724 mining, quarrying, and salt making: The Islamic World Mining in the Hapsburg Empire benefited from regal protection and support, and much of the imperial expansion was financed by profits from the mining industry In 1347 King Magnus Eriksson of Sweden visited the mine in Falun, then the world’s largest copper producer, and issued the Charter of Privileges; in 1360 he set out detailed mining regulations to improve regal control over production Some time later the Schwaz district of Tirol (in present-day Austria) assumed a leading role in silver and copper production and eventually became the second-largest city in the empire, after Vienna Mining towns in Schwaz and throughout central Europe were given their own relatively liberal social and economic regulations, primarily to attract people to settle the less-arable mountain lands Toward the end of the Middle Ages, the importance of the Schwaz district was documented by the Schwazer Bergbuch (The Schwaz Mining Book, 1556), the earliest book to describe mining regulations and laws and to illustrate mining practices and technical inventions In the same year Georg Agricola published his famous De re metallica (On the Nature of Metals), a systematic compendium on mining and metallurgy, including geological and technical aspects; the book veered from the purely descriptive approach and thus appealed to the more inquisitive minds of Renaissance and early-modern readers By the time those two volumes were published, capitalist companies—such as those of the Fugger and Turzo families, with their continent-wide trade networks—dominated much of the European mining industry and trade in metals, providing the finances to set up or modernize mines and to market their products Two methods dominated underground mining throughout the Middle Ages: fire setting and mining with iron tools By setting an open fire against a rock face, hard rock could be weakened as a result of its expanding and contracting as it was first heated and then cooled Fire setting produces adits and galleries with characteristic rounded cross sections, often reaching diameters in excess of 30 feet; it was used for mining massive ore bodies, such as the tin-rich stocks in Saxony and the Bohemian Erzgebirge For more-limited ore bodies, such as veins and seams, iron tools (notably the hammer and pick) were used to produce adits and galleries with rectangular or coffin-shaped cross sections Typically, progress in hard-rock mining was measured in inches per week The exhaustion of superficial ore bodies and the increased depth of mines required added effort to remove water, ensure sufficient ventilation to facilitate fire setting, and maintain acceptable working conditions Draining a large mine often required building an adit at the lowest possible level specifically to allow water to flow into the valley; all productive mines above the large mine had to pay one-tenth of their ore to the large-mine owner, in addition to the one-tenth they paid to the Crown Explosives such as gunpowder, although known during the Middle Ages, were not used in mining until the early 17th century An elaborate system of specialized labor maximized production and effective use of power The ore was sorted underground according to grade, and each grade was hauled separately, with the rich ore kept in locked wooden boxes Barren material and host rock were used to refill old galleries, and ore was extracted very selectively Large mines were worked continuously in shifts all year, and experienced miners were sought after and often free to move from one region to another For example, one of the administrators of the Spanish mine of Guadalcanal wrote to the government in 1551 to ask for 200 or more German miners As a result of changing geological, technological, and economic conditions, the same mine could be used in different centuries to extract different metals The Rammelsberg near Goslar, for instance, was a copper mine during the early medieval period; became a lead and silver mine in the revival after the Black Death, when the rich copper ore was exhausted but advances in smelting technology made it possible to profitably extract silver from the lead ore initially left underground; and finally became a zinc mine in the 19th century, based on the sphalerite-rich ore left behind by all earlier miners Salt was vital as a component of people’s diets and as a food preservative This, combined with the scarcity of salt in particular in areas away from the shores, meant that salt commanded high prices Underground salt mining can be traced in the Dürrnberg region of Austria to prehistoric times and again from about 1200 until 1989 Medieval salt miners built solution chambers directly into the rock underground, where salt-rich solutions formed Salt was extracted from the brines by evaporation in large salt pans—riveted metal pans suspended above wood-fueled fires The forming salt was scraped from the thickening solution and pressed into cone-shaped forms; after drying, the cones were ready for trade, either whole or smashed to grains and packed in barrels The same procedure was used where natural salt springs were exploited, such as in Soest in Westphalia, where the earliest known salt production dates to the sixth century, and in Lüneburg in northern Germany, which produced much of the salt used by the fishing industry in the Baltic and North Sea The Islamic World by Tom Streissguth The Arab conquest that began in the seventh century brought a new religious, social, and economic order to the Middle East, Iran, and northern Africa From their homeland in the