GEOMIN ++ Limestone plant Hermsdorf ++ Erzgebirgische Kalkwerke GmbH ++

Limestone plant Hermsdorf

Location and type of the operation

The plant department Hermsdorf of the GEOMIN-Erzgebirgische Kalkwerke GmbH does underground mining on the Calcite-Marble-deposit, which has the same name.

The deposit Hermsdorf is located in the East Ore Mountains (Osterzgebirge) southwest the village Hermsdorf between the valley of the Gimmlitz and the road Frauenstein - Rehefeld.

The first documentary mention of the limestone production dates back to the year 1581.

After century-long mining in up to 5 limestone-quarries, the underground production began in the year of 1880 in the part of the quarry "Fiskalischer Bruch".

In the preparation plant of the department Hermsdorf calcium carbonate fillers are manufactured in different grain sizes for the construction material-, construction chemistry-, color- and lacquer-industry.

The trade name of the fillers is Saxolith^®.

Geological-mineralogical description of the deposit

The limestone deposit Hermsdorf is about 500 million years old and originated during the transition of the Cambrian to the Ordovician. Stratigraphcally the thick-alternated beddings of Calcite-marble and Phyllite of the Herold-series are ranked with the Thumer-series.

The structure of the underground of the deposit is made of pre-Cambrian metamorphic rocks (Gneisses) of the Pressnitz-series and Proterozoic Metagranites (Leptynite) as well as Cambrian, lithological equivalents of the Breitenbrunner-series (Muscovite-slate). Besides these representatives of the late-Cadomian magmatism of the prograde metamorphism, the directly floor layers underneath the carbonate series are quartz-rich Phyllites and hornblende-chlorite-slate, which are submarine, basic Palaeo-vulcanites. They are the transition to the retrograde metamorphism in the greenschist-facies.

Especially important is the tectonic structure of the deposit. The main-foliation of the framework rocks forms a structural belt, whose axes have a east-westerly trend.

The white Calcite-marble from the deposit Hermsdorf consists predominantly of Calcite with few changing portions of quartz and phyllosilicates. The calcitic carbonate-portions were clearly affected by the metamorphosis and were included into the process of the slate formation. This slight influence of the marble by the formation of slate surfaces is illustrated by the layer-wise arrangement of quartz, chlorite and light mica, as well as by grain size differences of the Calcite, what give a fine banding to the carbonate.

The calcite crystals shows predominantly a granoblastic texture, with individual aggregates commonly showing mainly a twinning and orientation. Such twinning is typical for crystal-plastic deformation under moderate temperature conditions of about 300°C.

The calcite is completely re-crystallized during the metamorphism and subsequently re-crystallized. The average grain size of the calcites varies between 0,2 and 0.6 mm. Typically, the calcite-marble of Hermsdorf has low iron contents of the individual calcite crystals.

For the petrophysical parameters of the calcite-marble of Hermsdorf the pressure strength of 87,2 N/mm² and the flectional resistance to extension of 12,0 N/mm² were determined. The gross density is 2,69 g/cm³. Furthermore, the low water-holding capacity of 0,26 percentage by weight due to the metamorphism has to be emphasized. Therefore, a high frost resistance of 0,34 % mass loss is the result.

The marble is free from bacterial and organic components and doesn't contain graphite-interstratifications.

Excerpt from the operating chronicle

1540	First limestone mining
1647	First official lime kiln was built
1809	Limestone mining in the quarries "Fiskalischer Bruch", "Blauer Bruch" and "Waltherbruch"
1827	Building of the shaft furnace
1839	Free-drainage level to the quarries Fiskalischer Bruch" and "Waltherbruch" were driven
1842	Building of the furnace 1
1856	Building of the furnace 2
1870	Reconstruction of the shaft furnace to a "Ruedersdorf-furnace"
1880	Beginning of the underground mining from the quarry "Fiskalischer Bruch"
1890	Sinking of the first shaft in the quarry "Fiskalischer Bruch"
1891	Shut-down of the quarry "Waltherbruch"
1923	Reconstruction of the 3 lime kilns, building of an additional ring-kiln
1925	Beginning of the underground mining underneath the quarry "Waltherbruch"
1926	Driving of a haulage tunnel
1927	Construction of a terrazzo-plant
1934	Construction of a cement mill
1952	Development of the 2nd and 4th Sole over blind shafts
1965	Shut down of the ring-kiln
1986	Shut down of the last furnace
1990	Part of the Erzgebirgische Kalkwerke GmbH with its main department in Oberscheibe; under the administration of the trust establishment of Berlin
1992	Part of the GEOMIN-Erzgebirgische Kalkwerke GmbH with its main department in Lengefeld
1992	Set up of new production facility for fillers with world wide most modern and advanced optical classification device
1994	Market launch of the new filler product range called "Saxolith"
2000	Development and installation of production facility for round shaped rocks and granules offered under the product name "Saxorund"