An inquest has been told the cause of death of a prospector whose body was found down an abandoned mineshaft in WA's remote Mid West cannot be determined, but he had suffered injuries to his face, neck and one of his hands.

Key points: Raymond and Jennie Kehlet both went missing on a prospecting trip

Raymond and Jennie Kehlet both went missing on a prospecting trip Friend Graham Milne accompanied them and is considered a suspect by police

Friend Graham Milne accompanied them and is considered a suspect by police Mr Kehlet's body was found with blunt force injuries to his neck

The body of Raymond Kehlet, 47, was found three weeks after he and his wife, Jennie, were last seen alive on a prospecting trip to Sandstone, about 700 kilometres north east of Perth, in March 2015.

No trace has ever been found of Ms Kehlet.

An inquest has heard Graham Milne, a friend who went prospecting with the Kehlets, is considered a suspect in the case, but he has never been charged.

Graham Milne was the last person to see Raymond and Jennie Kehlet before they went missing. ( ABC News: James Carmody )

In evidence earlier this week, he denied having anything to do with the couple's disappearance and maintained he did not know what happened to them.

Autopsy showed a number of injuries

On Friday the inquest heard from forensic pathologist Judith McCreath, who conducted the post-mortem examination of Mr Kehlet's remains.

Dr McCreath said the body was in advanced state of decomposition, which meant she could not determine the definitive cause of his death.

But she determined he had suffered a number of bone injuries, including fractures to the cheekbone and eye socket, two breaks in one of his ribs and damage to the left side of the neck.

Raymond Kehlet's body was found at the bottom of a disused mine shaft. ( ABC News )

There were also injuries to Mr Kehlet's right hand, with Dr McCreath testifying the bones that joined his wrists to his fingers were in "many pieces" and the bones on the tips of three of his fingers were missing.

She said further examination confirmed there was a break in the hyoid bone in Mr Kehlet's neck, which could be caused by blunt force being applied.

"Whether that was from the fall, or implements or physical strangulation, I cannot say," she said.

Dr McCreath said the other injuries were consistent with something impacting with the bone and could have been caused when Mr Kehlet's body hit the sides or the base of the mine shaft.

She agreed they could have been caused by a blunt force weapon or a physical assault, but no one explanation was more likely than the other.

Jennie Kehlet's body has never been found. ( Supplied )

She testified the injuries Mr Kehlet suffered would not have precluded him from moving when he was at the bottom of the mineshaft.

But she said the injuries to his head could have affected his ability to move because they could have had "a concussive effect" or may have caused a bleed in the brain.

The inquest has now adjourned until February, when further evidence is expected to be given by other medical experts.