When are Mine Tailings Really Mine Tailings? Lessons from Western Australia’s Mining History
Some of Kalgoorlie’s streets were once, quite literally, paved with gold.
Before 1896, rocks containing telluride minerals from the Golden Mile were not recognised as rich gold ores. They resembled pyrite-bearing tailings and were discarded, spread across cart tracks and walkways, and even used as building stone.
Once the tellurides were correctly identified, the value assigned to those materials changed dramatically.
According to the Western Australian Museum, tellurides accounted for approximately 20% of the gold in the Golden Mile deposit and ultimately produced around 300 tonnes of gold.
The material had not changed. Our ability to recognise and recover its value had.
This story provides an important lesson for the way we think about mine tailings, mineral-processing residues and industrial by-products today.
What we describe as industry “by-products” or "tailings" may not be an inherently worthless material. It may simply be a material for which we do not currently have the knowledge, technology, market conditions or economics required to extract its greatest value.
The changing value of a mineral deposit
The Greenbushes mining area in Western Australia's Southwest provides another illustration of how the value attributed to mineral resources can change over time.
Tin mining began in the area in 1888, followed by tantalum mining in the 1940s. Development of the lithium orebody commenced in 1983, and the first lithium processing plant was commissioned in 1985.
Today, Greenbushes is one of the world’s best-known lithium hard-rock operations. According to Talison Lithium, the site’s processing facilities include a plant dedicated to re-treating historic tailings. The history should not be simplified into a claim that each commodity was recovered directly from the previous commodity’s tailings. What it does demonstrate is that the commercial significance of a mineral deposit can evolve as technology, geological understanding and commodity markets change.
Material once considered uneconomic may later become valuable. Tailings produced by an earlier process may contain recoverable minerals that were not previously targeted, recognised or technically feasible to extract. This creates a difficult question for mining companies considering what to do with their residue materials: Should they use or process those materials now, or preserve them as a potential future resource?
A liability and a future resource
Mine tailings and processing residues can create significant environmental, operational and financial obligations.
They may require long-term containment, monitoring, rehabilitation and management. Their storage occupies land, and their physical or chemical characteristics may create risks that must be controlled. Finding a beneficial use for these materials can therefore be highly attractive. Suitable residues may potentially be used as:
aggregates, fillers or engineered soils
feedstocks for ceramics and other manufactured products
sources of recoverable metals or minerals
These applications may reduce storage requirements, avoid the extraction of virgin resources and create new products or revenue streams. However, using a residue now may also reduce the ability to recover something more valuable from it later. When a material is incorporated into concrete or another widely distributed construction product, recovering its mineral constituents in the future may become technically difficult or economically impractical. A tailings stockpile can therefore represent two things simultaneously:
An environmental and financial liability requiring responsible management.
A stored resource whose future value is uncertain.
This helps explain why hesitation around the reuse of tailings is not necessarily resistance to innovation. In some cases, preserving a material may have genuine strategic value.
The question is not simply whether a residue can be used
That question is useful, but it is incomplete.
A stronger question is:
Producing a technically successful construction material does not automatically demonstrate that a residue has been put to its best use.
A low-value bulk application may consume large quantities of material, but it could also foreclose a future opportunity to recover critical minerals or other higher-value constituents.
Conversely, waiting indefinitely for a hypothetical future technology can leave large volumes of material in storage while their environmental and management liabilities continue to grow. The best decision requires a balance between present and future value, technical feasibility, environmental risk and commercial reality.
From lithium residue to geopolymer binders
This issue became particularly relevant during work examining lithium aluminosilicate residue, or LASR.
LASR is generated during the processing of spodumene for lithium production. Like many mineral-processing residues, it may initially be viewed as a tailigns stream requiring storage and management. However, its aluminosilicate composition also creates the potential for it to be used within geopolymer and alkali-activated binder systems.
