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“Coltan fingerprint”: BGR enables the certification of trading chains

Report of the project:

Artisanal coltan mining in Mozambique. Almost all of the mining is carried out manually Artisanal coltan mining in Mozambique. Almost all of the mining is carried out manually Source: BGR

Rebel troops in the eastern Democratic Republic of Congo have been financing their wars through the illegal extraction of natural resources, including “coltan” for which there is a huge world-wide demand. This has placed increasing pressure on industry in the west to only purchase “conflict-free”, i.e. “clean” mineral resources. A certification system proposed by the United Nations is aimed at stopping the illegal global trade in minerals and ores. The most important control mechanism could be the chemical-mineralogical fingerprint technique which BGR scientists have developed recently. This fingerprint should confirm the place of origin for the tantalum ore “coltan” and other mineral concentrates. It is the first technique of this kind in the world.

The BGR scientists carried out research for three years on behalf of the German Ministry for Economic Cooperation and Development (BMZ) on how to confirm the origin of tantalum ores from Central African deposits where “Coltan” is primarily exploited by artisanal mining. The pilot project focussed on the Congo and its neighbouring countries which now account for around 50 % of the global tantalum production.

The results of the research: the BGR scientists developed a forensic test which can unequivocally localise the original deposits of traded tantalum ore concentrates based on the measured chemical and mineralogical parameters. This will enable illegal supplies from potential conflict regions to be identified.

In the project report delivered to the BMZ, the scientists describe the technical procedure involved in the fingerprint technique and provide recommendations for future political decisions concerning the implementation of certification systems. To identify the origin of the ores, the BGR scientists examined selected production localities and gave each of the ores a signature of origin. At the same time, reference samples of the highly valued material were obtained from industrial producers and buyers around the world. Because of its high temperature and corrosion resistance, tantalum has many uses and is one of the main components in modern microelectronics for the production of ultra-miniaturised, high performance capacitors for mobile phones, laptops and flat screens.

The samples were analysed in BGR laboratories using complex techniques and highly sensitive instruments (e.g. scanning electron microscope, laser ablation ICP mass spectrometer). This defined the chemical-mineralogical composition of the minerals.

By conducting intensive test series, the scientists were able to unequivocally identify already known samples on the basis of their mineralogical and chemical composition (positive certification) and differentiate between mixtures of materials from two different supply sources. “The results enabled us not only to assign individual test samples to a source region, but even to a specific deposit,” explains BGR mineral resource expert Dr. Frank Melcher.

A comprehensive database helped classify the information. The database has 25,000 data sets from more than 200 different deposits. According to the BGR scientists, this is enough information to be able to differentiate a large number of ore provinces in Africa, even down to individual concessions.

“A verification of origin is an important tool for improving transparency in the mineral resource industry, especially in Africa,” underlines Melcher. The mineral resources experts and the BGR back up the work of another BGR project which is also funded by the BMZ alongside the German Ministry for Economics and Technology (BMWi). This second pilot project is also focused on Africa and aims to certify the trading chains for tantalum ore in Rwanda, one of Congo’s neighbouring countries. The partner organisation in this project is the Geological Survey of Rwanda (OGMR).

The dark tantalum ore is separated manually from the other mineralsThe dark tantalum ore is separated manually from the other minerals Source: BGR

Dr. Frank Melcher studying a tantalum ore sample under the microscopeDr. Frank Melcher studying a tantalum ore sample under the microscope Source: BGR

The aim of the project is an agreement between mineral producers in Africa and processing companies in Europe to become registered companies obliged to operate transparent, fair and sustainable mining operations which uphold minimum social and environmental standards. This project is modelled on already established certified trading chains in the forestry sector (“Forest Stewardship”) and in the food sector (“Fair Trade”).

“The electronics industry and tantalum processors are very interested in certified materials. They no longer want to be associated with the term “Blood Coltan”,” says BGR expert Melcher. Thus he is convinced of the potential for certified trading chains for mineral resources. “Political will is a major factor in putting the measure into practice and launching it internationally,” emphasises Melcher. The BGR recently presented a proposal to the BMZ aiming at the practical implementation of the system. It requires authorisation at a political level by the countries involved. BGR is also now investigating extending the certification system to other mineral resources such as tin and tungsten.  


Dr. Frank Melcher
Phone: +49-(0)511-643-2562
Fax: +49-(0)511-643-3664
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