Ferreira noted, “Fortunately, we're on the low end of the industry” in comparison with recent massive write-downs by other mining companies.

The general decline in minerals and metals prices, with the exception of gold, exacerbated by much more volatile iron ore prices negatively impacted Vale's financial performance. Vale's revenues fell 23% last year. Reduced prices of iron ore, pellets and nickel accounted for 95% of the US$13.935 billion drop in 2012 operating revenues.

Nevertheless, Vale reported record output of coal, pellets and phosphate rock during the fourth-quarter 2012. Vale's iron ore and pellet sales reached an all-time high figure of 303.4 million metric tons.

Eoin Treacy's view Justifying a major write down on the basis that it is on the lower side of the industry norm exemplifies just how carried away mining executives had become when the price of assets were at record highs. The question for VALE is whether they have written off enough of their poorly timed investments to give a true reflection of current value?

The share has been ranging mostly above $17 since May and found at least short-term support near $18 on Tuesday. A sustained move below $17 would be required to question potential for some additional higher to lateral ranging.