This 1964 cover image depicts a diver stepping off a barge anchored in the Raritan River near New Brunswick, N.J. He and his fellow divers, employed by blasting contractor McAlindin Construction Co., were operating a crawler drill in order to drill and shoot a trench that would carry a petroleum products pipeline under the river bed.

Before drilling could take place, workers with Gates Construction used a barge-mounted dragline and clamshell over the course of 30 days to remove mud up to 19 ft deep to reach the rock beneath the river bed.

The trench was 600 ft long, 9 ft deep and 7 ft wide. To clear a 12-ft wide path for the drill to operate, the excavation team had to carve a trench in the mud that was 80 ft wide at the top.

The divers had to move the drill entirely by feel in the murky water. Over nine days they drilled 115 holes and packed them with 4,800 lb of dynamite.…