European Geologist Journal 41

Sustainable exploitation of mineral resources within an area of the Natura 2000 network

By Jorge M. F. Carvalho*, João Meira, Célia Marques, Susana Machado, Lia M. Mergulhão, Jorge Cancela

*EDM – Empresa de Desenvolvimento Mineiro, SA,




Codaçal is the name of a relatively small exploitation cluster for ornamental limestones occupying an area of 98 ha in a Natura 2000 Network protected area located in Portugal. Supported by comprehensive geological, mining and environmental studies, a land use planning methodology was developed in order to address the compatibility between the longterm sustainability of this industry with the preservation of existing protected natural values. The obtained results allow the Codaçal mineral resources to be included in the municipal land use plan.




In very simple terms, mineral resources are geological bodies that have the potential to be economically exploited. They were and still are crucial to meet the supply needs of human society, being essential to key socio-economic sectors such as construction, information technology, and the automotive and aerospace industries. Recycling, substitution and reuse are flagships for efficient use of mineral resources but they alone cannot fulfil the present and future societal demand (e.g. Espinoza, 2012; Reck & Graedel, 2012; Steinbach & Wellmer, 2010; UNEP, 2013).


The exploitation of mineral resources can only take place where they occur and their long-term availability and exploitation depends on geological, technological and market conditions, but also on the constraints imposed by land use policies and practices. In most developed countries, where there is an increasing competition for land use, the access to mineral resources is an issue that recently started to be addressed. In the European Union it was formally identified in 2008 as one of the main constraints to the security of supply of mineral products (COM(2008) 699 final, 2008).


In Portugal, mineral resources have not received proper attention from national authorities and were usually regarded as unwanted by local political powers, despite their importance for the economy and social development and the long mining tradition. Mineral resources have often been overlooked in land use plans, thus limiting their access by the mining industry and hindering the future exploitation of valuable materials. The implementation of the Natura 2000 Network resulted in increased exclusion of mineral resources despite recommendations for the undertaking of mining activities in environmental protected areas (European Commission & Directorate-General for the Environment, 2010). However, in more recent years, concerted efforts by the Portuguese Geological Survey, the mining authority and the industry have allowed the implementation of several good practices leading to the integration of mineral resources in land use planning policies and tools.


This paper aims to present an example of such good practice in a Natura 2000 Network area where limestones are being exploited for ornamental uses, seeking the minimisation of conflict between the mining activity and nature conservation. In this regard, the competent authority for the management of the Natura 2000 Network area and an industrial association representative of the mining stakeholders worked together in a project aimed at the conciliation of exploitation activities in the protected area through improvement in their economic and environmental performance. That project, funded by European Structural Funds and by the mining stakeholders, was aimed at:


  • defining strategies for the sustainable development of the extractive industry in the protected area;
  • creating the geological and environmental background information for land use planning of the areas subjected to mining activity, and for the implementation of joint exploitation projects in each area;
  • characterising and monitoring the hydrogeological conditions within the protected areas, evaluating their vulnerability to the extractive industry;
  • inventorying, characterising and presenting a proposal for the management of the geological heritage within the protected area, in view of its association with ornamental stones as identity brands of the region;
  • developing a Communicationand Public AwarenessProgram to demonstrate the harmonisation between the extractive activity and nature conservation;
  • defining a panel of sustainable development indicators for the mining activity within the protected area.


The mining industry and the Natural Park of Serras de Aire e Candeeiros


In the central region of the Portuguese territory an uplifted limestone massive stands out from the surrounding landscape. As a result of the combination of lithology with tectonic uplift, this region presents a peculiar karstic landscape with several relevant surface and underground morphological structures, as well as a large number of associated habitats with endemic flora and fauna. Besides these natural values, the region is characterised by population settlements in small villages and a few industrial activities, including tanning, livestock farming and quarrying. These activities were considered as major threats to the conservation of natural values and for this reason the region was designated as a natural park in 1979: the Portuguese Natural Park of Serras de Aire e Candeeiros (NPSAC), with an area of 389 km2; which has also been a Site of Community Importance (SCI) of the Natura 2000 Network since 2000 (Ref. PTCON0015).


This natural park is located in the Lusitanian Basin (Pinheiroet al., 1996; Ribeiro et al., 1990; Wilson et al., 1989) where several litho-stratigraphic sections of Jurassic formations outcrop in extensive areas (Figure 1). The sections of Middle Jurassic age mainly consist of light cream-coloured limestones formed under very specific palaeoenvironmental conditions, leading to their occurrence as massive limestone bodies (Azerêdo, 1998). These are exploited as 2 m3 to 6 m3 blocks for ornamental/high-value applications in about 100 open pits in NPSAC (Carvalho, 2012). Each one of these quarries has its own owner because in Portugal limestones are classified as a raw material of private domain. They are not dispersed; instead, they are clustered in five main exploitation areas of suitable stone quality.




Figure 1: Geological setting of NPSAC in the Lusitanian Basin (adapted from the Portuguese Geological Map, 1:1,000,000, edited by LNEG).



Quarrying in NPSAC is one of the fundamental economic activities with local and regional impact, supporting one thousand direct jobs and generating wealth of over €100 million. Ornamental limestones exploited and transformed here are exported all over the world, having a significant contribution in the national trade balance of non-energetic raw materials. The region has a long mining tradition, preceding its designation as a Portuguese Natural Park and a Natura 2000 Network site. Indeed, the most outstanding monuments in the vicinity of the Natural Park were built with stones from this region. This is the case of the Alcobaça Monastery (12th-14th centuries), the Batalha Monastery (1386–1517) and the more recent basilicas of Fátima (1953 and 2007). Nevertheless, the mining activity for ornamental limestones only recorded considerable development after the mid-1980s in response to increasing demand from the domestic and European construction sector, supported by new technological developments and new forms of funding. A greater and more intensive development took place after 2000 as a response to market demands from China.


