General information and occurrence
In Poland, brown coal deposits occur in younger geological formations, mainly of the Tertiary age. Older brown coal deposits are known to occur also in the Jurassic, Carboniferous and rarely - Cretaceous and Triassic. The brown coals are intermediate in the qualification between hard coal and peat. Their characteristics and properties were markedly influenced by the type of the parent plant material and environment in which they originated.
Brown coal deposits originated both in sediments of platform areas and in sedimentary basins in orogenic belts. The coals form the extensive seams from a few meters to several dozen meters in thickness. They also occur in the form of lenses. The thickness of overburden is usually quite small which makes the opencast mining of the deposits possible. Seams of older brown coals are often situated too deep below the surface level for the opencast mining and require the underground mining. This is also the case of coal seams occurring in glacitectonic folds. The methods of the underground mining were lately used in Poland to mine coals in Babina and Sieniawa deposits.
There is brown coal deposits occurrying in Poland presented on the map.
Brown coal resources are documented with taking into account the following limit values of the parameters that define the deposit and its boarders for the opencast mining: the maximum depth of deposit base of 350 m, the minimum brown coal layer thickness in bed of 3 m and the maximum ratio of overburden and intercalation sum/deposit thickness of 12:1. The minimum weighted-average calorific value in a bed (with intercalations) should equal 6.5 MJ/kg (at the brown coal humidity of 50%). These are the basic criteria of geological-mining parameters and qualitative parameters for energy coals which are common in Polish deposits – typical ortholignites. For the purposes of the underground gasification or the production of liquid fuels in the ground installations (mentioned in the Energy Policy of Poland 2040) the limit values of the parameters that define the deposit and its boarders (balancing criteria) have not been established.
Resources and output
Poland’s anticipated economic resources of brown coal amounted to 23,201.64 million tonnes as of the end of 2020. The majority of resources – that is 23,201.00 million tonnes – constitute energy coals, remaining 0.64 million tonnes are bituminous coals (documented in C2 category Kaławsk-szyb główny deposit). There were also coals usable for the production of briquettes and coals suitable for the production of coal tar and liquid through a distillation documented in the past. Currently, all these coals are used and treated as energy coals only.
Table 1 shows resources and the current state of the exploration and development of brown coal deposits in Poland.
The anticipated economic resources within exploited deposits amounted in 2020 to 1,110.62 million tonnes and accounted for 4.79% of total anticipated economic resources. Brown coal is being exploited in Poland by five mines: Bełchatów, Turów, Adamów, Konin and Sieniawa.
More than 22% (5,185.33 million tonnes) of the anticipated economic resources constitute the resources of the deposits within the Poznań through. These are Czempin, Gostyń, Krzywin and Mosina deposits where potentially strip mining is nowadays precluded on the environmental grounds and in the connection with large scale of production farms. These are the main issues to be solved by the local societies, the ecological organizations and the supporters of the deposits development, before the exploitation starts. It might seriously complicate the deposit development in the future. On February 2nd, 2021 the Council of Ministers approved “The Energy Policy of Poland 2040” – in the document, the mining development of brown coal deposits for the energy purposes is not expected. The exception is the possible inclusion the following deposits to the exploitation:
- Złoczew;
- Ościsłowo (ZE PAK join-stock Company made a decision to not applying for the deposit development*;
- Gubin (as a reserve deposit)**.
The Energy Policy of Poland 2040 states: the research and development activity should be focused on the searching for innovations to obtain the reduction of the environmental burden coming from the brown coal exploitation and on searching for the new solutions allowing for the low-carbon, effective and flexible use of the raw material (e.g. gasification, liquid fuels).
Table 2 shows basic parameters of non-exploited deposits with anticipated economic resources exceeding 75 million tonnes.
The anticipated economic resources of brown coal amounted to 23,201.64 million tonnes in 2020 and decreased by 60.19 million tonnes (it means by 0.26%) in comparison with the previous year. The resources drop was mainly the result of the exploitation but also of the exploitation losses and of the declines/growths coming from the better deposit exploration which are showed by concession holders in their reports (and in their inventories of mineral deposit resources).
Economic resources of brown coal amounted to 937.69 million tonnes as of 31.12.2020 and decreased by 56.86 million tonnes (5.72%) in comparison with 2019. The economic resources changes were caused by the output, the resources declines coming from the losses, the better deposits exploration during the exploitation and from the elaborated supplements to the deposits development plans. In 2020 the supplements were prepared for 4 deposits: Adamów, Drzewce, Pątnów IV and Turów. In the case of Adamów deposit, the resources decreased also in the result of reclassifying the part of economic resources into the sub-economic resources (3.90 million tonnes).
The brown coal output, according to the data provided by the concession holders, decreased in 2020 by 5,555 thousand tonnes (10.51%) in comparison with the previous year and amounted to 47,300 thousand tonnes. The exploitation was carried out in 8 deposits, there was no output recorded for Sieniawa 1 deposit. The majority of the domestic output came from the outcrops exploited by PGE GiEK join-stock Company, especially from Bełchatów-pole Szczerców deposit (33,660 thousand tonnes), which accounted for 71.16% of the domestic production (in 2018 and 2019, the percentage contributions were much lower – that is 56.66% and 68.89%). The gradually increasing output from the Szczerców field compensates the depletion of the Bełchatów field allowing to maintain the stable level of the exploitation for the Bełchatów power station. The output from Bełchatów-pole Bełchatów deposit amounted to 2,538 thousand tonnes (5.37% of the domestic output in 2020, with the percentage contributions in 2018 and 2019 equal 19.92% and 8.28%, respectively). The output from Turów deposit was equal 5,067 thousand tonnes (10.71% of the domestic output). The exploitation level in deposits located in the Konin area (to the needs of ZE PAK join-stock Company) amounted to: Tomisławice deposit – 2,107 thousand tonnes (4.46% of the domestic output); Pątnów IV – 1,585 thousand tonnes (3.35%), Drzewce – 1,414 thousand tonnes (2.99%) and Adamów – 715 thousand tonnes (1.51%). The remaining output came from Sieniawa 2 deposit and was equal 213 thousand tonnes (0.45% of the domestic output). In comparison with 2019, the brown coal output increased in two deposits: - by 101 thousand tonnes (7.69%) from Drzewce deposit; - by 49 thousand tonnes (0.98%) from Turów deposit. In other deposits, there were the output drops recorded – the most significant for Bełchatów-pole Szczerców deposit amounted to 2,754 thousand tonnes (7.56%); for Bełchatów-pole Bełchatów deposit it was 1,836 thousand tonnes (41.98%); for Pątnów IV deposit 629 thousand tonnes (28.41%); for Tomisławice deposit 222 thousand tonnes (9.53%), for Adamów deposit 180 thousand tonnes (20.11%), and for Sieniawa 2 deposit 83 thousand tonnes (28.04%).
The potential extension of the brown coal resources base, in terms of the traditional opencast mining, is in particular connected with the formalization (the geological documentation in D category) of the already known brown coal occurrences for which the documentation has not been elaborated due to the low degree of the geological exploration. According to the current data, the Polish prognostic brown coal resources with potential balancing features amount to 18,251.79 mln tonnes***).
The figure shows changes in the resources and production of brown coal in Poland in the years 1989-2020.
In the Table 3 given below there is the state of resources exploration, the state of deposits development along with the output volumes presented for the whole country.
Table 1. Brown coal - million tonnes