I am playing on the Ultimate Pack currently, I started my ore processing with a Macerator, I upgraded that into a Rotary Macerator. Then a Creeper blew that up so I remade it, now my ore processing is not automated, but I use the GregTech Industrial Grinders. If you set it up so it automatically puts all the tiny piles of metals into Factorization Packagers, and takes all dusts into a bunch of furnaces (I currently do this with 7 Blulectric Furnaces), you've got a pretty good ore processing set up.
As for a zombie pigmen diamond farm: Get a Tier 5 Zombie Pigmen spawner (going to be a little hard unless you are one badass motherfucker) and make a spawner room. Put the soul cage in it, and put water leading to one hole. I don't know if water kills zombie pigmen, if it doesn't use attack turtles to slaughter those fuckers. Then you can use either Fabricators or Autocrafting tables, or an IC2 Compressor (depending on the modpack) to make gold. Then throw the gold ingots into a Fabricator or Auto crafting table with a minium stone- BOOM! DIAMONDS!
@Hydra, Minium Stones break very fast so you end up using a lot of gold and iron to make them. Also, the mod is in the pack for a reason, people like alchemy. If you don't, don't use it, but don't pull this pseudo mod user crap. If you can't stand EE so much, remove it from your launcher. I personally find this a very helpful mod early game, especially if you have GT on hard mode (like I do). Also, he wasn't asking for your opinion of the mod, he was asking how he could make a diamond farm using the mod. If you cannot help him in that question, don't bother mentioning it.