Mobile Plant

Encouraging sustainable use of quarry resources

Sustainability is a word that is seen and used more and more in recent times.

It is used by international bodies as a necessity for the world’s future, it is quoted by governments as a basis for their policies, it is used by environmental groups as a demand, it is quoted by scientists as a basis for their forecasts, and is now even seen on TV in ads promoting timber products.

It is commonly acknowledged by business as one of the essential elements of corporate governance, and can now be seen in the vision statements of public companies, in the due diligence requirements of boards of directors, and even in the corporate positioning and branding of companies.  

This is not surprising, as sustainability is arguably one of the key requirements for the continuity of life on Earth, and the world’s growing use of resources is pushing up against understood limits in some areas.

In the extractive industry in Australia all the major companies refer to sustainability on their websites, giving examples related to the environment, rehabilitation, water use, energy, waste, greenhouse gas emissions and community engagement. Obviously they are taking the subject seriously and many have annual sustainability reports.

With all this attention on sustainability by major quarry companies, does the community perceive our industry as sustainable?

The anecdotal evidence is that it does not. There are innumerable examples of applications for new or expanded quarry operations meeting significant community resistance, most often over pollution or land use issues that we often describe as “not in my backyard” (NIMBY) issues, and from this almost universal opposition the inference could be drawn that the community usually does not see us as good neighbours, or even tolerable neighbours, whose value to the community helps offset any inconvenience, such as might be thought about a hospital or a wind farm, where the community good or green credentials of sustainable energy generation are valued by the community.

So is there a case for a sustainable quarry industry as part of our community image, and does it matter?



Firstly, what is sustainability related to resources?

There is no universally accepted definition, with one of the simplest being that “a sustainable resource is a resource that is used up at the same speed that it is renewed”

This definition is commonly heard in relation to renewable natural resources, where the rate of exploitation is restricted to the rate of natural regeneration.

It can be applied to a sustainable catch rate of a fish species that needs to be restricted to the natural growth rate, and to other renewable natural resources such as forests harvested for timber and water extraction from an aquifer.

However, it is not often that the term “sustainable” is associated with natural resources that are effectively non-renewable. World oil reserves are usually considered as finite; although the Earth’s geological processes produce new oil, the time scale is infinitely greater than the human time scale.

The same is usually said of other natural resources such as minerals and construction materials quarried from the Earth. Their renewal is on a geological time scale of no practical use to humans, despite some minor renewal, or repositioning, such as sand replenishment in rivers and coastlines.

One of the most frequently quoted definitions is in the United Nations’ Brundtland Commission report, which defines sustainability as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

This definition goes beyond renewable, and implicitly considers additional elements such as total resources, usage rates and future usage patterns. This is more applicable to quarry resources.

On a global scale, the Earth will never exhaust its construction materials of rock and sand. World consumption of aggregates is about 20 billion tonnes per annum, and Australia’s is about 140 million tonnes, but rock-forming minerals constitute more than 90 per cent of the Earth’s crust, so it is impossible to globally exhaust this material or even significantly diminish it.

Therefore, applied against the Brundtland definition of not “compromising the ability of future generations to meet their own needs”, quarry resources could reasonably be classified as sustainable.

Of course, it’s not that simple, as quarry resources aren’t always located where we need them.


The location of demand for construction aggregates depends on population density, while geology controls the location and quality of the aggregate resources.

Population concentrations such as cities create demand for buildings and roads and all other aspects of urban infrastructure. As concrete is the world’s most used man-made material (about one cubic metre for every person on Earth, and much more in developed countries such as Australia), demand for aggregates for concrete and other construction materials is concentrated in population centres.

As this very same population requires land to live, work and be transported, there inevitably arises land use conflicts, pushing quarries further away from the demand (although in an absolute sense, extractive quarries occupy a miniscule fraction of the whole land area, equal to about 0.005 per cent in Germany for example3).

These land use conflicts, which sterilise quarry resources, are becoming increasingly common as more land is preserved for nature preservation, groundwater protection, animal habitat and plant biodiversity, and is driven by politicians who react to the community’s demands, often without taking a balanced view of long term resource needs.

In Europe, known gravel reserves have been reduced due to land preservation by more than 80 per cent and in Queensland a CCAA-commissioned study found known hard rock resources had been reduced due to government land use restrictions by 75 per cent.

Thus, there will probably be localised shortages of rock and sand resources around most major cities.



As transport and roads are readily available around population centres, this is not a practical limitation on supply, but as quarried construction materials are a high volume, low unit value material, the cost of increased transport distance becomes a significant and sometimes dominant factor.

This increased transport distance also has a serious environmental penalty. Extracting rock and sand in Australia produces very little carbon dioxide (about three to six kilograms of carbon dioxide (CO2) per tonne of product; hence our products are “green” from the embodied greenhouse gas perspective. However, when it is transported, the carbon dioxide emitted by trucking (1.5kg of CO2 per tonne of product) increases the embodied emissions of the delivered product significantly, such that at 10km, the embedded CO2 per tonne is four times that at the quarry gate, and more than 30 times at 100km. See Figure 1. 

To mitigate this distance issue, the EU and other authorities have adopted the “proximity principle” , which while initially applied to waste, equally applies to raw material sourcing, expressed as “raw materials should be sourced as close as possible to the location of their use”. This is a reflection of the major impact of the transport cost and environmental effect.

