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
Period 6 element years and is used in medical applications, industrial gauges, and hydrology. Although the element is only mildly toxic, it is a hazardous material as a metal and its radioisotopes present a high health risk in case of radioactivity releases. Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with water and carbon dioxide and is