The Manchester-based gang of Romanians struck at the secret works near Stafford Road during the early hours of October 23 last year, a judge heard.
CCTV recorded the intruders, most of whom had their faces covered, gaining access to the site through grounds at the rear of the premises and making an initial assessment of the challenge they faced, Wolverhampton Crown Court was told.
They left the area but returned with a large stone cutter which they used to remove beading from the aluminium surrounds of window and took out the glass, explained Mr Gary Cook, prosecuting.
The gang then made a hole in the shutters through which some of the men gained access to the computer room where they forced open a magnetic door that led to a corridor but all the doors to rooms off it were locked and could not be prised open, continued the prosecutor.
So the burglars returned to the computer room which they ransacked with an untidy search but found nothing of value. Only a CD and a piece of paper were thought to be missing when the break-in was discovered.
They were at the address for two hours before the alarm was activated, sending them fleeing from the grounds at around 4am.
The court was told that the targeted building housed "high value gold bullion-type stock."
Blood was found one of the gang cut himself on a broken shutter and forensic examination discovered it belonged to Gabriel Safta, who was not traced until almost a year later on October 10.
He told police that he became involved in the plot to pay off a debt and was remanded on conditional bail but did not surrender to it when he should have.
The runaway was later intercepted at Dover Docks as he tried to leave the country.
Mr Lee Masters, defending, said: "He had headed there in panic. When we talked about it he became very emotional over the consequences for his partner and mother.
"He had found a job and had paid off the debt that got him involved in the crime with the money he earned but he now has the threat of deportation handing over him after the Home Office spoke to him."
Safta, of Norman Road, Fallowfield, Manchester, had a previous conviction for burglary and admitted entering the premises, which are not being identified for security reasons.
He was sent to prison for 16 months by Judge James Burbidge QC who told him: "If this burglary had been successful the spoils would have been great. The building contained high value goods like gold bullion."