Excavation Monitoring: Reliable Data on the Life Index of Individual Groups of Mineral Commodities

Within the context of the so-called excavation monitoring, North Rhine-Westphalia (NRW) carries out an annual quantification of the available coverage of individual groups of mineral commodities. Currently, an expansion is scheduled. Besides the already ongoing monitoring of loose rock materials, the present methodology shall be adapted to solid rock materials as well. The practical significance of this topic and the fields requiring improvements were demonstrated in a first workshop organized by the Association of German Building and Raw Materials Industry, vero, in Dortmund on 15 March 2017.

With more than 60 participants, the workshop room was filled to capacity. Its goal was, in cooperation with the Geological Service (GS) NRW, to address problems and opportunities to work out solutions and improvements with regard to the results of excavation monitoring. Small discussion panels dealing with this topic had already been held in the past. Now, closing the gap between expectations and reality was the aim of the workshop. Thus besides the expansion of the concept to solid rock materials, a priority issue to be discussed was a realistic change regarding the loose rocks sand and gravel. Following the words of welcome by Raimo Benger (Managing Director, vero) and Dr. Ulrich Pahlke (Director of the Geological Service NRW), Dr. Volker Wrede (Division Manager Applied Geo-Sciences GS) and Ingo Schäfer (GS/Division 32) presented the methodology and previous experiences with excavation monitoring.

Concepts of Excavation Monitoring

The monitoring is based on data of the NRW raw material maps, of the monitoring surfaces (thus of areas for the safeguarding and recovery of near-surface resources, BSAB, and authorized lands) as well as of orthophotos from image flights, which are used to record the distribution and the thickness of the loose rock material.

For the needs assessment, the annual average of the past six years is determined, which shall provide a guideline for the next three years. Such data is separately collected for the individual commodity groups according to planning areas and is then published in annual reports.

The excavation monitoring also shows that areas with mineral deposits are often subjected to the regulations of nature conservation, landscape and water protection. Reduced by these areas, about 30 % of the mineral deposits can be regarded as the actually exploitable potential of NRW. According to the State Development Program of North Rhine-Westphalia, it is necessary to determine supply periods for certain areas for the safeguarding and recovery of near-surface mineral resources (BSAB). In the case of loose rock, this period should be determined for at least 20 years and in the case of solid rock for at least 35 years. During monitoring, the extraction progress will be recorded and the actual supply situation will be assessed based on the raw materials map of the respective state.

Realistic Assessment of Life Index

On map and in the report, everything seems to make sense. However, what is the situation in practice? Christian Grolig (vero) mentioned the essential problems of excavation monitoring from the companies’ point of view. According to him, the life index of supply reliability provides unrealistically long periods and the quantification is by far too optimistic. In particular, with regard to the significantly risen demand, he advised the planning of additional amounts with “buffering effect” for NRW, the scope of which has to be agreed. He also recommended the identification of unused BSAB and encouraged a discussion about “new” planning instruments for the adjustment of the life index. Under the pressure of the short lead-time always criticized by businesses, the search for an interim solution enabling the change of supply periods (transition from old LEP to new LEP, LEP = The North Rhine-Westphalia Regional Development Plan) should be treated with priority.

In addition to the discrepancies described, there is the problem of deposit losses, since monitoring does not consider the qualitative criteria of mineable raw materials, but solely their thickness – a “blemish” that needs to be corrected. A reorganization of the image flights for an exact determination of data in shorter intervals is likewise necessary. Comparisons to other regions, such as Rhinehessen, show that viable solutions are available: there, regional planning buffers the preset quantity target value with additional amounts for risk protection.

Practical experiences taken seriously

The ensuing discussion clearly showed the concerns linked to a resource planning worthy of improvement. Entrepreneurs described the serious consequences of this planning uncertainty. Thus, it is important to do everything that can be done, jointly and in a timely manner. This also means that the business data provided must enter future assessments. Designated areas for the safeguarding and exploitation of near-surface resources (BSAB) deserve a critical review and evaluation of the deposit conditions. The result must then be adjusted for qualitatively unsuitable deposits reported in the reserve estimation. Since such surfaces are considered as residual volume, they artificially expand the life index despite their “unfitness”.

The entrepreneurs demanded the Geological Service should not use the raw material volume as the sole benchmark for the safeguarding of raw materials in connection with the demand forecast. Raw material quality needs to be considered as well to achieve a reliable indicator for the supply situation in the course of the next decades. Therefore, as a participant clearly stated, the projections, currently containing only the speed of extraction, should also include actual sales figures as a reliable measurement for exploitable deposits and as a qualitative consideration of active deposits. A point that still needs to be worked on to achieve a real consensus with the GS.

However, if despite all disagreements a good and regardful exchange takes place, as could be observed in this workshop, it is a sign of grandeur. Both parties will continue an active dialogue, also with regard to the exchange of data for the ­resilient evaluation of deposits. This process must result in a long-term concept which justifies the investments of the companies and ensures the reliable supply of regional customers, even in the next decades. This workshop set a milestone for the goals and laid the foundation for the first step: creating mutual trust and breaking down mutual distrust. Now, the future-oriented work needs to be tackled and both sides must make their contribution.

The general management of vero showed that an open dialogue leads to success. In cooperation with state government, trade unions and environmental associations, they achieved that FFH, bird and water protection areas would not be included in the State Development Program of North Rhine-Westphalia as taboo areas, as it was provided for in the first draft version. This paves the way to raw material extraction in harmony with nature even in such areas.

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