TU Delft: Bestaande Kolenreserves (Slechts Engelstalig)

The webpages below are a summary of the information published by T.P.R. De Jong: Coal Mining in the Netherlands; the Need for a Proper Assessment. Geologica Belgica (2004) 7/3-4: 231-243. See also the following text: Coal Mining in the Netherlands for compressed information on this subject.

In the Netherlands several billion tonnes of mineable coal remained after closure of all mines in 1974. Mining activities in Dutch Limburg were suspended relatively early in comparison to surrounding basins, of which only DSK's Ruhr mines are still producing. In retrospective this saved the costs of uneconomic exploitation and limited further depletion. On the other hand, associated knowledge base and mining expertise virtually disappeared from the Netherlands. Almost 30 years later this may arise some fundamental questions: How far is coal depleted in the Netherlands? How do the remaining inland reserves benchmark compared to other basins? What factors determine technical, environmental and economic feasibility of coal production? How are productivities developing with the progress of automation? How do applicable production costs relate to market prices and what are the expected trends in future? Which production costs are fundamental (e.g. of geological origin) and which may be overcome by technological progress? After giving a concise overview of the "old" basin and its exploitation history, the remaining coal-bearing areas in the Netherlands are briefly described with regard to their technical mineability. Some factors affecting the current economic, technical and environmental boundary conditions of coal mining are discussed.

Location of the reserves

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1. South-Limburg
2. Central-Limburg, the Peel coal fields and Beatrix coal mine.
3. Achterhoek reserves

Three unexploited coal bearing regions are presently known in The Netherlands: Gelderland, the Limburg-Peel region, and the remaining fields in South-Limburg. The carboniferous of the Limburg regions is mapped in detail, until 1975 by the former mining industry and around 1985 by the Dutch Geological Bureau. Detailed study of the Gelderland deposits is more difficult, because of the limited data available. Each of these reserves are briefly described here, as far as relevant for the development and economy of underground mining operations. Its geography dictates possibilities for access to the coal and possibilities for planning of surface facilities. Coal bearing and geology determine the value of the coal deposits and their exploitation costs.

Evaluation of the reserves

The reserves can be evaluated in relation to a specific exploitation method. Without speculation on unproven or experimental technology, conventional deep mining can be regarded as the only method that is currently available for a significant degree of utilisation of the reserves. Mine productivity and comparison data of operations within Europe as well as globally are available in the literature (e.g. HESSLING, 1991; WALKER, 1996). It appears that the productivity of the coalface itself is often not the critical factor in limiting the viability of a mining operation. Similar drum shearers, conveyors and support systems that are used in non-European basins lead to viable production. Unfavourable for such high output systems is a disturbed geology. In such a case a more flexible method, e.g. Room and Pillar mining may be more favourable, although it is limited in depth. Some other important factors that limit the viability of many European mines are the high ash/coal ratio within the seam, high underground infrastructural maintenance costs, and high roadway development costs. Others are the low degree of equipment utilisation due to travel time, holidays, absenteeism etc. Besides, existing European mines are often large and complex and allow only limited productivity improvements. The large overburden ratio and hence large depth of the shafts makes development of new mines that are more efficient, which could replace the older mines, too expensive.

By means of comparison with state-of-the-art operations in nearby basins, and adapting that knowledge to local geological conditions, the Dutch coal reserves could be bench-marked in European and global perspective. Such a study would comprise geological, economical, and engineering aspects. Until today the necessary effort to investigate this using up-to-date knowledge has not been undertaken, largely motivated by the relatively low energy prices and the outcome of viability studies regarding continuation of the Beatrix project in the 1960's and recommencement of the Emma production after the oil crisis of the 1970's. On top of this, one can argue that the poor viability and perspective of most remaining (West)-European mining operations makes a viable revival of mining unlikely. Despite this, it is important to know if this unfavourable perspective, which is prevalent since the mid 1970's, is fundamental (e.g. of geological origin) or may be overcome by technological and organisational progress. Today's mining technology and insight is in many aspects different as those practised around the 1970's in Limburg and surrounding basins.

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Overview of estimated Dutch coal reserves down to a depth of -1500 m. The mineable reserves are taken as 12.5% (minimum scenario), 25% (average scenario) and 50% (maximum scenario) of the geological reserves. Note that the current yearly domestic demand amounts approximately 12 Mt/y in the Netherlands.

Higher VM steam coals (30% - 38%) are present in the Emma-north field and Achterhoek reserves. These are sufficient to play a significant role in inland power generation for many decades after development of the reserves (Fig. 8). Low VM coals and (semi) anthracites (20% and less) are found in the Peel reserves. When a technological extraction rate of 66% of the >100cm pure coals down to 1500m is assumed, technical reserves add up to 3150 Mt. For eventual future exploitation, when the most favourable parts of the reserves and productive automated technologies are implemented, production costs may approach market price. Critical factors yet to overcome are the lowering of investment costs, increasing the degree of utilisation and lowering of underground infrastructural costs (e.g. maintenance and roadway development). A much simpler underground infrastructure may bring this within reach (BERDING, 1979). Surface processing, energy, water drainage or coalface performance are less critical factors, even at greater depths. Only when the negative factors could be overcome, on condition of a positive drive from economy and society, a return of coal mining may be possible within the next decades. From other factors, the relatively high costs, risks, and duration of shaft delving will form the largest hurdle to re-start mining operations.