Apple, Exxon Mobil (NYSE: XOM), and Microsoft may get most of the attention, but with a market capitalization of around $200 billion, Australian mining behemoth BHP Billiton (NYSE: BHP) is with them in the land of giants.

The mining giant flies under the radar of many American investors. But here in Australia, the exact opposite is true. BHP's every move -- whether that be its failed takeovers of PotashCorp (NYSE: POT) and Rio Tinto (NYSE: RIO) or its recent acquisition of Petrohawk Energy -- is covered with a fine-toothed comb.

You'd be excused for thinking such a widely followed company could never become cheap enough for individual investors to profit. But you'd be wrong. While across Wall Street and Sydney's Bridge Street investors focus on short-term share-price movements, they kindly leave the long-term capital growth, dividend payments, and tax-free-compounding benefits to patient investors like us. By playing in that space, we can be big winners, too.

Long-term growth versus short-term problems
The flashing red and green ticks of share prices, the incessant volatility of markets, and the daily noise of mass media all conspire to shorten investors' focus. The solution is to put on your long-distance lenses. View the market and investments over years and decades, not months and quarters.

BHP might be as close to a great long-term investment as you can get in the stock market. It has low-cost, world-class, long-life resources and a deep pipeline of future growth opportunities. Long-term demand for its resources seems guaranteed, thanks to the insatiable appetites of China and India. To top things off, the shares look cheap.

But that hasn't stopped BHP's share price from heading backwards. In 2011, the shares have tumbled 12%, and at around $80, they're down 22% since they peaked at more than $102 in April. 

So what's up with BHP?

The market is fearful. A double-dip U.S. recession is a catalyst that could send commodity prices tumbling. Iron ore prices may already have peaked. As resource companies in Australia and abroad race to bring new mines to market, commodity supply is catching up to demand. China and India could miss a step in their climb to global dominance.

With all that uncertainty, perhaps it's no wonder the share price has been on a slide.

Is now the time to buy BHP?
At first glance, BHP appears cheap -- based on its current earnings.

My return on equity valuation indicates that fair value of BHP is north of $100 -- quite attractive when compared with its current share price of around $80. Clearly, some fear is baked into its current share price.

Yet while fear pervades the global stock markets, commodity prices remain resilient. Iron ore continues to trade near all-time highs. Strong demand from the developing world, combined with supply constraints, continues to support high iron ore and coal prices.

BHP estimates that 55% of global aspirational iron ore supply growth has failed to materialize. Tight labor markets, inflationary pressure, and the financial crisis have all hampered bringing new supply online.

That is excellent news for BHP. With 42% of BHP's 2011 earnings before tax and interest delivered by iron ore, the longer it takes for supply to match demand, the better.

Show me the money
BHP recently upped its final dividend by 22% to $0.55. That's nice, but with BHP almost doubling its capital expenditure this year to $20 billion, further dividend increases will be constrained.

BHP is effectively doubling down on its winning investments. Management is betting on the long-term growth of the developing world against the short-term problems of the developed world.

That's the type of thinking I applaud, and you should, too. I'd like to see BHP concentrate on its existing assets rather than pursue the empire-building aspirations of an overly acquisitive board. Hopefully that means the chatter about acquiring the likes of Anadarko Petroleum (NYSE: APC) and Woodside Petroleum prove to be nothing but rumors. The development of existing assets out of cash flow is a lower-risk path, especially during this time of inflated asset prices.

Like investors, BHP should focus on the long term. The growth assets it desires will go on a fear- induced sale one day. By focusing on developing its low-cost, long-term assets, BHP will ensure that it's in a position of strength when the inevitable downturn in commodity prices occurs.

Foolish bottom line
BHP is priced attractively -- both on a relative and fundamental valuation. If the old-developed world manages to delay the exciting and volatile conclusion to its overleverage and excessive health-care and pension entitlements, BHP investors will be well rewarded in both the short and long term.

That said, if you can patiently sit on the sidelines, at some point volatile and fearful markets could give you an even better entry point. In November 2008, BHP shares briefly dipped below $30. Such an opportunity should have investors trembling with greed.

The wonderful thing about investing is that opportunities are plentiful. BHP today is an interesting opportunity and will remain closely watched on our radar. But if world stock markets really do go into another fit of panic, we'll be ready to back up the truck and load up on shares of the Really Big Australian. You should be prepared, too.

The Motley Fool has recently opened an office in Australia. To be alerted to that "back up the truck" moment, sign up to receive a free email called Take Stock. We think it's a resource that Australian investors simply shouldn’t ignore. Join the fun Down Under.