Joshua Luke Cross (28) was sentenced to 15 months in jail on May 3 by Magistrate Adam Hills-Wright in Kalgoorlie's Magistrate's Court after pleading guilty to 10 charges, including three counts of aggravated burglary, three counts of stealing and one count of trespassing.

Cross admitted he had been the getaway driver for an unknown accomplice after they broke into the Burbanks mill near Coolgardie on three separate occasions in December.

Burbanks was closed at the time of the break-ins.

Once inside the mill Cross' accomplice used a hammer drill to rip up a concrete floor containing specks of gold. A vacuum cleaner was then used to suck up gold chips from the concrete.

Cross then drove to his grandmother's house where he processed the stolen loot in her back shed with mercury before selling the gold to an unwitting Kalgoorlie buyer.

The buyer paid $4000, $3000 and $9000 for the gold on three different occasions, with receipts for the gold discovered by police when they raided a house in South Kalgoorlie, but the money was not recovered.

Cross pleaded guilty to three counts of aggravated burglary, three counts of stealing and one count of trespassing for offences described by Magistrate Adam Hills-Wright as sophisticated and at the serious end of the spectrum.

Hills-Wright said Cross's offending must have involved some degree of planning, as police found  a balaclava on the front seat of his car and tape covering the vehicles interior light.

Cross' defence lawyer Kim Samiotis argued that Cross had long supplemented his unemployment benefit by processing gold in his grandmother's shed for a friend with a valid prospecting lease, which exposed him to dangerous levels of mercury.

This mercury, she said, had left him with memory loss and increased anxiety, and cognitive impairment.

Cross had 169 nanomoles per litre of blood in his system, well above the standard of 0-50.

Samiotis said the high levels required specialist treatment in Perth, and urged the Magistrate to spare him jail so treatment could be administered.

Hills-Wright disagreed, saying Cross' extensive criminal record meant a jail term was inevitable, especially since Cross was previously deemed unsuitable for a supervision order before sentencing him to 15 months jail.

Cross is eligible for parole.