A method, comprising: leaching, by thiosulfate, a gold and/or silver-containing material in an ion-exchange resin-in-leach circuit, the circuit comprising a co-current portion, wherein the co-current portion comprises at least a first tank and a second tank and the counter-current portion comprises at least a third tank and a fourth tank, wherein the gold and/or silver-containing material flows first through the co-current portion and second through the counter-current portion, wherein the leaching step comprises the sub-steps of: receiving, in the first tank via a first input, a first ion exchange resin, a thiosulfate leach solution, and the gold- and/or silver-containing material; receiving, in the second tank, a first mixed slurry from the first tank; receiving, in the third tank, a second mixed slurry from the second tank and a second ion exchange resin; receiving, in the fourth tank via a second input, a third mixed slurry and the second ion exchange resin; removing the second ion exchange resin and barren tailings from the fourth tank; introducing a first gold- and/or silver-loaded resin from a first output of the second tank into a precious metal stripping unit to strip gold and/or silver therefrom and thereafter introduce the first gold- and/or silver-loaded resin into the fourth tank via the second input; and introducing a second gold- and/or silver-loaded resin from a second output of the third tank into the first input of the first tank, wherein the counter-current portion is configured so that the second ion exchange resin flows through successive tanks at least from the fourth tank to the third tank, and the third mixed slurry flows through successive tanks at least from the third tank to the fourth tank, and wherein the first and second ion exchange resins are strong base anion exchange resins and wherein the resin has an affinity for other components, wherein the other components comprise trithionates, tetrathionates and other higher polythionates, and sulfates, and wherein an affinity of the first and second ion exchange resins for gold is greater than an affinity of the first and second ion exchange resins for mercury, wherein the affinity of the first and second ion exchange resins for mercury is greater than an affinity of the first and second ion exchange resins for pentathionate, wherein the affinity of the first and second ion exchange resins for pentathionate is greater than an affinity of the first and second ion exchange resins for tetrathionate, wherein the affinity of the first and second ion exchange resins for tetrathionate is greater than an affinity of the first and second ion exchange resins for copper, and the affinity of the first and second ion exchange resins for copper is greater than an affinity of the first and second ion exchange resins for trithionate. receiving, in the first tank via a first input, a first ion exchange resin, a thiosulfate leach solution, and the gold- and/or silver-containing material; receiving, in the second tank, a first mixed slurry from the first tank; receiving, in the third tank, a second mixed slurry from the second tank and a second ion exchange resin; receiving, in the fourth tank via a second input, a third mixed slurry and the second ion exchange resin; removing the second ion exchange resin and barren tailings from the fourth tank; introducing a first gold- and/or silver-loaded resin from a first output of the second tank into a precious metal stripping unit to strip gold and/or silver therefrom and thereafter introduce the first gold- and/or silver-loaded resin into the fourth tank via the second input; and introducing a second gold- and/or silver-loaded resin from a second output of the third tank into the first input of the first tank, wherein the counter-current portion is configured so that the second ion exchange resin flows through successive tanks at least from the fourth tank to the third tank, and the third mixed slurry flows through successive tanks at least from the third tank to the fourth tank, and wherein the first and second ion exchange resins are strong base anion exchange resins and wherein the resin has an affinity for other components, wherein the other components comprise trithionates, tetrathionates and other higher polythionates, and sulfates, and wherein an affinity of the first and second ion exchange resins for gold is greater than an affinity of the first and second ion exchange resins for mercury, wherein the affinity of the first and second ion exchange resins for mercury is greater than an affinity of the first and second ion exchange resins for pentathionate, wherein the affinity of the first and second ion exchange resins for pentathionate is greater than an affinity of the first and second ion exchange resins for tetrathionate, wherein the affinity of the first and second ion exchange resins for tetrathionate is greater than an affinity of the first and second ion exchange resins for copper, and the affinity of the first and second ion exchange resins for copper is greater than an affinity of the first and second ion exchange resins for trithionate.