General geology and mines of the East Tintic mining district, Utah and Juab counties, Utah, with sections on the geology of the Burgin mine and the geology of the Trixie mine
This report is a study of the rocks, geologic structures, and mines of a highly productive silver, gold, and base-metal mining district in the east-central Great Basin. The East Tintic mining district is in the east-central part of the East Tintic Mountains, near the east margin of the Basin and Range province in Utah and Juab Counties, Utah. The district occupies the northeastern part of the Eureka quadrangle and is about 5 mi (8 km) wide and 6 mi (9.7 km) long. Officially it is within the designated boundaries of the Tintic mining district, but it generally though erroneously has been regarded as a separate district since the late 1800's. Prospecting was first undertaken in East Tintic in 1870; although small quantities of ore were produced in 1899 and from 1909 to 1913, the district first achieved prominence in 1916 with the discovery of the totally concealed Central ore body of the Tintic Standard mine. Within a few years of this discovery, the Tintic Standard became one of the most productive silver mines in the world. Additional discoveries of important concealed ore deposits have continued to be made in the district, including the North Lily mine in 1927, the Eureka Lilly and Eureka Standard mines in 1928, the Burgin mine in 1958, and the Trixie mine in 1969. To December 31, 1975, the East Tintic mining district has yielded approximately 4.83 million short tons (4.38 million tonnes) of silver, gold, and base-metal ores, largely from concealed deposits overlain by many hundreds of feet of barren rocks. These ores have a gross valuation of approximately $231 million. The district first achieved prominence in 1916 with the discovery of the ore bodies of the Tintic Standard mine, which for a time was the world's richest silver producer (Lindgren, 1933, p. 588). By 1946 this deposit and a number of other deposits discovered and developed nearby had been exhausted, and the district became dormant. A dramatic revival of, mining activities in the East Tintic district began in 1956 after the discovery and subsequent development of the concealed Burgin ore bodies in an area 1 mile (1.6 km) southeast of the Tintic Standard that previously had been only superficially prospected. As in the earlier history of the district, the Burgin development has led to the discovery of other concealed deposits, focusing international attention on the revitalization of a nearly abandoned mining district by the application of geologic and geochemical techniques.