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.

 

Using a Hydraulic Piezometer for Long-Term Groundwater Monitoring Projects

Consistent, long-term groundwater monitoring is critical in maintaining a safe, compliant and stable geotechnical environment.

In Western Australia’s environmental and resources industries, the hydraulic piezometer offers a reliable, low-maintenance solution for gathering this data. Deployable in many different contexts, their robust design and simplicity make them ideal for long-term deployments in the toughest conditions this state has to offer.

In this article, we explain why hydraulic piezometers are ideal for long-term groundwater monitoring, how they are different from other sensors and how Monitel uses them in borehole and tailings applications.

What Is a Hydraulic Piezometer?

A hydraulic piezometer measures pore water pressure using a fluid-filled system that connects a porous ceramic tip to a remote pressure gauge. Unlike an electronic sensor, the pressure is transferred via a fluid column back to the surface, where it can be read with a Bourdon gauge or pressure transducer. Usually, the fluid will be de-aired water.

This setup means there are no sensitive electronics located at the measurement point. That makes the sensor more resilient to harsh conditions and electromagnetic interference and sets it up for reliable, long-term deployment.

Why Hydraulic Piezometers Are Perfect for Long-Term Use

Stable Readings in Low-Permeability Soils

These models are designed for clay-rich or compact soils where water movement is slow. Traditional sensors may struggle, but the hydraulic piezometer’s continuous water column ensures the stable, lag-free pressure transmission necessary for tailings dam, embankment and borehole monitoring.

Low Maintenance and High Durability

A hydraulic piezometer leaves no electronic parts exposed underground. That means they are less prone to corrosion, signal interferance and water ingress. Boasting a robust casing, they can also withstand aggressive groundwater chemistry.

Accurate Surface-Based Data Capture

Because the measurement components are located at the surface, data can be easily accessed and integrated into your preferred logging system. That means long-term systems can be scaled according to site needs and budget constraints.

Site managers can also record data manually, should they prefer.

Where We Use Hydraulic Piezometers

Tailings Dams and Retention Structures

Tailings facilities are critical in mining operations and their maintenance requires a thorough understanding of pore water pressure. To remain compliant with WA’s regulatory frameworks, site managers must monitor slope stability, seepage and other factors. The hydraulic piezometer is a popular choice for dam monitoring, offering reliable results in low-permeability zones and suffering from minimal electrical interference.

Groundwater and Borehole Monitoring

Hydraulic piezometers provide a clear picture of subsurface water pressure in boreholes. Used over time, they can reveal seasonal fluctuations, the effectiveness of dewatering programs and the long-term impacts of surrounding infrastructure and works. Highly resistant to corrosion, they can withstand saline and contaminated conditions in deeper installations.

Key Advantages of Hydraulic Piezometers

Reliable in Difficult Soils

Some sensors may falter in challenging conditions like clay or silt, but the hydraulic piezometer remains responsive and accurate. It’s water-filled systems help avoid the inaccuracies seen in some electrical sensors in those environments.

Immune to Electrical Interference

With no electronics in-ground, hydraulic piezometers are unaffected by electromagnetic interference. That makes them dependable on sites with heavy machinery and equipment.

Long-Term Operation in Harsh Conditions

The hydraulic piezometer is manufactured entirely of corrosion-resistant materials, promoting long-term performance in chemically reactive conditions and multi-year campaigns.

Compatible with Remote Logging

At surface level, these sensors can pair with pressure transducers and be connected to data loggers. With real-time, automated reporting, site managers can stay on top of compliance documentation.

Monitel’s Hydraulic Piezometer Range

Monitel utilises a hydraulic piezometer from Soil Instruments. It’s a trusted model constructed with high-quality tubing and sensor components and is compatible with most data readout systems. With a rugged design and flexible deployment options, our team have been able to successfully integrate this piezometer into groundwater monitoring systems across WA

To learn more about our range, click here.

How Monitel Delivers Hydraulic Piezometer Projects

Monitel works closely with site managers, environmental consultants and engineers to design, install and maintain piezometer monitoring systems. Our designs are tailored to each site’s geological and and regulatory context and include:

  • Customised installation plans for all site types

  • Potting and sealing techniques to preserve data integrity and reduce drift

  • Data logging integration with transducers and wireless systems

  • Scheduled site checks and system flushing for long-term accuracy

  • Reporting support to ensure your site meets DWER, WHS and internal audit requirements

Speak with Us About Long-Term Groundwater Monitoring

Whether you’re managing an emerging groundwater risk or are looking to support compliance reporting, Monitel can help. Our team construct tailored monitoring systems to address the ongoing challenges of boreholes, tailings dams and other infrastructure.

Using a hydraulic piezometer, our services combine durability and quality data with long-term value, ensuring you have the insights you need. To discuss your monitoring requirements, contact us today.

Vibrating Wire vs Hydraulic Piezometer: Which is Right for Your Project?

