Hmm..dosnt resemble any piece of armor that Ive seen. Looks more like something thats going to be part of a display? The scale, based on the actual mill, suggest to me that its a pretty good sized piece too, not that big, but a good size.
I doubt thats a piece/part of the EVA armor, because it appears to big, and the only piece that could resemble the picture, are those 2 circular details on the EVA chest, and thats it. That is, unless the piece being milled will have a considerably large amount of work to be done to it. Thats my opinion.