In 1988, with the implementation of the first land use plan for NPSAC, several conflicts arose between the mining industry and the policy guidelines and rules for environmental protection and nature conservation. In recent years, the mining activity in this region went through several difficulties due to the loss of licensed areas and the lack of alternatives in areas assigned for this type of activity by the territorial management entities. This happened because the rules and guidelines did not envisage how to harmonise the development needs of the mining activities with the nature conservation policy.


In 2010, a new land use plan and respective regulatory framework was implemented for the NPSAC. Recognising the social and economic importance of the extractive activity within the Natural Park, this new management plan established the general rules for the mining industry aiming at its compatibility with environmental protection and valorisation of natural resources. In view of those policy guidelines, a set of five Areas of Specific Intervention (ASI) for the quarrying development of ornamental stones were defined at the regional level in the new Natural Park Land Use Plan (Figure 2). These areas correspond directly to the main exploitation areas existing in NPSAC, occupying a total of 17.11 km2 and representing just 4% of the NPSAC area.




Figure 2: Geographical setting of the five sites selected as Areas of Specific Intervention related to quarrying activity within the Natural Park of Serras de Aire e Candeeiros. 



Methodology and results


According to the legal Portuguese land management framework, the aforementioned ASIs should be subjected to detailed land use planning at the municipal level aimed at the establishment of compatibility measures between rational mining activity, the environmental restoration of degraded areas and the conservation of existing natural values.


Taking into account these objectives, the adopted methodology for the land use planning of each ASI was based on comprehensive geological, mining and environmental studies. These were thought to support not only land use planning but also the reorganisation of the extractive activity within each ASI, for the responsible exploitation of ornamental limestones with the best mining practices.


To achieve these intents, the first working phase consisted of the acquisition of geological, mining and environmental data for characterisation and diagnostics. In the proposed land use planning objectives emphasis was put on: 1) information to be gathered about the ornamental capability of limestones within each ASI; 2) existing quarries and environmental recovered areas; 3) flora; 4) fauna and habitats; and 5) geological and other cultural heritage sites.


The geological and biological studies were carried out at a 1:2,000 scale, as legally required for this type of land use planning map. The geological studies comprised:


  • thematic geological mapping oriented to ornamental limestones;
  • fracturing studies;
  • hydrogeological studies;
  • diamond drilling.


The obtained results allowed spatial delimitation of lithological units suitable for ornamental purposes, 3D geological modelling of the mineral deposit hosted in those units, and an assessment of resources and reserves. The hydrogeological studies allowed the delimitation of areas of vulnerability and sensitivity within each ASI.


The biological studies, supported by existing NPSAC regional data, consisted of:


  • characterisation and mapping of vegetation units, giving particular emphasis to the survey of flora species more relevant for conservation within the NPSAC;
  • identification of fauna species;
  • identification, characterisation and mapping of biotopes and habitats.


Based on the qualitative evaluation methodology used by the Portuguese entity responsible for the management of the NPSAC, natural value maps were produced for flora, fauna and habitats. They resulted from the valuation of criteria such as the occurrence of species and habitats listed in the birds and habitats directives (Directive 2009/147/EC and Directive 92/43/EEC). The relevance of each natural value in the produced maps was expressed on an ecological relevance scale, from Low to Exceptional.




Figure 3: Methodology used for the compatibility between quarrying and nature conservation on land use planning. 



The second working phase was directed to the integration of all spatial data, making use of GIS support. The main focus was the coexistence of limestones suitable for ornamental purposes and other natural assets previously valued by means of qualitative and/or quantitative criteria, as presented in Figure 3.


The main intermediate results achieved through this methodology as well as the final land use planning proposal for one of the evaluated ASIs are presented in Figure 4.



Figure 4: Main intermediate results from geological and environmental studies carried out at the Codaçal ASI: a) aerial view of the Codaçal ASI; b) geological thematic mapping; c) delimitation of the suitable areas for limestone quarrying; d) existing licensed quarries; e) GIS integration of the natural values evaluation process; and f) land use spatial planning proposal for the Codaçal ASI (colours according to Figure 3). 



Final remarks and conclusions


The planning map proposal yielded for the Codaçal area – an example of what was done for all five ASIs of NPSAC – is just one step of the whole process for the inclusion of NPSAC areas hosting significant mineral resources in land use planning. Indeed, as mentioned before, that process involves the implementation of joint exploitation projects for each ASI, as well as a general waste management plan, an environmental impact assessment and an Intervention Plan in Rural Area. This Intervention Plan is the formal Portuguese designation for the detailed land use management plans that are held at municipal level for some areas of the territory that are thought to need a particular approach. It comprises a Regulation Document, a Land Use Map at the 1:2,000 scale (where several spatial land use classes are defined), and a Map of Conditioning Factors (containing the restrictions of public utility) at the same scale.


Nevertheless, although the present land use proposal is just one step of a long process, it is extremely relevant for the whole procedure; it represents a turning point in the relationship between mining industry stakeholders and environmental protection authorities after more than 20 years of land use conflicts. Working in a collaborative way, it was possible to accomplish a balance between nature conservation and the mining industry. Furthermore, that joint proposal is also relevant because it demonstrates how crucial geological knowledge is for the suitable practice of land use planning, achieving supporting solutions that prevent the sterilisation of mineral resources (i.e., withdrawing the possibility of being exploited), thus contributing to the sustainable supply of mineral raw materials to Europe from domestic sources.





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This article has been published in European Geologist Journal 41 – Sustainable land use: How geology can contribute.