Mine tailings—the result of the metallurgical process to which minerals are subjected to obtain metals that will later be refined and marketed—have always represented a major problem for the mining industry, as they have not only affected the environment but also the communities near the mines, generating social conflicts between mining companies and communities. As a result, many mines have had to shut down their operations. In addition, tailings also represent economic losses for mining companies, as these mine wastes often contain concentrations of valuable metals that could be used. Given these problems, the reuse of different types of tailings has become a real challenge for the mining sector, so many mining companies are developing technologies to solve the problem of tailings—wastes that can become highly polluting if they are not treated.

Hydraulic Dewatered Stacking (HDS)

One of these innovative green technologies is Hydraulic Dewatered Stacking (HDS), a technology patented by mining company Anglo American and being tested at the El Soldado copper mining unit in Chile, where Anglo American built a 250,000 m3 capacity HDS tailings facility.

HDS arose from the need to recover water from the large volumes of wet tailings—resulting from mineral processing operations where large amounts of water are generally used to recover valuable minerals—as such tailings often cause soil liquefaction.

"HDS is a simple approach that utilizes the free draining reject sands from CPR (coarse particle recovery technology) to deliver ef­fective dewatering channels throughout the tailings mass, accelerating consolidation and driving saturation levels towards (and below) 90% - mitigating much of the liquefaction risk. The tech­nology exploits hydraulic delivery systems and although operating costs will rise the approach will deliver comparable safety, water, closure performance while still being significantly less expensive than filtered tailings. Increased costs related to monitoring and measurement can be expected, but these higher costs are necessary regardless of the technology chosen." (Newman et al., 2022)

HDS Tailings Facility in El Soldado. (2022). Anglo American. https://www.angloamerican.com/about-us/our-stories/progress-on-hydraulic-dewatered-stacking

HDS aims at geotechnical and water recovery performance of filtered tailings, but without the carbon footprint.

HDS is a very innovative green technology that I heard about very recently and that is still being tested by experts in Chile, so in the future, when this type of technology starts to be implemented in my country, I would very much like to participate in a project related to it. It will definitely be a challenge to implement a new technology in different mines since all of them present different conditions of a diverse nature.

Implementing and adapting green technologies to the conditions of a company is the challenge for the green leaders of the next generation, to which we belong.

Reference materials:

Newman P. (December 8, 2022). Progress on Hydraulic Dewatered Stacking (HDS) – El Soldado, Chile. Anglo American. https://www.angloamerican.com/about-us/our-stories/progress-on-hydraulic-dewatered-stacking

Newman P, Bruton M, Burgos J, Purrington J. (2022). Innovations in Tailings Management – Hydraulic “Dry” Stacking. Anglo American. https://www.angloamerican.com/~/media/Files/A/Anglo-American-Group-v5/PLC/about-us/stories/hydraulic-dry-stacking.pdf