Piezometers can prove priceless in tracking pore water pressure in geotechnical and environmental applications. Two of the most common and versatile types are the hydraulic piezometer and the vibrating wire piezometer. Each has it’s own advantages and ideal uses and understanding those differences is the key to designing an effective and accurate monitoring system.

In this guide, we break down how each model works, where they perform best and how Monitel can support ongoing monitoring on your site. For more information, please contact our team.

What Is a Piezometer?

A piezometer is a geotechnical sensor used to measure pore water pressure. Accurate and reliable piezometer data is essential in evaluating slope stability, settlement, seepage and groundwater changes in critical applications like tailings dams, mine pit walls and borehole monitoring.

Piezometer data serves many purposes. You might be looking to prove compliance with WA regulations or are perhaps looking to improve engineering design. Regardless, proper sensor selection can have long term implications for site safety and data quality.

How They Work

They might be in the same “family” of sensors, but the HP and VWP function in two different ways.

Hydraulic Piezometers

A hydraulic piezometer operates with a water-filled system and a porous ceramic tip that allows pore pressure to equalise. Pressure is transferred through hydraulic tubing and into a surface gauge such as a Bourdon gauge or pressure transducer. They are non-electrical at depth, providing stability in chemically aggressive and electrically noisy environments.

Vibrating Wire Piezometers (VWP)

In a VWP, a diaphragm is connected to a tensioned wire. As pore pressure changes, the wire’s vibration frequency shifts – those shifts are then recorded and converted into readable pressure data. These sensors are ideal for automated or remote monitoring and are resistant to electrical interference, making them a popular choice for deep borehole installations and long-term systems.

Key Differences and Comparisons

Feature Hydraulic Piezometer Vibrating Wire Piezometer
Power at Depth No electricity required Requires electrical readout
Signal Output Surface-based gauge or 4-20mA Frequency-based data logger
Best For Low-permeability soils, corrosive or high EMI zones Remote monitoring, deep boreholes, long-term use
Sensitivity Excellent in soft clays or slow-draining soils Excellent overall, especially for changing pressure conditions
Installation More labour-intensive (requires filling system) Easier in complex sensor arrays
Durability High resistance to corrosion and EMI Rugged, stable, but less suited to chemical attack

 

Hydraulic or VWP? It Depends on Your Project

When to Choose a Hydraulic Piezometer

  • Tailings Dams: In fine-grained, low-permeability zones, hydraulic piezometers provide stable readings where electronic sensors may struggle

  • Corrosive Environments: Ceramic tips and non-metallic tubing hold up well in chemically aggressive tailings or groundwater

  • High EMI Zones: If your site houses heavy electrical infrastructure (like pumps or conveyors), hydraulic sensors will avoid any signal interference they produce

When to Choose a Vibrating Wire Piezometer

  • Deep Borehole Monitoring: VWPs are compact, accurate and can be easily integrated with multi-point borehole systems

  • Automated Monitoring: These sensors pair easily with data loggers, solar panels and remote telemetry for real-time insights

  • High-Temperature Zones: Monitel stocks high-temperature models designed for buried infrastructure, geothermal environments or tailings with heat build-up

Monitel’s Sensor Range

Hydraulic Piezometer

We stock an HP model designed by Soil Instruments. A flushable, passive sensor, it boasts a ceramic filter tip and twin fluid-filled hydraulic tubing. With an operating range of –50 kPa to 2000 kPa, it can support positive and negative pressure readings and maintains long-term stability in harsh subsurface environments.

You can read more here.

Vibrating Wire Piezometers

Monitel can supply a range of vibrating wire piezometers, each designed to address a unique environmental condition found in Western Australia:

  • VWP‑3000 Series: Designed for geotechnical and structural monitoring, with multiple filter options, 0.025 % resolution and long cable signal integrity

  • W9 Vibrating Wire Piezometer: A compact, robust sensor built for high-accuracy readings from –50 to 4000 kPa, with built-in temperature compensation and surge protection

  • W16 Kompakt Piezometer: A small‑diameter unit (19 mm) ideal for constrained installations, available in pressure ranges up to 1000 kPa with hermetic sealing and thermistor temperature sensi

Monitel’s Approach

At Monitel, we pride ourselves on a technology-agnostic approach to sensor selection. We match our systems to site conditions, reporting requirements and budgets – not brand allegiance. Whether your site suits a hydraulic or vibrating wire model, you can be confident your monitoring system is set up for success.

Our team can also support you with:

  • Sensor installation

  • Piezometer potting

  • Connection to remote data loggers and cloud-based dashboards

  • Compliance-ready reporting for mining, civil and environmental projects

Get in Touch Today and Learn More About Groundwater Piezometer Monitoring

If you’re unsure whether your project needs a hydraulic or vibrating wire piezometer, it’s important to seek professional advice. Monitel will review your soil conditions, project scope and monitoring goals to develop an effective and compliant monitoring system.

To speak with our team, please get in touch.