Brian Curtis Derby, 67, of Townsend, died just before 8 a.m. when the rocks fell on his heavy machinery at the Sterling quarry along Stone Crest Way, the Worcester County District Attorney said.
Firefighters and crews worked through the day and night to retrieve Derby's body from beneath the rubble.
Sterling leaders ordered that workers stop all earth removal operations until the Occupational Safety and Health Administration could investigate the cause of the collapse and working conditions at the site, the prosecutor's office said.
The Onyx Corporation, the sand and gravel company that runs the quarry, also stopped work at sites in Acton, Leominster, and Westford until Monday.
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