The only way to check the brake is to visually look at it..
I'm not sure if the Mintex have a squeel layer built into them or not.. I'm on my 2nd front set of the mintex pads, they have a very good life, On my second set I've been to two national tours on my current ones and about 10 local events with 4-6 runs at each event. Seems strange, check visually if there is a sharp difference in the fronts, I would say something isn't right. But check first, it might just be brake dust, or something.
