Ore Mountain Mining Region recognised as a UNESCO world heritage site - for which it has been nominated - it should help to preserve it for future generations as a "developing cultural landscape". From the first discovery of silver ore in 1168 in Christiansdorf in the territory of the present-day borough of Freiberg, which is part of the Freiberg Mining Field, mining was carried out uninterruptedly in the Ore Mountains until 1990. Amongst the raw materials mined over the course of centuries were ores of the metals silver, tin, zinc, cobalt, nickel, copper and lead; but anthracite and uranium were also extracted into the
Pnictogen be produced by fractional distillation of air. The principal method for producing phosphorus is to reduce phosphates with carbon in an electric arc furnace. Most arsenic is prepared by heating the mineral arsenopyrite in the presence of air. This forms AsO, from which arsenic can be extracted via carbon reduction. However, it is also possible to make metallic arsenic by heating arsenopyrite at 650 to 700 °C without oxygen. With sulfide ores, the method by which antimony is produced depends on the amount of antimony in the raw ore. If the ore contains 25% to 45% antimony by weight, then