(Adds details on the likely non-earnings impact, net debt guidance, background)
Aug 9 (Reuters) - Newcrest Mining Ltd (NCM) said it was likely that it would record a one-off non-cash earnings impact of A$260 million to A$270 million ($193.21 million to $200.61 million) in fiscal 2018 due to reduction in the carrying values of certain assets after tax.
The charge mainly relates to the Telfer and Namosi assets, the company said in a statement.
"The latest life of mine plan (of Telfer) indicates lower levels of ore mined and higher levels of waste from West Dome, lower gold recoveries, higher estimated closure costs and higher operating costs than previously forecast," the miner said .
Newcrest said that the likely reduction in carrying value will be recorded as significant items and not included in the company's underlying profit.
The gold miner had earlier flagged a one-off gain of A$6 million.
Newcrest added that it expects its net debt as at 30 June 2018 to narrow to A$1.04 billion, A$459 million lower than as at 30 June 2017.
The miner is scheduled to release its annual results after market on August 22.
In July, Newcrest said its fourth-quarter gold output rose 15 percent as a timely uptick in production at its flagship Cadia mine enabled it to meet production targets.
($1 = 1.3457 Australian dollars)
