Abstract: A method for separating diamonds from associated gangue in a diamondiferous material. The method comprises the steps of mixing the diamondiferous material with water to form a slurry and passing the slurry through laser radiation of known wavelength in the infra red part of the electromagnetic spectrum to cause Raman spectral scattering of the radiation from the slurry. The scattered radiation is collected and filtered to isolate diamond-relevant radiation and the filtered radiation is analyzed to determine whether it is indicative of the presence of diamond. Finally, on the basis of such analysis, high diamond content slurry is separated from low diamond content slurry.

Abstract: A swivel-less coupling suitable for producing oil from an underwater well through a riser to a floating vessel or for transferring fluids to or from such a vessel is formed of an inner drum and a surrounding annular surface. The surface carries one or more flexible pipes which can wind and unwind helically across it to accommodate limited relative rotation as between the inner end(s) of the pipe(s) which is fixed to the drum and the outer end(s) and the pipe(s) which is fixed at a point which is rotatable relative to the drum. The pipe or pipes may be carried on cradles which can move across the surface. Relative movement as between the inner and outer ends of the pipe may be regulated by a motor, which may be controlled by sensors noting any tendency for change in the relative positions due to forces acting on the vessel.

Abstract: A cryogenic cell comprises a sealed external annular chamber, adapted to be maintained under vacuum which chamber surrounds a heat shield. A section of the shield is exposed and is adapted to make contact with a closed cycle cooler. The shield encloses a sealed inner chamber adapted for the storage of a solid/liquid refrigerant. The shield has a relatively thin base and sidewall and the section which is exposed is a relatively thick upper collar which has a well leading to the top of the inner chamber immediately above and in contact with the top of the inner chamber. The inner chamber is connected at its lower end to a section containing an absorbent and the latter section is connected at its lower end to a further chamber suitable for the reception of a gamma radiation detector. The cryogenic cell is suitable for keeping the semi-conductor detector of a neutron borehole logging tool at the required low temperature.