By Alan Hewett
Imagine you are walking through the bush, far from civilisation. It’s a hot day and you stumble onto a creek partly hidden by overhanging trees and flowing majestically over moss covered rocks.
You kneel down and take deep, thirst quenching gulps. What could be better than drinking pure water in a pristine environment? Well, you could be in for a shock.
Not far away is an old abandoned gold mine, its ownership long forgotten. Over the years it has leached arsenic and mercury and goodness knows what other heavy metals into the creek and what you are drinking is poisoned.
There are approximately 50,000 abandoned mines throughout Australia and they have left a toxic legacy. During their operation, tailings – containing harmful compounds – were piled up on the surface or thrown into water sources where they pollute for centuries.
A more serious problem is acid and metalliferous drainage. This occurs when minerals containing sulphides are exposed to oxygen and water and form sulphuric acid. The acid then leaches into ground and surface water and affects soil, plants and animals.
Mining has been important for social and economic reasons. But mines are finite.
Although in recent years rules have been introduced to ensure rehabilitation and pollution controls, mines still present an environmental danger.
The Rum Jungle uranium mine in the Northern Territory has been closed for 48 years, yet it is still leaching dangerous chemicals into the Finniss River. The Australian taxpayer has forked out $18 million so far to clean up this mess, but it is expected that nearly $300 million will have to be spent to fully rehabilitate the area.
The mining industry uses a vast amount of water for processing and smelting. These mines are often in remote areas and use up scarce,valuable ground water.
It is important to remember that 97 percent of the earth’s water is salt, two percent is glacial and only one percent is available for mining, agriculture and drinking.
The price of gold has seen a resurgence of mines reopening, however, it takes 1690 litres of water to produce one tonne of gold ore and 773,000 litres of water to produce one kilogram of gold.
In the future which will be the more valuable commodity?