http://commissionwatch.com.au/pentridge-prison-facts/

http://www.cfmeu.asn.au/news/statement-from-dave-noonan-national-construction-secretary-cfmeu

Looks like very soft ground. I hope you were using more then the standard pads in the front. Because it doesn't look like enough was used for the rear.

Sounds like he knew and others knew of the recent excavations , I believe both contractor and pump company have liabilities here , that size of pump , operator and management of a company bear some responsibility in assuring that safe setup and adequate cribbing or mats should be provided onsite , look at the ruts in the ground that is made by what appears to be a skytrack or Lull forklift 

The pumps a 53m sermac. there was half a forest of dunnage in the front and the pump had put in over 200 cubic metres already. The problem with this site is there are a lot of undocumented graves and underground services. The operator was cleared by work safe investigators as was the owner of the pump

then it sounds like the owner and operator did what they was supposed to do and sounds as this falls on the backs of the contractor. after reading these articles sounds as though he is a scheister.

Operator error, no one made u setup there