Brown coal
In Poland, brown coal deposits occur in young geological formations, mainly the Paleogene and Neogene. Older brown coal deposits are known to occur also in the Jurassic, Carboniferous and locally even Cretaceous and Triassic in several places in the world. The brown coals are intermediate in qualification between hard coal and peat. Their properties were markedly influenced by the type of parent plant material and environment in which they originated.
Brown coal deposits originated both in platform areas and sedimentary basins in orogenic belts. The coals form extensive seams or lenses a few meters to several dozen meters in thickness. The small overburden thickness makes possible opencast mining of the deposits.
There are brown coal deposits occurrying in Poland presented on the map.
Seams of older brown coals are often situated too deep for opencast mining and require underground mining. This is also the case of coal seams occurring in glacitectonic folds. The methods of underground mining have been lately used in Poland to mine coals in Babina and Sieniawa deposits.
Brown coal resources are calculated to the maximum depth of deposit base of 350 m, the minimum brown coal layer thickness in bed of 3 m and maximum overburden/deposit thickness ratio of 12. The minimum weighted-average calorific value in bed (with intercalations) should equal 6.5 MJ/kg (at brown coal humidity of 50%). These are the basic criterias for energy coals which are common in Polish deposits.
Poland’s anticipated economic resources of brown coals amounted to 23,516.19 million tonnes as of the end of 2015. The resources comprise 23,515.55 million tonnes of energy coals, remaining 0.64 million tonnes are bituminous coals. There were also coals usable for production of briquettes and coals suitable for production of coal tar and liquid through distillation documented in the past. Nevertheless, all these coals are used and treated as energy coals only.
Table 1 shows resources and the current state of exploration and development of brown coal deposits in Poland.
Anticipated economic resources within exploited deposits amounted to 1,418.70 million tonnes (6% of total anticipated economic resources). Brown coal is being exploited by five mines: Bełchatów, Turów, Adamów, Konin and Sieniawa.
Strip mining of brown coal of Czempin, Krzywin and Gostyń deposits with total resources of 3,690 million tonnes is nowadays precluded on environmental grounds and in connection with high class and value of agricultural lands in area of the planned open strip mine. These are the main issues to be solved by local societies, ecological organizations and potential mining companies, before exploitation of these deposits starts.
Table 2 shows basic parameters of major non-exploited deposits with anticipated economic resources over 75 million tonnes.
Anticipated economic resources of brown coal amounted to 23,516.19 million tonnes in 2015 and increased by 5.6 million tonnes in comparison with the previous year. There was new deposit documented in 2015 – Gubin 2 with resources equal 1,033.8 million tonnes and the new documentation with recalculated resources for Dęby Szlacheckie deposit (+54.7 million tonnes) was approved. The new documentations were also elaborated and accepted for three other deposits: Gubin, Gubin 1 and Izbica Kujawska (the total resources decrease equal 1,018.92 million tonnes); exploitation and losses totaled 63.99 million tonnes.
Economic resources of brown coal as of 31.12.2015 amounted to 1,129.06 million tonnes. They decreased by 67.55 million tonnes due to the exploitation and losses.
Brown coal production, according to the data provided by the concession holders, decreased in 2015 by 867 thousand tonnes (1.4%) in comparison with the previous year and amounted to 63,135 thousand tonnes (table 3). The majority of the output came from Bełchatów-pole Bełchatów deposit (25.05 million tonnes – 39.7% of domestic production) and Bełchatów-pole Szczerców deposit (with production equal 17.03 million tonnes – 27.0% of domestic production). The production from other deposits accounts for: Turów – 11.6% of domestic production (7.33 million tonnes); Pątnów IV – 8.8% (5.58 million tonnes); Adamów – 5.0% (3.13 million tonnes); Tomisławice – 3.8% (2.39 million tonnes). The remaining production comes from other strip mines (Drzewce and Koźmin) and from Sieniawa mine.
The figure shows changes in resources and production of brown coal in Poland in the years 1989-2015.
Prepared by: Krzysztof Szamałek, Marcin Tymiński
Table 1. Brown coal - million tonnes