I think the research for productivity is very cheap.

This is the formula I found for mining speed research: count_formula = "(2^(L-6))500"
And this is the formula for the productivity research: count_formula = "(L-5)500"

It's almost as if the 2^ was forgotten :)

Its the same as base game productibvity

@Klonan
Maybe you could implement an option to use the standard-productivity technology..?

Its the same as base game productibvity

It seems to be about 5 times less? It would be nice if the cost was aligned, or maybe a shared tech?

mining-productivity-4: "2500*(L - 3)"
mining-drone-productivity-6 : "(L-5)*500"

Both for an additional 10% per level, I didn't compare the previous tech level costs as this was the obvious difference in a long game when quickly had 100's of levels.