Strabo Geography 3.2.9

[9] Posidonius, in praising the amount and excellence of the metals, cannot refrain from his accustomed rhetoric, and becomes quite enthusiastic in exaggeration. He tells us we are not to disbelieve the fable, that formerly the forests having been set on fire, the earth, which was loaded with silver and gold, melted, and threw up these metals to the surface, forasmuch as every mountain and wooded hill seemed to be heaped up with money by a lavish fortune. Altogether (he remarks) any one seeing these places, could only describe them as the inexhaustible treasuries of nature, or the unfailing exchequer of some potentate; for not only, he tells us, is this land rich itself, but riches abound beneath it. So that amongst these people the subterraneous regions should not be regarded as the realms of Pluto, but of Plutus. Such is the flourished style in which he speaks on this subject, that you would fancy his turgid language had been dug from a mine itself. Discoursing on the diligence of the miners, he applies to them the remark [of Demetrius] of Phalaris, who, speaking of the silver mines of Attica, said that the men there dug with as much energy as if they thought they could grub up Plutus himself. He compares with these the activity and diligence of the Turdetani, who are in the habit of cutting tortuous and deep tunnels, and draining the streams which they frequently encounter by means of Egyptian screws. ¹ As for the rest, ² they are quite different from the Attic miners, whose mining (he remarks) may be justly compared to that enigma, ³ What I have taken up I have not kept, and what I have got I have thrown away. Whereas the Turdetanians make a good profit, since a fourth part of the ore which they extract from the copper mines is [pure] copper, while from the silver mines one person has taken as much as a Euboean talent. He says that tin is not found upon the surface, as authors commonly relate, but that it is dug up; and that it is produced both in places among the barbarians who dwell beyond the Lusitanians and in the islands Cassiterides; and that from the Britannic Islands it is carried to Marseilles. Amongst the Artabri, ⁴ who are the last of the Lusitanians towards the north and west, he tells us that the earth is powdered with silver, tin, and white gold, that is, mixed with silver, the earth having been brought down by the rivers: this the women scrape up with spades, and wash in sieves, woven after the fashion of baskets. Such is the substance of what [Posidonius] tells us concerning the mines [of Iberia].