According to court documents and the St Louis Business Journal, Engelhardt was first served on April 13 with a deposition date of April 19.

An April 15 motion in US Bankruptcy Court reportedly argued that the date would not give him enough preparation time.

The union had since agreed to move the deposition from April 19 to April 25, the paper said, though the deposition – which related to Patriot’s upcoming April 29 hearing on its motion to reject collective bargaining agreements and modify benefits for retirees – would still go on as planned.

“Were Mr Engelhardt forced to sit for a deposition without having had adequate time to prepare, there is a serious risk that he might, as a former director of each company, inadvertently disclose privileged or otherwise protected information, which could then constitute a waiver of such privilege,” the paper said of the motion’s verbiage.

The former executive’s legal representatives also argued that the testimony would not have significant relevance to the issues on the docket for the April 29 hearing in St Louis.

Both Peabody and Patriot are based in the Missouri city and Engelhardt held seats for both – chairman of Peabody Energy from 1998 to late 2007, CEO from 1990 to December 2005 and CEO of Patriot from May to October 2012.

Patriot first announced on July 9, 2012 that it and its wholly owned subsidiaries had filed for Chapter 11 bankruptcy, at the time citing market conditions.

At odds now is the producer’s request to terminate union retirees’ benefits and set up a trust for those impacted, one move of many the UMWA has staunchly fought against.

The bankruptcy case was initially filed in New York State but is now formally known as In Re: Patriot Coal Corp et al, US Bankruptcy Court, Eastern District of Missouri, No. 12-51502.