Mr Mitchell is one of 18 sculptors participating in the seventh Oamaru stone symposium, held every two years, which started at Takaro Park on Saturday.
The symposium will culminate on the weekend of November 21 and 22 with entertainment and a silent auction of the art works.
Mr Mitchell, who is sculpting at the symposium for the first time, said it was "an experience worth having at least once".
His only prior experience was carving a garden seat from stone.
He planned to make a font as a centrepiece for his "chieftain's circle".
He was completing it with a friend.
"I'm doing the hard work, they're doing the beautiful bit," he said.
Sculptor Nigel Watson will sculpt a large penguin from a block of Oamaru stone, given by Bob Wilson from Parkside Quarry.
There was controversy earlier this year when an Oamaru stone statue of a penguin was shifted from the centre of the town to the Oamaru Blue Penguin Colony.
Waitaki Mayor Alex Familton intends asking the Waitaki District Council's new art assessment committee if it will approve siting it in a prominent public place.
