A single high level digger/crafter can make roughly a million dappers from 3 packers worth of choice mats, that's 6 bags.
So 100 million is 600 bags, or around 30.000 mats.
With a careplanner, you can dig a bag in about half an hour.
Given a number of bots (andd goldfarmers tend to use bots), say 4 teams of digger+cp'er botted, they could thus dig 8 bags per hour.
4 days to farm that 100 million for a small goldfarmer, if he's (as is typical) a Chinese company running the toons 24/7.
Edit: There have been people farming mats that way to grind crafting and they weren't goldfarmers, so this isn't theoretical
