Just when investors are struggling to maintain a firm global perspective on these highly dynamic commodity markets, along comes Joy Global (Nasdaq: JOYG) with its consistently refined dose of comprehensive market insight.

This giddy mining equipment manufacturer smashed consensus earnings expectations for its fiscal second quarter by a whopping 49%, and followed the intrepid performance with yet another reassuring assessment of long-term growth in commodity demand. Diving into these earnings, we find a welcome duo of increased bookings for both original and aftermarket equipment ... which conveys strength in both the near-term and long-term expectations for demand among raw material producers.

Notwithstanding the considerable uncertainty presented by Australia's proposed 40% resource tax -- which Joy Global warns will slow the decision-making process on some $34 billion in proposed projects -- new orders for original equipment worldwide rose 55% over the prior year. The company's order backlog continues to expand, reaching $1.7 billion by the quarter's end.

The China syndrome
While confirming that demand growth in China has moderated from the incredible rates we witnessed to begin the year, Joy Global interprets this as a positive development for the long-term sustainability of China's growth trajectory. I share this view, and will view any resulting near-term weakness in commodity prices as an invitation to press long positions in key raw material producers. What's more, Joy Global notes that for certain products like copper, demand from elsewhere around the globe is catching up to China and India. How commodities pulled out of the monster correction of 2008 was essentially all about China, but from here forward, the global demand landscape may become less of a one- (or two-) hit wonder.

Honing in on the phenomenon that I have identified as the greatest emerging investment story in the raw materials universe, Joy Global pointed to metallurgical coal as a particular point of strength. I have documented a historic shift, among even eastern U.S. coal miners like Patriot Coal (NYSE: PCX) and Massey Energy (NYSE: MEE), and strongly suggested that we are witnessing only latest resurgence of a multi-year bull market for met coal. To the extent that planned production expansions in Australia by key producers there like BHP Billiton (NYSE: BHP) could be delayed by Australia's resource tax, that demand picture grows stronger still.

Foremost among the materials that Joy Global believes could see particular near-term weakness from China's relative pause are iron ore and copper. The company notes that iron ore prices have already settled from a recent peak of $190 per ton down to $123 ... an abrupt 35% slide that has coincided with visible weakness in shares of the best-known producer: Vale (NYSE: VALE). Offering a touch of perspective, however, Joy Global notes that even today's slackened import volumes into China remain 60% ahead of 2008 levels.

Despite the recent decline in Chinese imports of copper, global demand for the malleable metal is still expected to grow by 8% in 2010. Joy Global adds: "The longer term outlook is that all copper capacity, including higher cost capacity, will be needed to meet future demand expectations." For the higher margin producers led by Southern Copper (NYSE: SCCO), this is music to miners' ears.

Strength from a surprising source
The degree of relative strength observed in the U.S. industrial sectors over recent months not only came as a pleasant surprise to this skeptical Fool, but it caught Joy Global off-guard as well. The massive coal stockpiles that plagued the domestic thermal coal industry have already been reduced by 30-40 million tons from their peak. Capacity utilization at domestic steel mills has improved to 74%, and still their inventories remain below historical averages. Although headwinds like Friday's worse-than-expected jobs report continue to blow ferociously, business conditions as they affect the domestic commodity markets have certainly come a long way from the bottom.

The global view
When fresh rounds of the European debt crisis turned U.S. equity markets sharply lower last month, I highlighted Joy Global and its rival Bucyrus (Nasdaq: BUCY) as two high-quality defensive stocks in which to ride out the returning tide of uncertainty. Joy Global's solid earnings result -- and resilient long-term outlook for sustained growth in global commodity demand -- serves to reinforce those selections. I encourage Fools to give careful consideration to their prospects for steady outperformance of the broader equity indices, and to convey my confidence in that assessment I have added both companies as picks within my Motley Fool CAPS portfolio.

When pundits tend toward panic at signs of a deepening European crisis or further moderation in China's growth rate, I encourage Fools to keep Joy Global's perspective in mind: "Commodity demand should continue to grow over the next several years and beyond today's limited excess mine capacity, and this should support strong fundamentals for demand and pricing for the next several years." When crafting an investment thesis to navigate a challenging economic environment, such comforting words serve to strengthen a Fool's resolve.

If you believe that China will be a keystone to recovery for countless companies with exposure there, then consider taking the Motley Fool Global Gains newsletter service for a free test-drive for 30 days. The Global Gains team watches China carefully as part of its search for exciting and Foolish investment opportunities around the globe.

Fool contributor Christopher Barker is the Nat King of coal and the wild boar of iron ore. He can be found blogging actively and acting Foolishly in the CAPS community under the name TMFSinchiruna. He tweets. He owns shares of BHP Billiton and Vale. Try any of our Foolish newsletters today, free for 30 days. The Motley Fool's disclosure policy is busy learning Mandarin.