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Avike Bay is a 270 degrees degree wide near-circular, 114 in deep bay on the Swedish coast of the Bothnian Sea, northeast of Sundsvall. The structure has a diameter of about 10 km. It was classified as a probable impact structure because of its extraordinary circular topography in the overwiew of impact structures in Fennoscandia. Recent studies lend further support to this interpretation. The structure has a submarine central mound, which is elevated some 40 in above the adjacent sea floor. It has a very distinct tangential and radial on-shore fracture pattern as seen in the topographic map. Along the southwestern shore of the Bay, an enigmatic quartzite breccia of unknown age occurs as part of a larger outcrop of polymict breccia with clasts of crystalline rocks and quartzite of unknown age. In thin section, planar fractures can be observed in quartz and feldspar grains. A detailed investigation showed that in a few cases the quartz grains contained microdeformation features closely resembling PDFs., QC 20111013

The mines in Nicaragua were nationalised in 1979 and a small-scale mining directorate (PEMIN) formed within the Ministry of Mines. Two types of small miners exist: associate companies and production collectives. Production and employment is given for small mines and placers. Mines are exploited by manual methods using primitive equipment for grinding, amalgamation and gravity separation. Ore grades are often 5-10 g/ton and can be higher. Research at the University of Technology, Lulea has indicated that gold recovery in stamp battery/amalgamation mills was below 50%; it is recommended that small cyanidation plants be installed which can improve recovery of the fine gold to 80-90%. A suitable plant has been designed at Cerro Cabezas, Colombia., The mines in Nicaragua were nationalised in 1979 and a small-scale mining directorate (PEMIN) formed within the Ministry of Mines. Two types of small miners exist: associate companies and production collectives. Production and employment is given for small mines and placers. Mines are exploited by manual methods using primitive equipment for grinding, amalgamation and gravity separation. Ore grades are often 5-10 g/ton and can be higher. Research at the University of Technology, Lulea has indicated that gold recovery in stamp battery/amalgamation mills was below 50%; it is recommended that small cyanidation plants be installed which can improve recovery of the fine gold to 80-90%. A suitable plant has been designed at Cerro Cabezas, Colombia.

Panama is going through a period of intense exploration activity, with 147 concessions for exploration and exploitation covering almost a quarter of its territory. Concessions for over half this area belong to just three groups: Cyprus Amax, the Panamanian company Minamerica Corporation and its subsidiaries, and the group of companies owned by the director of the Chamber of Mines. The US, Panama is going through a period of intense exploration activity, with 147 concessions for exploration and exploitation covering almost a quarter of its territory. Concessions for over half this area belong to just three groups: Cyprus Amax, the Panamanian company Minamerica Corporation and its subsidiaries, and the group of companies owned by the director of the Chamber of Mines. The US

On the basis of petrographic observations it is suggested that garnet, biotite, cummingtonite, magnetite and sphalerite precipitated as fine crystalline aggregates or as iron-zinc-manganese-bearing silicate gels onto the seafloor, and crystallised in a sub-seafloor hydrothermal-diagenetic environment. Overprinting regional metamorphic conditions, related to deformation, are unlikely to have produced the garnet-biotite-cummingtonite-rich assemblages, considering the irregular and rounded crystal outlines of garnet, reminiscent of concretionary and colloform textures, the fine-grained nature, and apparent low degree of grain boundary equilibration of biotite and cummingtonite and the lack of reaction textures. Tourmaline having a wider lateral distribution than the sulphide zone, is suggested to be a guide mineral for other Zn-Pb mineralisations in Bergslagen., On the basis of petrographic observations it is suggested that garnet, biotite, cummingtonite, magnetite and sphalerite precipitated as fine crystalline aggregates or as iron-zinc-manganese-bearing silicate gels onto the seafloor, and crystallised in a sub-seafloor hydrothermal-diagenetic environment. Overprinting regional metamorphic conditions, related to deformation, are unlikely to have produced the garnet-biotite-cummingtonite-rich assemblages, considering the irregular and rounded crystal outlines of garnet, reminiscent of concretionary and colloform textures, the fine-grained nature, and apparent low degree of grain boundary equilibration of biotite and cummingtonite and the lack of reaction textures. Tourmaline having a wider lateral distribution than the sulphide zone, is suggested to be a guide mineral for other Zn-Pb mineralisations in Bergslagen.