Anglo American posted an annual loss of $3.1 billion on Thursday after taking an impairment of $3.8 billion, mostly due to its ailing diamond unit, as it races to restructure into a major copper producer following a bruising takeover battle with BHP last year.

The miner wrote down the value of its embattled diamond business again as it seeks to ready the division for disposal.

Anglo is considering either selling or listing De Beers, the carrying value of which is now about $4bn. That includes about $2bn worth of stock, a similar amount to last year.

Anglo American posted a $3.1 billion loss on Thursday, dragged lower by a De Beers diamond unit writedown, and pared its dividend, while the market welcomed its progress towards asset sales and reduced debt.

The diversified miner posted a worse loss than expected as it booked billions of dollars worth of impairments.

Anglo American Plc took another writedown on its struggling De Beers diamond unit, and posted a slide in profit, as the miner moves ahead with a radical overhaul of its business.

Anglo American (OTCQX:AAUKF) (OTCQX:NGLOY) said Thursday it wrote down the value of its struggling De Beers diamond business by another $2.9B, after already writing down the business by $1.6B to $7.6B last year.