Rigid frame truck vs articulated dump truck: telling them apart in satellite imagery

If you're trying to read fleet mix from imagery instead of a site visit, the first thing you hit is that most haul trucks look like a gray rectangle from above. At 30 cm to 50 cm GSD you're not resolving tyres, mirrors, or decals. You're resolving shape, and shape is enough once you know what you're looking for.

Reading the silhouette

A rigid frame truck (the classic Cat 793/797 or Komatsu 930E body style) has one continuous chassis. From directly overhead it reads as a single solid rectangle, slightly wider at the rear where the dump body sits than at the cab end. There's no break in the outline. The tray often overhangs the rear axles a touch, giving the back end a squared-off, almost blunt look compared to the tapering front.

An articulated dump truck (ADT) is built in two pieces joined by a hinge, and that hinge shows up in the overhead view as a visible kink. Instead of one clean rectangle you get two shorter segments meeting at an angle, with the tractor unit narrower than the box behind it. On a straight haul road the bend is subtle. On a curve, or where a truck is mid-turn into a loading bay, the articulation point is obvious even at VHR resolution because the two halves are pointed in slightly different directions.

Shadow helps confirm what the plan view hints at. Late morning or mid-afternoon passes throw a shadow long enough to trace the body outline even when the truck itself is low contrast against the bench. A rigid frame casts one straight shadow line. An articulated unit casts a shadow with a visible elbow in it, matching the hinge. If you've got a run of trucks on the same road and a few show that elbow while others don't, you're looking at a mixed fleet, not an imagery artifact.

Size is a rougher cue but still useful. Rigid frame trucks in the 190-400 tonne class run noticeably longer and wider than the ADTs typically used for softer ground or shorter hauls, so a consistent length difference across trucks on the same road is itself a signal, even before you look for the hinge.

Why the distinction matters off-site

For a benchmarking exercise, truck type feeds straight into your cycle-time math. A rigid frame fleet on a hard, well-maintained haul road moves differently than an ADT fleet working a wet pit or a newer cut without full road prep. If you're estimating competitor activity from outside the fence, knowing if the trucks on a haul road are 793s or 730s changes what that count implies about tonnes moved, since payload capacity per truck isn't the same across the two types.

It also matters for sanity-checking your own count. If an operation is known to run rigid frame equipment and your imagery shows a run of articulated silhouettes on a haul segment, that's worth a second look before you report the number. Either the mine has brought in ADTs for a specific cut, or you're misreading the kink, and either way it's a flag rather than something to pass over.

None of this replaces walking the yard or pulling a fleet manifest. It's a read you can do from a single clean pass of VHR imagery, repeated daily, which is the whole point when you don't have access to telematics or a gate pass. Mine Fleet Activity turns that daily pass into a truck count on the haul network along with a road-condition read, so you're not manually counting rectangles on every frame.

If you're benchmarking haul fleet utilisation from outside the fence and want that count run daily instead of by hand, that's exactly the gap this product fills.