The mod is very nice. Problem is, when used together with Angel's, it adds stone to the gas wells (if the option to add stone is active), making them unusable, as no building is able to mine both gas and stone.
What kinds of idea are you after?
A nice idea would be making the quarries not give just one kind of mineral (plus tone), but a random mix of them, making it more difficult to separate.
Also, if you are after compatibility with other mods, it would be nice if you could detect Bob's/Angel's combination and, if they are active, the quarries would give only the modified Angel's ores not the vanilla ones (Iron, Copper, etc).
On a side note, about balancing, I feel the energy cost of the quarries way too low for the benefit they provide. I would multiply the current cost by, at least, an order of 10. I feel you should have to have, like, 5 to 6 steam engines just to power one quarry.