Mrs Howard said she was forced to take matters into her own hands after the sport’s governing body was ‘‘incapable of fulfilling their job’’. 

While work was being done to install a fence on Thursday, a tractor sunk in soft ground in an area of the property rumoured to contain a mass greyhound grave. 

Mrs Howard then used other heavy machinery to excavate the site.  A ‘‘surface’’ scrape uncovered layers of greyhound bones and asbestos wrapped in black plastic.

 Dog food bags, dated 2010 and 2011, were also found. She filmed and photographed much of the excavation, including the discovery of bones. The footage has been provided to the Newcastle Herald and can be seen on theherald.com.au. 

 Excavation of the site was forced to stop when asbestos was discovered and WorkCover and Cessnock City Council were notified. 

Greyhound Racing NSW has not disputed the presence of animal skeletons on the property, but said there was no evidence of animal cruelty at Keinbah. 

‘‘We found two complete skulls, 15 jaw bones and piles of bones,’’ Mrs Howard said.

‘‘And that is just on the surface. We haven’t started to dig into the dirt yet.

‘‘We were excavating in an area that Greyhound Racing NSW were told dogs may be. 

‘‘When Greyhound Racing NSW chose not to, we decided to excavate ourselves.’’

The discovery comes after a two-day inquiry into allegations of mass graves and animal mistreatment exonerated the previous owners of the Keinbah Trial Track.

The inquiry was triggered after Mrs Howard urged Greyhound Racing NSW to excavate her property after hearing rumours it had previously been a well-known dumping site for slow dogs. 

A report outlining the findings of the inquiry found allegations of dumping untold numbers of greyhounds levelled at those who managed the property before Mrs Howard were based solely on rumour and had no factual basis.  

In an interview conducted prior to the inquiry but included in the report, trainer Tom Pullman, who previously managed the track, had admitted to shooting dogs after they were injured at the track and burying them in an area of the property known as ‘‘the contour’’. He said there were no more than 16 dogs that had been buried on the property by him and they were all located within a 20-metre radius. 

 But Mrs Howard said the ‘‘contour’’ and the hole excavated on Thursday were in  different parts of the property. 

‘‘This is not the area where the previous owner said the dogs were shot and put,’’ Mrs Howard said. 

Practical Environment Solutions general manager Tony Milligan confirmed the presence of asbestos 

‘‘It’s a massive and major issue,’’ Mr Milligan said. 

‘‘The three forms of asbestos were chrysotile, amosite and crocidolite.’’

The Herald attempted to contact Mr Pullman on Friday night but was told he did not want to comment.