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Julio F. Gumucio

Julio Francisco Gumucio Valdivieso was born of Basque ancestry in Cochabamba, Bolivia on April 19, 1900, the son of Emilia Valdivieso Quiroga and Natalio Gumucio Ponce de Leon. He attended the Colegio Primario de Niños grammar school, and then the Sucre High School, graduating at the age of 17. He received a scholarship to attend the School of Mines in Oruro, Bolivia, and during the summer months he worked in the mines to gain experience. After a stint in the Bolivian Army he graduated in 1925, completed his thesis and received his diploma in 1928.

While still in college he married Delmira Cortes Tovar in 1924, and together they had six children. In 1925 he was hired as an Assistant Surveyor by Patiño Mines, the largest mining company in Bolivia. In 1929 he was promoted to Sectional Engineer, leading eventually to the positions of Divisional Engineer, General Mine Foreman, Mine Superintendant, Chief Engineer (at Llallagua), and Interim Manager for Empresa de Estado Araca.

In 1932 he discovered what was considered to be a new variety of sphalerite at Llallagua; it was named in his honor by Robert Herzenberg as gumucionite, but was never considered an independent species. According to his son, a few years later he thought he had found another new species, calling it delmirite (after his wife), but it was never published.

From 1933 to 1935 he served his country again as General Representative of the Bolivian Department of Roads, designing a system of roads that was used by the Bolivian Army during the Chaco War with Paraguay. In 1936 he and a group of friends invested in a gold mine, but it never proved profitable. In 1939 Patiño Mines appointed him General Manager of their largest railroad, and in 1944 he was promoted to General Manager of Patiño's largest mining subsidiary, Compania Minera y Agricola Oploca de Bolivia. The following year he was taken hostage for four days by a mob of miners, after which he retired from Patiño and moved to Cochabamba, where he managed his investments for a while in a local printing and publishing company.

In 1946 he was named General Superintendent for the Bolivian Development Corporation (building a road from Cochabamba to Santa Cruz), an in 1948 the Bolivia Government appointed him to a bilateral commission with Brazil that oversaw the construction of the Transcontinental Railroad linking the Atlantic and Pacific. Returning to private life in 1950, he spent time investing in hardwood lumber, and cataloging his impressively large and complete mineral collection. In 1951 he sold a portion of this collection to the Bolivian Mining Bank.

In 1956 he moved to Argentina where he served as General Manager for Geotecnica S.L. The following year, at the urging of his children (who had already relocated to southern California), he resigned and moved to Palo Alto, California where he worked for a while as a consulting mining engineer. In 1960 The International Development Bank, recognizing the disaster that had resulted from the nationalization of the Bolivian mines, hired Gumucio to serve as their advisor to Corporacion Minera de Bolivia, as it tried to rebuild the Bolivian mining industry. After five successful years in that post he finally retired, at the age of 65, returned to Palo Alto, and spent his remaining years becoming a Master at playing Duplicate Bridge.

In 1974 he sold the remaining portion of his mineral collection (about 2,000 specimens) to Eugene and Sharon Cisneros (Mineralogical Research Company). The collection consisted primarily of Bolivian minerals, including some very nice specimens from the Colquechaca mine – pyrargyrite and argyrodite, among others. There were well over 1,000 specimens of paravauxite, metavauxite, and vauxite from Llallagua. None of his specimens carried labels, and Sharon had to carefully take notes while asking him where each one had come from.

Julio Gumucio died in Palo Alto on February 27, 1981. __________________________________

HERZENBERG, R. (1932) Gumucionitte, una nueva variedad arsenical de blenda. Rev. Mineral., Geol. Mineral., Soc. Argent. Mineral. Geol., 4, 65-66.
HERZENBERG, R. (1933) Gumucionit, eine neue arsenhaltige Varietat der Schalenblende. Zentralblatt fur Mineralogie, A, 1933, 77-78.
GUMUCIO, M. A. (2008) In Search of My Ancestors, from Vizcaya to California.
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