Mansfeld Basin, Saxony-Anhalt, Germany

GEOLOGY: Black, bituminous shales (marl slates) of the Zechstein group not more than bout 25 cm thick, occurring abundantly in permian sediments east and southeast of the Harz Mountains. The slates contain copper and silver ores that are usually finely disseminated, but locally the copper concentration may reach around 3% (w/w), such as in the Mansfeld basin (Mansfeld copper slates) and, further south, near Sangerhausen.

HISTORY: Mining activites at Mansfeld started around 1200, first working for silver with a first heyday in the 16th century, and continued until 1969, when the mines were finally closed. The highest production rates of both copper and silver were reached during the years from 1945 to 1969, when the mines were worked despite being not profitable due to shortage of foreign exchange in the former GDR.

The Mansfeld basin includes the towns of Hettstedt, Mansfeld, Klostermansfeld and Eisleben. A fairly rich mineralisation was observed in the vicinity of faulting zones giving rise to the formation of the so-called copper ridges. Though, many of the minerals did only occur in microscopic quantities. Among the better known localities not explicitly noted in the locality list are: Zimmermann Shaft (at Hettstedt), Eduard Shaft (south of Hettstedt, near Siersleben), Otto Shaft (southeast of Eisleben), Hermann Shaft (at Helfta, southwest of Eisleben), Hans-Seidel Shaft and Walter-Schneider Shaft (both at Klostermansfeld).

References:
- Siemroth, J. & Witzke, T. (1999): Die Minerale des Mansfelder Kupferschiefers. Schriftenreihe des Mansfeld-Museums (Neue Folge) Nr. 4, 1-66. [includes slag minerals]
- A. Wittern (2001): "Mineralfundorte in Deutschland", Schweizerbart (Stuttgart), xx pp
- S. Jahn, H. Hörold, B. Friedrich (2000): Der Kupferschieferbergbau bei Mansfeld, Eisleben und Sangerhausen I. Mineralien-Welt, issue 3, 17-32.
- S. Jahn, H. Hörold, B. Friedrich (2000): Der Kupferschieferbergbau bei Mansfeld, Eisleben und Sangerhausen II. Mineralien-Welt issue 4, 32-56.
- Knoll, H. (2008): Interessante Mineralien aus den Schlacken der Kupferschiefer-Verhüttung. Mineralien-Welt 19 (1), 36-47.

- http://www.kupferspuren.eu/