Shares in Atlas Iron were lower after the iron ore miner flagged a $258 million non-cash hit to its bottom line after writing down the carrying value of some exploration projects and non-core tenements.

Atlas secured the projects during the four takeovers it undertook between 2009 and 2011.

Managing director Ken Brinsden described written down assets as "strategic" and said they were still expected to play a key role in the company's growth over the coming years.

However Atlas believed the impairment charge would position its balance sheet favourably to withstand any future iron ore price volatility.

"The company is well positioned financially with $423 million cash on hand as at December 31 and undrawn financing facilities of $50 million to complete its Horizon 1 development objectives," Mr Brinsden said.

"We are now expanding into a more robust iron ore price environment and therefore expect to be generating substantial growing cashflows as we execute on our Horizon 1 and 2 strategy."