My next door neighbor in Tampa in the late 60's matches your description.He was welsh, trained as a mining engineer. He worked in the senate post office in the 50's and 60's. He retired to Tampa Fla. where he died in the late 60's. He has married around the end of WW1 and he wife died in 1941. I do not think he had any children. My dad says he was buried in Norfolk Va with is wife Eva.