Nickel

Ferrous ore is added by Thermal Expansion. Ferrous is used to make Invar a component in several of the higher tier Thermal Expansion machines.

Processing
Ferrous ore can be smelted using any smelting machine or furnace

To double or even triple your ore out put you will need to use one of the processing machines. The dust from these machines will need to be smelted in a smelting machine or furnace.

Ferrous can be made into Ingots or Dust after which point it can be converted in to Nuggets or Storage Blocks It is also used to make Invar Ingot

World Generation
Ore world generation is controlled in the config files of the mods that add it. To have only one type of an ore generated turn off the ore generation in the config files for all but 1 of the mods. Thermal Expansion and CoFH Core offer you the ability to tweak the spawn rate of all modded and vanilla ores.

Note: GregTech Nickel is equivalent to Ferrous