Sara Biolchi, Stefano Devoto, Stefano Furlani, Igor Belamarić, Franco Cucchi, Radoslav Dodig, Goran Glamuzina, Jernej Jež, Bogdan Jurkovšek, Tea Kolar-Jurkovšek, Karmen Peternelj, Fabiana Pieri, Luca Zini, Gordana Zwicker Kompar, Irina Žeger Pleše
Based on the outputs of fieldwork on exploitation areas and the spatial distribution of existing legislation, a list of possible platy limestone exploitation areas is provided for each country (Fig. 4.16). All of these locations were estimated as high potential localities/polygons exclusively on the basis of physical/geological properties of platy limestone (WP3). This does not, however, mean that these are possible exploitation areas, because there are numerous limitations to such, and these localities need to be evaluated from the perspective of natural heritage, limitations, regulations and similar.
From a geological point of view, the occurrence of platy limestone is extremely limited in the Italian part of the project area and of generally poor quality.
Among the 124 limestone quarries in the Italian part of the Carso/Kras, only 24 quarries exhibit limited horizons of platy limestone: among them 16 lie in areas covered by obligations or limitations. The remnants quarries are not able to provide adequate quantities of material for exploitation. However, small quantities of thin limestone slabs are widespread over the Carso/Kras, and are gathered as waste material in many quarries.
One of the outputs of the project is the geological characterization and mapping of the platy limestone units for the entire Adriatic Karst Region: in fact, the geologists highlighted that in Slovenia and Italy the platy limestone horizons belong to the same geological formations and are very similar if not practically identical.
Since the difficulty of re-using old plates or opening new quarries or exploiting abandoned ones (due to the absence, rescinding or termination of a permit or conflicts with legislation), it is suggested efforts be directed, for limited exploitation, at nearby Slovenia, where this type of rock is more widespread (see Paragraph 3.3.2).
After careful consideration of the situation in the field and a quality assessment of limestone slabs, two localities were selected (Fig. 4.16) within the wider area of Komen limestone occurrence (Fig. 4.17), which can be proposed as relevant for limited exploitation, with the need of synchronous paleontological monitoring:
In all other locations there are either relatively small outcrops of platy limestone on or near the surface or it is of poor quality. Given the predominantly horizontal or sub-horizontal beds, a re-acquisition of platy limestone in large areas would need to be initiated. However, from an environmental standpoint this is virtually impossible in the Kras/Carso area. Even in the two proposed sites large quantities of high-quality limestone slabs are simply not present.
In addition, both quarries come with legislative conflicts, because they lie in areas protected by Natura 2000. This is why, for any future exploitation of abandoned quarries, it is necessary to: 1. secure a permit from the Slovenian Environment Agency for an environmental impact assessment and the issuance of environmental protection consent; and 2. apply to the ministry responsible for mining, which has the authority to issue mining rights to concessionaires.
Geological investigation revealed the widespread occurrence of platy limestone in the studied RoofOfRock project area in Croatia. At many locations, limestone plates as well as slabs are of good quality and assessed as appropriate for use, and have also been traditionally widely exploited for local use. As a traditional activity with low impact on the sensitive karst environment we propose the gathering of limestone slabs on the surface ( branje kamena); however, since it is illegal, we suggest identifying some exceptions to the laws.
For the opening or re-opening of smaller platy limestone quarries we identified the following areas with high potential PL occurrence (Fig. 4.16):
Istra/Istria
The main occurrence of platy limestone in Istrian County lies within the Pula platy limestone unit of Albian age. The Pula platy limestone has an average bed thickness of 4 to 60 cm. The outcrop is characterized by an alternation of platy and thick-bedded limestones. Fieldwork identified one quarry in Istra/Istria, which is not included under any type of natural protection and is characterized by extensive platy limestone outcrops. The above-cited quarry is located in Bale.
