Sensor technology · The case for LiDAR

Why LiDAR has become the bulk-material standard.

Three reasons in one sentence: the resolution captures actual surface shape (not assumptions), the technology is solid-state and maintenance- light, and a single system feeds stockpile, conveyor, bunker and truck data into the same dashboard.

OWL EYE®  ·  What LiDAR actually does

A laser, a clock, a 3D model.

A 3D-LiDAR sensor sweeps a near-infrared laser beam across a surface hundreds of thousands of times per second. For each return pulse it measures the time of flight — distance accurate to millimeters at industrial ranges. Stack hundreds of thousands of those distance points together and you have a point cloud: a digital twin of the actual material surface.

From a point cloud, software reconstructs the volume between the surface and the floor (or any reference plane). Calibrate the bulk-density of the material once, and volume becomes mass with the same accuracy. ±1 % at billing-grade.

Solid-state and contactless. No moving parts on most modern industrial LiDAR sensors (Livox, Hesai and certain SICK models). Nothing wears out. Nothing touches the material. Nothing requires re-calibration after a maintenance interval.

„LiDAR took bulk-material volume measurement from periodic surveying to continuous monitoring. Same accuracy, every minute, around the clock."

In production 24/7 at K+S, Aurubis, Nordzucker, proFagus, Egger, thyssenkrupp and 40+ other industrial sites across Europe.

±1 % volume accuracy
0 moving parts
24/7 continuous capture
5 – 200 m range envelope
Why LiDAR — the five core reasons

Five properties that made it the standard.

Surface-shape, not assumption

A 3D point cloud captures every contour. No "cone-shape" approximation, no per-pile shape parameter to maintain. What the surface looks like is what gets measured.

Sub-percent accuracy

±1 % volume on a calibrated install. Stable enough for billing, inventory reporting, year-end audits and FIFO control.

Per-zone, per-material

One pile can have multiple zones with different materials and densities. LiDAR resolves them by polygon; volume and mass per zone come out automatically.

Solid-state and contactless

No mechanical wear, no contact with the bulk. Optical-window cleaning every 6-12 months — that's the whole maintenance story.

One system, one dashboard

The same LiDAR platform scales to conveyor cross-section, bunker fill-level, truck load profile and mobile mapping. One software, one API surface, one team to train.

Hardened in real industry

It works because we use it ourselves.

OWL EYE® was built inside the active mining operation of the Sachtleben Minerals Group. Every spec is field-tested before it's sold — because we were the first customer.

Salt warehouses with optical fenster fully encrusted by crystal growth — OWL EYE® STOCKPILE survives with the optional compressed-air cleaning. Heavy fertilizer-plant dust — OWL EYE® BUNKERS measures through it with multi-echo signal processing. Steel-plant slag piles with thermal gradients — same OWL EYE® software stack reads them in real time.

That's why "LiDAR works" is a different statement when Sachtleben says it versus when a sensor catalogue says it. We've hit every edge case in our own operations — and engineered around each one.

„We engineered OWL EYE® for our own mining operation first. Whatever runs reliably here, runs reliably for our customers."

40+ industrial sites across Europe — sugar, salt, mining, recycling, cement, steel, ports, power.

What to look for in a LiDAR system

Five things that separate industrial from prototype.

Not every LiDAR install is created equal. Buying a sensor is the easy part — what surrounds it is what determines whether you get billing- grade data five years from now or a science project.

Material-density calibration

Volume × density = mass. The density isn't theoretical — it must be measured per material on commissioning, and re-checkable against weighbridge data on demand.

Sensor-vendor independence

Livox, Hesai, Pepperl+Fuchs, SICK — each has strengths. A platform locked to one vendor will stop being best-in-class within 36 months.

Solid-state preferred

Mechanically rotating LiDAR is fine for surveying. For 24/7 industrial — solid-state outlasts everything else by years.

Open APIs (REST, OPC UA, SAP)

Your data must flow into your existing PLC, MES, ERP. A 'black box' dashboard is a maintenance liability.

Self-cleaning option

Optional compressed-air pulse on the optical window. Closes the dust-vs-LiDAR gap; mandatory in fertilizer, salt, cement contexts.

FAQ

Why LiDAR — common questions.

The most-asked decision-relevant questions about LiDAR versus alternatives.

