Shallow debate?

Issue 19 | Autumn/Winter 2007

Photography: Melissa Di Ciero

Dr Gavin Mudd.

When it comes to uranium mining, have industry and government looked at the true long term environmental costs?
Dr Gavin Mudd is a lecturer in Environmental Engineering and his latest research gives new perspectives to the mining of mineral resources, in particular uranium.

If only we could receive a dollar for every mining company that claims to be sustainable - indeed, many mining companies now publish annual 'sustainability' performance reports as well as financial reports.

Over the past decade Australian mining companies have been at the forefront of a global paradigm shift - but how can we quantify sustainability for mining? Don't ore bodies eventually run out? Is it truly sustainable to mine environmentally contested minerals such as coal and uranium? Will mining leave a polluting environmental legacy behind?

These and related issues have been the subject of wide-ranging research carried out by Monash University's Department of Civil Engineering. The research investigates how to develop an approach to quantify 'sustainable mining', and what the trends are affecting the future sustainability of the mining industry in Australia and globally. This research focused on the sustainability of uranium mining in particular, as well as similar issues affecting the gold sector of the mining industry.

Based on this extensive research, it is now clear that, eventually, carbon dioxide emissions from uranium mining may negate any perceived greenhouse benefits from nuclear power.

The environmental costs of mining, especially in terms of energy, water, chemicals and greenhouse emissions, look set to increase over time as ore grades decline - ultimately challenging the true environmental sustainability of mining.

It is this 'environmental cost' which is at the true heart of the mining debate - not the amount of resources remaining.

Metals from primary production - mining - are typically considered to be finite and non-renewable. A given mineral deposit has a known economic size and, once mined, is exhausted - miners then searching for the next big deposit.

In Australia, there's strong evidence to suggest that exploration success will continue. There is as much gold identified in mineral deposits today as the total mined over the past 150 years. For uranium, there is more than ten times the amount known in current mineral deposits as has been produced over the past 50 years.

The real issue, however, is not whether the cycle of exploration and production can continue well into the future, but the long-term trends of ore grades, that is the amount of a given metal per tonne of ore mined. For most metals, the current ore grade is considerably lower than say 25 years ago, and sometimes drastically lower than a century ago. For gold ore, the long-term decline is by a factor of 25 or more, while for uranium, it's about 10-fold.

It is this data which has for the first time been compiled and clearly documented for Australia by the University's Department of Civil Engineering.

So, why is ore grade important? The simple answer is that society is continuing to demand an ever-increasing amount of metals. To produce an increasing quantity of metals from deposits with declining ore grades means that even more ore has to be mined and processed. The costs associated with this increase dramatically and greater amounts of energy, water and chemicals are required. This results in increased solid wastes which must be disposed of, and an increase in pollutant emissions, especially carbon dioxide or metals from the solid wastes.

The linking of raw metal production data to environmental aspects enables the future sustainability of mining to be better understood - that is, the projected environmental costs of uranium, gold and other mining is more accurately able to be quantified.

Our research confirms the need for governments and the mining industry to consider long-term projections when compiling their data and to ensure this information is made publicly available. It is only then that the commonly used term 'sustainable mining' will be recognised as little more than an oxymoron.