According to what Eysee posted on Findagrave he had these sons
MITCHELL — In Alameda, February 3, 1902, Robert Martin Mitchell, beloved husband of Marie Mitchell, and father of Frank. George E., Robert M. Jr.- and William A. Mitchell, a native of Dublin, aged 81 years 6 months and 16 days. "The funeral will take place to-day (Wednesday), at. 1:30 o'clock, from the parlors of H. IF. Suhr- & . Co., 1137 Mission street, between Seventh and Eighth. Cremation private. Cypress Lawn Cemetery, by electric funeral car from Eighth and Harrison streets. Please omit . flowers.
San Francisco Call, Volume 87, Number 67, 5 February 1902
... plus one in Victoria, Australia
Henry Capel Mitchell, b. 1862, Newstead (Frank? )
... at least these 3 in NZ
Robert Ernest Mitchell, b. 1866. (George Ernest, I think it should be)
Robert Martin Mitchell jn b. 1871
William Arthur Mitchell, b. 1873.
Shareholder of the "Berkeley Castle Gold Mining Company" at the Thames Goldfield, Auckland, NZ
https://library.victoria.ac.nz/databases/nzgazettearchive/pubs/gazettes/1869/1869%20ISSUE%20056.pdfManager of the "Adelaide Gold Mining Company"
https://library.victoria.ac.nz/databases/nzgazettearchive/pubs/gazettes/1873/1873%20ISSUE%20069.pdfand the "Vale of Avoca Gold Mining Company"
https://library.victoria.ac.nz/databases/nzgazettearchive/pubs/gazettes/1871/1871%20ISSUE%20053.pdfShareholder of another one
https://library.victoria.ac.nz/databases/nzgazettearchive/pubs/gazettes/1882/1882%20ISSUE%20055.pdfCollector or rates for Kauaeranga
https://library.victoria.ac.nz/databases/nzgazettearchive/pubs/Provincials/Auckland/1873/1873%20Auckland%20Gazette%20Issue%2034.pdfMentioned many times on NZ newspapers
https://paperspast.natlib.govt.nz/newspapers?items_per_page=10&phrase=2&query=robert+martin+mitchell&snippet=trueWhat a difference a second forename makes!
