Press release of 12 March 2018

Masters of the rocks

Professional networking for mineral sample preparators in Freiberg

Andreas Bartzsch

Andreas Bartzsch, head of the preparation lab at HIF. Photo: HZDR/ Detlev Müller. Download

Analysis technology has become so sophisticated that it now affords astonishingly accurate insights into the structure of rocks and minerals. But it is not only rock in its natural state that comes in for analysis but also specially prepared samples. There is a dedicated laboratory for this at the Helmholtz Institute Freiberg for Resource Technology (HIF), part of the Helmholtz-Zentrum Dresden-Rossendorf. From 13th to 14th March, mineral sample preparators from universities and research institutes in Germany, Austria and Switzerland will be gathering together here.

Sample preparation is highly specialized work that is extremely important to the exploration and industrial use of natural resources. These expert technicians prepare geological samples which are then examined using hi-tech equipment. This allows deposits to be better evaluated, innovative raw material technologies to be developed and even new insights to be gained into the structure of the earth’s crust. Andreas Bartzsch, who is head of the special laboratory at HIF, estimates that there are no more than 30 facilities in Germany where preparators are employed. He has now organized a workshop for this particular professional group, intended to improve networking and promote the exchange of ideas. A number of shared problems will be discussed, and practical solutions will be sought.

Significance for research and industry


Grain mounts as shown in the picture are needed in order to analyze mineral raw materials using scanning electron microscopy. Photo: HZDR/ Frank Schinski. Download

Andreas Bartzsch is a highly qualified geological technician and co-founder of ERZLABOR Advanced Solutions GmbH, a start-up company which offers commercial sample preparation and raw material analysis. The material comes from all over the world, including samples brought by HIF staff from their travels and others sent by research partners. Bartzsch returns them in an analyzable form. Together with his three colleagues, he prepares around 2,000 mineral samples per year.

These fall into different categories depending on how the raw materials are to be analyzed: a polished thin section is approximately 30 microns thick, i.e. less than a human hair, and so transparent that it can be examined with an optical microscope. By contrast, a polished thick section measures approximately 100 - 200 microns. The HIF laboratory also specializes in grain mounts in which the natural rock is ground to fine grains, mixed with graphite powder and then embedded in a special resin. Using a scanning electron microscope, raw materials can then be examined in detail, allowing the quantity and distribution of valuable elements to be ascertained.

From unformed rock to the perfect sample

Andreas Bartzsch is largely self-taught and has begun passing this knowledge on to colleagues, students and even schoolchildren. Many of his peers also came into the profession from other career paths; there is currently only one training course for aspiring sample preparators. “I started practically at zero,” he says. “There is also hardly any written body of professional knowledge. The experience, the techniques and tricks of the trade that go into producing a perfect sample from natural rock are passed on from person to person. With this network meeting, we intend to create a platform for colleagues in the profession to get to know each other and to exchange ideas.”

A wide range of specialist technical equipment is available in the HIF lab, yet in the basement of the research institute, much of the grinding and polishing is still done by hand. Anyone joining the team is put through their paces in terms of precision workmanship: “We need glass plates as slides for the sections, and we buy these in. However, the surfaces are far too uneven for our purposes. We have to work on them until the glass is the same thickness all over. It’s all about microns, which means thousandths of a millimeter. Normally, a machine does that. But in order to understand and operate such a machine correctly, everyone on this team has to be capable of doing the job manually.”