Many months ago I decided to see what the ratio was for mithril flakes to drop from the various node types in Lothlorien, when I say many months that is exactly what it was to get this info:
100 mithril flakes from Lothlorien metal nodes:
KHAZAD IRON ORE : 31
RICH KHAZAD IRON ORE : 54
KHZAD GOLD : 11
RICH KHAZAD GOLD : 4
as you can see from the above results the best droppers (if a mining node can be said to drop) of flakes are the K-IRON ore nodes, should point out that I didn't target any speciifc type of node, just took what there was.
Guard, 65.
Stay frosty.