SPT Testing in Mine Tailings & Tailings Dams: Why Sonic Drilling Delivers Geotechnical Data

Written By Irina Kopylova

Tailings Storage Facilities (TSFs) are among the most critical structures in the mining industry. Their long-term performance depends on accurate geotechnical investigations, representative soil sampling, and reliable in-situ testing.

One of the most trusted methods for assessing subsurface conditions is the Standard Penetration Test (SPT). When combined with Sonic Drilling, SPT testing provides mining companies and geotechnical engineers with high-quality data to assess tailings dam stability, foundation conditions, liquefaction potential, and environmental risks.

At Legion Drilling Australia, we perform Standard Penetration Testing (SPT)using our Comacchio MC900P Sonic Drilling Rig, providing continuous core samples and reliable SPT N-values in one efficient drilling operation.

What is a Standard Penetration Test (SPT)?

The Standard Penetration Test (SPT) is one of the world’s most widely used geotechnical field tests for determining soil strength and density.

The test is performed by driving a split-spoon sampler into the ground using a 63.5 kg hammer that falls 760 mm, in accordance with ASTM D1586 and Australian Standard AS 1289.6.3.1.

The number of hammer blows required to drive the sampler through the final 300 mm of penetration is recorded as the SPT N-value.

This value helps engineers determine:

  • Soil density

  • Bearing capacity

  • Foundation suitability

  • Relative strength

  • Settlement potential

  • Liquefaction risk

  • Engineering characteristics of tailings and natural soils

Why is SPT Testing Important for Mine Tailings?

Mine tailings are highly variable materials that often contain fine-grained sediments, sands, silts and waste rock deposited over many years.

Understanding how these materials behave under load is critical for safe tailings dam management.

SPT testing helps engineers:

  • Assess tailings density

  • Identify weak zones

  • Evaluate liquefaction potential

  • Improve slope stability analysis

  • Support foundation design

  • Monitor changes within Tailings Storage Facilities (TSFs)

  • Reduce geotechnical uncertainty

Reliable field data supports safer mining operations and better engineering decisions.

Why Sonic Drilling is the Preferred Method for Tailings Investigations

Unlike conventional drilling techniques, Sonic Drilling uses high-frequency vibrations to advance the drill casing with minimal disturbance to the surrounding material.

This provides significant advantages when drilling through saturated tailings and difficult ground conditions.

Benefits include:

  • Near 100% continuous core recovery

  • Minimal sample disturbance

  • Reduced risk of cross-contamination

  • Faster drilling rates

  • Cleaner boreholes

  • Improved sample quality

  • Better geological logging

  • Excellent performance below the groundwater table

These advantages make Sonic Drilling one of the most effective drilling methods for mine tailings investigations across Australia.

Combining Sonic Drilling with Standard Penetration Testing

Legion Drilling’s Comacchio MC900P Sonic Drilling Rig allows continuous sonic coring and Standard Penetration Testing from the same borehole.

This provides engineers with:

  • Continuous geological core

  • Reliable SPT N-values

  • High-quality soil samples

  • Efficient field operations

  • Reduced mobilisation costs

  • Faster project completion

  • Improved geotechnical confidence

Instead of relying on one testing method, engineers receive both continuous geological information and verified in-situ strength data.

Fully Automated SPT Hammer for Accurate Results

Legion Drilling uses a fully automated, safety-guarded 63.5 kg Standard Penetration Test hammer designed to provide consistent hammer energy throughout every test.

Advantages include:

  • Consistent energy delivery

  • Repeatable SPT results

  • Improved operator safety

  • Compliance with ASTM D1586

  • Compliance with Australian Standard AS 1289.6.3.1

  • Reduced operator variability

Automation improves testing accuracy and provides engineers with greater confidence in the recorded SPT N-values.

Applications of SPT Testing

Our Sonic Drilling and SPT services are commonly used for:

  • Tailings Storage Facility investigations

  • Tailings dam stability assessments

  • Mine waste investigations

  • Geotechnical site investigations

  • Foundation investigations

  • Environmental drilling

  • Contaminated land investigations

  • Dam safety reviews

  • Infrastructure projects

  • Mining developments

  • Rehabilitation projects

  • Ground improvement assessments

Supporting Tailings Dam Safety

Reliable geotechnical investigations are essential for responsible tailings management.

SPT testing combined with Sonic Drilling supports:

  • Tailings dam design

  • Dam expansion projects

  • Liquefaction assessments

  • Slope stability analysis

  • Foundation design

  • Environmental monitoring

  • Long-term tailings management

  • Risk assessments in accordance with ANCOLD guidelines

Accurate field data enables engineers to make informed decisions and improve the long-term safety of mining operations.

Why Choose Legion Drilling?

Legion Drilling is one of Australia’s leading providers of:

  • Sonic Drilling

  • Standard Penetration Testing (SPT)

  • Geotechnical Drilling

  • Environmental Drilling

  • Cone Penetration Testing (CPT)

  • Mine Site Investigations

  • Tailings Dam Investigations

  • Continuous Core Sampling

Our experienced drilling teams deliver safe, efficient and reliable drilling services across mining, infrastructure, environmental and construction projects throughout Australia.

With depots located in Brisbane, Sydney, Townsville, Albury-Wodonga and Darwin, we can rapidly mobilise to projects nationwide.

Contact Legion Drilling

If you’re planning a Tailings Storage Facility investigation, mine tailings assessment, or geotechnical drilling project, Legion Drilling has the expertise and equipment to deliver high-quality results.

Using our Comacchio MC900P Sonic Drilling Rig and fully automated Standard Penetration Testing system, we provide accurate geotechnical data trusted by mining companies, geotechnical consultants and environmental engineers across Australia.

Contact Legion Drilling today to discuss your next project and discover how our Sonic Drilling and SPT testing services can support safer, more informed engineering decisions.


Irina Kopylova
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