As Pliny says in his Natural History, Book 33, dedicated to metals, there existed in antiquity a real gold rush. See http://www.antiquitatem.com/en/the-gold-rush-in-antiquity-minery-pliny
The Phoenicians arrived to Hispania early in the first millennium BC , and later Carthaginians and Greeks, attracted precisely because of its mineral wealth. From the third century BC, the Romans began their expansion from the Levant and Baetica (Andalusia) inland, to the two plateaus and northwest, attracted by its mines.
Strabo dedicates the Book III of his Geography about Iberia and tells us in Chapter 2.8, referring to the Turdetania (in other passages he refers to the peninsular Northwest):
Of the various riches of the aforenamed country, not the least is its wealth in metals: this every one will particularly esteem and admire. Of metals, in fact, the whole country of the Iberians is full, although it is not equally fertile and flourishing throughout, especially in those parts where the metals most abound. It is seldom that any place is blessed with both these advantages, and likewise seldom that the different kinds of metals abound in one small territory. Turdetania, however, and the surrounding districts surpass so entirely in this respect, that however you may wish, words cannot convey their excellence. Gold, silver, copper, and iron, equal in amount and of similar quality, not having been hitherto discovered in any other part of the world. (H.C. Hamilton, Esq., W. Falconer, M.A., Ed.)
Pliny the Elder conveys to us the same opinion in Naturalis Historia, 33.25 (78) now referred to Northwestern Hispania (Asturias, Galicia, Lusitania):
Asturia, Gallæcia, and Lusitania furnish in this manner, yearly, according to some authorities, twenty thousand pounds' weight of gold, the produce of Asturia forming the major part. Indeed, there is no part of the world that for centuries has maintained such a continuous fertility in gold (John Bostock, M.D., F.R.S., H.T. Riley, Esq., B.A., 1855)
vicena milia pondo ad hunc modum annis singulis asturiam atque callaeciam et lusitaniam praestare quidam prodiderunt, ita ut plurimum Asturia gignat. neque in alia terrarum parte tot saeculis perseverat haec fertilitas.
In the same passage which we were quoting Strabo gives us news of the gold extraction methods:
Gold is not only dug from the mines, but likewise collected; sand containing gold being washed down by the rivers and torrents. It is frequently met with in arid districts, but here the gold is not visible to the sight, whereas in those which are overflowed the grains of gold are seen glittering. On this account they cause water to flow over the arid places in order to make the grains shine; they also dig pits, and make use of other contrivances for washing the sand, and separating the gold from it; so that at the present day more gold is procured by washing than by digging it from the mines. The Galatæ affirm that the mines along the Kemmenus mountains3 and their side of the Pyrenees are superior; but most people prefer those on this side. They say that sometimes amongst the grains of gold lumps have been found weighing half a pound, these they call palœ; they need but little refining.4 They also say that in splitting open stones they find small lumps, resembling paps. And that when they have melted the gold, and purified it by means of a kind of aluminous earth, the residue left is electrum. This, which contains a mixture of silver and gold, being again subjected to the fire, the silver is separated and the gold left [pure]; for this metal is easily dissipated and fat,5 and on this account gold is most easily melted by straw, the flame of which is soft, and bearing a similarity [to the gold], causes it easily to dissolve: whereas coal, besides wasting a great deal, melts it too much by reason of its vehemence, and carries it off [in vapour]. In the beds of the rivers the sand is either collected and washed in boats close by, or else a pit is dug to which the earth is carried and there washed. The furnaces for silver are constructed lofty, in order that the vapour, which is dense and pestilent, may be raised and carried off. Certain of the copper mines are called gold mines, which would seem to show that formerly gold was dug from them. (H.C. Hamilton, Esq., W. Falconer, M.A., Ed.)
Pliny also describes in more detail the method and harsh operating conditions. He dedicates the book 33 of its Natural History to metals and he gives us valuable information. Read the article http://www.antiquitatem.com/en/the-gold-rush-in-antiquity-minery-pliny
In view of the greed and hunger for gold (Vergil and Pliny call it “sacra fames”, sacred hunger) of the Romans,it is easily understandable the justification which the historian Florus gives us about the war of Augustus against the Cantabrians and the foundation of Asturica Augusta . He says in the passage 2,33,60
The natural advantages of the place favoured his plan; for the whole district bears gold and is rich in chrysocolla, vermilion and other pigments; he, therefore, ordered that the soil should be tilled. Thus the Astures, digging deep into the ground in search of riches for others, gained their first knowledge of their own resources and wealth. (translation t by E. S. Forster, as printed in the Loeb Classical Library edition, published in 1929.)
Favebat consilio natura regionis; circa enim omnis aurifera 2est et chrysocoliae 3miniique et aliorum colorum ferax. Itaque exerceri solum iussit. Sic Astures 4nitentes in profundo opes suas atque divitias, dum aliis quaerunt, nosse coeperunt.
