Police yesterday hunted two gunmen who hijacked a tractor-trailer carrying a $1.6 treasure in gold, silver and precious metals and then abandoned the rig, apparently leving the loot intact.

Two masked men wearing camouflage jumpsuits and carrying snub-nose black revolvers hijacked the tractor-trailer on Wednesday at 6 a.m. after George A. Smith, the truck driver, had stopped to check a possible defect in the equipment while en route to a Handy & Harmon refinery in Attleboro, Mass. After chaining Smith to a tree unharmed, the hijackers, both in the late 30s and about 5-foot-8, maneuvered the 40-foot rig from 1-95 onto Route 49, abandoning the truck on a secluded trail in the pachaug State Forest, about 10 miles from the scene of the hijacking.

Searchers in helicopters and planes spotted the truck at 7:30 p.m. that evening.A dozen armed police officers in camoulfage suits stayed in the woods Wednesday night through intermittent thunderstorms, hoping the thieves would return. Before the rig was opened yesterday morning, officers dusted it for fingerprints and looked for other physical evidence.

The haul of unrefined gold and silver worth $1.6 million was the largest heist in the states history.