Chalk
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 origin and chemical composition and use.
Lacustrine chalk, also known as „meadow limestone” or „lacustrine limestone”, is a calcareous sediment of the Quaternary age, associated mainly with post-lacustrine series formed in times of the Last Glaciation. It is used in agriculture as calcareous fertilizer. Accumulations of lacustrine chalk occur mainly in northern and north-western Poland, often at the base of deposits of peat and calcareous gyttja. Chalk deposits occurence is presented on the map.
Chalk is a weakly coherent and porous limestone rock, mainly used in the manufacture of rubber, paper, chemicals, dyes and cement. Cretaceous limestones of the chalk type used in production of cement (Chełm deposit) are discussed in the section dealing with limestone and marl raw material of the cement industry. Chalk deposits found in north-eastern Poland are related to erratics of Cretaceous chalk embedded in Quaternary glacial sediments (for example, the Mielnik and Kornica deposits).
Chalk deposits are being documented to the depth of 10 meters, with minimum deposit thickness of 1 meter, maximum overburden of 2.5 meters, maximum ratio of overburden to deposit thickness of 0.3 and minimum alkalinity (CaO) of 40 %.
The table 1 given below shows resources and the current state of exploration and development of chalk.
Anticipated economic resources of chalk in 2012 amounted to 199.05 million tonnes and decreased by 106 thousand tonnes in comparison with the previous year. There was Ludwinek deposit crossed out of “The balance…” (with resources of 9 thousand tonnes). One deposit – Mosina – was documented in 2012.
In 2012, production of chalk increased by 19 thousand tonnes to the level of 147 thousand tonnes. Lacustrine chalk production amounted to 16 thousand tonnes (the same level as in 2011) and writing chalk production to 132 thousand tonnes (increased by 20 thousand tonnes).
The figure given below shows changes in domestic resources and production of chalk in Poland in the years 1989-2012.
Prepared by: Agnieszka Wałkuska
Table 1. Chalk - million tonnes