So northwestern Hispania was extensively prospected and exploited by the Romans. Of these mines it has been an indelible mark on the landscape and in the retina of every traveler who is fortunate to contemplate it: the “Medulas”, near Ponferrada, in the province of León, is the largest Roman “open” mine of gold, because they opened it, they opened the mountain, as I will explain.
(About the name “Medulas”, it is no agreement: some relate it to the Latin "metalla", metal , and who relates it to the name of a mythical mountain in clashes of Cantabrians against Romans, the Mons Medulius. If it is so, we have the problem of to explain the origin or meaning of Medulius.)
Nota bene: The present city of León is named not from the fierce animal of the African savannah but from “Legio Septima Gemina “ which was camping right there for protection and control of west peninsular area of strategic interest given its undoubted mineral wealth and the presence of local people always warlike. (derived from legionem , it is Leon, The Legion)
It is a ruined landscape of such beauty and a witness to the history of such importance that UNESCO declared it a World Heritage Site in 1997.
Photo: Patrimonio Natural de Castilla y León
Author: Håkan Svensson (Xauxa)
Some scholars, for example Antonio Garcia Bellido, have estimated that 500 million cubic meters were removed; if we assume a yield of 3 grams per tonne (current holdings in the area give 1.8 to 2.8 grams) for 250 years of exploitation would the extraordinary figure 1,635,000 kg. Recall that Pliny reported that these mines produced 20,000 pounds per year in the whole area.
The price, always oscillating, of gold to date July 17, 2013 is 31.39 euros in London. Applying this rate to the extracted gold, we will obtain the hardly intelligible figure for 51.322.650.000 €. This is a somewhat absurd, ahistorical and unscientific exercise, but it serves to imagine the importance that these mines had to meet the insatiable hunger for gold (Pliny called sacrum famis) of Rome.
In the “Medulas” worked continuously from 10,000 to 20,000 slaves, later manumitted, in the terrible conditions that Pliny describes (see http://www.antiquitatem.com/en/the-gold-rush-in-antiquity-minery-pliny .
Interestingly and contrary to general opinion, in this part of the Empire mine workers are free and not slaves, unlike other places.
Pliny tells us various forms of gold mining; so he says in Naturalis Historia XXXIII, 22:
indeed, there is no gold found in a more perfect state than this, thoroughly polished as it is by the continual attrition of the current. A second mode of obtaining gold is by sinking shafts or seeking it among the debris of mountains (John Bostock, M.D., F.R.S., H.T. Riley, Esq., B.A., 1855)
nec ullum absolutius aurum est, ut cursu ipso attrituque perpolitum. alio modo puteorum scrobibus effoditur aut in ruina montium quaeritur;
Thus, gold is extracted from the floodplain by the system called "ruina montium", "collapse or fall of the mountains" because the mountain was coming down literally on the strength of the water, using a technique based on hydraulic power. Pliny the Elder describes it perfectly in Book 33, 72 and 73 (33,25)
The word "ruin" is the noun of the same root as the Latin verb "ruo, ruere" meaning rush, collapse, jump.
The third method of obtaining gold surpasses the labours of the Giants even: by the aid of galleries driven to a long distance, mountains are excavated by the light of torches, the duration of which forms the set times for work, the workmen never seeing the light of day for many months together. These mines are known as "arrugiæ;" and not unfrequently clefts are formed on a sudden, the earth sinks in, and the workmen are crushed beneath; so that it would really appear less rash to go in search of pearls and purples at the bottom of the sea, so much more dangerous to ourselves have we made the earth than the water! Hence it is, that in this kind of mining, arches are left at frequent intervals for the purpose of supporting the weight of the mountain above. In mining either by shaft or by gallery, barriers of silex are met with, which have to be driven asunder by the aid of fire and vinegar; or more frequently, as this method fills the galleries with suffocating vapours and smoke, to be broken to pieces with bruising- machines shod with pieces of iron weighing one hundred and fifty pounds: which done, the fragments are carried out on the workmen's shoulders, night and day, each man passing them on to his neighbour in the dark, it being only those at the pit's mouth that ever see the light. In cases where the bed of silex appears too thick to admit of being penetrated, the miner traces along the sides of it, and so turns it. And yet, after all, the labour entailed by this silex is looked upon as comparatively easy, there being an earth—a kind of potter's clay mixed with gravel, "gangadia" by name, which it is almost impossible to overcome. This earth has to be attacked with iron wedges and hammers like those previously mentioned, and it is generally considered that there is nothing more stubborn in existence—except indeed the greed for gold, which is the most stubborn of all things.
