Her World War II career was short lived; however, after decommissioning, she was reactivated in 1962 for use as a research ship for the U.S. Bureau of Mines, where she served as Grass Valley.

Suncook conducted shakedown and training off the California coast until 8 July, when she departed for Pearl Harbor.

Suncook remained in the vicinity of Bikini and Kwajalein Atolls until September, supporting the atomic bomb tests known as Operation Crossroads.

She reached Seattle, Washington, on 30 September and remained there until June of the following year, undergoing radiological clearance.

In September 1962, she was again transferred, this time to the U.S. Bureau of Mines for use as a research ship at the Marine Mineral Technology Center at Tiburon, California.