An AE export bus is limited to 8 unique items. If you have more than 8 ores that require processing in one machine you will need an additional export bus and another side of the machine, else you will have to build an additional machine.
Another solution would be to program an ME storage bus to all your ores. A storage bus has endless preformatting compared to the export bus, but you will need to pump the items out of the chest using whatever method you choose, should it be autarchic gates or translocators.
My ore processing system consists of 3 GT grinders. Each with an export bus. One for mercury cell grinding, the other to for all others. Once my system receives an ore, it'll automatically output them to my grinder. The products are recovered and then send to the respective processing areas. Dusts are automatically send to furnaces via export bus and tiny dusts have been preformatted into a storage bus attached to a chest. These are then pumped out into a bank of autocrafting tables formatted to creating full dusts. Those dusts are then recovered and once again, send to furnaces.
Additionally for things like quicksilver and thorium, those are automatically send to my canning machine via export bus. For things like uranium ore or iridium ore, those are automatically send to my compressor via export bus as well.
For things like compressing, if you are considering having them for "on-demand" building recipes. i.e. If you need a compressed metal block for a certain recipe, you may want to consider IC2 machines that can be overclocked. Though it would increase the energy demands, you had mentioned that is not a problem.
Consider this example for producing AE processing chips (the golden/diamond ones used in almost every AE recipe). My AE system will send the quartz to an overclocked furnace via ME interface should I need silicon. Then my system builds the raw core and then sends it back out to the same furnace to be cooked.
Another would be my diamond making system. When I request 8 diamonds, my system will send 64 coal, in 8 coal increments to my rotatory macerator, form the respective coal balls/chunks and then send them to my singularity compressor for compressing. This is achieved by using ME interfaces.
For AE automation, export buses are for things that should be done continuously. They can be controlled with level emitters, but that's another topic. Interfaces allow for programming of recipes like << 1 ingot = 1 dust >>. This is useful for times where you might need diamond dust. The system would simply understand that sending a diamond here will result in the reception of a dust.