At the 2025 Western Australian School of Mines Minerals, Energy and Chemical Engineering Symposium in Kalgoorlie, Ramon Skane presented work titled From Tailings to Technology: Geopolymer Strategies for Lithium Mine By-Products.
The investigation used techniques including X-ray fluorescence, particle-size analysis, X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy to understand the residue’s chemistry, mineralogy, particle characteristics and microstructure. That characterisation informed its incorporation into experimental geopolymer composites. Laboratory formulations demonstrated the potential to achieve compressive strengths in the order of 15-30 MPa and above, depending on the formulation and test conditions.
These results indicated that LASR could potentially contribute to useful cementitious products. But strength was only one part of the question. A commercially credible application would also need to consider:
variation in the residue between production batches
material preparation and processing requirements
activator selection and availability
fresh and hardened performance
durability under the intended exposure conditions
production cost and practical scalability
transport distance and local demand
compatibility with existing manufacturing processes
the potential future recovery value of residual minerals
The technical question was whether the material could work in a geopolymer.
The larger question was whether that represented its most responsible and commercially valuable use.
What should be assessed before repurposing tailings?
There is no universal answer for mine-tailings valorisation. Each residue, deposit, process and proposed application must be assessed on its own merits.
A sound evaluation should consider at least five areas.
The material’s mineralogy, chemistry, particle-size distribution, morphology and microstructure influence both its technical behaviour and its potential value.
Without this information, product development can become an expensive sequence of trial mixes with limited understanding of why the results change.
The residue may contain recoverable metals or minerals that were not targeted by the original process. Their current concentrations, future market importance and the feasibility of later recovery should be considered.
A material’s total chemical composition does not, by itself, determine its environmental risk. The leaching mobility and release of constituents under realistic service and exposure conditions may also need to be assessed, particularly when a residue is proposed for use in a construction product.
The material must provide a useful and repeatable function within the proposed product.
For cementitious applications, this may include workability, setting behaviour, strength development, durability, dimensional stability and compatibility with other constituents.
A technically successful laboratory formulation is not automatically commercially viable.
Feedstock consistency, processing requirements, transport, manufacturing compatibility, regulatory acceptance, market demand and cost all influence whether an application can operate at meaningful scale.
Finally, the decision should consider what future options may be lost or created.
Can valuable constituents be recovered before the remaining material is used? Can the residue be stored in a way that improves future accessibility? Does the proposed product create durable value, or merely relocate the material?
This long-term perspective is essential when decisions made today may affect the availability of a resource for decades.
“By-product” classifications are a judgement made in time
Western Australia’s mining history demonstrates that the boundary between industry by-product and resource is not fixed.
Telluride-bearing rock once used on Kalgoorlie’s streets became valuable gold ore when its significance was understood. Greenbushes evolved as changing technology and markets created value from tin, tantalum and lithium resources, and its current operations include the re-treatment of historic tailings. Modern mine residues may undergo similar reassessment. Some will become sources of critical minerals. Some may be suitable for construction materials, geopolymer binders or other manufactured products. Others may be best treated, contained or preserved until a safer or more valuable pathway becomes available.
Responsible valorisation is therefore about understanding the material well enough to identify the use - or sequence of uses - that creates the greatest value while managing environmental and technical risk.
So, maybe an industrial by-product classified as a “tailing” isn’t an inherent property of a material. It is a judgement made at a particular moment, using the knowledge, technology and markets available at the time. The materials we discard today may be the resources future industries wish we had preserved.
Assessing opportunities for mine residues and industrial by-products
Reformix helps organisations characterise, assess and develop practical applications for mine residues, industrial by-products and alternative construction materials.
Our work can include material characterisation, environmental assessment, geopolymer and binder formulation, experimental-program design, product development, pilot-scale validation and commercialisation planning.
The objective is not simply to find any use for a residue. It is to establish whether a technically sound, environmentally responsible and commercially credible pathway exists.
If you are evaluating a mineral-processing residue or industrial by-product, contact Reformix to discuss the material, the available technical data and the potential pathways for its responsible use.
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