Backfilling sands are used for making a hydraulically placed fill – a mixture of sand and water to fill depleted mining excavations. Documented backfilling sands deposits occur in the areas of an intensive underground mining, especially those of the hard coal and copper mining in the southern part of Poland, mainly in the Upper Silesian Coal Basin area and in Lubin vicinities. One of the major requirements which sand deposits should meet to be classified as backfilling sand deposits is the location at the distance less than 50 km from the place where the raw material is to be used.
The majority of backfilling sand deposits is located around the Upper Silesian Coal Basin. Three main deposit areas can be differentiated: eastern, western and northern. The eastern area (where the majority of the raw material volumes is exploited) extends from Kuźnica Warężyńska through the Pustynia Błędowska Desert as far as the vicinities of Jaworzno. It is characterized by the occurrence of sands of fluvioglacial and partially eolian origin, attaining up to 70 m in a thickness (Pustynia Błędowska Desert). The second area with the largest resources covers the proglacial stream valley of the Odra River in a part of the Racibórz Basin and a western part of the Silesian Upland. The average thicknesses of the deposits located within this area are within the range of 15 – 20 m. The northern area covers the Mała Panew River valley where fluvioglacial sand deposits occur, characterized by the significant thicknesses (up to 40 m). The deposits are explored well enough but have not been developed so far. Moreover, sandy-gravel deposits up to 30 m in thickness occur in the copper mining areas in the vicinities of Lubin. The large number of documented backfilling sands deposits in Poland together with the declining demand are 2 main factors for not delineating the prognostic areas for this raw material at the moment*.
The clastic rock raw materials occurrence in Poland (including backfilling sand) is presented on the map.
The table given below shows resources and the current state of exploration and development of backfilling sand deposits.
In 2018, the anticipated economic resources of backfilling sands amounted to 2,512.08 million m3 (or about 4,270.54 million tonnes as recalculated using a weight-to-volume ratio 1.7 t/m3). The resources decreased in comparison with 2018 by 3.00 million m3, mainly due to the exploitation and losses. The minor resources drop (-30 thousand tonnes) was the result of the approval of a new geological documentation with recalculated resources for Siersza-Misiury deposit – elaborated due to the exploitation end.
The economic resources decreased by 25.01 million m3 (it means by more than 30%) in comparison with 2018, mainly due to: - the exploitation concession for Szczakowa pole I changes (-11.54 million m3) – there was a new, much smaller mining area delineating for this deposit; - the extinction of the concession for Siersza-Misiury deposit (-9.4 million m3); - the elaboration of a new deposit development plan for Pustynia Błędowska – blok IV deposit (-1.18 million m3); - the exploitation and losses.
The output of backfilling sands from 6 exploited deposits decreased by 697 thousand m3 in comparison with the previous year and totaled 2,324 thousand m3 (3,951 thousand tonnes) in 2019. The exploitation increased from 3 deposits, whereas from the 3 remaining ones the output dropped and the exploitation from Siersza-Misiury deposit ended. The exploitation from Kuźnica Warężyńska and Szczakowa pole I deposits is still on hold.
The figure given below shows changes in domestic resources and production of backfilling sands in Poland in the years 1989-2019.
Prepared by: Agnieszka Malon
* Galos K., Miśkiewicz W., 2020 - Piaski kwarcowe do produkcji betonów komórkowych (quartz sand for cellular concrete manufacture), piaski kwarcowe do produkcji wyrobów wapienno-piaskowych (quartz sand for lime-sand products manufacture), piaski podsadzkowe (filling sand). In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r. (eds. Szamałek K., Szuflicki M., Mizerski W.): 309-313. PIG-PIB, Warszawa.