The Boungou mine is located in Burkina Faso's Eastern region about 355 km (220 miles) from Ouagadougou.
The attack comes amid a surge in violence in the country that has internally displaced hundreds of thousands of people over the past few months, sparking "an unprecedented humanitarian emergency", the U.N. Refugee Agency said.
The mining area has become unsafe for SEMAFO, which is in control of two gold mines in Burkina Faso.
Although the Boungou mine site was secure, Semafo suspended operations out of respect to the victims and those impacted, Desmormeaux added.
"The company would like to express its honest sympathy to families of the victims in addition to its firm support of Burkina Faso's security forces", Semafo said.
Semafo president and CEO Benoit Desormeaux said that given the scale of the attack, it will take time to deal with the situation properly as the company looks to support those affected.
On Wednesday morning "unidentified armed individuals" ambushed five buses carrying local employees, contractors and suppliers of the Samafo mining company, said Saidou Sanou, the governor of the country's Est Region.
Semafo's share price dropped sharply this week, falling by about 19% since Wednesday announcement of the road ambush, closing at C$3.32 a share in Toronto on Thursday.
The attack is the third related to Semafo in the past 15 months, after two incidents a year ago left at least seven people dead. At least 30 people were killed after the militants targeted a cafe popular with foreigners.
In August this year, the army suffered its worst attack with 24 soldiers killed in an assault on a base in Koutougou, near the Mali border.
A security source said "a military vehicle that was escorting the convoy hit an explosive device".
In December 2018 the gold producer reported that government security forces had been attacked on a road about 40 kilometres from the Boungou mine, resulting in five deaths.
Semafo said Thursday it continues to work with all levels of authorities on the safety and security of those working for the company.