Surface mining
Visualising virtual brown coal landscapes by merging GIS and remote sensing data

Introduction

Geographically the East German brown coal deposits which are the largest in Germany are located in the Halle / Leipzig / Bitterfeld region and in the Lausitz region near the Polish border. In the Lausitz region the brown coal seam reaches an average thickness of 12m. The seam is covered by an overlay shelf of 40–107m in thickness which can be removed by gigantic excavators. With 650m in length the excavators used in the Lausitz region are the largest movable man-made structures on earth. Up to 60m in depth can be removed in one step.

Because of the decreasing demand for brown coal most of the surface mining activities will not be continued in the future.

Effects on the environment

Large parts of former East Germany are shaped through brown coal surface mining activities. The most dramatic effects on the environment are related to groundwater, air quality, and the visual quality of the landscape.

Naturally the landscape is an agricultural landscape with large forested sections. During the four phases of the surface mining process (exploration, development, production, and reclamation) the relatively flat landscape is transformed into a landscape of completely different character.

In the case of the pilot study 'Jänschwalde' the zone of active mining is moving north leaving an area of approximately 24km2 in the south to be reclaimed. In this section there are two very large depressions (90m relative to the surroundings) of 4km respectively 2km in length and 800m in width. Extensive pumping of groundwater of up to 170m3 per minute prevent the holes from being flooded.

The reclamation involves massive terrain alterations for stability and safety reasons. Because of the highly acid soil conditions (pH 3 or less is possible) after the terrain modelling also soil improvement measures are essential as a prerequisite for further land use like forestry or agriculture. Reclamation of such large areas take a long time. By the year 2010 the smaller one of the two depressions is to be filled in and the larger one to be flooded by the natural rise of the groundwater level. In 2030 the whole area will be reclaimed.

Major goals of the pilot study

Major goals of the pilot study 'Dynamic visual simulation – reclamation surface mining site Jänschwalde' (Hehl-Lange and Lange, 1996) are to explore ways how existing data (eg terrain data, satellite imagery) can be utilised and how landscape change can be visualised in three dimensions over time. The visualisations shall be used as the basis for the design of the new landscape and as a means of communication among the numerous involved institutions.

Clients

• Ministry for the Environment, Nature Protection, and Spatial Planning, Brandenburg, Germany

• Lausitzer und Mitteldeutsche Bergbauverwaltungsgesellschaft (LMBV)

• Lausitzer Braunkohle AG (LAUBAG)