Backfilling sands
Backfilling sand is used in making hydraulically placed fill – a mixture of sand and water to fill voids created by underground mining. Over the last few decades it has been the most popular form of underground mining backfill. Documented backfill sand deposits are situated mainly in areas of intense underground mining, especially those of hard coal and copper mining in the Upper Silesian Coal Basin and Legnica-Głogów Copper District. One of the major requirements which sand deposits should meet to be classified as backfill sand deposits is location in distance less than 50 km from the place where the raw material is to be used.
The majority of backfilling sand deposits are situated around the Upper Silesian Coal Basin. Three main deposit areas are differentiated: eastern, western and northern. The eastern area which is the center of production of that raw material extends from Kuźnica Warężyńska through the Pustynia Błędowska Desert as far as the vicinities of Jaworzno. It is characterized by occurrence of sands of fluvioglacial and locally eolian origin attaining up to 70 m in maximum thickness in the Pustynia Błędowska Desert. The second area with the largest resources comprises the Pleistocene valley of the Odra River in a part of the Racibórz Basin and western part of the Silesian Upland and its sand deposits are 15 to 20 m thick at the average. The northern area comprises the Mała Panew River valley with its sand deposits up to 40 m in thickness. The deposits are well explored but still undeveloped. Sandy-gravel deposits up to 40 m in thickness also occur in copper mining areas in the vicinities of Lubin.
Clastic rock raw materials occurence in Poland (inlcuding 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 2014, anticipated economic resources of backfilling sand totaled 2,508 million (or about 4,264 million tonnes - as recalculated using weight-to-volume ratio 1.7 t/ m3). Resources increased by 161 million m3 mainly due to taking into account the calculations of Chróstnik deposit resources approved in 1990. In 2014 there were new calculations for this deposit made and new sand and gravel deposit (Chróstnik 1) was allocated from it. Nevertheless, the final growth of the Chróstnik deposit resources amounted to 81.6 million m3. There was Tworóg Mały deposit (Śląskie Voivodeship) crossed out of the Balance in 2014.
Economic resources, calculated in deposit management plans decreased by 238 thousand m3 in comparison with 2013. There was new calculation of these resources approved for Siersza-Misiury deposit.
Production of backfilling sand totaled 3,811 thousand m3 being 162 thousand m3 bigger than in the previous year. It was the 1st year of the production growth after 6-year drop. The most significant growth occurred in Kotlarnia p.północne deposit (by 100 thousand m3). The exploitation from Bór (Wschód), Szczakowa pole II and Kuźnica Warężyńska deposits is still on hold.
The figure given below shows changes in domestic resources and production of backfilling sands in Poland in the years 1989-2014.
Prepared by: Agnieszka Malon
Table 1. Backfilling sand - million m3