RADIOMETRIC ORE SORTING METHOD AND APPARATUS

摘要

- 33 -ABSTRACT OF THE DISCLOSUREA method of and apparatus for sorting pieces orparticles of radioactive ore where the particles aremoved one after another substantially horizontally thendischarged into a gravity-accelerated trajectory whichis substantially free-fall but can be controlled tofollow a modified path by a low-friction slide plate.The falling particles pass a plurality of radiationdetectors arranged in line along their path with in-creasing velocity due to gravity providing the requiredseparation of the pieces so that each detector issubject to the radiations of essentially only one pieceat a time. The size and number of detectors and thepath length covered by the detectors is determined bythe size of the pieces and the cut-off grade and accur-acy required. All counts corresponding to a particularpiece and derived successively from the plurality ofdetectors are accumulated since accuracy increases andpercentage of probable error decreases with increasedtotal count. The position and velocity of each pieceare determined during their fall to provide closetracking of the particle's path in space and time. Ifthe pieces are sufficiently closely sized the decisionto accept or reject a particle may be made on the basisof total accumulated counts being greater or less than apreset figure. If the pieces are not closely sized thenthe size of each particle is also determined and used ina counts/time/size computation which is compared withset cut-off grade data to provide a decision to acceptor reject the particle.