A policeman walking the beat on a dark night sees a man down on his hands and knees searching for something under a streetlight.
“Excuse me sir,” he says – helpful servant of the public that he is “what seems to be the problem?”
“Hello oshi…offi…officer,” replies the man – obviously a little the worse for a night of drinking – “I…I appear to have lost my keys”
The kind-hearted policeman lends a hand, and the two spend a few minutes scouring the ground to no effect, before the policeman asks “Are you sure this is where you lost them?”
“Nonono” replies the drunk “Didn’t lost them here oshifer – I lost them across the road.”
“Then why are you looking here?”
“The light’s better.”
Ba-doom tssch, as my daughter would say – echoing the classic cabaret drum-and-cymbals punctuation to an obvious punchline.
Forms of this particular parable though – variously termed ‘the streetlight effect’ or ‘the drunkard’s search’ – have been codified in Social Science theory since at least the 1960s, and there is at least one version circulating on the web as a thoroughly creditable “Nasreddin story” (a traditional middle eastern form of ‘wise fool’ tale, supposedly based on 13th century populist philosopher Nasreddin Hoca, in which moral or pedagogical points are illuminated with pithy folk wisdom) – pointing to some useful philosophical bones beneath its vaudevillian exterior.
The crux of the tale here is to illustrate the logical trap of focusing our investigative effort in the areas where it is easiest to make observations, rather than those that hold the greatest potential for discovery. This moral holds particular relevance for the business of mineral exploration as the national discussion in Australia turns to how to find the resource wealth that will sustain the industry through the 21st century and beyond.
The fundamental challenge of future mineral exploration is one of simple calculus: the depletion rate of many resources globally – the speed with which industrialised society is extracting existing mineral endowment from the ground to feed the needs of urban development and increasing living standards around the world – is outstripping the rate at which new deposits are being discovered. Addressing this growing problem efficiently calls for diversity in the style and geography of exploration efforts, balancing the potential for mineral discovery against the associated technical and social risks. For all the mineral exploration opportunities to be found in places like Sub-Saharan Africa or Central Asia, for example, the Sovereign risk attendant on their political and economic history mean that it would be a brave (or perhaps foolhardy) company who would invest all their eggs in such a basket – and nominally well-explored but stable jurisdictions such as Australia also have an important part to play in this solution.
Despite the intellectual and social capital invested in the mining industry in this country however, the all-important balance of risk and reward has been seen as tipping away from Australia as an exploration domain of choice in recent years.
Exploration expenditure nationally – the dollars poured into identifying and characterizing mineral deposits – has risen dramatically over the past decade. In part, this just reflects the expected upswing of a periodic cycle of investment – one more dizzying rise in a bi-polar industrial history of boom and bust stretching back to the earliest days of European colonisation – albeit with highs and lows increasing in magnitude through the latter half of the 20th century. More worryingly, this decade of enhanced spending has not been accompanied by a corresponding rise in discoveries. Quite the reverse – even allowing for a degree of time lag in the full size and value of discoveries being realized, the 10 years to 2010 actually saw fewer mineral discoveries in Australia than any equivalent period over the past 40 years. In real terms, it follows that the cost of discoveries has risen sharply – squeezed in a pincer of increased outlay and decreased success rates (Fig. 1).
To some degree, these statistics may be skewed by the lack of game-changing ‘Super Giant’ discoveries in the country over this period – the Olympic Dam and Mt Isa systems of the geological world, whose massive scale and rich grades of mineralisation place them in world-leading positions. Such spectacular concentrations of mineral endowment are surpassingly rare, but their concentrated bulk can so dominate the resource landscape that they account for a substantial share of the market – and profitability – of the mining industry. Looking in more depth at the results however (Fig. 2), we can see this appeal is misplaced – persistently high relative costs exist across all scales of deposit in Australia, with discoveries in this country significantly more expensive than most other areas of the world over the past decade. Welcome though it might be to the group lucky (or fore-sighted) enough to peg the ground, discovery of another Oyu Tolgoi – the ‘world class’ gold resource currently giving expectant parent Rio Tinto such political and economic labour pains with its troubled birthing process in Mongolia – in the Neoproterozoic rocks of the Paterson orogen would do little to change this fundamental landscape.
This value equation contributes to a pervasive view of exploration maturity in the Australian landscape – a perceived depletion of the residual search space. This has its positive side – such is our knowledge of exposed geological character across this wide brown land that it might reasonably be hoped the mature and well-informed exploration industry would no longer be so credulous as to swallow Harold Bell Lasseter’s fraudulent Depression-era tales of quartz reefs exposed in Australia’s rugged interior, awaiting discovery with their illusory “nuggets as thick as plums in a pudding.”
With this familiarity though, comes a matching degree of contempt – with the industry – or at least the financial markets – increasingly of a view that there are no more Telfer deposits or Kambalda nickel camps sitting around at the surface waiting to be stumbled across. “All the ground” it is said “has been walked” – all the rocks kicked by the boots of keen-eyed prospectors – with much of the formerly energetic Australian exploration industry seeing greater opportunities overseas in less thoroughly examined terrain.
But how valid is this pessimistic outlook? The vast majority of the Australian landscape – up to 80% by some estimates – is essentially un- (or certainly under-) explored for minerals – with the ancient Archean and Proterozoic rocks that have proven so richly endowed around the country masked by extensive blankets of regolith and younger cover sequences that have discouraged previous generations of explorers.
