I'm at Mine I and my pickaxe is Efficinecy 6, Unbreaking 3, Slicing 1, Autosmelt 1, Haste 2, LuckyMining 1, and I haven't got a single zombie spawn for like 2 days. When I first joined, I got them like every 30 seconds. Is there some level or something where you no longer get them? I saw something somewhere here on the forum that made it seem like maybe you only get them from stone, so I went to A and mined for a while, still nothing.