Using a Hydraulic Piezometer to Support Tailings Dam Monitoring

Monitoring pore water pressure is central to understanding the integrity of a tailings dam. In WA, tailings safety is strictly regulated and it’s important to gather accurate, reliable data to support your reporting and decision making. For many, a hydraulic piezometer  is the sensor that provides that information.

In this article, we outline how hydraulic piezometers work, why they’re ideal for tailings dam monitoring and how Monitel can design a monitoring system tailored to your site.

What Is a Hydraulic Piezometer?

A hydraulic piezometer measures pore water pressure with a porous ceramic tip and fluid-filled tubing. As water pressure increases, it acts upon a fluid column within the system, with pressure measurements read via a Bourdon gauge or digital pressure sensor at the surface.

Hydraulic piezometers are ideal in circumstances where electric or vibrating wire sensors are unviable. In clay, silts or chemically aggressive environments, the simplicity, responsiveness and versatility makes this sensor a reliable choice. At Monitel, we often use the hydraulic piezometer for groundwater, tailings dam and borewell applications.

Legal Requirements for Tailings Dams

Tailings dams are amongst the most critical structures on a resources site. Elevated pressure within a dam’s walls, foundations or surroundings can lead to seepage, settlement or even structural failure. WA has addressed these dangers with several regulatory frameworks:

• Work Health and Safety (Mines) Regulations 2022

• Mines Safety and Inspection Regulations 1995

• DWER tailings management guidance

These regulations mandate proactive monitoring to identify and act upon tailings dam risks. Hydraulic piezometers provide the data necessary for compliance and ensuring public safety.

Why Hydraulic Piezometers Are Ideal For Tailings Monitoring

Highly-Responsive in Low Permeability Soils

In clay-rich tailings or compact embankments, pore water moves slowly. Whilst that can make accurate monitoring a challenge for many types of sensor, the hydraulic piezometer has no such struggle. It excels in these conditions by transmitting pressure through the de-aired fluid column, ensuring stable and consistent readings in low permeability soils. That makes them suitable for groundwater piezometer applications where electrical sensors suffer from delay and volatility.

Resistant to Electrical Interference

Hydraulic piezometers use mechanical pressure transmission, not in-ground electronics. That means they’re unaffected by electromagnetic interference and can maintain top-performance near high-voltage equipment, pumps and conveyors. On top of that, their immunity to signal noise ensures cleaner data and fewer false readings overall.

High-Performance During Long-Term Use in Corrosive Environments

Tailings and groundwater are notorious for aggressive chemicals that degrade conventional geotechnical sensors. Hydraulic piezometers boast a ceramic tip and chemically inert tubing to protect them against corrosion and long-term degradation. These features extend service life and reduce the frequency of maintenance or replacement.

Surface-Based Readouts

Because the hydraulic piezometer’s sensing element is at ground level, data can be easily accessed via Bourdon pressure gauges or integrated pressure transducers. These are house in lockable, weatherproof enclosures and can be connected to your preferred data logging system.

Monitoring Applications Within a Tailings Safety Program

In a tailings dam, hydraulic piezometers can be installed to monitor:

• Starter wall foundation checks: Assessing pore pressure before and after deposition phases

• Embankment stability analysis: Capturing trends during upstream, downstream or centreline raises

• Beach zone saturation monitoring: Watching for pore pressure buildup during and after deposition

• Post-closure assessments: Ensuring long-term water pressure stability within decommissioned cells

With reliable pore-pressure data, you can support active decision-making around response planning, dewatering requirements and risk mitigation. You also promote compliance with audits and inspections conducted by WA’s various regulatory bodies.

Monitel’s Hydraulic Piezometer Range

At Monitel, we often deploy Soil Instruments’ Hydraulic Piezometer. It operates via a passive, twin‑tube system that transmits pore pressure from a porous ceramic tip deep in the ground to a surface readout station at surface level.

The system is flushable, allowing the removal of trapped air to maintain a “hard” hydraulic circuit. It supports positive pressures up to 2000 kPa and negative pressures down to –50 kPa.

Contact Monitel to See How the Hydraulic Piezometer Can Work on Your Site

Monitel works closely with environmental and resources operators across WA to design, install and maintain tailored piezometer-based monitoring systems. Whether its a hydraulic unit or something else, our team selects the most appropriate sensor for your facility.

Should you need, we also offer remote data logging, secure alert systems and technical reporting assistance to streamline your compliance efforts and provide peace of mind.

For more information, speak with the Monitel team today.