In addition to optimum sourcing of virgin quarried materials, there are well established means to reduce overall demand by efficient use and recycling, thereby ensuring the minimum demand for establishing new quarries.

Firstly, “efficient use” means simply to exploit a virgin resource to produce the maximum quantity of usable product for a given quarry location. This can include extraction design, processing equipment, product mix and economies of scale presented by a large quarry, and is a direction in which most quarries are now headed because of the business need for reduced costs. However, many of these efficiencies are being increasingly hampered by environmental issues of buffer zones, setbacks, vegetation offsets and sight lines, and these constraints are having the inadvertent and contrary effect of reducing extraction efficiency and hence sustainability.

Equally “efficient use” can be assisted by users such as specifying authorities tailoring or “relaxing” product standards, so the highest quality and scarcer resource is reserved for the uses of highest need, and uses that do not need the highest quality product can be met by lower quality resources.

It is fairly obvious that rock used as sub-base in a country road does not need to be of the same quality as rock used for aggregates in very high strength concrete, but some Australian authorities appear reluctant to recognise such realities.

Secondly, recycling can and is playing an increasing role in substituting for virgin resources, and is even more valuable because often it has a proximity advantage to the place of demand. A recycling centre in an exhausted quarry or on waste land near a city is well located to both receive C&D materials for processing and supply them.

In fact, because of the nature of the aggregate product, it could be said that it is not “consumed” in manufacture, such as say for oil, but is merely transformed (that is, solid rock to solid concrete), and that recycling “transforms” it back to its near original form (solid concrete to crushed aggregate). A built environment can be seen as an “urban deposit” of concrete ready for extraction through recycling.

Recycled aggregate use is increasing rapidly in Australia for suitable uses, with about 80 per cent or more of roadbase in the Sydney region being recycled C&D material. This serves the dual purpose of substituting for virgin materials and removing a potential waste product. However, because of limitations on the practicality, properties and volumes, and sometimes unnecessary limitations by specifiers, recycling can never supply a majority of total demand. Europe, with much stricter recycling laws than Australia, averages six per cent of total demand met by recycling, while its best performing countries (UK, Belgium, Netherlands) meet a maximum of 20 per cent of demand with recycled materials.

So in and around cities, we may locally run short of economic virgin quarried materials, but with an understanding of the factors affecting supply and demand, this can be mitigated.

Therefore, in a pure material supply sense, I contend that quarried materials are a “sustainable resource”.

Again, of course, that is not all the picture.


The other, no less important, component of sustainability is the peripheral, undesirable effects of the extraction, manufacturing and transport processes.

Environmental impacts such as air, noise and water pollution, water consumption, visual intrusion, ecosystem degradation, vegetation loss, increased road and rail traffic, greenhouse gas emissions and waste production are among these.

The industry seeks to minimise all these impacts – in fact, it is part of the requirement of all our approvals, and in general I suggest the industry is more and more aware of this need, and is rapidly improving its performance.

Indeed, it is generating a positive out of the necessities in such areas as reuse of depleted quarries to provide the community with cost-effective and much needed land for development, waste disposal facilities or open space recreational areas.

Rehabilitation of sites is becoming more sophisticated, with large sites affording opportunities for large-scale land reforming, creating new public use areas of great benefit to the community, which would otherwise never have been available.

The part completed and ongoing Penrith Lakes area – with its Olympic rowing course, white water rafting facility and large recreational park and water areas – is a facility of much value in western Sydney that, but for the extraction industry, could most likely not have been afforded by the community.
Finally, I would like to deal with the public perception of our industry and sustainability. It has become apparent to all of us that our industry requires a “social licence” from the community to operate. Apart from all the approval processes and legal requirements, if the community does not want or appreciate the industry, we will find it increasingly difficult to operate, eventually making the products so costly that other more expensive and less suitable substitutes may emerge.

This social licence depends on how the community perceives us, and sustainability has become a key part of public expectation.

We have been perceived by some in the community as an industry that exploits the natural environment for short term gain with little consideration of the future. But often there is little appreciation of the benefits arising from the use of our products – the roads, the offices, hospitals, the drainage systems, the airports and the homes.

I would therefore like to introduce a recent Australian definition of sustainability that I think captures this. It is from Dr Martin Parkinson, formerly the secretary to the Treasury of the Australian Government and now the Secretary of the Department of Prime Minister and Cabinet. Parkinson has said sustainability requires:

“… That each generation bequeath a stock of capital – the productive base for wellbeing – that is at least as large as the stock it inherited …”

And that:

“… For example, reducing our natural resource base and using the proceeds to build human capital or infrastructure may offer prospects of higher future wellbeing …”

This introduces the important concept of the beneficial use of our virgin resources to create valued products, as part of sustainability. As our industry supplies quarried materials that are manufactured into buildings and roads, we are adding to the infrastructure that improves the wellbeing of the community, which offsets or more than offsets the reduction in the natural resources, and hence maintains or increases sustainability.

The quarrying industry provides essential materials for the economic growth and wellbeing of society, and it does so sustainably. If we are to have a long term and prosperous future, I suggest our industry must be unashamed of its role and be much more forthright in getting this message of a sustainable and valuable industry into the community consciousness. 

Geoff West is a consultant to the quarrying industry, offering management and leadership training. He is also a former Vice President of the Institute of Quarrying Australia. For more information, email Geoff or visit his LinkedIn page.

Leave a Reply

Send this to a friend