Police, CIB and Work Cover have investigated the death of a man at the Dimboola Grainflow site today.

The 59-year-old Dickerson Earthmoving employee was working at the site when it is believed he suffered a fatal heart attack around 9.15am.

Horsham Detective Senior Constable Neil Roberts said that there were others working with him when the incident occurred.

"His workmates tried valiantly to resuscitate him, performing CPR until the ambulance arrived. Paramedics took over and worked on him for over an hour but were unable to revive him. He was pronounced dead at the scene," he said.

"The Coroner will perform an autopsy to establish the cause of death, but his medical history suggests he may have suffered a heart attack, an aneurism or similar."

Investigating bodies have completed their investigations into the incident.

Detective Roberts said that the Grainflow site will remain closed for the rest of today.