High specific activity of radium isotopes in baryte from the Czech part of the Upper Silesian Basin- An example of spontaneous mine water treatment

Radium-bearing barytes (radiobarytes) have been known since the beginning of the 20th century. They are mainly found as precipitates of low-temperature hydrothermal solutions. In anthropogenic environments, they frequently occur as crusts on oil industry equipment used for borehole extraction, in leachates from uranium mill tailings, and as a by-product of phosphoric acid manufacturing. Recently, we recognized Ra-rich baryte as a precipitate in the water drainage system of a bituminous coal mine in the Czech part of the Upper Silesian Basin. The precipitate is a relatively pure baryte, with the empirical formula (Ba0.934Sr0.058Ca0.051Mg0.003)(Sigma 1.046)S0.985O4.000. The mean specific activity of Ra-226 was investigated by the two-sample method and it equals 39.62(22) Bq/g, a level that exceeds known natural occurrences. The values for Ra-228 and Ra-224 are 23.39(26) Bq/g and 11.03(25) Bq/g. The radium content in the baryte is 1.071 ng/g. It is clear that the Ra-rich baryte results from the mixing of two different mine waters-brines rich in Ba, Sr, and isotopes Ra-226 and Ra-228 and waters that are affected by sulfide weathering in mine works. When this mixing occurs in surface watercourses, it could present a serious problem due to the half-life of Ra-226, which is 1600 years. If such mixing spontaneously happens in a mine, then the environmental risks will be much lower and will be, to a great, extent eliminated after the closure of the mine.Web of Science102art. no. 10

3D visualization project of view-towers in the Moravian - Silesian region

Import 09/10/2006Prezenční548 - Institut geoinformatik

Minerals formed by the weathering of sulfides in mines of the Czech part of the Upper Silesian Basin

This study describes the occurrences of sulfate minerals in mines of the Czech part of the Upper Silesian Basin. This mineralization originates from the oxidation of Fe disulfides contained in the coal matrix and enclosing sediments. The oxidation occurs in the presence of formational brines and chemotrophic bacteria. The brines have a pH between 6.3 and 8.5 and total solute content of up to 300 g/l. They are rich in Na, Ca, K, Mg, Ba and Sr and Cl– is the major anion. The minerals of the pickeringite–halotrichite series with coexisting magnesiocopiapite are formed primarily in drier places and areas where the water is only slightly mineralized. In more humid places where the brines are more concentrated, a diverse assemblage of up to 20 different sulfates are found (e.g. natrojarosite, sideronatrite, metasideronatrite, tamarugite, magnesiocopiapite, bílinite, starkeyite, blödite, rozenite and siderotil). These sulfates are accompanied by halite, sulfur, goethite and a number of phases of uncertain identity, such as sulfates containing Sr and REE. This is an example of mineral paragenesis formed by weathering in a saline evaporite environment, which is extremely rare in Europe but is found in arid regions elsewhere (e.g. in the Atacama Desert in Chile).Web of Science7851286126