mm — pad 3 reads far better than stockpile 7 in a report a client will actually open.
Tonnage inherits your volume accuracy. A 5% volume error is still a 5% tonnage error, plus whatever your density assumption adds. See How accurate is the volumetric calculator?
Leave it unset when weight isn't the point. Cut/fill earthworks balances don't need a material.