Update: Missing man John MacKay has been located safe and well.
Previous: A land and air search are being conducted for an elderly man who went missing while prospecting near Collie yesterday.
The 70-year-old man, John Donald MacKay, was last seen along Bell Brook Road and Toorak Road in Yourdamung Lake, about 30km north-west of Collie.
Mr MacKay was prospecting with a friend when they became separated around 5pm on Sunday, May 12.
Police are conducting a land search with the assistance of State Emergency Service as well as Department of Biodiversity, Conservation and Attractions personnel.
Helicopters are also being utilised from police and DFES for the search.
Mr MacKay is described as light skinned, about 181cm tall, solid build, with a moustache and white hair.
He was last seen wearing dark clothing, a wide-brimmed hat and steel capped boots.
Concerns are held for his welfare and anyone who sees him, or has information regarding his whereabouts is asked to contact police on 131 444.