Fertilizer manufacturer Yaran Siilinjärvi has the only phosphate mine in Europe. Ore is extracted from the open pit, which has been operating since 1979. Ore is enriched into apatite concentrate. It is made into phosphorus as a raw material for fertilizers and feed phosphates. The excess aggregate from the enrichment process, or tailings, is pumped to a landfill area of approximately 500 hectares, which is growing at an annual rate of 10 million tonnes. The challenge for the dumping area is dust rising from the area in windy weather. Those side effects have been minimized by various means, such as irrigation, various chemicals and snow plows.
Decommissioned landfills are landscaped and planted with vegetation to bind dust. Yara is constantly looking for new ways to reduce harm and improve safety. At the beginning of 2020, Yara Siilinjärvi launched a modeling project with Numerola, which investigated the wind conditions in the area and also future scenarios.
– We wanted to use wind modeling to find out how different wind conditions affect the dust sensitivity of a landfill. We chose Numerola because they had convincing experience of similar projects, says Mikko Airaksinen, Yara Siilinjärvi’s infrastructure manager.
The environmental permit requires the prevention of dusting, as well as continuous monitoring and documentation. Yara Siilinjärvi wanted to find out how dust sensitivity could be proactively reduced with structural solutions, such as support embankments.
Numerola made accurate wind modeling based on flow calculations for 2020, 2025, 2030 and 2035 – taking into account the continuous change in the area, the increase in altitude and the impact of climate change on wind.
– We started cooperating with Numerola in early 2020. In the first phase, the current wind conditions in the landfill were modeled. We found that the edge and support embankments of the basins form less windy areas. This observation inspired us to order a follow-up study that modeled how lowering or raising the height of the embankments affects wind conditions.
A new type of paste disposal technology introduced a couple of years ago has reduced annual dusting. Based on the wind modeling, the area can be designed and built with solutions that further reduce dusting.
The topographies made by Numerola helped to outline the future. It is a huge area that is constantly increasing in height. We now have a clear vision of how we can leverage the results in the design and operational work of the area’s structures. We have already further refined our plans based on the results.
The collaboration with Numerola increased the understanding of the possibilities of simulation in the mining industry.
– The cooperation was smooth and rewarding in all respects. We learned a lot about the possibilities of modeling.