I calculated most optimal ratios for electric drills and electric furnaces, you will need to use Tier 1&2 speed modules to achieve intended speed boost.

Ratios for mining-smelting iron and copper:
4x 90% Electric drills = 5x 40% Electric furnaces (ratio divergence 0,25%)
6x 90% Electric drills = 7x ...

There is couple mishaps in Finnish translations.
Pipe-to-ground is translated as "Maanalainen pumppu" which means "Underground pump". Correct translation would be "Maanalainen putki" (Putki = pipe)