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 2013, anticipated economic resources of backfilling sand totaled 2,470 million m3 (or about 4,199 million tonnes - as recalculated using weight-to-volume ratio 1.7 t/ m3). Resources decreased by 161 million m3 mainly due to the crossing out Ochojec deposit from “The balance…” and a new documentation with recalculated resources approved for Kotlarnia Solarnia deposit in 2013.
Economic resources, calculated in deposit management plans decreased by almost 50 % in comparison with 2012 (through the changes in concession for Kotlarnia p. północne deposit exploitation).
Production of backfilling sand totaled 3,649 thousand m3 being 113 thousand m3 smaller than in the previous year. It was the 6th consecutive year of the declining production. There was not exploitation from Bór (Wschód) deposit carried out in 2013 and the exploitation from Kuźnica Warężyńska deposit is still on hold.
The figure given below shows changes in domestic resources and production of backfilling sands in Poland in the years 1989-2013.
Prepared by: Agnieszka Malon
Table 1. Backfilling sand - million m3