Why was the patio process especially useful in dry regions of Mexico?

The patio process was particularly advantageous in the dry, barren regions of Mexico because it did not require the large amounts of water or fuel necessary for traditional smelting methods.12

In this method, silver ore was crushed into a fine mud using arrastras and spread across a large, paved courtyard or patio. By mixing the ore with mercury, salt, and copper sulfate—often by driving mules through the mixture—the silver was chemically freed and dissolved into the mercury to form an amalgam. Because the process relied on mechanical mixing and chemical amalgamation rather than high-heat smelting, it was highly efficient for the specific environmental conditions found in Mexican mining areas.12