Why Tailings Storage Facilities Are High-Stakes Infrastructure
A tailings storage facility (TSF) — commonly called a tailings dam or tailings pond — is one of the largest structures most mining operations will ever build. These impoundments retain the fine-grained mineral waste (tailings) and process water that remain after ore processing. A single TSF at a large copper or gold mine may contain hundreds of millions of cubic metres of material and store a water pool of tens to hundreds of millions of litres.
The consequences of TSF failure are severe and well documented. The Fundão tailings dam failure at Samarco in Brazil in November 2015 released approximately 40 million cubic metres of tailings slurry, killed 19 people, and contaminated 600 kilometres of river systems. The Brumadinho tailings dam collapse in Brazil in January 2019 killed 270 people and caused devastating environmental damage across the Paraopeba River basin. Both disasters have driven fundamental changes in global TSF regulation, monitoring requirements, and engineering standards.
The International Council on Mining and Metals (ICMM) published a Global Industry Standard on Tailings Management in 2020, requiring independent review, heightened monitoring frequency, and “early warning systems” for facilities with high or extreme potential consequences. Regulators in Canada, Australia, South Africa, and the European Union have introduced or strengthened monitoring requirements in recent years. The direction of regulation is clearly toward more frequent, more automated, and more independently verified monitoring.
The Limits of Manual Monitoring
Traditional tailings facility monitoring has relied heavily on manual survey methods: periodic staff measurements of freeboard (the distance from the water surface to the top of the embankment), manual gauge readings, and ground survey benchmarks to track embankment movement. For many smaller or lower-risk facilities, this approach was accepted practice for decades.
The fundamental limitation is temporal resolution. A monthly or weekly manual survey provides a snapshot at the moment of measurement. It cannot reveal what happened between surveys — whether freeboard dropped sharply during a heavy rainfall event and then recovered before the next inspection, or whether the water level has been trending steadily upward. By the time a manual survey reveals a dangerous freeboard condition, the window for a controlled response may be narrowing.
The 2019 Mac (Mining Association of Canada) framework document on tailings monitoring specifically notes that “real-time, continuous monitoring is superior to periodic manual monitoring for detecting dynamic events and trends” and recommends continuous instrumented monitoring at facilities with high or very high consequence classification.
Non-Contact Radar for Continuous Freeboard Monitoring
Non-contact radar level transmitters are well suited to tailings pond water surface monitoring for several reasons specific to the environment:
No contact with process fluid. Tailings water chemistry varies widely — often acidic, with elevated concentrations of heavy metals, sulphates, and process reagents. Contact-based level sensors corrode or foul in this environment. A non-contact radar transmitter mounted above the water surface is unaffected by water chemistry.
Weather independence. Radar microwave signals penetrate fog, dust, and light precipitation — common conditions at open tailings facilities in various climates. Ultrasonic sensors, which are an alternative for non-contact level measurement, are sensitive to temperature gradients and wind conditions that affect the speed of sound in air. Radar is not subject to these errors.
Long range measurement capability. Modern radar level transmitters measure reliably over ranges of 30 metres or more. This covers the full range of typical freeboard conditions without the sensor needing to be repositioned as water levels change seasonally.
Low maintenance requirements. Instruments installed at remote outdoor monitoring points must be reliable without frequent site visits. Non-contact radar transmitters have no moving parts and no wetted components that require cleaning or replacement. Power supply via solar panel and data communication via cellular or satellite telemetry make fully remote operation practical.
Multi-Point Monitoring Networks and 3D Mapping
Large TSFs — which may span hundreds of hectares — cannot be adequately monitored by a single measurement point. Water levels, beach elevations, and embankment conditions vary around the perimeter. Progressive mining operations now deploy networks of radar sensors at multiple monitoring stations around the facility perimeter, creating continuous data from multiple points simultaneously.
When combined with periodic drone-based LiDAR or photogrammetric surveys, multi-point continuous water level data enables construction of three-dimensional surface maps of the facility. These maps reveal not just the current water elevation at each point, but the beach slope geometry — the angle and width of the exposed tailings beach between the embankment crest and the water’s edge. Beach slope is a critical indicator of embankment stability in many TSF designs; changes in beach slope can indicate embankment settlement or deformation before visible signs emerge.
SCADA Integration and Automated Alerts
Continuous radar level data from TSF monitoring stations is most valuable when integrated with SCADA or a dedicated environmental monitoring platform. Integration enables:
Real-time freeboard calculation. The transmitter measures water surface elevation; the control system subtracts from the known embankment crest elevation to calculate freeboard continuously. Alarm thresholds trigger when freeboard falls below defined minimum values — allowing operators to respond before a critical condition develops.
Rainfall correlation. Integrating level data with on-site rainfall gauges allows the monitoring system to distinguish normal water level rise during heavy precipitation from anomalous rises that might indicate embankment seepage or other structural concerns.
Regulatory reporting automation. Many jurisdictions now require regular reporting of TSF freeboard data to regulatory bodies. Automated data logging from continuous sensors provides the timestamped records required for compliance reporting without manual data entry.
Emergency notification. When freeboard approaches a critical minimum, automated notifications via SMS or email to on-call engineers, mine management, and regulators allow a rapid, coordinated response — not a delayed reaction after an overnight event is discovered the next morning.
The Bottom Line
The global mining industry’s approach to tailings facility risk has changed fundamentally since 2015. The expectation of regulators, insurers, and communities is that high-consequence facilities are monitored continuously, not periodically. Non-contact radar level monitoring networks provide the continuous, weather-independent, low-maintenance measurement infrastructure that makes this possible at practical cost.
A radar monitoring network across a large TSF represents a small fraction of the facility’s total construction and operating cost — and a fraction of the cost of a single regulatory enforcement action or environmental incident response. The risk-reduction case is straightforward.