Are you sure you dodged all the red and blue ore attacks?
I had the same problem. Try to Dodge alle laser attacks and also this attack where he is rolling or throwing the stone.. if you know what i mean..
Red, blue, even white. I'm sure for 100%
Welp sorry to say but the lasers don't count for that achievement.
There are two indicators that could have given it away to you. First that only the colors red and blue are mentioned. If the lasers would matter white would be mentioned as well.
Second that the achivement is referring to ore attacks. The lasers are not based on ores.
So now for the mechanis you need to do for that achivement.
First there is the blue aoe that is either coming from the outside or the inside. The boss has a blue glowing ore in his hands during the animation which also indicates the direction.
Second the big red aoe with the blue circle safespot. The blue area may sometimes and when that happens you can and must iframe the red aoe. The boss holds a red glowing ore in his hands for this mechanic.
There is also a secondary aggro attack where he throws blue glowing rocks of which I'm not sure if they count or not. This should only matter if you are range dps or heal.
Thanks for helping. Already got it 
problem solved.
Glad you got what you wanted!
Thread closed.
