Grinding is a type of crafting featured in Elepower that allows you to pulverize ingots, lumps and blocks into dust. Pulverizing lumps allows for ore duplication.
Pretty much every type of lump has an equivalent dust. You can put a lump in a Pulverizer or a Grindstone to get 2 dust of the same type. Afterwards, you can place the dust in a furnace to get ingots.