Two alleged West Australian gold thieves have walked free with all charges against them dismissed, following a police forensics bungle which a defence lawyer argued would have "undermined public confidence in the justice system".

Shane Steven Hodgson, 50, and 34-year-old Joshua Luke Cross were accused of stealing $100,000 worth of gold-bearing material from the Carosue Dam gold mine, about 120 kilometres north-east of Kalgoorlie-Boulder in WA's Goldfields.

The men each pleaded not guilty to four charges of stealing from January and February last year and a two-day trial was due to begin in the Kalgoorlie Magistrates Court next Wednesday. 

Mr Cross had also pleaded not guilty to one additional charge of trespass.  

The trial dates were set last October.  

However, WA Police this week applied to adjourn the trial to a later date, revealing in court the laboratory engaged by police, Perth-based Source Certain International, had analysed the wrong material.  

Wrong material analysed

The court heard it was noted in the police running sheet — a formal document which keeps track of dates and progress of investigations — that the draft report of the analysis was received by detectives from the Kalgoorlie-based Gold Stealing Detection Unit on March 18 this year.  

The document also noted on July 1, seven weeks before the trial was due to start, that police asked to test gold samples from mill liners at Carosue Dam against the material found in a car belonging to one of the accused. 

Mr Hodgson's lawyer Paul Holmes told the court the defence was made aware of the additional laboratory analysis on July 23, and the running sheet was only provided this week.  

Police prosecutor Senior Constable Matthew Fullgrabe tried to explain the sequence of events to the court to further his application for an adjournment.  

But his argument was restricted as he said he only had the running sheet to go off, as he had been unable to contact detectives, who were unavailable on another investigation.  

"Officers were under the impression that the analysis was completed," he said. 

"It was not until July that they realised the wrong material had been analysed."

Defence critical of police

Mr Holmes said the case should be dismissed, rather than adjourned, saying he had spent 26 hours reviewing telephone intercepts and aerial photographs, researching gold finger printing technology and preparing for cross examinations. 

He also argued the police estimate of the value of the allegedly stolen gold was "hypothetical" as it was dependant on the laboratory analysis.

"It's an amount that they've (police) thrown at a dart board to quantify the allegation," he said. 

Mr Holmes said it was hard to determine the source of the gold, saying there was "no link" to prove it came from Carosue Dam.   

He said the material had been mixed with various sources of gold and mercury had also been used.  

"If I can be a bit critical of police, there was only a rush at the very end when the trial date was getting closer," he said.   

"Police were out of time some time ago." 

Mr Cross' defence lawyer Ashley Watson told the court it was unclear how much longer re-testing would take, and despite the "flurry of activity" by police in July as the trial approached, he said it was "too little, too late".  

"These are detectives in the gold squad," he said. 

Magistrate awards court costs

Magistrate Janie Gibbs said two lost days to the court was "significant", noting there was no explanation from police for the four-month delay where "they had the opportunity to get further samples".  

"Initially, I believed police were not at fault, that it was an oversight, but I don't think that position can be maintained," she said. 

She said if she adjourned the trial to a later date, the earliest it could begin would be April next year due to the availability of the defence lawyers. 

That would have been two years and two months after the prosecution began, Magistrate Gibbs said, which was too long for the accused to have the charges "hanging over their head".  

She also noted the defence submissions that an adjournment would result in a "serious injustice" and "significant expense".  

"The prosecution has an obligation to ensure matters are progressed in a timely manner," she said.  

Magistrate Gibbs awarded court costs of $14,036 and $8000, respectively, to Mr Hodgson and Mr Cross.   

Mr Holmes was also assured the charges could not be refiled at a later date.  

"I seek assurances from the police that this is the end of it," he said. 

Magistrate Gibbs said filing new charges for the same incident "would be an abuse of process".