(yes, another Zinc related issue xd) Finding enough Zinc to do anything

I don't know if this is a result of an older model of world generation from a prior version of the pack, or if it's just me not doing something right, but it feels like Zinc is a lot more rare than other ores, especially Iron, Copper, and Tin. Especially as Zinc is required for Brass, it feels like there's not nearly enough without mining out entire chunks to gather it.

Lemme know if I should do anything, or if I'm doing anything wrong here! XD