When fortune is put on any type of pickaxe, the fortune enchantment would no longer work and I tested this with a 4x4x4 of coal ore in creative. I would have a pickaxe without fortune and a pickaxe with fortune and mine the 4x4x4. (There were 2 of the these coal 4x4x4)  They both ended up with giving the player 64 coal. I continued to use this fortune enchantment with carrots for crops. (Due to how when you mine crops with fortune you can get more of the crop.) I planted the same range of crops and with and without fortune I got around 3 stacks of carrots. I can show you a screenshot of what I have done for my tests.