Joel Shirriff, Global Practice Lead, Terminals & Transportation, discusses how to manage resources on remote mining sites.
As prospecting for mineral resources extends further into the hinterland, new mine sites are often located in extremely remote areas where essential utilities like water and electrical power may not be available. While many of us take access to water for granted, in some geographies it can be nearly as precious as the minerals being extracted from the earth. This makes it essential to consider new sources and means of water conservation.
Similarly, mining projects are often very energy intensive. If a project can’t tie into the existing electrical grid, it needs to generate its own power. In today’s economy, this means considering renewable and low carbon options. Notably, when developing both water and energy solutions, you must also consider them in parallel with the project’s transportation needs.
Fresh water is becoming one of the world’s most precious resources. While some remote mine sites can draw water from nearby lakes and rivers, environmental regulations may limit access to these sources or the volumes of water that can be used. For their part, many of the world’s most active mining jurisdictions are in very arid regions—like the Atacama Desert of Chile and Peru, or the desert regions of northern Africa—where water is extremely scarce. As a result, projects must both reduce their water consumption and find alternate sources of water for use in the minerals process.
Fortunately, innovative water system solutions exist. Ausenco has applied the following to recent projects:
While most tactics for water conservation are local to the mine site, they may require transportation through pipelines or conveyance of filtered tailings and waste material to a disposal site. The bigger challenge comes from the introduction of new water sources from the ocean, or return of filtrate, as the port may be quite some distance from the mine site where it’s needed. This requires the incorporation of ancillary infrastructure and a water pipeline into the project’s transportation plans to minimize the incremental costs in the utility corridor.
Unlike water, energy can come in many different forms and be transferred in equally different ways. While people often equate power supply with high voltage electrical transmission lines, alternative fuel sources and renewable energy have changed the way we think. However, there are still challenges with various alternative energy sources.
For example, while wind and solar energy are becoming more affordable, they can’t yet provide adequate or consistent power for a mining project. Hydroelectric power generation can provide consistent power if enough water is available, but it can be cost prohibitive to develop on its own for a single project. Despite having been common practice in earlier decades, the days of importing heavy fuel oil or coal to generate power are long gone.
This may explain why liquefied natural gas (LNG) has become the new hydrocarbon of choice for generating power with lower emissions. To manage the movement of LNG, options include:
No matter what configuration you select, think through the social benefit of also providing power to the local communities along the route or near your operating facilities. The people who live in these communities will likely provide labour to the mining operation. By providing power in return, miners can help improve not only employee productivity, but also quality of life for the entire community.
While miners have various options to generate power, the infrastructure investment required to become self-sufficient can be cost prohibitive. As a result, Ausenco is always looking for better ways to curtail peak energy demands, reduce total consumption and minimize environmental impacts.
One way to reduce the power required in mills and process plants is to optimize their design to enhance efficiency by, for example, designing the plant to use site topography and gravity—rather than pumps—to naturally move product from one area to another. Alternatively, for open pit mines that may be several miles away from the plant or located at a higher elevation, in-pit crushing and conveying can result in significant project savings by reducing the number of trucks. Where the overland conveyor to move product to the plant runs downhill from the mine, gravity takes over once the belt is started, so the system can generate power to feed other equipment.
Rather than investing in power generation, another option is to access existing power by moving part of the mineral process plant downstream. Although this puts more demand on the transportation system to move higher volumes of material, the net cost to the project may be considerably lower than building and operating power generation infrastructure. While there will always be a need for power at the extraction site, the reduced demands may present an opportunity to successfully use renewable energy sources.
The key here, as in all challenging mine site development, is to consider a wide range of options, test your assumptions and select solutions that deliver true value to both the company and the various project stakeholders.
As part of a mine expansion in Chile, a company recently asked Ausenco to develop a new marine terminal facility near Iquique, as well as a 160 km long slurry pipeline to deliver copper concentrate from the mine site process plant. A major component of the terminal site featured a sea water desalination plant to provide fresh water for the mine. In developing the coastal design and marine structures for this terminal, our teams incorporated both a sea water intake pipe and an outfall for brine dispersion back to the ocean. The design included a new water line and pumping stations so the company can now lift water 4,400 meters above sea level and run the slurry pipeline down to the terminal in parallel. Filtrate from the concentrate dewatering process is then incorporated back into the freshwater pipeline to reduce water consumption.
With over 90 years of industry experience, Ausenco has supported more than 500 bulk cargo operations and designed 80% of all slurry pipelines worldwide. Drawing on our extensive in-house technical expertise, we do more than provide unbiased opinions on how best to move your product from Mine to Market. We also deliver fully integrated transportation logistics systems that are fit for purpose and work holistically with both upstream production facilities and the downstream distribution network.
Looking for support on your next project? Our team of experts are ready to help, reach out to Joel Shirriff to learn more.