Australian mining billionaire Andrew “Twiggy” Forrest was ordered to sit for a seven-hour deposition as his US legal battle intensifies with hedge fund mogul Paul Tudor Jones II over a soured green energy partnership.

The suit brought by Tudor Jones’ family office in 2023 claims it helped Forrest’s Fortescue find US renewable energy projects in which to invest as part of a joint venture but was “suddenly and abruptly” cut out of a $135-million (A$216.6-million) bid on a power-plant portfolio.

Though Fortescue’s bid was accepted, the deal ultimately fell through. Nonetheless, Tudor Jones’ family office may seek potential lost profits from the abandoned partnership.

Forrest, who is not named as a defendant, had fought being deposed in the case, but a federal judge in Connecticut last week ordered Australia’s second-richest person, to answer questions by Tudor Jones’ family office. Much of the deposition is likely to focus on Forrest’s relationship with former US Senator Joe Manchin of West Virginia. In his April 4 order, US Magistrate Judge Robert M. Spector said there was evidence showing Forrest was directly involved in the bid and spoke to Manchin about it.

According to Tudor Jones’ family office, Fortescue pursued part of the power-plant deal that included a facility in West Virginia to curry favor with Manchin. Forrest allegedly wanted Manchin to support then-President Joe Biden’s Inflation Reduction Act, which provided further incentives for renewable-energy investment.

But after the passage of the law in 2022, Forrest allegedly pushed to back out of the acquisitions and the partnership with Tudor Jones’ family office. In a message, Forrest had called it “at least the most stupid deal I’ve seen for a long while.” The West Virginia plant was eventually sold to a company partially backed by motivational speaker Tony Robbins.

The lawsuit doesn’t accuse Manchin of any wrongdoing. It also doesn’t allege his and Forrest’s interactions were improper. Manchin did not immediately respond to a request for comment sent to the Washington-based advisory firm where he now works.

A spokesperson for Fortescue said the company “disputes all claims made by the Jones family office.”

A spokesperson for the Tudor Jones’ family office declined to comment.

According to the lawsuit, the deal called for Fortescue to provide capital to fund the initial purchases of plants and related expenses. Meanwhile, Tudor Jones’ family office was to use its “deep understanding” of North American power and natural gas markets to assess and value assets and raise funds. It would then have the option to buy a 50% interest in the facilities. The family office says it spent $6-million researching deals.

Fortescue has argued that there was no formal deal with the family office and any oral promises about reimbursing due diligence costs were too vague to be enforced. Lawyers for the Australian company have also said Tudor Jones’ family office was free to make its own bid on the power plants.

The case is Kid Shelleen LLC v Fortescue Future Industries Pty Ltd, 23-cv-1311, US District Court, District of Connecticut (New Haven).