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 backfilling sand deposits are situated mainly in the areas of intense underground mining, especially those of hard coal and copper mining in the Upper Silesian Coal Basin and Lubin vicinities. One of the major requirements which sand deposits should meet to be classified as backfilling 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 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 2015, anticipated economic resources of backfilling sand amounted to 2,567 million m3 (or about 4,364 million tonnes as recalculated using weight-to-volume ratio: 1 m3 = 1.7 t). Resources increased by 59.34 million m3 mainly due to the documentation of new deposit – Marklowice 1 (63.03 million m3), which was allocated from the northern part of Marklowice deposit. All resources within Marklowice deposit are classified as anticipated subeconomic.
Economic resources increased by 6.41 million m3 in comparison with 2014, due to the new deposit management plans approved for Obora deposit. The majority of resources were reclassified from non-economic to economic.
Production of backfilling sand totaled 3,549 thousand m3 (6,033.33 thousand tonnes) being 262 thousand m3 lower than in the previous year (table 2). The production dropped in six deposits (out of seven under exploitation). The most significant decline (more than 70 thousand m3) occurred in Obora, Kotlarnia p. północne and Bór (Zachód) deposits. 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 1989-2015.
Prepared by: Agnieszka Malon
Table 1. Backfilling sand - million m3