Mineral Resources in Flanders

Resources in Flanders

The subsoil in the Flemish Region is mainly composed of sedimentary deposits of Tertiary and Quaternary formations. Hence, natural resources include construction and industrial minerals like clay, loam, sand and gravel. Since the discontinuation of coal-mining operations, these construction minerals have now become the only extracted and commercialised mineral natural resources in the Flemish Region. Construction minerals are essential resources for the economically and socially important building and infrastructure sectors. Bricks, tiles, argex granules, glass, mortar, concrete and glazed stoneware pipes are all fabricated with Flemish surface raw materials. Quartz sand and its derived products, such as cristobalite, silicon and water glass (sodium silicate), have numerous high-grade applications. They are used as important additives or fillers in paints, detergents, good-quality plasters, paper, toothpaste, automobile tyres, tile cements, transparent plastic films, et cetera. Silicon is also the main base material for the production of semiconductors like chips and solar cells.

Direct employment in the extraction industry amounts to about 3,500 jobs in the Flemish Region. In general, approximately 152,000 people work in the Flemish construction industry, which is dependent on a continuous supply of construction minerals.

Some of the main resources exploited in Flanders are clay and loam deposits. These deposits are exploited in open pit mining above the water table. The abundance of clay and loam makes Flanders a net exporter of baked end products such as bricks and roofing tiles. Clay and loam are found over a vast area of Flanders. Loam is mostly found in the southern parts of the region as an aeolian deposit dating back to the last ice ages. However, the main clay deposits of the region are the result of Tertiary marine deposits. The most important deposits are the Ypres clay in West Flanders and the Boom clay in the Rupel and Waasland region. Apart from these marine deposits, Quaternary alluvial clays are found in the valleys of the main rivers and in the Campine area.

Another important Flemish mineral resource is represented by the abundance of sands in the region. Depending on their quality, these sands are used as filler sand, building sand or masonry sand. They are extracted in open pit surface mines above the groundwater table as well as by dredging techniques below the water table.

Silica sands constitute an important and very valuable sand deposit. They occur in the eastern part of the Province of Limburg and the northern part of the Province of Antwerp. These pure silica sands formed the basis of a thriving glass-making industry in the areas concerned. Nowadays, these sands are also used to produce higher value end-products, such as tridymite and cristobalite, which are exported across the world.

The gravel deposits in East Flanders form the last important Flemish mineral resource. Two different types of gravel deposits are distinguished. The oldest terrace gravel deposits were deposited on the Campine plain at the beginning of the ice ages. They consist of relatively unclean gravel deposits which occur above the current water table. As a result, they are extracted in dry open pit mines. Because the gravels contain impurities, these gravel deposits get washed before they can be commercialised. The second gravel deposits occur in the current alluvial plain of the River Meuse (valley gravel). They consist of very clean gravels which were deposited during the later stages of the ice ages. Only a limited amount of these gravels can be extracted through dry open pit mining. The majority is extracted from below the water table.Because of the limited extent of these gravel deposits in the Meuse Valley area, former and current extractions have had a big impact on the environment of the area. For this reason, the extraction of valley gravel is gradually discontinued.

Geological Maps and Models

In order to define the best locations to exploit the available mineral resources, an up-to-date and detailed geological database is available.

Recently, the Tertiary sub-crop maps of Flanders have been revised in cooperation with the Belgian Geological Survey. Since plenty of the Flemish mineral resources are of Tertiary age, this map combined with the thickness map of the overlying Quaternary strata allows for the definition of areas which are suitable for mineral extraction from the Tertiary strata.

Flanders also has profile-type geological maps of the Quaternary strata.  However, some of these profile-type maps are difficult to interpret, which is why Flanders ordered the design of thematic maps for specific purposes. One of these maps aimed to define the sand occurrence in the Quarternary Flemish Valley. The Flemish Valley was deposited by a huge braided river system during the ice ages. Consequently, the sand content of the deposits can vary considerably in thickness, quality and average content over very short distances. The design of this map allows the authorities to better judge on the merits of demands for new exploitations and to reduce the surface area of the envisaged exploitations.

A very important tool for designing thematic maps and models is the Database of the Soil and Subsoil of Flanders (DOV, dov.vlaanderen.be). This database, which is free of charge, is available to the public at large and contains any available geological information, such as borehole and cone penetration tests as well as Tertiary sub-crop and Quaternary geological maps. Most of the borehole and cone penetration tests also contain an interpretation of the geology encountered. The database is continuously updated and extended as more information becomes available. It is the result of a cooperation agreement between the Environment, Nature and Energy Department, the Mobility and Public Works Department and the Flemish Environment Agency.

For several years now, Flanders has been building a geological 3D model from the most recent top sediments to the deep solid subsurface on the basis of DOV data. This 3D model will give a clear insight into the structure of Flanders’ subsoil. This will increase the understanding of the subsoil and will promote the sustainable use thereof. This 3D model will serve as input for educational purposes, research for infrastructure works and storage provision, geological knowledge building, an estimation of natural resources,..

