Das Döhlener Becken bei Dresden - Unbekannter Bergbau

Abbau, zur Förderung, Wasserhaltung, Wetterführung,
radiometrischen Aufbereitung und Haldenwirtschaft im ehemaligen
Bergbaubetrieb „W. Agatz“. Methoden der geologischen
Dokumentation und der untertägigen Vorratserkundung
durch den Geologischen Dienst werden erläutert.
Das Ende der Urangewinnung durch die SDAG Wismut
bedeutete das Ende von 447 Jahren aktiven Bergbaus im
Döhlener Becken. Die bergbaulichen Arbeiten sind damit
aber noch nicht endgültig abgeschlossen. Erhebliche
Aufwendungen sind erforderlich, um die Bergbauanlagen
aus der Bergaufsicht entlassen zu können. Der
Nachfolgebetrieb WISMUT GmbH verantwortet seit 1990
die Verwahrung und Sanierung der Hinterlassenschaften
des ehemaligen BB „W. Agatz“. Mit der Erarbeitung des
WISMUT-Umweltkatasters wurden Grundlagen zur
Verwahrung und Sanierung geschaffen. Beschrieben werden
die geplanten und bereits abgeschlossenen
Sanierungs- und Verwahrungsarbeiten. Besonders ausführlich
wird die Flutung des Grubengebäudes behandelt, die
mit dem Erscheinungszeitpunkt dieser Monographie noch
nicht abgeschlossen sein wird.
Zwei ehemalige Uranerzaufbereitungsanlagen mit ihren insgesamt
6 Schlammteichen (IAA) im Raum Dresden/Freital
unterliegen laut „Wismut-Gesetz“ nicht der Sanierungspflicht
durch die WISMUT GmbH. Unter der Regie des
Umweltamtes der Stadt Dresden stehen die Sanierungsund
Verwahrungsarbeiten am Standort Dresden-Coschütz/
Gittersee kurz vor ihrem Abschluss.
Nach etwa 15 Jahren Verwahrung und Sanierung radioaktiv
kontaminierter Standorte im Bergbaugebiet des Döhlener
Beckens sind erste positive Auswirkungen nachweisbar.
Den Schluss dieser Monographie bildet eine Abhandlung
über technische Denkmale und Zeugen des Bergbaus sowie
die bisherigen Bemühungen und geplanten Maßnahmen
zu deren Erhaltung und Erneuerung.
Summary
Thorough investigation of the origin of the Döhlen Basin, its
extent and mineral resources began around 1800. Most
noteworthy are the large comprehensive works published
by C.F. NAUMANN and B. V. COTTA (1845), R. HAUSSE (1892) and
H. HARTUNG (1906).
This monograph on the Döhlen Basin covers a period of mining
that lasted without interruption from 1542 to 1989. During
that time, materials as diverse as coal, copper, alum, limestone,
and uranium were exploited at various occasions.
Coal mining flourished particularly in the 19th century for
several reasons: The nearby Freiberg ore mining and smelting
works caused a huge demand for industrial fuel.
Concurrently, the capital of Saxony in the immediate vicinity
offered a market for coal and provided personnel with
administrative and technical skills. In several instances
novel mining techniques, useful for ore mining, were introduced
and tested in the Royal Coal Works.
The geology section of this monograph presents a comprehensive
survey of the fossil flora and fauna of the
Döhlen Basin. In addition to listing the species, it also considers
paleoecological aspects of the biocenoses. Several
biotopes and litho-facial types of plant communities are
described.
Some peculiar findings are worth mentioning: the famous
“mass grave of saurians” (rather reptiles) contains numerous
skeletons of small amphibians, the ‘giant Arthropleura’,
plants of the coal swamps preserved in live position,
halophile algae as well as footprints of tetrapods and invertebrates.
Remarkable are the complete absence of fish and
the scarcity of remnants of an advanced mesophile flora.
The fossil-bearing strata are comparatively thin and do not
yield much biostratigraphic information.
There were four large deposition periods, partially of cyclic
character. The monograph discusses the lithologies with
respect to pyroclastic strata, coal petrography, facies, variety
of clast composition and chert formation. Volcanic
deposits are associated with andesitic volcanism tied to the
Elbe River lineament and rhyolitic pyroclastic matter from
outside the basin.
The geochemistry, stratigraphy, tectonic setting and grades
of the basin’s uranium-(vanadium-) ore deposit are published
here for the first time. The deposit contains
resources of about 7,000 t uranium, an equal amount of
vanadium and in addition molybdenum, arsenic, lead, zinc
as well as large amounts of iron as pyrite. Copper and tin
are rare. Three possible primary sources of the metals are
discussed, all located northwest of the basin: Older
Paleozoic schists, the younger Paleozoic volcanic complexes
of Tharandt and Meißen and the monzonite complex of
Meißen.
The monograph lists numerous minerals of the basin fill and
the underlying basement. It also provides detailed information
on the secondary minerals formed in the mines and
burning mine waste dumps. Whawellite is found mainly in
clastic dykes. It is remarkable also from a historical point of
view.
There is evidence of early epigenetic thermal water. Weakly
metamorphosed sediments and the degree of carbonisation
give some indication of the thermal gradients existing
during the formation of the basin. It is assumed that the
thermal regime of the basin was driven by a deep-seated
crustal magma chamber. Felsic tuffs and tuffites are present
in every formation of the basin fill. Their relation to volcanic
events in the vicinity (Tharandt, Meißen) has not yet been
established.
The tectonic elements derived from mine maps, plans and
cross-sections and a 3-D presentation show that the
Döhlen Basin is a half graben down-faulted along a system
of north-westerly trending normal faults. Only locally, i.e. in
the Bannewitz area at the north-eastern edge, a monzonite
rise is relatively uplifted along a south-westerly dipping normal
fault causing the graben to be fully developed. In total,
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