I am puzzled about the current state and history of mining precious metals in the Forbidden Lands. I can understand the collapse of mints and the Blood Mist's effect on trade and the use of currency. On my first read it seemed that the ores themselves may have disappeared. So I did wonder if the dwarves were singing them away from near the surface and using them to prepare for music which will create the next great growth of the world.
(And the perfectly circular “caldera” of the mountain within the Arina Forest is obviously from whence the first notes of the new world-making song will be heard, originating in the depths of the earth. And the great many pillared and strangely geodetically-resonant fretwork dome being build atop the mountain will help shape the song; just like Stonehenge's musically resonant properties... As Brior said elsewhere regarding the whys and whats of the mountain: (feel) “free to come up with something on your own.”)
What it appears to be is that mining for precious metals stopped during the Blood Mist, as did the minting of coins. As with British history after the departure of the Romans in 410 AD the use of coins in the Forbidden Lands seems to have declined, and economic life became a fairly primitive one based largely on barter and agriculture; Britain managed a paltry 200 years of straitened circumstances, compared to the 300 of the Blood Mist.
The statement in the PHb, page 37, “There are no silver mines in the land and no is one coining silver here” does appear be be contradicted in the GMG, page 159, “they will find that the local lord needs new slaves for his silver mine.” But not if the mine has been established post Blood Mist.
Is there more lore to be had? I have boxed set and Raven's Purge, so don't know if this is touched on in any other of the “canon” works.
I'm also curious if anything about the FbL history of coin mints and who controlled the mints is available.
I think I'll be using the history of Philip of Macedon's control of silver resources and coinage as inspiration for some world-building intrigue to entangle the PCs in.