Going with your "industrialization" idea. There are some things that grow well underground and you could have the origin being a fungus that grows rapidly in the conditions created by mining, which isn't far-fetched at all.
In Colorado, for example, Bats, have taken up residence in abandoned mines. They leave their droppings on the floor of the mines, and various insects and bacteria feed on the droppings.
Come up with a way for the organism to get introduced to the mines, such as a nearby cave, maybe a cave utilized to get to the ore more quickly.... (the deposits are into the mountain several Kilometers, and going through the cave got thethem there more quickly.) Then, when introduced to the mine, there is something in the mine (the ore or tailings) that makes the organism grow much more quickly. (maybe the cave's proximity to the ore made for the right environment for it to grow at all, then when actually put in the midst of the nutrient which makes it grow faster, it's growth increases to the point where it can be gathered in more than just small quantities in the cave?