When we talk about the Hermosa Difference, it means aspiring to set a new bar for sustainable mining in the 21st century by designing and building Hermosa from the ground up with advanced technology and techniques that make it safer and more environmentally conscious.
As a Tailings Facility Engineer at Hermosa, tailings management is my area of expertise and a prime example of how we’re using advanced technology and techniques to be safer and more environmentally conscious.
We are designing Hermosa as an underground mine, meaning it has a significantly smaller surface footprint than open pit mines, requiring just 750 acres. That design also includes particular attention to water management. In fact, Hermosa will use 75% less water than other area mines.
Part of our ability to drastically reduce water use can be attributed to how we approach tailings management. As one of the first mining projects in the United States to use “dry-stack tailings” storage, the Hermosa project is deploying a proven, innovative technique to help bolster its sustainability.
Tailings, the leftover materials from processing that mostly consist of finely ground rock, are traditionally stored with a high moisture content. We are differentiating ourselves by using a facility that will filter the tailings and remove most of the water that comes with them. Once treated, that water then gets recycled throughout the site for other purposes.
Following that process, the tailings will be stored in a dry stack. This means an extremely low water content, making the structural components of the tailings deposit safer and more stable in the short and long term and limiting impacts on the environment and the local community.
Also as part of our tailings management, the Hermosa project intends to approach its underground mining effort by backfilling the stopes, which are tunnels or spaces used to access the minerals, as we progress.
The backfill materials will be the post-mining native rock that has no mineral value, treated to a consistency that allows it to be injected like a paste and dried to a cement-like state. Called “cement paste backfill,” this advanced method greatly reduces the volume of stored tailings on the surface.
One of the things that is most exciting for me is that there are not many dry stack tailings facilities in the U.S. This is a proven, advanced approach in tailings management. I am excited to work on this project and adapt the tailings management process to this advanced technology.
South32 has committed to complying with the global industry standards on tailings management for all of its operations, including Hermosa. This standard requires mining companies to take a risk-based approach to the design, construction, and operation of tailings facilities, which means prioritizing health, safety, and sustainability. It’s a strong commitment where mining companies consider the points of view of stakeholders including local community members, with the objective of designing and building this facility with the highest standards. That’s the Hermosa Difference in action.