This mod introduces a 3 new resources that do not spawn in the starting area and become relevant shortly before/after blue science automation. Most crafting recipes are modified to be a little more complex, adding additional logistic challenges while (trying) to preserve the vanilla feel.
The resources are:
aluminium, won from bauxite and melted into an alloy, becomes an ingredient in lightweight appliances like robotic frames and light weight structures, but also other mid to late game entities like stack inserters, blue belts and advanced turrets.
lithium, won from lithium brine and used mainly for batteries, but also as ingredient in solid fuel, lubricant and as an alloying element in the aluminium production
quartz, which can be molten to silcium, which is used for solar panals and red+blue circuits
Also adds a small electric engine as an intermediate product for almost all things that move (inserters, assembling machines, turrets, mining drils, etc) (I know this has been done before)
I strongly recommend starting a new game with this mod.