Excellent article
https://www.reuters.com/article/us-semafo-attack-security-exclusive/exclusive-mine-workers-demanded-more-protection-before-deadly-burkina-faso-attack-idUSKBN1XT0JN
So, current cost of flying management is estimated at $1.5 - $2 million. To fly everyone, $3.8 million annually (high estimate).
It really doesn't look good when the company does not respond to Reuters for a quote/ other information. Semafo has been totally silent for 2 weeks now. More than overdue for another statement from the company.