The incident took place yesterday afternoon on NH-78 under Nourozabad police station area in the district.
According to police, while one of the women was crushed under the wheels of the dumper, another one drowned in the Johila river as the tractor-trolley fell into it after the crash.
"As the speeding dumper hit the tractor-trolley, a woman sitting in it fell on the road and got crushed under the wheels of the dumper. However another woman succumbed in the mishap as she was trapped inside the tractor," Umaria Superintendent of Police (SP) Chandra Shekhar Solanki said.
The deceased women were identified as Asha Kol (25) and Koushalya Kol (22), he said, adding that they were working as labourers.
The injured persons are undergoing treatment in Shahdol district hospital.
Further investigation into the case is on.