Hoping this is updated to include the third level of Crystallizers added to Angel's Refining in version 0.12.3.

Until then, this is a quick fix to add the mining productivity bonus to Crystallizer 3: In the seablock-mining mod zip file, open control.lua in notepad. In the code, crystallizer and crystallizer-2 are each referenced 3 times. Change 'crystallizer' to say 'crystallizer-2' and change 'crystallizer-2' to say 'crystallizer-3'. This will give you the mining bonus on the level 2 and 3 crystallizers.

Obviously this is a super niche mod, many thanks to minno all these years later.

I was also hoping that there would be an update for that as they are nearly unlocked, with the changes to the game i wonder if there would be a different way to do it without invisible beacons, as it doesn't show up in the bonuses tab because they dont have a bonus and i cant see what my mining productivity is because i dont have any miners XD

also the fact that helmod has no idea that there is a bonus,
but also yes thanks to minno for making this work