engleski

Management of mineral resources in karst areas ; case study of County of Dubrovnik-Neretva

The current state of land use uncertainty and the need to streamline cumbersome environmental and land use permitting processes have been identified by the mining industry as a serious impediment to new mine development in Croatia. Mineral resources are an especially significant component of societal wealth. However, the exploitation of these resources to alleviate poverty and therefore strengthen civil society requires a delicate balancing of a number of issues, which include economic importance, mineral potential, responsible exploitation, social equity and environmental protection. These issues that are critical to long term mineral resource development, at present, typically addressed individually through different, though inter-related, geoscientific research and development. Different geographic information systems (GIS) are presently being developed by the Croatian Geological Survey which is involved in mineral resource management, land management and environmental management. Land-use decisions, mineral development plans, provisions for mitigation/remediation of environmental and societal health impacts/hazards and, therefore, socio-economic development plans are often non-optimal and therefore governance of responsible mineral exploitation does not materialise and this in turn can have a curtail influence on the quality of water in vulnerable aquifers such as karst which covers half of Croatian national territory. Karst aquifers are among the most highly vulnerable to contamination, particularly where the overlying soil is thin. This vulnerability results from: (1) the presence of point source recharge features such as sinkholes, (2) solutionally widened flow paths, and (3) rapid velocities of ground water and contaminants. Aggregate stone quarries karst in general can bi treated as potential point sources of contamination. A balanced approach using geoinformation data was applied to mineral resource management in the county of Dubrovnik-Neretva in the southern part of the Croatian karst region. Based on lithological characteristics, active and abandoned quarries a general potential of mineral raw materials was evaluated using GIS and digital map data at a scale of 1:100 000. The applied research framework was harmonized with the Strategy for management of mineral resources in the republic of Croatia. The territory of county of Dubrovnik-Neretva hosts 13 different types of mineral resources located at 73 sites. Exploitation of stone aggregate and dimension stone is present at 21 locations while other sites are either abandoned or were never in exploitation after exploration was performed. In the County three types of construction raw materials are exploited: stone aggregates and dimension stone, while potential due to different types of calcarenous rocks (limestone and dolomite) is perspective for exploitation: calcarenous raw material for chemical industry and marl for as a mineral raw material used for production of cement. The County produces 2, 3% crushed stone aggregate in of the total production in Croatia. The most relevant non-metallic mineral resources in County is dimensional stone. The performed evaluation of dimension stone potential revealed that a number of locations approved for exploitation were made without proper geoscientific evaluation and responsible exploitation capabilities within the environmental context are questionable. The geological potential for mineral resources after application of restriction zones (areas of possible environmental impact) for exploitation mineral resources for dimensional stone cover an area of 323 km² and crushed stone aggregates an area of 182 km² . The geological potential other non-metallic mineral resources cover an area of less than 40 km² . Due to the application of restrictions defined within the marine protection zone of 1000 m the geological mineral potential for dimensional stone was reduced from 323 km² , to 239 km² . The performed evaluation and management strategy gives recommendations for responsible exploitation and restoration of abandoned quarries in the respect of protection of the karst environment within potential areas without administrative restrictions for mining. Also a specific problem is the tradition of stone excavation in the region dating back to Roman times and which resulted in world famous masonry work (Dubrobnik, Korčula, Ston) and which now is being threatened by rigorous administrate restrictions which have no geoscientific foundation that the karst environment is threatened by these activities. The main problems connected with exploitation of mineral resources in karst are: 1) destruction of public local road infrastucture, 2) noise, 3) dust, 4) general “ feeling” of negative environmental influence, 5) abandoned pits that are used for waste disposal. In order to locate and sustainably manage mineral resources in karst areas it necessary to apply a geoscientific GIS based approach as in the case of county of Dubrovnik-Neretva in order to predict and avoid possible negative effects on mining activities on the environment, by determining most favourable zones of mineral exploitation within county spatial-plans.

GIS; mineral resources; karst

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