You might think that with the share prices of iron ore miners down an average 65% since January 2014, now might be an opportunity to buy in.

But you’d be mistaken.

Fortescue Metals Group Limited (ASX: FMG) has dropped 44%, BC Iron Limited (ASX: BCI) is down 82%, Atlas Iron Limited (ASX: AGO) has lost 77% and Mount Gibson Iron Limited (ASX: MGX) 55% since the start of this year.

But as far as they have fallen, there’s always the potential for them to lose another 100% from here.

As usual for commodity companies, they have tracked the iron ore price down. Currently trading at around US$75.80 per tonne, the commodity has lost 44% since November 2013, and broker Citi has drastically cut its forecasts for the next two years.

From Citi: “We expect iron ore prices to fall into the $50s – We have downgraded our price forecasts and now expect prices to average $74 in Q1, moving down to an average of $60 in 3Q15 – briefly dipping into the $50s – with annual averages of $65 in 2015 and 2016.”

The bigger iron ore miners Rio Tinto Limited (ASX: RIO) and BHP Billiton Limited (ASX: BHP) had expected higher cost Chinese production of iron ore to come off. But as Citi notes, “the resilience of Chinese iron ore production has often been underestimated.”

While many mines have closed and are unlikely to reopen while prices are depressed, it hasn’t been enough to offset the massive supply of iron ore coming onto the market, nor the reduced demand from China’s steel industry which isn’t growing as fast as predicted.

For higher cost Australian producers, such as the juniors and Fortescue mentioned above, they have a number of difficult decisions. Some of the junior miners also face another issue. Because much of their ore is a lower grade, they receive a discounted price – below the spot price.

And if you think the bigger miners like BHP and Rio might be a bargain, consider that a 44% fall in the iron ore price, translates into much bigger falls in earnings.

All else being equal, BHP would see a 77% fall in earnings before interest and tax (EBIT) for iron ore, while Rio would see a 68% fall in EBITDA. An even starker contrast is that a 44% fall in iron ore prices would wipe out around US$4.5 billion in half year revenues for Rio – the miner reported a net profit of US$4.68 billion for the six months to June 2014.

That’s an over-simplification of course as it ignores increased production, lower costs, fluctuations in exchange rates, tax and myriad other data. But it does give you an idea that now is probably not the best time to be investing your hard earned into risky assets such as iron ore miners.

While mining services companies bite the dust, iron ore miners crushed and natural gas stocks soar, there's a 'hidden' set of resources stocks the market is simply overlooking. Discover the names and codes of these 3 surprising ASX plays now in The Motley Fool's brand-new FREE report. Simply click here for your free copy now.