When these operations are all completed, beginning at the last, they cut away the wooden pillars at the point where they support the roof: the coming downfall gives warning, which is instantly perceived by the sentinel, and by him only, who is set to watch upon a peak of the same mountain. By voice as well as by signals, he orders the workmen to be immediately summoned from their labours, and at the same moment takes to flight himself. The mountain, rent to pieces, is cleft asunder, hurling its debris to a distance with a crash which it is impossible for the human imagination to conceive; and from the midst of a cloud of dust, of a density quite incredible, the victorious miners gaze upon this downfall of Nature. Nor yet even then are they sure of gold, nor indeed were they by any means certain that there was any to be found when they first began to excavate, it being quite sufficient, as an inducement to undergo such perils and to incur such vast expense, to entertain the hope that they shall obtain what they so eagerly desire.
Another labour, too, quite equal to this, and one which entails even greater expense, is that of bringing river from the more elevated mountain heights, a distance in many instances of one hundred miles perhaps, for the purpose of washing these debris.(Pliny the Elder, The Natural History ; John Bostock, M.D., F.R.S., H.T. Riley, Esq., B.A., Ed.)
tertia ratio opera vicerit gigantum. cuniculis per magna spatia actis cavantur montes lucernarum ad lumina; eadem mensura vigiliarum est, multisque mensibus non cernitur dies. arrugias id genus vocant. siduntque rimae subito et opprimunt operatos, ut iam minus temerarium videatur e profundo maris petere margaritas atque purpuras. tanto nocentiores fecimus terras! relinquuntur itaque fornices crebri montibus sustinendis. occursant in utroque genere silices; hos igne et aceto rumpunt, saepius vero, quoniam id cuniculos vapore et fumo strangulat, caedunt fractariis cl libras ferri habentibus egeruntque umeris noctibus ac diebus per tenebras proximis tradentes; lucem novissimi cernunt. si longior videtur silex, latus sequitur fossor ambitque. et tamen in silice facilior existimatur opera; est namque terra ex quodam argillae genere glarea mixta – gangadiam vocant – prope inexpugnabilis. cuneis eam ferreis adgrediuntur et isdem malleis nihilque durius putant, nisi quod inter omnia auri fames durissima est. peracto opere cervices fornicum ab ultimo caedunt. dat signum ruina, eamque solus intellegit in cacumine eius montis vigil. hic voce, nutu evocari iubet operas pariterque ipse devolat. mons fractus cadit ab sese longe fragore qui concipi humana mente non possit, aeque et flatu incredibili. spectant victores ruinam naturae. nec tamen adhuc aurum est nec sciere esse, cum foderent, tantaque ad pericula et inpendia satis causae fuit sperare quod cuperent. alius par labor ac vel maioris inpendii: flumina ad lavandam hanc ruinam iugis montium obiter duxere a centesimo plerumque lapide; ……
in priore genere quae exhauriuntur inmenso labore, ne occupent puteos, in hoc rigantur. aurum arrugia quaesitum non coquitur, sed statim suum est. inveniuntur ita massae, nec non in puteis, et denas excedentes libras; palagas, alii palacurnas, iidem quod minutum est balucem vocant. ulex siccatur, uritur, et cinis eius lavatur substrato caespite herboso, ut sidat aurum.
Water from springs, rain, and melting snow was collected in large reservoirs, which led by a system of well built gravity canals to the mines themselves, over long distances. Galleries were cut into the sterile strata many metres deep that overlay the layers of auriferous conglomerate. When the sluices of the dams were opened, enormous quantities of water flowed into the galleries, which were closed at their ends. The pressure thus built up caused the rock to explode and to be washed away by the water flow, forming enormous areas of tailings, several kilometres in length. The process is vividly apparent on the working face at the main Las Médulas site. The operating face of this spectacular form of mining slowly moved across the landscape. The system of water canals and conduits has been traced over large areas of the site, and measures at least 100 km.
Interestingly this principle of pressurizing the water is currently used by modern machines of waterjet cutting, more precise and versatile than laser cutting, plasma or electric discharge to work with all types of material discharge. The technique has certainly evolved, but the general principle is that used by the Romans specialists.
In summary and as it is recognized in the own documentation by the Unesco, "The Archaeological Zone ofthe “Medulas” is thus an excellent example of historical process in which natural elements and human intervention appear constantly intertwined."
Indeed, the only thing missing to the Romans was the development of some of the most sophisticated modern technique, such as cyanide leach gold or merger of arsenic, modern technique which mining companies use today in the same area of the Northwest Hispanic. But these companies tend to have opposition from local residents groups and environmentalists because the movement of millions of tons of debris generates severe pollution.
Clear that in antiquity the Romans established a military camp and a legion, the “Legio VII Gemina " (Twin Seventh Legion) to control the area. It would be for nothing …
But the gold rush is still very high and the barriers to their removal usually are easily overcome precisely because gold itself transformed into paper money or digital money, newer yet.