Water Usage Limitation and Alternatives

As mentioned in a previous GRT article, one of the greatest impacts of climate change on the mining industry is the availability of water – now and in the future. How will the mining industry adopt water alternatives when extreme droughts become more frequent? 

Water Sustainability

Are environmental regulations, health and safety concerns or potential profit loss a concern right now?

One option is finding viable, sustainable water sources. If the mining projects are located near the coastline, a potentially viable option is a seawater and a desalination plant. However, a plant can cost from between $2 million to $1.8 billion. There is also the need to manage the brine produced from the desalinisation plant to consider. Alternatively, investment into R&D to find / develop processes that do not require copious quantities of water in mining processes. For example, the Rio Tinto Argyle Diamond Mine in North West Australia is the world’s largest single producer of diamonds, and it is located in a part of Australian where 40oC days are common. The water for the project is sourced from two dams located at Lake Argyle. The large quantity of water that was extracted for processing uses had serious impacts on the ground water levels in the surrounding local area. In 2005, the mine utilised over 3500 megalitres of water from the Argyle Lake. By 2009, they were able to reduce water usage to a mere 300 megalitres. This is water usage drop of over 95%. This was accomplished by capturing and recycling water utilised by the mines processing plant and capturing the seepage from the tailings. This water effective measure was coupled with the dewatering of the underground mine and from the surface pit operations. Water from both of these sources was collected and stored in two dams at lake Argyle.  

Alternatively, Minera Esperanza Copper mine located 180km from the city of Antofagasta in Chile is one of the driest locations on earth. The mine requires approximately 20million cubic metres of water a year to operate. To meet this demand, the mine uses untreated seawater. There is a pipe network that has been constructed to transport the seawater over 145k to the mine site from the coast of Chile. The water use process includes filtration of the seawater. Up to 80% of the water is desalinated for human use, cooling and concentrated washing. The unfortunately consequence of this desalination plant is the carbon footprint. The carbon footprint has been described to have dramatically increased since the construction of the desalination plant. Other large companies such as BHP have shown interest in this fresh water-generating alternative by announcing their plans on building a desalination plant in Chile.

However, even if mining companies do adopt a desalination plant and decide to store the water in dams, it exposes the dam to flooding, heavy erosion and land destabilisation, hence why additional support and infrastructure may need to be constructed. Whenever there are dam structures located near mines for the purpose of mine processing there a number of steps that should be taken to ensure the water is stable and suitable for use. In their product arsenal Global Road Technology have a range of products that have been specifically designed to assist in cases such as these. These products and their mechanics will be explained in a subsequent article.

Energy Alternatives

Certain considerations must be taken into account when companies apply for permission for mine development. When mining companies are granted access for mine development in a certain area, an analysis will be required to be undertaken on the range of hypothetical severe weather events that may occur in the geological area. For example, in case of severe weather events mining companies will be required to have a document that reveals alternative measures, precautions and alternative routes for processes such as diesel transportation, water shortages and social unrest, to name a few.

Secondly, what procedures will be followed if power is disabled or rail lines are out of service as a result of severe winds or cyclone activity? What alternatives are available for power, or energy storage, is this technology a viable option? All these questions, and many more will have to be resolved to ensure that the project is well structured and prepared for a variety of challenges, especially over the long term (which is harder to predict). There are a multitude of various scenarios that must be considered and mitigated for when looking at impacts of climate change on a mine site. In Australia, in particular, the climate is unpredictable and severe. The range of weather events that will have to be taken into consideration ranges from severe drought, to extreme flooding, cyclone events, high velocity wind, tornados and hail. Each scenario will have to be mitigated against individually. Each mine will have to have its own specified set of procedures and tools to deal with the situations as they arise. 

The most successful method of energy generation has been proven to be a combined effort of renewable energy and diesel generators. At this point in time, stand-alone battery systems are quite costly, especially on a commercial and industrial scale. Many of the renewable energy systems onsite are connected to use energy as produced by the renewable energy technology with a backup diesel generator if conditions change. The most effective renewable energy has proven to be solar systems, with a growing application of wind systems in recent years.

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Geophysical Analysis

Before any mining operation is approved, an extensive geophysical evaluation will be conducted on the soil and geological structures located on the mine site. These findings will be compared against the possible vulnerabilities that may be exposed to the effects of climate change. Based off these findings, a risk analysis report will be utilised to validate the risks of the project and any possible legal and financial liabilities that may result from climate change sourced disasters or accidents. An analysis is undertaken on the hypothetical severe weather events that may occur based off its geographical area. For example, if the soil structure is coupled with extreme weather, such as flooding, wind and cyclone systems, it could potentially display a domino effect of costly impact. It is fundamental that routine checks for soil and mine integrity are undertaken on a regular basis to ensure safety to the workers. 

The only certain thing is change

From the last few articles released by GRT, there has been a common relationship that has continuously come up. Challenges! In the mining industry, the range of challenges is wide, making it difficult to predict and mitigate every possibility that could occur. Almost on a yearly basis the resource industry is adapting to new conditions, which results in the adopting of new precautions, measures and mitigation techniques to keep up with the changes. The world around us is continually changing, and as those changes are integrated into our work processes, the way in which operate will change with it. These few topics discussed in this article are merely the next steps in this updating process. These are only few of a much longer list of the type of adjustments that we expect will be adopted over the next 10, 15, 20 years or even longer. The list of updates continue to grow every day, however, it is important that we continually adjust our behaviours to minimise the consequences of our actions, and adopt more efficient methods of getting the job done efficiently, effectively and cost effectively. We are simply adapting to the ways of future business.

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