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<br /> <br />Video Detector <br />A Reticon Line Scanner and means of illumination (lamps with an intEnsity of <br />15,000 lumens) necessary for generating gating signals and effective rock <br />areas are an integral part of the sorting circuit. <br />logic <br />One logic unit per channel is part of the system and functions to correct the <br />gamma count appropriate to a rock for the geometry of the rock, and to deter- <br />mine whether or not the normalized count exceeds a pre-set "Cut-off" level. <br />(0.015% U308) <br />In the event that a rock exceeds the cut-off level, the logic unit directs the <br />opening of the air blast valves to deflect such a rock away from tho:~e ore <br />particles whose corrected gamma count does not exceed the cut-off level. <br />A process flow diagram is depicted in Figures 1.1-3 and 1.1-a~ and <br />C~ <br /> <br />describes the sequence of ore movement, the wash water circuit and the <br />disposition of ore grade and non-ore grade material. Essentially, all rock <br />removed from the mine is gamma scanned at the mine mouth while it is in the ore <br />cars, using a Geoco 951-A photomultiplier tube and NaI crystal which has a <br />performance record established by the manufacturer at the 95% conficence level. <br />If any radiation above background is detected, the entire ore car load is <br />sorted; otherwise, it is deposited in the mine waste pile for transport to the <br />waste dump. The run-of-mine ore (that which was gamma scanned at the mine mouth} <br />is dumped into the mine ore bin, crushed once in the -6, +2 inch jaw crusher, <br />washed free of slimes or dust, and deposited into the sorter feed bins;. The ore <br />is then processed by the system described above. After processing thE, non-ore <br />grade rock is conveyed to the sorter reject stockpile, and the ore grade rock is <br />conveyed to the ore stockpile. All sorted waste is probed each day before trans- <br />port to the waste dump, using a probe that is calibrated every other day and has <br />a lower limit of detection of 0.01% 0308; if the sorted waste contains rock <br />which is above the sorter cut-off grade, the sorted waste is re-sorted. A11 <br />~_~ <br />