General information and occurrence
Native sulfur deposits occur in the vicinities of Tarnobrzeg (Osiek, Baranów, Machów and Jeziórko deposits), Staszów (Solec and Grzybów deposits) and Lubaczów (Basznia deposit) in the northern part of the Carpathian Foredeep (map).
The native sulfur output has been significantly declining in the world economy for the last couple of years. The output of the native sulfur in Poland is quite expensive, therefore it is being replaced by the much cheaper sulfur obtained from the sour gas and oil fields. In Poland there are four sour gas and oil fields documented. Sulfur is recovered from BMB (Barnówko – Mostno – Buszewo), Cychry, Zielin and (temporarily) Górzyca fields.
Native sulfur is a product of a volcanic origin, nevertheless in the majority it is being created in the process of the sulfates reduction (mainly gypsum and anhydrite) with the participation of bacteria and hydrocarbons.
The sulfur occurs in the above mentioned areas in the form of fillings of fissures and small cavities in chemical Tertiary (Miocene-Torton) rocks, mainly post-gypsum limestones. The content of sulfur in these rocks may reach up to 70% at the most, ranging from 25% to 30% at the average. The output of the native sulfur has been carried out only from Osiek deposit recently using the Frasch hot water method. In 2017, there was the exploitation concession issued and the deposit development plan approved for Basznia-1 deposit. The deposit was allocated from the abandoned Basznia deposit. It resulted in the economic resources of the native sulfur growth by about 6 million tonnes. In 2019, the exploitation of Basznia-1 deposit started. Except for the exploitation from underground deposits, native sulfur is in small amounts being obtained from the volcanic deposits. The other sulfur source is the recovery of the sulfuric acid in the processing of copper ores and lead and zinc ores. Such recovery is of the limited economic importance mainly due to the protection of the natural environment.
Resources and output
Table 1 shows resources and the current state of exploration and development of native sulfur deposits, whereas Table 2 shows similar data for deposits from which sulfur is obtained from the sour oil and gas fields.
When documenting sulfur deposits the limit values of the parameters that define the anticipated economic resources are: the minimum sulfur content in the sample contouring the deposit of 10%, the minimum average sulfur content in deposits bed of 10%, the minimum deposit richness of 75m% and the maximum depth of deposit base of 400 m.
The anticipated economic resources of the native sulfur amount in 2020 to 494.08 million tonnes and those of sulfur from the oil and gas fields to 0.37 million tonnes (365.34 thousand tonnes). The output of native sulfur from the only active mine Osiek gradually decrease in comparison with the previous years and amounted to 417.5 thousand tonnes in 2020. The exploitation of Basznia-1 deposit was minor and in 2020 amounted to 4.9 thousand tonnes. The total output of the native sulfur in 2020 was equal 422.38 thousand tonnes. In turn, in the result of the oil and gas fields desulfurization there were 24.74 thousand tonnes of the sulfur as a by-product obtained, from which 23.6 thousand tonnes came from BMB (Barnówko – Mostno – Buszewo) deposit.
The figure given below shows changes in domestic resources and production of sulfur in Poland in the years 1989-2020.
The prognostic resources of the native sulfur are currently being assessed at 82 million tonnes, whereas the hypothetical resources at 231 million tonnes*.
Prepared by: Robert Bońda
* Gąsiewicz A., 2020 - Siarka, siarka rodzima (native sulphur). In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r. (eds. Szamałek K., Szuflicki M., Mizerski W.): 213-217. PIG-PIB, Warszawa [in Polish].