Complex sentence: Anaconda Copper Mining Company (also known from 1899 to 1915 as the Amalgamated Copper Mining Company) was an American mining company known as one of the largest trusts of the early 20th century.
Split into simpler sentences: Anaconda Copper Mining Company (from 1899 to 1915, known as the Amalgamated Copper Mining Company) was an American mining company. It was one of the largest trusts of the early 20th century.