SPRUCE PINE, N.C. (828newsNOW) — Two North Carolina facilities that manufacture the high-purity quartz used for making semiconductors, solar panels and fiber-optic cables have been shut down by Helene.

Sibelco and The Quartz Corp shut down operations in the Appalachian town of Spruce Pine on Thursday ahead of the storm. The town is home to mines that produce some of the world’s highest-quality quartz.

Since the storm, both companies have issued statements saying that their top priorities are making sure their employees are safe. Sibelco says some employees are “unreachable due to ongoing power outages and communication challenges.”