we THINK both, but the way the RNG is so messed up, it's possible for a human to do the same amount of digging, and get a lucky streak, and outperform the Elf. In fact, I knew of a couple times where my human and a guildmate's elf, would usually have one of the characters get 3-4 times the gems as the other, that way - and it was just as likely to be the human as the elf.
%#$%#$%^ RNG.....