Suppose that we have to process a mixed galena-sphalerite (PbS-ZnS) sulphide ore by differential flotation. The contents of the feed are 6,1% Pb and 2,78 % Zn. The resulting galena concentrate contains 80,34 % Pb and 1,09 % Zn, while the following sphalerite concentrate contains 55,06 % Zn and 1,36 % Pb. If the mass of the resulting tailings stream is 88,1 % of the total feed and the Pb and Zn assay in the tailings are the same, Calculate : 1) The weights of galena and sphalerite concentrates, separately 2) The recoveries (%) in Pb and Zn circuits; and 3) The Pb and Zn assay of the tailings (same)