Benkovac area (Zadar County)
There is a major platy limestone occurrence in the Benkovac region, with Late Paleogene platy limestone units, located between the village of Smilčići and Mejanica hill. This unit boasts the most commercial quarries of “Benkovac stone” and consists of 100% platy limestone (Fig. 4.18). The best quality plates are homogeneous calcarenites or calcilutites, with thicknesses varying between 2 and 5 cm. The total surface of this outcrop amounts to some 3000 ha and there are no limitations for exploitation, since the area lies outside any protection category. In Zadar County, there are 28 official commercial quarries of platy limestone.
Brač island (Split – Dalmatia County)
The island of Brač features high potential platy limestone for quarrying in the southern sector.
Two areas are considered as high potential on the island of Brač, belonging to the Gračišće platy limestone unit (Fig. 4.19) and Gornji Humac platy limestone unit.
One active quarry of platy limestone in the area of Gornji Humac at Vestac has a high potential for further exploitation. According to the detail study, the volume of platy limestone here amounts to some 15.000 m3, and the area lies outside any protection categories. Another important quarry is located in the western part of the sector. According to the study the quarrying potential is estimated at 5 billion m3 of platy limestone (Fantovi doci and Podgažul platy limestone units). The Fantovi doci outcrop is recognized under the Natura 2000 network as a relict forest of Pinus nigra subsp. dalmatica, but the Podgažul outcrop remains an area of potential platy limestone exploitation, with nearly half the estimated stone volume. The ministry for mining is the only authority authorized to issue mining rights to concessionaires.
Šolta island (Split – Dalmatia County)
High potential platy limestone is identified in several areas on the island of Šolta: in Koludrovi doci lies a flat area between Stomorska and Gornje Selo characterized by a Klacina platy limestone unit; and between the villages of Gornje Selo and Grohote in the central part of the island, at Kupište, where a Milna platy limestone unit occurs. A high potential local occurrence is also identified between Grohote and Necujam. There are no conflicts with legislation, except the general restriction defined for islands.
Pelješac peninsula (Dubrovnik – Neretva County)
Potential quarries are located in the Lovište location, which is situated on the western side of the Pelješac peninsula. The quarries are quite small and are suitable for local requirements for platy limestone material. Five quarries have been recognized and classified as potential: 4 quarries are located in the Gornji Humac platy limestone - Pelješac, and 1 in the Donja Nakovana. Almost all of the Pelješac peninsula is under Natura 2000 protection. The other quarry in Donja Nakovana is abandoned, so mining rights must be requested from the ministry for mining, and from the administrative department in the county or city responsible for regional planning and construction.
Korčula Island (Dubrovnik – Neretva County)
Two areas for possible exploitation of platy limestone have been recognized: the Gornji Humac-platy limestone unit at Vela Luka, in the western part of the island (though in conflict with legislation regarding its proximity to the sea coast); and the Milna and Pupnat – platy limestone units at Žrnovo in the eastern part, where the area is under the protection of Natura 2000. All quarries are abandoned, requiring permits from the ministry for mining and from the administrative department in the county or city responsible for regional planning and construction.
In Herzegovina, the Dretelj-Zvirovići quarry is proposed as a possible exploitation area for platy limestone. It is located northeast of Čapljina and is an abandoned quarry where the Dretelj platy limestone unit is excavated. This quarry has terraced floors excavated over a length of some 200 m along the main strike-axis of platy limestone layers. The quarry is some 140 m wide, with the trend to develop quarrying toward the north in the future. Southeast of the Zvirovići-1 quarry, several smaller quarries occur.
Other interesting sites suggested in the frame of WP3 for future consideration include the Podveležje site, east of the city of Mostar and the village of Dobrć, the Drinovci site south of Grude; the area around the Raška Gora and Vrdi sites north of Mostar; the Polog (Žovnica) site west of Mostar; and the Borićevac site northeast of Posušje.
Numerous abandoned and active (mostly illegal?) quarries of high quality platy limestone occur in all of these sites.
