Badano wpływ osadu ściekowego na aktywność enzymatyczną pokrywy glebowej na terenie po otworowej kopalni siarki w celu oceny możliwości jego wykorzystania w leśno-łąkowej rekultywacji terenów Kopalni Siarki "Jeziórko". Wyniki, uzyskane po sześciu latach od zastosowanych zabiegów rekultywacyjnych wskazują, że osad ściekowy, dodany w odpowiedniej dawce, wpływał na ogól korzystnie na właściwości biochemiczne i chemiczne gleby. Oznacza to, że zastosowany osad może być brany pod uwagę, jako jeden ze środków służących do rekultywacji gruntów toksycznych.

The paper presents results of the research on the influence of sewage sludge on the enzymatic activity of the anthropogenic soil on the area of the former borehole sulphur-mine as well as· the effectiveness of sewage sludge utilization for forest-meadow reclamation of this ground.

Engineering activity may lead to uncontrolled changes in the geological environment. This paper presents an example of structural changes in fluvial sand of the Praski terrace (in Warsaw) caused by the activity of a temporary concrete batching plant. Our investigations made it possible to identify the material responsible for the structural anomalies observed in the bottom of the trench excavation. The compound responsible for the cementation phenomenon was identified as ettringite – hydrated calcium aluminosulphate: Ca ₆Al ₂[(OH) ₁₂(SO ₄) ₃]·26H ₂O. The source of ettringite were most probably significant volumes of contaminants coming from the temporary concrete batching plant (e.g., from the rinsing of concrete mixers and/or installations for concrete storage and transportation). While penetrating into the ground, ettringite caused extensive cementation of the soil mass, mainly in the saturation zone. As a result, the mineral (chemical) composition of the inter-grain space changed and the structure of the sand was strengthened. The estimated zone of volumetric changes in soil properties was about 6 thousand m ³. However, analysis of the chemical composition of groundwater for its potential sulphate contamination, did not reveal any anomalous concentrations of sulphates.

The shortage of investment areas may be at least partially satisfied by the development of reclaimed post-mining areas. These are often subsidence zones levelled with hard coal mine waste or reclaimed sub-level old dumps of this waste. From the geotechnical point of view, such grounds represent anthropogenic grounds containing mine waste, and they are considered as possessing unfavourable properties in terms of the foundation of building structures. The paper initially presents the analysis of the properties of waste from the hard coal mining industry, emphasising that they expose several beneficial properties enabling their safe use. The second part of the article is devoted to the determination of soil density using the DPSH probe. It has been found that the applicable standards lack complex relationships that would allow for a reliable interpretation of the measurement results in a wide range of soil types. The last part presents exemplary results of measurements made with the DPSH probe at a construction site. The obtained results allowed for the formulation of several conclusions regarding the possibility of building on a ground made of hard coal waste and the use of dynamic sounding to assess the geotechnical properties of such anthropogenic soil.