Here is an energy plot AKA an IsaMill Signature Plot AKA a Ultrafine Grinding Test Report. This test is performed using a Netzsch Grinding lab mill.
I also include links to great articles about this powerful ultra-fine grinding technology.
1) IsaMill- 1:1 Direct Scaleup from Ultrafine to Coarse Grinding
3) Industry/Research Papers from Conferences
An IsaMill by Xtrata/Glencore is the Cadillac of ultra-fine grinding.