Tailings management is today at the centre of a global discussion within the mining industry.
Since the tragedy taking place at the Corrego do Feijão mine in Brasil in 2019, an international panel of experts has been analyzing and discussing new standards for the management of tailings facilities.
The result is a set of guidelines released in August 2020 – the Global Industry Standard on Tailings Management – which is opening a new vision for tailing facilities and their management, including a stronger safety concept for the surrounding areas.
Besides safety, also environment and finances can benefit from innovative management of tailings. The truth is, that what has always been considered as waste, still contains a good amount of valuable product that can be recovered and reused – provided of course that the right technology is available to support this process.
In facts, most coal fines (<1mm) were previously discarded due to unavailability of processing technologies to produce a premium product for export. Further research has shown that most of the fine coal is normally contaminated by <45 µm particles which cannot properly and efficiently be removed by cyclones.
Following is what Virto-Cuccolini could experience back in 2014-15 when first testing the use of X-Line multi-frequency screening technology within the recovery of a tailing facility in Vreiheid, South Africa.
In that case, our objective was to test the ability of our X-Line rectangular screens to reduce the content of ash within anthracite coal waste fines from 35 to 16% at a yield of 40-50%. Virto-Cuccolini’s X-Line screens were installed at the recovery plant to screen about one mln tons of fines being drained from three different dumps.
In particular, a scalping screen had the task to separate the main product pumped from the pond between the oversize > 3mm and the undersize < 3 mm.
The undersize was screened by two Virto-Cuccolini’s screens at 100 µm with a flow rate of about 40 t/h, of which about 30% was a solid product. At this stage, the first macro-dewatering process took place.
After this, the product was further separated by density through four spirals and finally treated by four Virto-Cuccolini’s X-Line dewatering screens which refined the job at 250 µm, leaving the product at a final humidity of about 15%. The final product showed an ash content below 16%, which could make into metallurgical quality coal. At full production, the plant was delivering about 160-200 tons of screened product per day.
Here is the video of this incredible first experience for us: