The only suggestion that I can come up with to bring hammer and bomb mining in line would be to add a forge boon to hammers that increases the amount of resources dropped when breaking a seam with the hammer (kind of like Fortune from minecraft), paired with a debuff from all bombs (applied to the blocks, to counter pairing a bomb miner with a hammer-wielding partner, perhaps calling it ‘brittle’ or such like) that decreases the number of resources dropped from blocks in the blast radius and negates any effect that the luck stat and the extra drops boon would have on it.
The exact value for the increased drops from the hammer boon and the decreased drops from bomb debuff should be calculated from the metrics gathered so far, such that the yields of hammer mining and bomb mining would be adjusted to meet in the middle of the difference between the two pre-199.