Solid Energy had considered placing the mine into care and maintenance as soon as it bought out Cargill, but deferred that decision until October 2012, despite the mine operating at a loss, which had a detrimental financial impact on the business.
"There was a delay in decision-making around the future operation of Spring Creek Mine and the continued operation of the mine had a detrimental effect on Solid Energy's debt levels," the report said.
"The investment decisions made by the board and management, and the delay in decision-making in respect of Spring Creek, resulted in a company that was not resilient to the substantial and sharp drop in international coal prices."
The Auditor-General said the company's decision to invest $128 million in the coal handling and processing plant at Stockton open-cast mine in Buller was justified, but the investment in a Taupo wood pellet plant was outside its core business and involved significant capital expenditure.
"In the case of the Taupo wood pellet plant, the assessment did not recognise some key risks.
"For example, Solid Energy did not fully understand the complexities and risks associated with developing new or emerging markets with relatively new products. Solid Energy's forecasts were too optimistic and did not adequately consider a downside scenario."
- The Greymouth Star