As spring fever spreads like wildflowers across the northern hemisphere, the fever down under is a different kind of affliction altogether.

Met coal mania has spread quickly from the core of demand emanating from China and India, to the most coveted supplies trapped inside of Australia's richest ores.

This strengthening, global secular bull market for coal has triggered an outbreak of consolidation and fast-tracked development initiatives that continue to drive what I consider some of the most compelling investment opportunities of the decade.

While momentum has recently returned in dramatic fashion, I see the roots of this bull market cycle in the pre-crisis run-up that saw the Market Vectors Coal ETF (NYSE: KOL) surge above $60 per share before a panic-driven correction caught hold. Along with the ETF's constituent stocks -- led by CONSOL Energy (NYSE: CNX) -- coal shares have yet to recapture those pre-crisis heights.

Despite the depth of the ensuing correction, the long-term indicators for sustained coal demand never faltered, and even near the height of the panic I argued that Chinese demand would spark a healthy rebound. Also, India's role in fueling this demand must not be overlooked. Equipment maker Joy Global (Nasdaq: JOYG) pointed out last month that India's demand for imported coals will grow far faster than previously anticipated after Coal India reduced guidance for domestic production.

Returning our Foolish gaze to Australia, we find ample corroboration that this bull market continues to gather steam. Peabody Energy (NYSE: BTU) recently raised its bid for Australian coking coal miner Macarthur Coal to $3.3 billion, which also has a $3.5 billion all-stock offer from Australia's New Hope to consider. Amid swirling speculation regarding a possible bid from Swiss miner XSTRATA, complications from a separate deal pending with Macarthur, and the conflicting interests of some heavy-hitting stakeholders, I give Peabody's effort to acquire Macarthur slim chances of success beneath the $4 billion mark. Steelmakers POSCO (NYSE: PKX) and ArcelorMittal (NYSE: MT) hold major stakes in Macarthur, and are likely to exert considerable influence over the process.

With Macarthur still in play, and the outcome uncertain, Peabody tossed another ball onto the court by announcing a possible deal forthcoming with Coal India. Although the company provided little detail, an Australian newspaper reports that Coal India may purchase stakes in a quartet of Peabody's Aussie mines and some additional international assets ... all for about $1 billion. Is Peabody monetizing assets to raise capital for a twice-sweetened Macarthur bid? That's hard to say, but Fools are encouraged to stay tuned for additional developments in the fast-moving world of Pan-Asian seaborne coal.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.