ABSTRACT: It was demonstrated in many articles that interferometric satellite data (InSAR) from ERS-1/2 SAR sensor give the products from which a Digital Terrain Model can be extracted. A three-pass interferometry (DiffSAR) is a strong and crucial remote sensing technique to monitor of terrain movements like land subsidence. The practical results of InSAR technique application for land subsidence monitoring for the Upper Silesian Coal Basin, a densely urbanised, heavily industrialised area were demonstrated in many papers of second author. Mining subsidence causes damage to buildings and other structures, changes surface drainage patterns and can be associated to deep fracturing of the ground. Knowledge of the spatial distribution of the endangered area may help in landuse planning and compensation strategies. The main aim of the work presented in the paper was to demonstrate the synergism of optical and SAR data for environmental monitoring, precisely for land subsidence monitoring caused by coal mining activity and its impact on environment. The space maps in the form of color compositions were elaborated based on Landsat 5 optical data. To monitor the impact of coal mining activity on environment the maps showing land movements (subsidence) were elaborated from ERS SAR SLC data using Atlantis InSAR Workstation. Next, two remote sensing technologies (interferogram and multitemporal composition from ERS also with multispectral compositions from Landsat) were fused for improvement of the interpretation of land cover in the regions of subsidence. This kind of multisource spacemaps can be useful not only for environmental monitoring "ex post" but also for future urban and regional planning purposes