Most of the global copper comes from porphyry copper sulphide ore deposits associated with molybdenite ( MoS2; so-called moly) as a valuable by-product to concentrates and the sulphur source of pyrite as the gangue mineral reporting to tailings together with the host rock components. The following diagram is a typical flowchart showing major unit operations from mining to the production of value-added concentrates. The last stage of production of a final Cu-concentrate and a separate moly concentrate is shown in the box with the dotted line. However, this part is ignored for simplification. The Cu and Mo grades of the ore feeding the process plant and of the concentrate together with those of the tails are indicated on the flowchart (all in \% wt., representing steady-state operation). a) If the ore tonnage to the process plant is 75,000 tonnes/day, given the copper assays, what is the percent copper recovery in the concentrate? b) What are the mass flows into the concentrate stream and tailings (tonnes/day)? c) What are the \% Mo content of the primary stage concentrate and ratio of concentration for Cu and upgrading ratio for Mo? OPEN PIT MINE (Drill \& blast, load \& haul) Ore to 0.76%Cu the mill 0.020%Mo MILL/CONCENTRATOR (Crushing \& conveying, concentrating)