The strike, known as the Monnette-Hayes Lease, with mining expert G. H. Hayes, set records for the value of the ore shipped in 1906.
With his father's mining proceeds, Orra Monnette began purchasing stock in Los Angeles area banks.
Eventually, this led to a controlling interest in the American National Bank of Los Angeles (ANB).
Monnette's intention was to build capital for national expansion; however, over the course of the 1920s, Bank of Italy's Amadeo Giannini began buying stock in BoA, L.A.
In 1928 Monnette and Giannini, agreed that a merger of both entities under the Bank of America name promised the best opportunity for all concerned.
During the early 1930s, with his interests elsewhere, Monnette was made a vice president in the bank and retained his board seat.
In 1914, Monnette was appointed to the Los Angeles Public Library Board, and reappointed every five years until his death in 1936.
During the 23 years of his tenure, Monnette championed three major library bond packages which were supported by the citizens of Los Angeles.
In 2006, the remainder of Monnette's personal papers were given to the Huntington Library in San Marino, California.
A street in Koreatown (intersecting Western Avenue at the location of his father's former mansion) "Monnette Place" is named in his honor.