On Friday, the court ruled the families may now see the material leading to that decision. They are trying to clarify when the full file will be released.
The judgment said it was important there was transparency, "and not false speculation and mis-understanding".
A WorkSafe spokesman said today it would not appeal the decision.
Its concern had been the principle of maintaining privilege rather than any specific concern about releasing the documents.
"WorkSafe refers to the view stated by Justice Mallon that the documents raise no new or independent issues."
A number of the High Court documents were released in 2017 to The Listener journalist Rebecca Macfie, after 12 charges against Peter Whittall were dropped, and insurers for Pike River Coal paid $3.41 million to the families.
That 2017 story revealed that the decision to drop charges followed months of negotiation between lawyers, with MBIE making moves towards a plea bargain with Mr Whittall, in the hope he would at least plead guilty to one representative charge.
While this was happening, police announced there was not enough evidence for manslaughter charges.
The papers and correspondence revealed concerns that Mr Whittall had a "good defences ... which would in part involve a considerable focus on the role of the Department of Labour's inspectorate".
There were allegations around the quality of MBIE's evidence fathering.
Other factors were witness unavailability, contests between experts, expected pre-trial issues, the fact the company had been held to account and a Royal Commission held, and the high cost.
The file was reviewed under the Solicitor-General's prosecution guidelines as to whether there was enough evidence for a prosecution, and if it was in the public interest.
This advice has never been released.
The latest court case released to that Solicitor-General file.
