Selected properties of soils located within the depression cone of a planned excavation of the Drzewce open cast pit (central Poland)

Abstract

Open-pit lignite mining requires drainage of the deposit. The depression cone, formed as a result of these activities, has a varied surface and depth, and these features are shaped primarily by the geological structure and by the thickness of the caprock layer. In some of the areas covered by the depression cone, soil productivity may deteriorate, and a related yield reduction may occur, providing the basis for the payment of applied compensations for the owners of such areas. The aim of the study was to assess the condition of selected soils in the vicinity of the planned excavation (Field B) of the Drzewce lignite open pit mine (central Poland). Six profi les were excavated in organic and mineral-organic soils. The locations of the test points were chosen to represent soils that meet the criteria of habitats prone to drainage degradation. The morphological structure of the studied soils and their analysed properties indicate that they have already been drained (probably due to the infl uence of climate and cultivation), but does not exclude the possible acceleration and enhancement of this process by the commencement of mining activities. For most of the analysed features, a high correlation between their value and organic matter content was observed. Given that the possible commencement of opencast mining operations may signifi cantly accelerate and enhance the already initiated mursh-forming process, it is reasonable to conduct systematic research at the measuring points proposed in the study. Keywords