Keaton Energy Holdings has declared a 25.9-million ton coal reserve for its 74 percent-held Delmas Project in Mpumalanga.

Of this amount, 24.3m tons were in the proved category and 1.6m tons in the probable category, the company said on Wednesday in a statement.

This followed further exploration drilling on the project and the completion of a feasibility study, Keaton Energy said.

"The feasibility study found that, after the application of modifying factors, the majority of the shallow bituminous coal of the No 5, No 4 and No 2 seam resource could be converted to a reserve."

The updated mineable in situ coal resource estimate for the project is 163.4m tons, inclusive of the 25.9m ton reserve.

"The conversion of coal resource to coal reserve is very significant; it shows that the project is robust and it takes us a major step towards bringing Delmas into production," Keaton Energy Managing Director Paul Miller said.