Is anyone else having problems with this one? I've been in Scarlet Gorge for over 2 hours now and 0 spawns/gold samples. It's almost 1am atm, so it's not like there are hoards of people snatching them up. Scarwood Reach trees the sequel?
You need to look inside the various caves where they do "mining", i found the two caves at Frayworn Rock and around Ironroot Draw to be the best, provided there aren't a 100 people camping them, you can complete it in one small area in 20 mins
As Slipmat said check the caves and tunnels where they do mine at. Like up in riverfull you can find about 10 spawns there: 2 in the cave with the spiders, 3 in the cave where you can save 3 npc's in, and the rest are in the 2 tunnels going up to the top (might be more).
I was surprised at how random the spawn timers were though, like sometimes as soon as I pick one up, it would respawn in the same place 2 seconds later, other times it would take 10 minutes before it would respawn.