The impairments for the 2014 financial year are a result of the review of exploration and development assets at the Mount Monger operations in the Goldfields, particularly the Cock-eyed Bob and Maxwells underground deposits, which are being evaluated as long-term prospects until firm development plans are finalised.

The Cock-eyed Bob underground mine has been factored into Silver Lake's 2015 financial year production but an extension of the decline is being evaluated.

The recent decision to put the Lakewood processing facility on care and maintenance also contributed to the impairment.

The company is trying to sell Lakewood but doesn't expect a deal to be finalised until the December quarter.

The impairments are in addition to the $42 million in write-downs posted in the December 2013 half-year against the mothballed Murchison gold operation.

The company said impairment charges were non-cash and didn't affect its cash position or operations.

Silver Lake had cash and bullion of $34 million at June 30.

"With the Murchison gold operations on care and maintenance, the company is focused on the Mount Monger operations, which recorded another strong annual [unaudited] result of $58 million earnings before interest tax, depreciation and amortisation in FY2014," Silver Lake managing director Les Davis said.

The company also decided to de-recognise deferred tax assets, mainly relating to FY2013 tax losses, of $53 million.

Silver Lake said it did not impact its ability to utilise the losses in future financial periods.

The amounts are still subject to audit but final full-year accounts will be released on Friday.

Silver Lake sold 172,838 ounces of gold in FY2014 and has set FY2015 guidance at 125,000-135,000oz gold.

Shares in Silver Lake dropped 2.3% to 43c.