The men, mines, and geology of the Verde Mining District, Jerome, Arizona
The town of Jerome roosts on the slopes of Cleopatra Hill in Yavapai County, Arizona; and is steeped in a rich history of copper, zinc, gold, and silver ore mining from an ancient volcanogenic massive sulfide deposit that formed on a sea floor more than 1.74 billion years ago.
Author, geologist, and mining historian David Briggs' new contributed report, ‘History of the Verde Mining District, Jerome, Arizona’, reviews the mining history of Jerome from the Spanish discovery of copper in A.D. 1583 at what is now the United Verde Mine site to recent remediation efforts of Freeport McMoRan c. 2010.
The United Verde Mine was the most prolific producer in the district. Between 1883 and 1975 it produced nearly 3 billion pounds of copper; 52 million pounds of zinc; 1.3 million troy oz. of gold; and 48.3 million troy Oz. of silver. (See Table 1, pg. 4 for a summary of production in the district.)
Snapshot of the geology of the United Verde Mining District. The oldest stratigraphic units exposed in the Verde Mining District are a part of the early Proterozoic Ash Creek Group, which is characterized by at least two mafic to felsic cycles of largely submarine volcanics that are stratigraphically overlain by a thick sequence of volcaniclastic sediments deposited along the steep slopes of an ancient intraoceanic island arc (Anderson, 1989 and Gustin, 1988). Evidence for subaqueous deposition of these units is supported by the presence of pillow basalts and hyaloclastitic (quench) textures, presence of black-smoker-type massive sulfide and exhalative chert, and turbidites and textures suggesting soft sediment deformation (Lindholm, 1991). The Ash Creek Group was deposited in a deep water oceanic environment, which is similar to the Izu-Bonin-Mariana arc, a modern day analog located in the western Pacific Ocean (D. Briggs, 2018).
High-grade ore -10-20% copper - was transported directly to the Jerome smelter, while low-grade ore was first treated on the hillslope by heap roasting with cordwood; a practice that undoubtedly reduced air quality.
By 1922, the economy of mining and falling ore grade caused the United Verde mine to begin open pit mining to complement ongoing underground workings.
Mine fires plagued the United Verde operation, killing miners, caving ground, hampering production and causing the 1,000-foot No.2 shaft to be abandoned. Efforts to extinguish the mine fires using water or carbon dioxide failed because there was no way to prevent oxygen from filtering into the burn area. Uncontrolled burning of underground ore seams would at times fill the open pit with dense smoke.
The roles of James Douglas, Eugene Jerome, James Thomas and William Andrews Clark in establishing the United Mine Verde Mine and the towns of Jerome and Clarksdale are described in detail.
By 1920, the Jerome mining camp was a polyglot village with more than 20 nationalities, including: Americans, Chinese, Irish, Italian, Mexican, and people of Slavic origin. Life in the camp was primitive, austere, and the air, water, environment and sanitary conditions were degraded by smelting ore and deforestation of the surrounding Black Hills. Labor problems during WW1 were managed by forcing the ringleaders into cattle cars and marooning them in the Mojave Desert outside Needles, California.
By the 1950s, ore production was falling, forcing those living in Jerome to slowly transition from mining to a small but burgeoning tourism economy. The Jerome Historical Society, founded in 1953, worked with the local mine companies, business leaders, and the community to strategize a move from mining to tourism bolstered by artisans and craftsman.
In the final section of this exemplary history, the author revisits recent reclamation efforts and explores the future of mining in the Verde mining district.