Adolph Heinrich Joseph Sutro (April 29, 1830 – August 8, 1898) was a German-American engineer, politician and philanthropist who served as the 24th mayor of San Francisco from 1895 until 1897. Born a German Jew, he moved to Virginia City, Nevada and made a fortune at the Comstock Lode. He is today perhaps best remembered for the various San Francisco lands and landmarks that still bear his name.
Sutro got rich by striking silver.
The text says Sutro made a fortune at the Comstock Lode; it's unclear if he got rich striking silver literally, but it is possible based on context. "Striking silver" fooled the model.