Council officials are facing disciplinary investigations over a £132 million hole in their budget for cleaning up old opencast coal mines, the Sunday Herald can reveal.

East Ayrshire Council is set to launch the probes this week after a damning independent review exposed a series of serious failings in the council's control of coal companies.

Last year the council commissioned the Scottish Government's former chief planner Jim Mackinnon to review how it ended up £132m short of the money needed to restore landscapes scarred by 22 mines after the collapse of two major coal companies.

His report, a censored version of which is due to be published after a special council meeting in Kilmarnock on Tuesday, pulls no punches. Procedures for assessing the value of insurance bonds meant to cover the cost of restoration were "wholly deficient and defective", it said.

The bonds were "not based on the actual estimated cost of restoration", according to a council summary of the report. Figures provided by mine firms were accepted without independent assessment, in breach of council policy.

The failure to appoint independent assessors was "completely inexplicable", the summary said. Monitoring progress on sites was "wholly inadequate", letting planning consents be broken and creating "extensive environmental degradation".

Opencast sites were not visited or inspected regularly, and East Ayrshire Council did not have enough skilled staff to regulate the industry. "Neither elected members nor senior management were provided with any accurate or authoritative assessment of the scale of the problem or the funding required to address it.

"The review team concludes that there are significant management and communication failings, particularly within the planning service, and that the regulatory aspect of the planning service was not given the priority that was required in relation to the operations of opencast coal operators."

The review also found the council had contravened Scottish Government guidance in the way it granted permissions to individual firms.

In a report to councillors, the council's chief executive, Fiona Lees, said they would be asked to "consider and agree proposed arrangements for a formal disciplinary investigation". The plan was "to fully investigate each identified instance of failure to fulfil statutory, policy and/or professional obligation".

Lees said that after the investigation, "any disciplinary action which requires to be taken will be".

The Royal Society for the Protection of Birds (RSPB), which is concerned about mining damage to wildlife sites, pointed out the problem is not confined to East Ayrshire.

Aedán Smith, head of planning at RSPB Scotland, said: "This is symptomatic of a longstanding, institutionalised culture of light-touch regulation of the coal industry … at all levels, which must have no place in a sustainable modern Scotland. Many communities across Scotland are badly affected."

Smith described the go-ahead given in November to a new opencast mine at Cauldhall in Midlothian as incredible. "There needs to be a national moratorium on new extraction until a new regulatory system is in place and there needs to be national action to restore the legacy of ruined landscapes created by the opencast coal industry," he argued.

Rod Smith, an opencast coal industry specialist, praised the council and added: "Mackinnon's work will be of considerable benefit to some other local authorities provided they're prepared to listen and learn."

But Greta Roberts from the local Mining & Environment Group Ayrshire questioned whether the whole truth would emerge. "How can we be confident that no stone will be left unturned if we can't see the full evidence?" she said.