Hi DJ, totally awesome video as always - with mill train activity, no less! This is my favorite one of your series so far.
Just wanted to share a tip about simulating iron ore. In my 1:87 stockpile, I used aluminum oxide sandblasting media. Here's what it looks like thru the lens of my cellphone camera:
The color in the center of the pile seems a bit off, the stuff toward the left is how it appears "in person."
NOTE: You should probably try to buy it from a local vendor, to (1) save on shipping costs and (2) to see exactly what color they are selling - apparently it comes in different colors!