Reclaiming the Pit and Shaping the Landscape of the Future at Marlin Mine

Every mine faces a challenge: how to safely process and store their tailings. Faced with this question, the Marlin mine employees demonstrated ingenuity, suggesting a first-for-Guatemala, or anywhere in Central America: instead of hauling the material to a conventional tailings storage facility, they proposed that the open pit could be refilled with its own filtered, compacted tailings.

What are tailings?
Tailings are the waste that is left after the mined mineral has been removed from the ore. Tailings generally leave the processing plant in liquid form, which flows into tailings ponds, where the solid material settles to the bottom. Once the water has been safely removed, the muddy or sand-like material remains.

This innovative technique solves three problems at once: it eliminates the need for a separate mine tailings storage facility that requires long-term monitoring and maintenance, eliminates the environmental risk from the pit’s exposed rock surfaces, and it restores the landscape to a natural profile. And they will go one step further. Once the pit is backfilled, they will landscape and plant robust natural vegetation on the reclaimed hillside, leaving the countryside in a similar landscape before mining commenced.

Innovative technology, and a Central American first
Osiel Orozco, Marlin’s Open Pit Superintendent, and a 10-year employee, has been managing the project for three years. “This is not just a fill,” he says. “It’s an engineered structure.”

With the help of international specialists, they did extensive geotechnical, hydrogeological and geochemical modelling. In three years, over 3.2 million cubic meters of tailings have been filtered, mixed with cement, and laid in place. The structural foundation is designed to last, even in this seismically sensitive area, where drought and floods alternate with the seasons.

This is a core aspect of the mine’s closure plan, says Orozco. “This is a very expensive process and a big effort. The company is showing that it is a responsible citizen through this voluntary investment. What we are doing here is concurrent reclamation of the mine in the best way possible.”

Building a legacy
The result is more than a technological breakthrough; it’s the creation of a treed hillside. The reclaimed pit will retain water in dry seasons, support wildlife, and provide enjoyment for future generations. Says José Carlos Quezada, the mine’s General Manager of Environment, “When the mine eventually closes, you will never see where the open pit was.”

He notes that nearly everything, even the replanted trees, comes from the Marlin mine itself. The mine’s forest nursery has been in operation for 12 years, producing 150,000 trees a year. Says Quezada, “We have reforested 700 hectares in and around the mine and have exceeded environmental commitments with the National Institute of Forests. Our objective is to continue reforesting the area and hopefully reach 1,000 hectares.”

Quezada shares his vision of the legacy that the team is building. “If I come back in 10 years, I would be standing in front of the Marlin mine and I would see it completely reforested. To see the big pit we filled and what we had achieved, and to remember all the people that worked here. It will touch my heart. This is our legacy. We are leaving this place better than we found it.”

Watch the Marlin mine Water is Life video for more on the community contributions and concurrent reclamation efforts of the Marlin team. http://3blmedia.com/News/Water-Life-Clean-Water-and-Concurrent-Reclamation-Marlin-Mine