The mining activity in Iacobeni Cârlibaba area dates back as far as the XIII-th century, the first documentary certification being before 1241. After 1775 (when Bucovina was annexed like province to the Austrian Empire) Iacobeni Cârlibaba area was scientifically examined by Austrian geologists. Geologically and structurally, the Gândacu Suh rzelul Mare mining area belongs to the Crystalline Mesozoic Zone of the Eastern Carpathians. The Crystalline Mesozoic Zone is made up of a system of Alpine Nappes, called the Eastern Central Carpathian Nappes (S ndulescu, 1984). The exploration and geological surveying work was done in the metamorphic basement of the Sub-Bucovinian Nappe. In the Iacobeni Cârlibaba mining area, the manganese ore deposits are located in the epimetamorphic Tulghe 2 level (Tg2) of Tulghe lithogroup and the polimetalic sulphures ore deposits in the Tulghe 3 level (Tg3). Geographically, the area Gândacu Suh rzelul Mare is situated in the Suhard Mountains, on the right slope of the Golden Bistri a river, from an administrative point of view belonging to Cârlibaba, Cioc ne ti and partially to Iacobeni. The prospection works outlined three research perimeters: Puiu - Suh rzel, Humoru and Diaca Gândacu. The geological study in the area Puiu Suh rzel showed the presence of polimetalic sulphures ore in acid riolitic metavulcanites, sericite or sericite-chloritic schists. In the same perimeter, in the superior drainage basin of the Recele brook, its discovered a manganous level in black quartzite with intercalations of sericite-graphitic schists. The manganese ore is predominantly siliceous, made up of lens and nests in parallel disposition. On the left slope of the Suh rzelul Mare brook it uncovered polychrome limestone ores. In the Humoru and Diaca Gândacu perimeters the prospection works highlighted a primary ore of manganese consisting of rhodonite, rhodochrosite, manganese silicates, quarts, calcite, pyrite, etc. The secondary ore of manganese, resulted from the alteration of the primary ore, appears sporadically and it is made up of manganese and iron oxides and hydroxides. The prospection and research works in the three perimetres ended in the interval 1991-1996.