Written by Administrator   
Monday, 29 October 2007

relative. The proportion of Diamonds to the amount of blue ground process­ed at the major South African pipe mines can be computed in carats per 100 loads of ore (a load is approxi­mately 4/5 of a short ton). In one year in the mid-1950's, for example, the number of carats produced per 100 loads by four of the principal mines was as follows: Wesselton, 18.50 carats; Bultfontein, 19.30 car­ats; Dutoitspan, 10.80 carats; Jagersfontein, 6.30 carats. Therefore, the average recovery for these mines was 13.725 carats per 100 loads of blue ground treated. Stated another way, it was about 0.16 carat per ton, or roughly one part diamond to 27,-000,000 parts of blue ground. The famous Premier Mine yielded 27.80 carats per 100 loads in the same year, but approximately 70% of the pro­duction was of industrial quality.