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How to Make Mining Water Sustainable

I was surprised to read that mining uses about 20% of the earth’s water. Although nearly everything needs water for production, such as food, plastic or cars, I couldn’t help but wonder why on earth so much water was needed for mining. Was it to rinse off huge, sparkling diamonds, or perhaps to quench the thirst of hard working miners? Interestingly, I found that water is needed for nearly every step of mining.
 
Common types of water usage in mining include:
 
1. Mill water: water is needed to crush and grind ore (rock that has cool elements that can be extracted for money).
 
2. Mining water: water that collects in a mine and which has to be brought to the surface by water management methods in order to enable the mine to continue working.
 
3. Process water: water is needed to extract metals using chemicals.
 
Water sustainability in mining
 
Mining hasn’t done a great job in water sustainably for years due to lack of government enforcement. Luckily, many industry leaders are now encouraging the use of green technologies due to its huge cost saving benefits and the government enforcing new sustainability policies. In fact, the mining water and wastewater treatment market is expected to grow from $2.29 billion in 2011 to $3.60 billion in 2016.
 
Examples of companies adopting new, sustainable water strategies include:
 
1) Areva, Trekkopje Uranium Mine, Namibia – Switching from freshwater to seawater
 
Areva, located in a severely water restricted area of Namibia, was originally using freshwater from aquifers to run its mine. After committing to minimize its environmental impact, the company decided to switch to desalinated seawater by building the Erongo Desalination Plant approximately 50km (31 miles) from the mine. The plant produces 30% more water than is needed for the mine, which is then used for communities and other industrial sites.
 
Trekkopje Uranium Mine
source
 
2) Xstrata Copper, Lomas Bayas Mine, Chile – Reducing water evaporation
 
Xstrata Copper found that water evaporation was leading to 40% of Lomas Bayas’ total water loss. The main culprit was water usage in its leaching system where an acidic solution was sprayed over crushed ore. The company replaced its existing sprinkler system with a more advanced water efficient drip-feed system. This helped to decrease water evaporation by a staggering 54%.
 
Lomas Bayas Mine
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3) Rio Tinto, Argyle Diamond Mine, Western Australia – Water recycling
 
The Argyle Diamond Mine is located in sweltering temperatures of 104ºF (40°C) with an annual rainfall of only 750mm. Although water conservation is imperative in such a water restricted area, Rio Tinto had been using 3,500 megalitres of water from nearby Lake Argyle to run its operations in 2005. Rio Tinto now recaptures the water it uses in its processing plant and recycles almost 40% of it. This has helped to reduce water usage from Lake Argyle by an impressive 95%.
 
Argyle Diamond Mine
source
 
Although steps are being taken by companies to decrease their environmental impact, there is a long way to go before the industry heals the damage that mining has placed on local ecosystems. If you know of any companies you feel are leading the way in mining sustainability, we would love to hear from you. Send us a tweet @castagra.
 

0ba8618 Aisha Tejani
Aisha Tejani is a contributing writer of Castagra Products, a storage tank and wastewater coatings manufacturing company that is highly acclaimed for its sustainable coatings and cold weather coating applications. Castagra products are NSF-61 certified and are used by the world’s top water and wastewater contractors.