The productivity boost to the sediment recipes is a nice touch to a really nice mod. However, it doesn't seem to apply to the sediment recipe itself, so infinite mining productivity research tends towards having a "mine stack" with lots of chem plants, one ore assembler, and then smelters/foundries/etc.
Would it be imbalanced, or something you've chosen against already, if the mining productivity also applied to the chemical plant sediment recipe?
[edit] completely ignore this, I modded it in myself and immediately discovered the problem: sediment-to-ore productivity doesn't affect the input quantity required, so productivity scaling throws off the ratios. A "miner" in this mod is a set of chem plants around an assembler, which sprays out more and more ore as the productivity goes higher, but the ratio itself doesn't change.