During construction of the Los Angeles Aqueduct, the City of Los Angeles found deposits of Tuff at Fairmont Butte that closely resembled German Trass and Italian Pozzolana and was an ideal ingredient to blend and use in the production of cement. The City constructed a quarry and regrinding plant at the base of Fairmont Butte to excavate the tuff, grind and blend it with Portland cement which was used in the construction of the aqueduct's Mojave conduit.