Giant quartz veins occur along brittle faults in the ca. 1865 Ma Great Bear magmatic zone. They comprise two or more generations of subparallel veins and stockworks in zones as much as 100 m wide and 10 km long. They contain local concentrations of hematite/specularite, pyrite, copper sulphides, and pitchblende. Fluid inclusions in the veins at two uranium showings, Crowfoot and Ted, were examined. The homogenization temperatures (Th) range from 96 to 217°C for Type I (2-phase liquid-rich) inclusions at Crowfoot, and from 122 to 169°C for Types I and III (3-phase liquid-rich) inclusions at Ted. Type II (2-phase vapour-rich) inclusions yield grossly different Th (228 445°C range), which do not represent true Th, but do suggest fluid mixing, as does the wide salinity range from 0.18 to 31.6 weight per cent NaCl equivalent. These data are consistent with the formation of the veins in a tensional epizonal environment.

Experiments on the electrokinetic properties of amphibole asbestos dust samples from various localities of South Africa showed that amphiboles have similar surface properties. The electrokinetic studies on quartz serve as an aid and augment the investigation of the amphibole asbestos dust surfaces as quartz has been the subject of detailed study by several authors.Investigation was carried out using the streaming potential and microelectrophoresis techniques, where possible. The isoelectric point of the mineral amosite was found to OCCUT at pH 3.1 to 2 and that of crocidolite at pH 3.3 to 4 whereas quartz is isoelectric at pH 2.2 through a reaction with hydrogen and hydroxyl ions exclusively.Due to the manner in which amphibole fibres are formed there is an edge and face structure on the amphibole fibre surface. The total surface charge on the amphibole fibres is therefore a function of the combined face and edge charge. The experimentations confirmed that the face charge on amphibole fibres is therefore due to the presence of silica and the edge charge due to the layers of metal cations sandwiched between layers of silica.Several samples of commercial arnosite and crocidolite have been used in the investigation but the majority of the results were obtained from reference samples of crocidolite and amosite supplied by the International Union against Cancer. The importance of the surface properties of dust particles in the development of dust related disease is an area where little is known, this paper compares the surface properties of two of the major amphibole asbestos minerals with that of a known pathogenic mineral quartz. 675