Sustainable Mineral Resources Strategy

The competition for land use is very pronounced in Flanders. Due to the dense population, the area available for minerals extraction is very limited. In order to facilitate the need for raw materials, Flanders has developed a legal framework.

The Flemish Sustainable Mineral Resources Strategy is based on the General Surface Mineral Resources Plan. On 4 April 2003, the Flemish Government ratified the Flemish Parliament Act on Surface Mineral Resources. This act defines the basic objective of the policy regarding the management of surface mineral resources as follows: “To sustainably meet the needs for surface mineral resources of current and future generations”.

This basic objective is further put into practice by:

• Extracting in such a way as to allow the economic, social and environmental components to mutually reinforce each other to the maximum extent;
• Guaranteeing development perspectives for the sector, taking account of the business economic security, in view of long-term socio-economic acceptable extraction opportunities, in order to meet society’s needs;
• Using surface mineral resources in an economical and efficient manner;
• Extracting optimally within extraction areas on the basis of an economical use of space;
• Promoting the use of fully-fledged alternatives for primary surface mineral resources and the maximum re-use of waste, in order to curb the needs for primary surface mineral resources;
• Taking the maximum preservation and development of nature and the natural environment into account in extractions.

The General Surface Mineral Resources Plan supplies a number of concepts and indicators regarding a sustainable extraction policy. Furthermore, the general plan analyses the needs for surface mineral resources for the next five years on the basis of economic studies, market research and consultation. The bottlenecks and actions which are highlighted by this analysis and which are necessary to implement the sustainability objectives are described in great detail. Finally, it is also examined which impact the General Surface Mineral Resources Plan has on the environment and agriculture and which are the socio-economic consequences and financial implications of a sustainable extraction policy.

A Flemish Parliament Act has been drawn up, specifically for the extraction of gravel in the Province of Limburg. This Act on Gravel allocated a fixed quota of gravel to the different extractors and introduced a levy on the production of the gravel, in order to secure the realisation of the rehabilitation and social consequences of the future reorganisation of the sector. The levies are also being used to search for alternatives for gravel production. On 15 July 2005, the Flemish Parliament Act on Gravel was amended. This amending Act confirms the allocated tonnages but also allows consultations to be started on the future of gravel extraction with all Limburg parties involved. The latest important modification of the Act on Gravel (the amendment of the Gravel Flemish Parliament Act of 3 April 2009) makes extraction of gravel possible in certain specific cases and lays the foundation for a project-based approach. This project-based extraction of gravel will only be allowed when it leads to an improvement of the ecology and biodiversity of local nature. It has to be evaluated in the future to which extent this project-based gravel extraction is meeting the demand for gravel in the Flemish Region.

The surface mineral resources plans are based on development perspectives for a period of at least 25 years and comprise actions for the next five years. As such they lay the foundations for the sectoral proposals regarding spatial planning (regional spatial implementation plans) and for the drafting of other specific policy plans. They are evaluated every five years on the basis of the aforementioned objectives.

The Flemish Spatial Structure Plans recognise 19 regions as extraction areas. Special Surface Mineral Resources Plans are drafted for all regions recognised as extraction area. These Special Mineral Resources Plans examine the current and future needs for the considered mineral resource. On the basis of this evaluation and in consultation with local authorities and the general public, existing extraction zones can be extended, reduced, sustained or given a new land use destination. In some cases new extraction areas are proposed to ensure the future needs of the considered mineral resource. Once consensus is reached, the Special Mineral Resources Plan is presented to the Flemish Government for ratification.

Several measures have been taken to guarantee a sustainable and efficient extraction of minerals.

For this reason mineral extractions are governed by the VLAREM regulation. VLAREM is the environmental regulatory process in the Flemish Region of Belgium for any activities and/or projects that have an impact on the environment. The strengths of VLAREM are that:

• it creates one clear framework for any activities that may affect the environment;
• it is composed of different conditions for specific activities e.g. minerals extraction;
• the permitting procedures have fixed time-frames;
• it is flexible, allowing additional conditions to be formulated by the Government if required, e.g. where conditions are not specific enough for certain sites.

An example in which the VLAREM process has been used in practice is slope failure. The conditions for minerals extraction (section 5.18 of VLAREM II) contain specifications for slopes resulting from mineral extraction, such as slope inclination to prevent slope instability. Recently, the Flemish Government has commissioned an extensive study to investigate the problem of slope instability. This study can lead to recommendations for the slope specifications contained within VLAREM.

Other initiatives have also been taken by the Flemish authorities in order to produce the available mineral resources as sustainably as possible. Within this framework the extraction sector has to produce the available mineral resources through cautious and optimal extraction. This means that in case a sand body is overlain by clay, the administration will impose the selective production of the clay layer, after which the sand body can be exploited. Moreover, the administration encourages selective production outside the extraction areas so that mineral resources, which become available in big earthworks, can also be validated effectively.

In order to make sure that the exploited mineral resources will not pose any threat to the environment, the Act on Surface Mineral Resources also introduced the certificate of origin. This certificate is issued to the extracting companies after they have filed a report which contains several chemical analyses of the extracted minerals, amongst other things. The certificates prove that the extracted minerals have a natural composition and that their use will not pose an environmental threat.