His obituary on Find a Grave indicates he worked for Union Carbide under the auspices of the Manhattan Project.
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Obituary on Find a Grave:
The Arizona Daily Star, Tucson, 6 May 2009
James L. Lake 90, of Tucson, passed away on May 1, 2009.

He was preceded in death by his loving wife of 59 years, Mary Jo and his second wife, Margaret.

Survivors include his daughters, Nancy Benson, Mary Lake (Richard) Thompson; grandchildren, Jim and David Benson, Ann Reidy, Sara and Abby Thompson and nine great-grandchildren.

Born in Cleveland and raised in the iron mining area of Minnesota, James received his Bachelor's degree from the University of Minnesota in 1940, with a major in metallurgy and geology. During the war years he was employed by Union Carbide Company, and later as chief metallurgist of the company's uranium-vanadium operations under the auspices of the Manhattan Project.

From 1946-1953 he worked with US Steel Corporation on taconite concentration, and then returned to Union Carbide where, from 1957-1964, he was manager of the Colorado uranium-vanadium operations. Before joining Hazen Research as vice-president in 1964, he was manager of Union Carbide's mining and geologic activities and was headquartered in New York. He returned to Denver, CO and worked at Hazen Research.

Funeral service will be held at EAST LAWN PALMS CHAPEL, 5801 E. Grant Rd., on Saturday, May 9, 2009 at 1:30 p.m. In lieu of flowers donations may be made to the College of Optical Sciences, UA, 1630 E. University Blvd., 85721, or Colorado School of Mines, P.O. Box 1410, Golden, Colorado, 80402.