Your first Oritech machines are simple, but they still expect a solid stock of basic ores.

Start by looking for exposed cave ores, surface ore boulders, or a good mining route. The most important early materials are copper, iron, coal, and nickel.

Nickel is especially important because it appears in several early machine and alloy recipes. Redstone, gold, and a few diamonds will also become useful very quickly, so do not ignore them while mining.

Keep an eye out for amethyst geodes as well. You will want access to budding amethyst later when the progression path reaches fluxite production.