 From these projects flowed a cornucopia of gold, silver, copper, lead, zinc, mercury, granite, limestone, and petroleum.These properties, largely developed internally, multiplied the value of the company many times from 1954 through 1980, when Rosario was acquired by AMAX, Inc.In 1969, Rosario discovered the Pueblo Viejo oxide gold deposit in the Dominican Republic, which became at startup in 1975 one of the largest gold mines in the Americas, producing more than 400,000 ounces per year.