According to Aston, solicitors for Collins have filed proceedings in court over “his alleged entitlement” to equity participation under the terms of his employment contract.

In late March, Aston said Collins’ legal team alleged the equity participation claim was valued at about $157 million – which represented 5% of the midpoint of “valuations of Aston’s Maules Creek project and Dingo tenements” it acquired.

“Aston Resources intends to vigorously defend these proceedings,” the coal explorer announced yesterday.

Collins became the managing director of another Tinkler Group-affiliated company, MM Mining in February 2010 – prior to Aston Resources’ initial public offering in August that year.

Aston previously said Collins’ claim coincided with termination of his employment with MM Mining.

A well-known entrepreneur, Tinkler clinched a deal to acquire the Maules Creek open cut project from Rio Tinto subsidiary Coal & Allied for $480 million in the tougher times of November 2009.

The deal was completed by Aston three months later with the help of Asian finance.

The Maules Creek project was underlying the later float of Aston and its market cap had since surpassed $2 billion.