Analysis · 10 min read
Drone aeromagnetic vs fixed-wing: where each approach wins.
Fixed-wing aeromagnetic surveying is the legacy of mineral exploration. Drone aeromag is the newcomer. Both have legitimate use cases; the industry has not yet caught up to where each one actually belongs. This is the frank comparison.
The honest frame
Drone aeromag is not a universal replacement for fixed-wing. It is a specialist tool that wins decisively at target scale (blocks of ≤10 km²) and loses at regional scale (surveys spanning >1,000 km²). Exploration managers who assume it replaces fixed-wing everywhere will over-spend on the wrong scale. Exploration managers who assume it replaces nothing will continue paying fixed-wing economics for work that drone does better.
Where fixed-wing wins
Regional reconnaissance. Surveying a 2,000 km² belt for first-pass targeting. Fixed-wing covers the distance in days; drone would need weeks and multiple deployments. Endurance and speed dominate.
Rugged, non-permissive terrain. Areas where rotor-based aircraft cannot be based or recovered safely — mountain passes, marine coastline, contested airspace. Fixed-wing flies from established strips and stays on station.
Integrated multi-geophysics. When the survey needs mag + gamma + EM simultaneously over a large area, fixed-wing platforms carry the payload; drones, today, mostly do not.
Where drone wins
Target-scale resolution. For a 5 km² anomaly that the regional survey has already flagged, drone flies at sub-5 m line spacing and 20 m terrain-following altitude. Fixed-wing cannot match that resolution without becoming dangerous. Feature definition improves 2×+.
Brownfield and extension. Mines that want to survey ground immediately adjacent to active operations — where regulatory clearance for fixed-wing is a three-month exercise and drone clearance is days.
Cost per km² at small blocks. Mobilisation is the dominant cost for fixed-wing at small areas. Drone has no mobilisation premium at small scale. Below 20 km², drone is typically one-fifth the cost.
Turnaround. Two weeks, processed and interpreted, is a realistic drone timeline. Fixed-wing, because of scheduling and queue effects, is routinely three months.
A decision rule
If you have a regional mag survey and you need to densify over a target block of ≤15 km², drone is the right tool. If you are flying a first-pass survey over a greenfield belt, fixed-wing is the right tool. If you are in between, the right answer is often to scope both — fixed-wing for the belt and drone for the priority targets.
Where vendors mislead
Three patterns to watch for. Vendors quoting drone at regional scale based on "extrapolated hours" — the scheduling and weather overheads are not linear. Vendors quoting fixed-wing at target scale and accepting 50 m line spacing that cannot resolve the feature. Vendors quoting either without a ground-truth reconciliation plan — a survey without a calibration well or magnetic observatory is a survey you cannot defend.
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