Two Perth prospectors have been hit with substantial fines for damaging a Pilbara Aboriginal heritage site after excavating a 50m trench in search of gold. Dennis Johnston, 70, and his 74-year-old co-accused, who cannot be named for legal reasons, appeared before the South Hedland Magistrates Court on April 11. In July last year they drove to a crown reserve about 160km south of Port Hedland, on the grounds of the protected Woodstock Abydos rock art site. The court was told Johnston used an excavator to dig a trench 50m long and 50cm deep, while the other man used a metal detector to prospect for gold on the broken ground. The Woodstock Abydos site is an outdoor art gallery which contains rock carvings of extinct species and other art formations dating back tens of thousands of years. During sentencing, Chief Magistrate Steven Heath said the area was significant. He said the pair had used bush tracks to get there, avoiding signs that would have indicated not to go there, but had also probably disturbed the land in their travels. Johnston and the 74-year-old were charged under section 17 of the Aboriginal Heritage Act 1972 for excavating the site and regulation 10 for driving on to the site. Johnston was also charged with breaching regulation 7 for towing the excavator on to the site and fined a total of $12,650 as the primary offender. The 74-year-old co-accused was fined $4450. The Department of Planning, Lands and Heritage said the fines were significant and reflected the importance of the continued protection of Aboriginal heritage sites.