The Belize Institute of Archaeology was informed of the destruction last week, and archaeologists say this is not the first such incident. Bulldozing the ancient mounds for gravel is a widespread problem.
Although the pyramid is on private land, all pre-colonial ruins are under government protection. Police are investigating the incident, and prosecutors may bring charges against the construction company.
Dr John Morris of the Belize Institute of Archaeology said the workers would have known what they were doing when they destroyed the pyramid.
"It is incredible that someone would actually have the gall to destroy this building out here," he told local TV channel News 7. "There is absolutely no way that they would not know that these are Maya mounds," he said.
Noh Mul means 'big hill' and the site is believed to have been home to about 40,000 people between 500 and 250 BCE. There are roughly 80 buildings, all on the private property, but only the temple centerpiece was destroyed.