I read the whole article looking for some indication as to the mechanism by which the power plant or mining operation are warming the lake. If there is one, it'

I read the whole article looking for some indication as to the mechanism by which the power plant or mining operation are warming the lake. If there is one, it's not in the article. I assume offloading waste heat from the power plant and/or mining operation? That would have to be one hell of an operation to noticeably change the surface temperature of a lake that big. I wonder if anyone has anything more granular than "feels like a hot tub."