What changed when a quarry group measured its stockpiles by drone and ended inventory write-downs

October 1, 2026 · 3 min read

Boral's six Victorian quarries measured inventory twice a year by manned aircraft survey, with results arriving months later against an assumed flat base, so book stock drifted badly. Site teams now fly their own drone surveys and process them in Propeller. The vendor publishes a 24 hour turnaround and write-downs ended in under six months.

The short answer

A construction materials company with six quarries supplying the Melbourne market replaced a semiannual third party aerial survey with drone photogrammetry flown by its own site teams. The vendor publishes survey data turned around within 24 hours instead of two or three months, about 25,000 dollars of variance across all six sites on the most recent statutory survey, and inventory write-downs ended in under six months. The account below is the maker's own case story, so read every number as the vendor published it, not as an audited result.

What the job looked like before

Inventory was measured twice a year by a manned aircraft survey. Results arrived months later and volumes were computed against an assumed flat base, so a pile stacked against a hillside was wrong by construction. Between surveys the sites produced about a million tons, and book stock drifted until the next statutory count corrected it with a write-down.

What they put in

Drone photogrammetry flown by site teams and processed in the Propeller platform, producing measurement reports for volume, tonnage and material, with the base surface corrected for real ground conditions such as piles against a hillside at the Montrose site. The aircraft model was not published.

What changed, in their numbers

About 25,000 dollars of variance across all six sites region wide on the most recent statutory survey, per the quarry support manager. Data turned around within 24 hours versus two or three months previously. Inventory write-downs ended in under six months per the case study title. Production of a million tons across the six month interval between the old surveys. Statutory reporting twice a year. All published by the vendor. Cost and payback were not published.

What this does not tell you

It does not publish the cost of the aircraft, the software subscription or the training, so the saving cannot be netted. It does not state the size of the write-downs before the change, only that they ended. And the sites fly their own surveys, which means someone on each site became a pilot and that approval path is not described.

What to verify before you fly

What your stockpile variance has cost you in write-downs and disputes over the last two years. Whether your sites can fly their own surveys or should hire an operator, which the aerial services page on this site exists for. Who flies and under what approvals, a question for a qualified specialist. And whether your accountants will accept drone derived volumes for statutory reporting.

Sources: https://www.propelleraero.com/success-story/how-boral-sites-in-victoria-measure-and-manage-their-stockpiles-ending-inventory-write-downs-in-under-six-months/

Describe your sites and how you measure stock today to Amelia, the aerial concierge on this site. It will sort seeing from measuring and tell you whether owning an aircraft or buying the survey as a service fits.

Related on this site

The value was not the aircraft. It was turning a twice a year, months late measurement into a routine one the site could run itself, with a base surface that matched the real ground.

Put it to the test on your own job

Tell Joe what you are running and he will apply this to your numbers, including telling you when a robot is the wrong answer.

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