The use of and availability of fresh water is an ongoing concern in many parts of the world. In this guest post, Emerson’s Ron Pozarski shares his thoughts on water management challenges in the mining industry.
There is an abundance of water on our planet–over 70% of Earth’s surface is water–but most of that water (97%) is salty, with only about 3% fresh water. Of the fresh water, 77% is in the form of ice and snow, 22% is stored below ground in aquifers and in the soil, and only about 1% is readily available in lakes and rivers. While we have a great amount of water, only a small amount is available for humans, agriculture, and industry. And demand is increasing twice as fast as population. Are reliable water supply, efficient use and effluent management critical to success?According to the U.S. Geological Survey (USGS), mining operations accounted for over 4 Billion gallons of water use in 2005, which accounts for only about 1% of total water use. In Australia, the National Water Commission (NWC) estimates that mining accounts for about 4% of water use.
While mining may account for a small percentage of total water use, water is crucial for mining operations and in regions with extensive mining operations, mining can be the primary consumer of water.
Increasingly scarce and tightly regulated supplies, along with increased competition for human, agricultural and other uses, are causing mines to look for alternatives. Desalination is one method, albeit an expensive one, to turn salt or brackish water into potable water. The use of SWRO (Seawater Reverse Osmosis) desalination is expanding rapidly, and should become more cost effective as that market continues to mature. In the U.S., saline water accounts for about 37% of water supplied for mining.
More research is being done identifying ways to use salt water directly in the mining process. CSIRO (The Commonwealth Scientific and Industrial Research Organisation) is Australia’s national science agency and is looking at where salt water can be used in mining, including crushing, grinding, flotation, and separation.
Recently the CSIRO project leader, Dr. Hal Aral told International Mining magazine that mines are taking desperate measures to secure water, “Highly saline underground waters are often the only water available to miners in inland Australia… And in northern Chile, seawater is pumped tens of kilometres to mine sites at higher altitudes.” Direct use of salt water and desalination can certainly help, but the cost of transportation and treatment of salt water may be prohibitive in some cases.
According to the Australian Government National Water Commission, mining plays a major role in Australia’s economy but faces a number of water management problems including:
- Lack of integration between mining operations and regional water planning processes
- No water markets or barriers to water trading in some areas
- Lack of consistency between mining sector regulations and water sector regulations
- Uncertain water supply arrangement
As a result, the Commission has proposed that wherever possible, mining activities should be incorporated into regional water planning and management. Globally, governments and industry are struggling to find a balance between the economic benefits of mining and the interests of other users. Whatever the result, we can anticipate ongoing scrutiny being given to water supply and usage as supplies tighten and competition for this resource increases.
Have you secured your supply of this precious resource for the future?