In Kalutara district, Sri Lanka a significant number of rock quarries has been opened during the last decade: from 2005 to 2015. The main reason behind this rapid increase of the number of Rock quarries was the development projects, such as port expansion project, highway projects, port city and airport, which were carried out simultaneously. In general, mining is considered as a destructive industry which affects the environment and surrounding echo-systems; and hence it is useful to assess the resulted environmental impact. The removal of the vegetation cover is often considered as one of the worst detrimental aftermaths of mining. However, assessing the impact on the vegetation cover due to mining is a difficult task. This study describes assessment of the devegetation caused by new mines started in the time period of 2005-2015. The objective of the study is to assess the area of the uncovered vegetation by using Google Earth imagery. A remote sensing and geospatial approach is adopted with an image processing technique to analyse the discrepancy resulted in the vegetation cover. Google Earth images, acquired from 2005 to 2010, are used to monitor the change in vegetation cover due to mining activities. Initially, locations of 10 rock quarries, opened during the specified time period, are identified by visually inspecting the Google Earth images. Since the Google Earth imagery consists of high resolution satellite imagery, the clarity is significant enough to visually demarcate the boundaries of vegetation and quarry sites. Images acquired, in the time period of January to March from the two bounding years are selected for each quarry. Two images, representing 2005 and 2015, for each quarryare exported to a GIS platform and georectified. The georectified images are then classified into two classes (namely vegetated area and non-vegetated area) and subsequently assigned with pixel values of 1 and 0 respectively. Changes of vegetation cover due to rock quarrying in the given time period of the study area are delineated by computing the arithmetic difference of the two images acquired in the bounding years through a raster calculation. The result depicts that an average of 16998.4 m2 of vegetation has been removed by a rock quarry in Kalutara district over the time period of 2005-2015. Given the fact that Google Earth images are freely available, and frequently the environmental impacts are assessed by the authorities, the approach utilized in this study has the potential for monitoring and assessing the devegetation over much broader scale than demonstrated in this study. Consequentially, the results can be included for the interpretations when the authorities define the guidelines.