Northfield Mt. Project

by kfrego

In 1968 and 1969 there were about 20 people from Lyon Mt. and Merrill, NY working on the Northfield Mountain Pumped Storage Hydro Electric Project near Greenfield, MA. Most of them were on the same crew. Northfield was a $183 million construction contract. Morrison-Knudsen had the civil construction. Main features of the contract included excavation and embankment of a 300 acre reservoir (capacity 5.6 billion gal) 800 feet in elevation above the Connecticut River. An upper intake structure with a 1000′ long x 20′ angled shaft. Underground 700′ were four 12′ diameter penstock tunnels, an underground power house (300′ long, 80′ wide, 150′ high), four draft tubes, a tailrace tunnel (4400′ long, 40′ wide, 40′ high), and an intake structure into the Connecticut River. Twenty miles of the river between the dams at Turners Falls, MA and Vernon,VT would function as the lower reservoir for the project. An access tunnel (2500′ long by 24’high by 30′ wide) was required to access the underground power house. Other access tunnels and shafts were required for maintenance and construction access.

I decided to quit my job as a correction officer at Green Haven and went to work for Allie Chase at Northfield. All of the tunnels at Northfield were excavated by drill and blast methods. The large drill carriers were called jumbo’s. We had a jumbo which was built around the frame and cab of a R-35 Terex off highway rock truck. The steel beam frame was about 50′ long and the upper components were about 20′ high. It was huge and heavy. We often had to use a D-7 Cat to assist moving the jumbo’s. The drills were Gardner-Denver 123 hammers mounted horizontally on 14′ guide shells. The drills were air powered and used water for dust control and hole flushing. Hydraulic cylinders were used on the drill booms to position them. The top deck of the jumbo had three drills, the center deck had four drills, and the bottom three drills were operated standing on the ground.

A few weeks after starting at Northfield we had a loose slab of rock on the upper face of the tunnel. It was a hazard for the crew when drilling. Ally Chase, Tommy Sims, and several others worked diligently to dislodge the slab of rock. They rattled it with the drills and worked with scaling bars on the top deck of the jumbo. The rest of the crew was busy preparing to drill. When the slab came loose, it was in slow motion. It was also much larger than anybody anticipated. The slab slowly tilted off the face and on to the top deck of the jumbo. The top deck slowly collapsed as it took the weight. When the deck hit the center drills underneath, the weight of the slab caused the front of the jumbo to go up in the air until it hit the top of the tunnel. Everything on the jumbo slid off as the crew vacated for solid ground. When it was all over no one was hurt. We used a bull dozer to pull the jumbo out from under the rock slab and out of the tunnel.

I was on the top deck when the slab came down……………..but not for long.