At FLSmidth, we understand the importance of efficient test work when confirming the applicability of gravity separation for a given ore body. We also recognise the consequences that poor testing processes can have, such as incorrect equipment selections – the addition of a gravity circuit when it is not needed – and non-representative sample data that leads to ill-informed recommendations.

We offer a test work service that follows an industry standard operating procedure, designed to provide objective results that allow you to make informed decisions with confidence. We conduct this test work in either our own SLC laboratory or in another accredited G-TEC (Gravity Technology Evaluation Centre) facility, which aims to provide consistent sample testing across the globe.

These facilities utilise a range of gravity separation equipment, including an industry-standard Knelson KC-MD3 concentrator along with other Knelson technologies. They are capable of testing a wide variety of ores and can operate a number of tests, including:

• Extended Gravity Recoverable Gold (EGRG) Testing

• Gravity Circuit Modelling

• Gravity Grade Testing

• Alluvial Gold Testing

• Gravity Amenability Testing (GAT)

• Continuous Variable Discharge (CVD) Pilot Testing

EGRG Testing

The EGRG test is a widely accepted industry test used to determine the theoretical maximum amount of gold that can be recovered from a sample. This test is a multi-stage test that utilises the KC-MD 3 Laboratory Knelson Concentrator with sequential grinding.

GRG Modelling

This test utilises a computer-generated model called KC-MOD*Pro for estimating the impact of installing a Knelson Concentrator into a grinding circuit. It can interpret results in a standard milling circuit based on several parameters. This allows you to determine whether a Knelson Concentrator would be useful at your facility prior to installation.

With our expertise, we ensure that these tests will be performed correctly, allowing you to optimise gravity concentration equipment and metal recovery procedures at your plant.

Gravity Grade Testing

Gravity Grade Testing is a derivative of the industry-standard Gravity Recoverable Gold (GRG) test. It uses enhanced gravitational forces combined with patented Knelson technology to provide a comprehensive grade estimation for the given test sample. This test is an excellent tool for those involved in resource estimation of gold where high confidence in reported results is desired.

Alluvial Gold Testing

Alluvial samples will generally be tested using a 2-pass batch test. A minimum sample size of 50 kg is recommended to reduce the difficulties of getting a representative alluvial gold sample. By examining these samples, we can help you to determine the appropriate concentrator needed.

Gravity Amenable Test (GAT)

GAT is designed to evaluate the applicability of Knelson continuous separation technology for a given ore body. The multi-pass testing protocol allows for the generation of a grade versus recovery correlation.

CVD Pilot Testing

CVD testing is designed for the testing of bulk mineral samples through the Knelson Continuous Variable Discharge Concentrator. It is performed at a pilot scale and requires at least 500 kg of sample, with the particle size not exceeding 2mm.

Improved confidence in your metal recovery processes

Utilising our test work services provides a variety of benefits, including improved flowsheets, higher confidence, and maximised metal recovery.

Improved confidence in reported results


Our test work services provide specific details needed to make informed decisions about your plant’s processes. We make sure that the information given is correct and relevant, allowing you to make changes with confidence.



Optimised flowsheets and gravity circuit selections


Our EGRG test data provides detailed liberation, GRG content and size by size GRG data which can be used for scaleup via circuit modelling, greatly assisting you with flowsheet development and optimal gravity circuit selections. Our GRG Modelling also allows you to determine the effectiveness of a Knelson Concentrator in your specific gravity circuit prior to installation.



Maximised recovery of resources


With our test work services, we are able to calculate the maximum amount of gold that can be recovered from a sample. This data, combined with our proprietary gravity circuit modelling, allows you to accurately predict the amount of gold you can expect to achieve from your process. 


Optimise gold recovery

Our test work services provide numerous features that aim to keep safety, efficiency, and quality in mind.

Test work equipment

At our accredited mineral processing laboratories, we utilise a range of equipment designed to provide the most accurate data possible. The equipment we use includes:

• Knelson KC-MD3 Concentrator

• Knelson KC-CVD6 Concentrator

• Tyler Mesh Vibrating Screens

• proprietary KC-MOD*Pro Software

• range of milling equipment.

Safety precautions

Safety is paramount when conducting any type of test work. This is why at our facilities, we ensure that qualified and appropriately trained technicians carry out the testing and that all lab safety/sample-specific safety protocols are followed.

Testing facilities

All of our testing facilities utilise a variety of technologies that are capable of completing all of the tests necessary to provide you with the correct information about your plant’s process. Stationed strategically across the globe, these facilities analyse thousands of samples each year, reducing delays and keeping customer satisfaction as the number one focus. 

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