Chalk is a calcareous, soft and porous sedimentary rock with a high calcium carbonate content and a very fine-grained structure. It is used in many industries: rubber, paper, chemical, pharmaceutical, cosmetic, ceramic, for the production of paints and lacquers, plastic, building materials, agriculture, for the soil liming and as a fodder chalk for the animals breeding. The natural raw material is being increasingly replaced by lime meals doming from the processing of limestones and marbles and by a raw material gained from the process of solutions precipitation.
In Poland, chalk is the name traditionally given to two different mineral raw materials: lacustrine chalk (calcareous tufa) and proper chalk rock (still often called as ”writing chalk” in Polish literature). The raw materials differ in an origin, a chemical composition and use.
Proper chalk is an organogenic marine sediment of a white or creamy color constituted mainly from planktonic organism remains: coccoliths and crusts of forams. In Poland, it occurs in Cretaceous deposits (the Lubelszczyzna area) and in the area of north-eastern Poland where Cretaceous deposits occur in the form of ice floats within Quaternary sediments.
In the Lubelszczyzna area (Chełm vicinities), “writing chalk” is exploited for the cement production. Deposits occurring in this area are presented in the chapter Limestones and marls for cement and lime industries.
Deposits of “writing chalk”, documented within ice floats, occur numerously in the area of Kornica and Mielnik on the Bug river on the border of Mazowieckie and Podlaskie Voivodeships. There have been 20 deposits documented, from which 10 are constantly or temporarily exploited.
Lacustrine chalk is a very humid, clammy mass usually of white, white-yellow or grey color. It originates from the biochemical precipitation and the accumulations of a carbonate sediment on the lake bottoms. The significant role in this process play plants which pick up a dissolved calcium dioxide (CO2) from water. This results in solution saturation changes and a calcite crystallization. Except for carbonates, lacustrine sediments contain the organic matter and the material brought from the land. Lacustrine chalk and gyttja usually contain minimum 80% of calcium carbonate (CaCO3), whereas the sediment containing 50-80% of calcium carbonate is called as calcerous gyttja. Very often lacustrine chalk and gyttja beds occur below the peat beds. It results from the shallowing and encroachment of a sedimentary reservoir (lake).
Lacustrine chalk deposits are usually of the Quaternary age and occur in northern and north-western Poland. There are also Tertiary chalk accumulations documented, which are being exploited as a co-occurring raw material in brown coal deposits in the vicinities of Bełchatów.
The chalk deposits occurrence is presented on the map.
According to the Regulation of the Minster of the Environment of the 1st of July 2015 (number of Polish act: Dz. U. 2015, poz. 987) the limit values of the parameters that defines the deposit (Appendix 8) are:
- lacustrine chalk and calcareous gyttja (table 38) are documented with the minimum deposit thickness of 1 m, the maximum ratio of overburden to deposit thickness of 0.3 and the minimum alkalinity (CaO) of 40% (71.2% CaCO3);
- proper (“writing”) chalk (table 39) is being documented to the depth of 70 m, with the maximum overburden of 15 m, the maximum ratio of overburden to deposit thickness of 0.2 and the minimum alkalinity (CaO) of 44.8% (80% CaCO3).
Table 1 shows resources and the current state of the exploration and development of chalk.
Anticipated economic resources of chalk and calcareous gyttja in 2017 amounted to 207.259 million tonnes and decreased by 0.107 million tonnes (0.1%) in comparison with the previous year.
In 2017 there has not been any chalk deposit documented. Nevertheless, as a result of the verification process there was Sławoszewo II deposit included in “The balance…” (Zachodniopomorskie Voivodeship). Sławoszewo II is a peat deposit in which calcareous gyttja occurs as a co-occurring raw material. Due to the inclusion of Sławoszewo II deposit in “The balance…” anticipated economic resources increased by 0.001 million tonnes.
In 2017 there were new documentations with recalculated resources approved for 2 lacustrine chalk deposits which resulted in the resources correction of Skic-Kujan deposit located in Wielkopolskie Voivodeship (+0.171 million tonnes) and crossing out Lubiatowo III deposit (Zachodniopomorskie Voivodeship) from “The balance…”. Lubiatowo III deposit has been totally exhausted.
The output of lacustrine chalk and proper chalk amounted in 2017 to 0.198 million tonnes and increased by 0.023 million tonnes (13.1%) in comparison with the previous year.
The “writing chalk” was exploited from 9 deposits, including Sewerynów 1 deposit from which the exploitation has just started. The output amounted to 0.176 million tonnes (which accounted for 88.9% of the total chalk output) and increased by 0.013 million tonnes (7.7%) in comparison with the previous year.
The output of lacustrine chalk was carried out from 4 deposits including the 1st year of the exploitation from Lubiatowo IV deposit. The output was equal 0.022 million tonnes (which accounted for 11.1% of the total chalk output) and increased by 0.010 million tonnes (88.9%) in comparison with 2016. The output growth is mainly the result of the beginning of Lubiatowo IV deposit exploitation. The level of the lacustrine output returned to the level recorded recently, after the temporary decline in 2016 (0.012 million tonnes) caused by the exploitation end and closing of Lubiatowo III mine.
Lucastrine chalk is also temporarily produced during the disclosing brown coal deposits for the exploitation in Bełchatów vicinities. In 2017 from Bełchatów-pole Szczerców deposit there was 0.050 million tonnes of lacustrine chalk exploited (the amount is not included in Table 2).
Economic resources of chalk in 2017 documented for 9 deposits amounted to 14.448 million tonnes which accounts for 86.7% of the total anticipated economic resources of these deposits. The economic resources increased by 1.607 million tonnes (11.1%) in comparison with the previous year due to the documentation of economic resources for Lubiatowo IV deposit (+1.427 million tonnes) and the resources updating for Roszczyce II deposit.
The figure given below shows changes in domestic resources and production of chalk in Poland in the years 1989-2017.
Prepared by: Wojciech Szczygielski