From another convo with YI (with Imperial Wazoo, another poster on i hub). Clarity would be good here. I'll try to make the call today.

On the web cam, in the middle of the picture, is a flat rectangular foundation. The mill site goes there. He said the concrete has been poured already & is set and cured completely. The flat area is it. It is covers with a tarp at present. He said to look for the steel of the pre-fab building to get bolted together soon. Yesterday, you could see the lower walls getting prepered. The workers assembled the carpentry framing