A free presentation on the evolution of water quality at the Humboldt Tailings Disposal Facility (HTDF) will take place Wednesday, Nov. 15, at Northern Michigan University. It is scheduled from 1-5 p.m. in the Huron Room of the University Center. The event is sponsored by Eagle Mine and hosted by NMU’s Chemistry Department.

Devin Castendyk holds a doctorate in environmental science and is a pit-like specialist from Denver, Colo., who works as a consultant for Hatch Associates. He will address the physical and chemical processes currently used at the HTDF, the current monitoring approach used by Eagle Mine and the science behind how the facility will be closed without the need for long-term maintenance.

Castendyk’s talk is titled “The Continuing Evolution of the Humboldt Pit: from open pit mine to flooded pit to tailings disposal facility to integrated watershed.” Continuing education credits are available for professional licensing. Refreshments and light snacks will be available.

The 350-foot deep Humboldt pit formed following the closure of an open pit mine and was previously used by the Ropes Gold Mine for the disposal of ore tailings. In 2014, Lundin Mining began depositing sulfide-rich, nickel-ore tailings from the Eagle Mine into the HTDF.  This practice will continue until the mine closes in the early 2020s. Once pit water quality meets discharge limits, surface water will flow to the adjacent wetland and, ultimately, the middle branch of the Escanaba River.