In April 1951, Erich Holm von Prosch, a PhD geologist, traveled to Turkey on behalf of C. Deilmann Bergbau (Bentheim, Germany) to visit various mineral extraction sites in southeast Anatolia (Batman, Maden, Siirt). Details of his visit are not yet known, but thanks to his exact records we know the itinerary or the route. In addition several Turkish mining experts are mentioned on the photos , e.g. Cevat Taşman, Necdet Egeran or Nuh Naci Tilev.

Interesting documents such as his visa application (Doc.1), and more than 150 black and white photos have survived, often labeled on the back by himself.