The four convicts, Kwesi Kwaku, 19, Atia Kwame, 25, Nanjo Kwabena, 19, and Clement Okyere, 33, pleaded guilty and each person will serve 30 years in jail.
They were charged for conspiracy to commit crime and robbery.
He said on December 27, the complainant lodged a complaint with the police at Asankragwa in the Amenfi West District of the Western Region that, he and his colleagues were attacked by the convicts when they were returning home from a mining site.
He said the incident occurred around 1700hrs and the convicts, who were armed with guns, made away with a quantity of black sand gold concentrate worth GH¢50,000.00.
Detective Amponsah said on January 19, the convicts were involved in a similar robbery case and when arrested, they were identified by the complainant as those who robbed them.