[4]: 13, note 27 [5] But in April 1861, as the American Civil War began, word got out that silver and some gold and copper lodes had been discovered by John Moss and others in what became known as El Dorado Canyon, in New Mexico Territory, now Nevada.

George A. Johnson came up river and made a deal to supply the mines with his steamboats at a lower price than that provided overland across the Mohave Desert from Los Angeles.

At the beginning San Juan, or Upper Camp, was at the top of the canyon miles from the river near the modern town of Nelson.

[4]: 15, and Note 33 [9]: 611 In late 1863, Col. John R. Vineyard, at the time a California State Senator for Los Angeles, completed a ten stamp mill the first in the canyon, on its north side just below Lucky Jim Camp, at what soon became El Dorado City.

George Alonzo Johnson's steamboat company losing this downstream ore trade and making fewer trips up to the Canyon responded by raising its freight rates.