A search is continuing for an 83-year-old prospector missing without food or water in Western Australia's Mid West region.
Trevor McDonald hasn't been seen since Saturday afternoon after going prospecting in an area about 50km south of Meekatharra.
Police say he is physically fit but has a heart condition and isn't carrying a mobile phone.
He and his wife had been intending to meet back at their caravan after heading off in separate directions near the Bluebird mine.
"He had a plan with his wife that he was going to walk out about a kilometre with his metal detector and then return ... but he did not come back," Inspector Dave Hooper told ABC radio on Monday.
"Unfortunately because he was going on a short walk, which he apparently does quite often, he didn't have water or food with him or any form of communication."
Police have launched an aerial and land search with support from State Emergency Service officers.
They say the weather conditions have so far been favourable.
Any drivers who may have seen Mr McDonald walking or resting along the side of the Great Northern Highway are asked to contact police. He may be wearing a brown jumper over a green and black checked shirt and black jeans.
