CHARACTERISTIC OF THE KRIVA BARA DEPOSIT AND EXTRACTION TECHNIQES

Abstract

The “Kriva bara” deposit is located on the left terrace of the Iskar River in Sofia valley. The area of Sofia valley is built of Neogene ponds and Quaternary sediments. Fieldsurrounding mountains are made of Paleozoic, Triassic and Jurassic sediments formed in a different facial environment and which have a specific layers arrangement and substantial composition. The "Kriva Bara" field is made up of the alluvial deposits of the Iskar River, represented by sands, gravel and clay, including thick layer of ballast, small lenses and thin layers of sandy clays. Alluvial deposits lie horizontally. The application of extraction techniques aims to achieve the complex and safe carrying out the extraction works, observing the environment protection and achieving healthy and safe working conditions.