General information and occurrence

Native sulfur deposits occur in the vicinities of Tarnobrzeg (the Osiek, Baranów, Machów and Jeziórko deposits), Staszów (the Solec and Grzybów deposits) and Lubaczów (the Basznia deposit) in the northern part of the Carpathian Foredeep (map).

The declining tendency of the native sulfur output has been visible in the world economy. The output of the native sulfur in Poland is expensive, therefore it is being replaced by the much cheaper sulfur obtained from the sour gas and oil fields. In Poland, there have been four sour gas and oil fields documented. Sulfur is recovered from the following fields: BMB (Barnówko – Mostno – Buszewo), Cychry, Zielin and (temporarily) Górzyca.

Native sulfur is a product of volcanic exhalations 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 native sulfur deposits occur in the above mentioned areas in the form of fillings of fissures and small cavities in the chemical Tortonian sediments, 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 the Osiek deposit recently using the Frasch hot water method. In 2017, there was an exploitation concession issued and a deposit development plan approved for the Basznia-1 deposit. This 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 the Basznia-1 deposit started. Except for the exploitation from underground deposits, the 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 and silver 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.

Table 1. Native sulfur - million tonnes

Table 2. Sulfur from the sour oil and gas fields - million tonnes

During documentation of the native 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 a deposit 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 2021 to 498.56 million tonnes and those of sulfur from the oil and gas fields to 0.34 million tonnes (341.10 thousand tonnes). The slight resources growth of the native sulfur in comparison with the previous year was recorded for the Osiek deposit (about 4.8 million tonnes). It was the result of the resources correction in a mining report covering the year 2021. The output of the native sulfur from the so far exploited Osiek mine has been gradually decreasing in recent years, however it slightly grew in 2021 and amounted to 444.61 thousand tonnes. The exploitation of the recently documented Basznia-1 deposit was minor and amounted to 4.49 thousand tonnes. The total output of the native sulfur in 2021 was equal 449.10 thousand tonnes. In turn, in the result of the oil and gas fields desulfurization, there were 24.24 thousand tonnes of sulfur as a by-product obtained, from which 23.32 thousand tonnes came from the BMB (Barnówko – Mostno – Buszewo) deposit.

The figure given below shows changes in domestic resources and production of sulfur in Poland in the years 1989-2021.

Table 3. List of native sulfur deposits - thousand tonnes

Table 4. List of the sour oil and gas fields - thousand tonnes

The prognostic resources of the native sulfur are currently being assessed at 82 million tonnes, whereas the hypothetical resources at 231 million tonnes*.