Comparison

When is Radar actually a better choice than LiDAR? +
Three clear cases. (1) Permanent heavy dust — cement clinker bunkers, coal silos with constant dust circulation. LiDAR's optical window blinds within hours; Radar sees through. (2) Single-point fill-level only — you don't need surface shape, just average height. Radar is simpler, cheaper to maintain. (3) Very long ranges (>300 m) — LiDAR signal-to-noise drops; Radar maintains useful return at km-scale. For everything else — clean indoor storage buildings, multi-zone piles, billing-grade accuracy, conveyor cross-sections, truck-load shapes — LiDAR's resolution wins by an order of magnitude.
Stockpile measurement vs stockpile monitoring — what's the difference? +
Stockpile measurement is a single capture event with a numeric result — volume in m³, tonnage in t, signed report. It answers the question: "How much is in this pile right now?" Manual surveys, drone flights and terrestrial laser scans are all measurements. They are point-in-time snapshots. Stockpile monitoring is a continuous stream of measurements over time, with trend, FIFO aging, dead-inventory detection and alarms. It answers: "How did this pile evolve over the shift, the week, the year — and what should we do next?" Periodic measurement is enough for audits, year-end stocktaking or due diligence. Continuous monitoring is required for operational decisions: dispatch planning, reclaim sequencing, throughput reconciliation against weighbridge tickets, alarm on overfill or unexpected reclaim. OWL EYE® STOCKPILE delivers both on the same platform: each individual scan is a fully signed measurement with ±1% accuracy, and the time-series of those scans — archived as 3D block models — is the monitoring layer. Customers run it 24/7 in live mode or on a schedule (per shift, per hour). For one-off survey-grade audits we additionally offer Bulk Inventory with a terrestrial Riegl scanner.
Doesn't dust kill LiDAR? How do you handle dusty environments? +
Dust degrades LiDAR but rarely kills it. Three layers of mitigation: (1) Multi-echo signal processing — modern industrial LiDAR returns multiple echoes per pulse and the algorithm picks the right one (the dust echo gets filtered out). (2) Optical-window cleaning — once-a-year visual inspection in normal industrial settings, every 6 months in dustier ones. (3) Compressed-air auto-cleaning — optional pulse on the window every 30 min, available on all OWL EYE® platforms for very dusty installations (cement, salt, fertilizer). In our experience: LiDAR works fine in 90 % of "dusty" industrial environments. The 10 % where it doesn't are the cases where Radar legitimately wins.
What about ultrasonic sensors? They're cheaper. +
Ultrasonic is fine for single-point fill-level in small vessels (under ~10 m, calm material, no temperature gradients). It fails on every dimension that matters for industrial bulk-material monitoring: range maxes out around 10-15 m, accuracy is ±5-10 % on uneven surfaces, dust and vapour scatter the sound waves, and there's no surface-shape information at all — just one average distance. Cost is the only LiDAR-vs-ultrasonic argument. For one small dosing hopper at €500 it's the right call. For anything stockpile-scale, the price difference is dwarfed by the inventory error you accumulate over a year.
How does LiDAR compare to a belt scale? +
Different jobs. A belt scale measures mass flow at one specific belt — accurate to 0.5-1 % when calibrated, but only at that point and only for the moving material. LiDAR measures volume in any geometry: stockpiles, bunkers, trucks, plus the cross-section of moving belts. In practice they complement each other. The belt scale is your reference for material on a single belt. LiDAR gives you stockpile inventories, bunker fill, truck-load profiles, multi-belt overview, and FIFO tracking — none of which a belt scale can do. Sachtleben uses both: LiDAR for everything stationary or geometric, belt scales as a periodic re-calibration reference for the LiDAR mass output.
How does LiDAR compare to a drone survey for stockpiles? +
Different jobs. A drone survey produces a photogrammetric point cloud from a single flight — accurate to 1–3 % with a surveyed network of ground control points and 3–5 % without, but only at that moment, only when weather and airspace cooperate, and only with a certified pilot on site. Stationary LiDAR like OWL EYE® STOCKPILE measures continuously, 24/7, in rain, dust, snow, fog and at night — no pilot, no airspace permit, no weather window. Each scan updates per-pile volume in the dashboard within minutes, so the operations team and finance work from the same live number. In practice: drones make sense for one-off as-built surveys or vast remote sites without infrastructure. For any yard where the volume number drives daily dispatch, reconciliation or contract release, continuous LiDAR is the right call. See LiDAR vs drone for stockpile monitoring for the full side-by-side.
Why not just stick with manual surveying or drone flights? +
Frequency and cost. A manual survey or drone flight gives you a snapshot — accurate (we offer it as a service ourselves), but valid only for the moment of capture. The next morning, after a shift of intake and reclaim, your inventory is wrong again. Permanent LiDAR gives you the same accuracy continuously, every 5 minutes if you want, around the clock. For a typical mid-size industrial site that runs 200+ shifts per year, the case for permanent LiDAR is not the price of the surveys it replaces — the inventory is usually surveyed one to four times a year — but the time between them, when inventory discrepancies of typically 2–4 % against book stock go unseen. Plus you get FIFO tracking, alarms, and shift-by-shift reporting that periodic surveys can't deliver at any cost.
How does LiDAR compare to a weighbridge for truck dispatch? +
For dispatch, the comparison is one-sided. A weighbridge produces one mass number per truck after a 30–60 s stop-tare-ticket cycle, and tells dispatch nothing about how the truck is loaded. A LiDAR drive-through gantry produces a full 3D load shape in 8 s: volume, per-zone fill, centre of gravity and an under-/over-fill flag — all delivered while the truck is still under the gantry. In practice this means LiDAR catches problems the weighbridge cannot see at all: a truck whose volume is correct but whose density is wrong (mixed material), a tipper loaded heavily on one side, a partial fill that the contract penalises. Dispatch decides at the gantry exit, not after the truck has already left the yard. The full side-by-side data table is on the LiDAR vs weighbridge page.
What is the throughput advantage of LiDAR vs a weighbridge? +
A single weighbridge with a stop-tare-ticket cycle of 30–60 s clears ~60 trucks per hour at peak — and that is a clean theoretical peak; real operations with a queue and ticketing fall well below it. A two-lane OWL EYE® Truck Terminal gantry, drive-through at 5 km/h with an 8 s scan, sustains 200+ trucks per hour. The throughput gap matters most during shift-change peaks at quarries and recycling yards, where a queueing weighbridge becomes the bottleneck for the entire site. The LiDAR gantry removes that bottleneck without adding personnel — drive-through means the driver does not leave the cab, no operator ticket, no scale-house manning. The full throughput line is in the LiDAR vs weighbridge data table.

Want to talk LiDAR for your site?

We survey your building, plan the sensor positions and come back with a detailed proposal — within a week. Or, if your site is wrong for LiDAR, we'll tell you so.

info@sachtleben-technology.com +49 7831 969 22-190