Global miner Anglo American said Friday that net losses improved in 2013, but was weighed down by a vast impairment charge on assets, weak growth and strikes in South Africa. Losses after taxation narrowed to $961 million (702 million euros) last year, from $1.470 billion in 2012, Anglo said in a results statement. The London-listed group took a $1.9 billion impairment charge on assets, principally in relation to its Brazilian Barro Alto nickel project. Underlying operating profit before exceptional items rose six percent to $6.6 billion, as currency gains offset lower commodity prices. Revenues grew one percent to $33.1 billion, it added. "Against a backdrop of weaker growth in the world economy in 2013, particularly in the emerging and developing economies, commodity demand remained soft with a decline in average realised prices for most of the commodities Anglo American produces," said chief executive Mark Cutifani. "For our business, the effects of such a difficult macro-economic environment were exacerbated by operating challenges at key operations and adversarial labour relations in South Africa. "Despite the challenges, significant operating improvements in copper, metallurgical coal and diamonds in the second half of the year and the sharp fall in the South African rand in the final quarter, drove a 6.0-percent increase in underlying operating profit to $6.6 billion."