Duke Energy on Tuesday filed another 345 pages of nonconfidential documents with the N.C. Utilities Commission, which is investigating the CEO change that followed Duke’s merger with Progress Energy.

A May 15 e-mail from Duke CEO Jim Rogers to then-Progress chief executive Bill Johnson announced the resignation of Duke’s South Carolina president, Catherine Heigel.

“Bill, we have just lost our second top-tier female leader to another company. ... We need to talk about this,” Rogers wrote.

In previously-released e-mails, Rogers wrote that Heigel and another departed Duke executive, Gianna Manes, felt they would have limited roles in the combined companies.

Johnson responded that Heigel’s departure “is a hazard of having high-quality employees.” The merger closed July 2 and Johnson was quickly forced out, a move Rogers and Duke directors have attributed to differences among top managers of the two companies.

The rest of Tuesday’s filings were on meeting arrangements and routine matters. Duke also filed documents marked confidential and off-limits to the public.