Drills' default behavior in Create vanilla is to drop exp orbs after breaking an exp-dropping block, as if the player broke it themselves.
However, if the drills are mounted on a contraption which is sent off to bore through the world (as is common), the exp is fundamentally lost unless the player babysits it just to collect the exp orbs, which kinda defeats the purpose of making a boring machine in the first place.

It'd be nice if the drills could transfer dropped exp to tanks mounted on the same contraption as they do items mined to mounted storage