TECO Energy has agreed to amend the terms of its previous coal mining subsidiary sale agreement with Cambrian Coal.

A subsidiary of Booth Energy Group, Cambrian Coal purchased TECO Coal in October for an agreed price of $170m.

The deal was to be sealed by the end of December. However, the latest amendment made to the Securities Purchase Agreement extends it to 20 February 2015.

Amendment details have been filed with US Securities and Exchange Commission (SEC) as Current Report on Form 8-K.

TECO Energy CEO John Ramil previously said: "This agreement best positions us to execute our strategy to exit the coal business in as expeditious a manner as is reasonable, while still receiving fair value for TECO Coal."