As the demand for silver spread in the mid-1870s, both exploitation of silver resources and production innovation surged. The final 25 years of the nineteenth century witnessed quadrupled silver production, over and above that seen in the initial three-quarters of the century. Worldwide silver mining approached a staggering 120 million Troy ounces each year. New silver discoveries in the US, Central America, Europe and Australia helped fuel demand.
By 1920, production had again nearly doubled, approaching 200 million Troy ounces per annum. Breakthroughs in silver mining techniques allowed easier separation of precious silver from lower grade silver-containing ores. These processes included “dewatering,” “steam-assisted drilling,” and “fuming.” The increased ability to haul larger amounts of ore helped develop additional silver production innovation in the areas of bulk mining and refinement.
After 1910, electro-refining created new sources for silver, which were previously underutilized. By this time, high-grade ore deposits were largely depleted in most known silver producing regions. “Froth flotation,” a process developed to allow extraction of concentrated silver from zinc, copper and lead alloys allowed continued high production early in the twentieth century.
