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Tailings ponds are among the most hazardous environments a survey crew can be asked to work on: variable-density slurry, steep submerged batter slopes, chemical exposure, and no reliable footing if a boat capsizes. The scenario below is a representative Canadian operation, not a named client, and it illustrates how UAV- and USV-mounted echo sounders let teams collect the depth and volume data they need without putting people on the water. It is offered as a typical example of the safety and efficiency gains, not as an audited set of results.
The problem with crewed bathymetry on tailings ponds
Most mine sites still need recurring bathymetric data on their tailings storage facilities: capacity and freeboard verification, deposition mapping, sediment accumulation, and inputs to dam-safety and regulatory reporting. Historically that meant a crewed boat, a single-beam transducer over the side, and two or more people on water that is rarely safe to fall into. Slurry density makes flotation and self-rescue unpredictable, access ramps are often soft, and weather windows on exposed ponds are short.
The result is a survey that is slow to mobilize, expensive to staff safely, and frequently deferred because nobody wants to send a crew out. When the data finally gets collected, coverage is sparse because a crewed boat can only run so many transects in a shift.
A representative scenario
Consider a typical Canadian operation with a roughly 40-hectare active tailings pond requiring quarterly volume reconciliation. The site safety case effectively prohibits routine crewed boating on the pond. The survey manager needs repeatable depth coverage, defensible volume figures, and a method that keeps people on the bank. This is exactly the gap that drone- and drone-mounted bathymetry systems are built to close.
The UAV and USV bathymetry approach
Two complementary tools cover most tailings-pond work. For rapid single-beam profiling flown directly over the water on a DJI airframe, the Echologger ECT 400S echo sounder is a compact, well-suited choice. For full-coverage bottom mapping from an uncrewed surface vessel, the Cerulean Surveyor 240-16 MBES delivers swath data without a crew on board.
Single-beam from the air: Echologger ECT 400S
The ECT 400S is a single-frequency sensor operating at 450 kHz with a 5-degree conical beam (-3 dB). Its measurement range runs from 0.15 m to 100 m, which comfortably covers the shallow-to-moderate depths typical of a tailings pond. The sensor itself weighs about 275 g; a full kit with SkyHub, altimeter, housing, cables, and mounts comes in around 1.6 kg in the standard housing. It ships with tilt and temperature sensors and an RS232 interface with a SkyHub connector, and it is suited to DJI platforms including the M300 RTK and M350 RTK. Flying the transducer over the water means the only thing exposed to the slurry is a sensor on a tether, not a person.
Full coverage from a USV: Surveyor 240-16 MBES
Where a single transect line is not enough, the Surveyor 240-16 brings true multibeam coverage. It operates at 240 kHz with a 16-element receive array, an 80-degree cross-track transmit beam, and a 4-degree along-track transmit beam. Angle-of-arrival processing yields sub-degree angular resolution (<1°), with range resolution quoted at 0.5% of the range setting over a 0.5–50 m measurement range. A built-in IMU provides pitch and roll compensation, and the sensor weighs 1.8 kg (2.4 kg total system) over an Ethernet plus SkyHub interface. Mounted on a small remote-controlled survey vessel, it maps the pond floor at density a single-beam boat cannot match, with the operator standing safely on shore.
Comparing the two methods
| Attribute | Crewed boat (single-beam) | UAV / USV bathymetry |
|---|---|---|
| People on the water | Two or more per survey | Zero; operator stays on the bank |
| Exposure to slurry | Direct, continuous | Sensor only, on a tether or hull |
| Coverage density | Sparse transects | Dense profiles (ECT 400S) or full swath (Surveyor 240-16) |
| Mobilization | Boat, ramp access, crew rescue plan | Backpack-portable payload or small USV |
| Weather window use | Limited by safe boating conditions | Wider; short, repeatable missions |
How the data comes together
On the drone side, the ECT 400S streams depth through SkyHub, which time-stamps and georeferences each sounding against the aircraft's RTK position. The role of SkyHub in integrating complex drone payloads is what makes single-beam-from-the-air practical: it handles payload power, logging, and synchronization so the operator can focus on flight lines. For a deeper treatment of how these workflows fit together, see the pillar guide on advanced drone surveying with SPH Engineering, and the dedicated walkthrough of drone bathymetry with the Surveyor 240-16 MBES.
For sites that also need to characterize embankment integrity or buried structures, the same airborne survey discipline extends to airborne ground penetrating radar with ZondAero. The point is that a single remote-sensing program can answer several questions a crewed boat never could.
Why managers make the switch
The driver is rarely a single dramatic number; it is the cumulative effect of removing people from a hazard, surveying more often because mobilization is trivial, and getting denser data that produces more defensible volumes. A program that was deferred for safety reasons becomes a routine quarterly task. If you are scoping a tailings or environmental survey program, you can request a quote and the Measur team will help match the right echo sounder, airframe or USV, and processing workflow to your site conditions.
Key Takeaways
- Tailings ponds expose crewed survey teams to slurry, capsize, and chemical hazards that UAV and USV methods remove entirely.
- The Echologger ECT 400S is a 450 kHz single-beam sensor with a 0.15-100 m range and a 5-degree beam, flown over the water on DJI platforms.
- The Cerulean Surveyor 240-16 MBES delivers 240 kHz multibeam coverage with an 80-degree cross-track swath and sub-degree angular resolution from a USV.
- Keeping the operator on the bank means zero people on the water and exposure limited to the sensor.
- Denser coverage produces more defensible volume and capacity figures than sparse crewed transects.
- Low mobilization effort lets teams survey more often and use shorter, safer weather windows.
- The figures here describe a representative Canadian scenario, not an audited client result.
