Patent Number: 043404430
Section: claims

1. A method for determining the gold content of an auriferous material, comprising the operations of irradiating a body of the material with neutrons and determining the intensity of .gamma.-rays having an energy of 279 keV arising from the reaction .sup.197 Au (nn') .sup.197.sbsp.m Au.fwdarw.279 keV. 2. A method according to claim 1, wherein there is used a neutron source which does not produce neutrons which have an energy sufficient to excite fast neutron reactions in non-auriferous constituents of the auriferous material. 3. A method according to claim 2, wherein there is used a neutron source which produces neutrons by means of the deuteron-deuteron or deuteron-beryllium reaction. 4. Apparatus for determining the gold content of an auriferous material, comprising means for passing discrete samples of auriferous material past a source of neutrons, and means for determining the intensity of .gamma.-rays having an energy of 279 keV arising from the reaction .sup.197 Au (nn') .sup.197.sbsp.m Au.fwdarw.279 keV. 5. Apparatus according to claim 4, wherein there is included means responsive to the means for determining the intensity of .gamma.-rays arising from the reaction .sup.197 Au (nn') .sup.197.sbsp.m Au .fwdarw.279 keV to separate those samples of auriferous material having a gold content above a predetermined value from those which do not. 6. Apparatus according to claim 4, wherein the neutrons are provided by a tube source utilising the deuteron-deuteron or deuteron-beryllium reaction to generate the neutrons. 7. Apparatus according to claim 4, wherein the means for passing discrete sources of auriferous materials past a source of neutrons comprises a plurality of tubes regularly disposed parallel to one another around the periphery of a central tube adapted to contain a source of neutrons having energies which are insufficient to excite fast neutron reactions in non-auriferous constituents of the samples of auriferous material, and means for directing the samples of auriferous material into the said tubes. 8. Apparatus according to claim 7, wherein there is a separate .gamma.-ray detector channel and responsive sorter associated with each of the said tubes.