我矿职工遵照毛主席“开发矿业”的伟大指示,于1966年初进行了金刚石砂矿不分级跳汰的试验,经过三年多的努力,终于改制成功了不分级跳汰机,并于1969年9月投入生产。三年多的生产实践证明,选别效果 In accordance with the great instruction of Chairman Mao’s “Development of Mining Industry”, mine workers conducted a trial of non-grading of diamond sand mines in early 1966. After more than three years of hard work, they finally succeeded in restructuring the graded jig without success and in 1969 Put into production in September. More than three years of production practice proved that sorting results