The most extensive mining fields serving the construction effort are now centred around Kiełbasin.  6 pits are currently in operation, 2 have already been closed down, and another 2 will open this month.  Section III is in the highest demand for aggregate of various grain sizes and different permeability characteristics.

– Here, on Section III, we are transporting the material over the maximum distance of 10 kilometres – says Piotr Rutkowski, Coordinator of Area III.  – This is very important, because transport plays a huge role in determining the price of one tonne of the raw material.  A network of technological roads proves equally significant to enable minimising transport along public roads.  Short distances covered by the deliveries and transport of the materials along technological roads are the achievements of Phase II.  Moreover, Piotr adds, successful methods of ordering the material by the building crews have been developed.

For those having no knowledge of the subject matter, sand is sand.  Yet, the variety of the excavated material is of fundamental importance.  At the present stage, about 80% of the material is obtained to form the frost-resistant layer.  The strictest criteria must be met when preparing the material for the gravel columns.

– Things are similar to making a raisin cake – jokes Jan Godlewski, foreman at the Kiełbasin excavation pit, when describing the working principle of the automatic sorting machine. – The material must be meticulously sieved and separated, then mixed in proper proportions, and tested again.  

At present, one of the three pits operated under Jan’s direction specialises exclusively in producing the material fit for column formation.

– One could say that preparation of 500 tonnes of the material a day takes as much effort as the preparation of 5000 tonnes of sand for the frost-resistant layer.  The latter needs no sieving – Piotr Rutkowski adds.  The daily output per pit on the current Phase ranges between 2000 and 5000 tonnes on average.  The total tonnage of the material excavated for Section III has now reached 1 800 000.  The entire project has consumed 7 300 000 tonnes.