It is not that these covered domains are barren. Indeed, two of the most celebrated exploration successes in the past decade (the Tropicana gold resource and the company-making De Grusa copper discovery – about which, more below) were made under cover – and in areas widely perceived to be over-mature for exploration. The resources exist then…but to make their discovery and exploitation practical on a routine basis, we need a way to lower the risk involved in exploration. For all its heroic resonance, we shouldn’t simply rely on the storied Margaret Hawke effect.
For those unfamiliar with this dramatic masterpiece of recent industrial theatre, back in the winter of 2009 Hawke was a junior exploration geologist at Sandfire Resources. In fact, to give a perhaps more accurate view of the landscape, with her employer – as were so many junior mining companies at the time – savaged by the Global Financial Crisis like a child’s toy shaken by a maltreated Pitbull (I won’t quite go the full Shakespearian “Winter of our discontent” route…but times were certainly tough for the industry) Hawke, one of the last 3 employees left on the shrinking company payroll, was pretty close to being the entire exploration team at Sandfire. At the end of an otherwise unsuccessful exploration campaign, and with the company about to up-stakes and leave the field to lick their wounds, she took the bold initiative (some tellings of the tale might describe it as inexperienced presumption – but given the spectacular success of the play, we really have to respect the form of the heroic narrative) of signing off on a final drill hole without the approval of her absent boss. The spectacular copper, gold, and zinc mineralisation intersected in that last roll of the dice literally saved the company.
For every De Grusa jackpot though, there are likely a dozen ‘last rolls of the dice’ (and inexperienced presumptions) where the end result is the brass name plate of another failed small-cap mining company being quietly unscrewed from an office building in West Perth. These tales are less well reported though – with few participants keen to broadcast their failure from the rooftops.
Luck – perhaps not always of the spectacular form enjoyed by Sandfire in 2009 – will inevitably play a role in any discovery, with the true craft of a good explorationist like Hawke being to make sure you’re in the right place and looking in the right direction when your numbers come up. The question then is how do we use our luck more effectively in exploring for mineral systems beneath the blanketing rock?
Tools do exist to peer beneath this cover – an arsenal of geophysical methods to distinguish varying rock characteristics beneath the surface, geochemical approaches to resolve the cryptic fingerprints of a buried mineral system – and these tools have been widely applied across the exploration industry since the middle decades of the 20th century – with some noted success stories. The broad limitations of such techniques to date are made clear, however, in the statistics that show us that 50% of significant Australian mineral discoveries over the past 60 years were less than 15m beneath the surface, and only 10% under more than 200m of covering rock, truly in the realm blind to surface discovery (Fig. 3) – and those largely in the so-called brownfields environment, beneath or in immediate proximity to other known mineral deposits.
We can illuminate this search space then, but our efforts to date have in essence provided only a fitful firelight that can show us little more than shadows on the walls of the cave.
This limitation is widely appreciated – and extensive geoscience research and exploration targeting efforts have long been directed at improving our resolution and understanding of these faint signals – mindful certainly of the tremendous competitive advantage that any breakthrough may offer.
Instead of focusing on this narrow question of how to better detect mineralisation, however, perhaps we should be turning our attention to the critical decision making involved in targeting our drill rigs and sampling programmes in the first place. Before baiting your hook, after all, it is a good idea to address the question of whether there are any fish around. Or even any water.
This is the philosophy underpinning the Mineral Systems approach to exploration targeting – where rather than the traditional (and, to give its due, previously highly successful) methodology of characterizing an individual mineral deposit and seeking to replicate its discovery, exploration search space is instead defined by application of a rigorous conceptual model of how mineral endowment is concentrated within geological systems – incorporating understanding of the physical and chemical processes of ore fluid generation and metal solution, mobility and deposition across a range of scales. This approach focuses the explorer on mappable expressions of high quality mineralisation at the scale appropriate to the exploration decision – be that global, regional, or local. The process may not by itself identify the telltale signs of mineralisation, but the holistic view enhances the efficiency with which promising targets can be identified – and equally importantly, rapidly rules out search space where the geological fundamentals don’t line up – offering significant efficiencies to the exploration process.
Emeritus Professor David Groves – respected scientific researcher and former President of the Geological Society of Australia – articulates this concept through analogy to real estate. A rational person wouldn’t choose which house to buy on the basis of the bathroom fittings alone. No – the first thing you consider – so early in the piece that it might not usually even be thought of as a conscious choice – is the country you want to buy in. Then the state or city, then the suburb, then maybe even the street. Only at this stage would you concern yourself over which particular property to consider investing in, and it’s individual details and attractions.
It ultimately matters little how palatial the residence and impressive the swimming pool if the house is in rural Tasmania and your primary motivation is actually living close to a good school in Paris.
The power of such a holistic approach is amply demonstrated by the remarkable recent success of the petroleum exploration industry, where this style of systems-based prospectivity analysis was adopted some 30 or more years ago. It may seem hard to credit from a modern computationally intense scientific perspective – but many of the major discoveries made during the pioneering era of 20th Century petroleum exploration (think here of the Elysium fields of Texas, California, and even Saudi Arabia) were in no small part down to boots-on-the-ground prospectors recognising signs of oil and gas seeping out of the geological strata and probing for the source with an exploratory well – “I drink your milkshake”, in the evocative words of robber baron oil tycoon Daniel Plainview (an Oscar winning performance from Daniel Day Lewis) in 2007’s “There Will be Blood”.
In a classic model of needs-driven innovation, saturation coverage of accessible terrain during the later 20th century – the end of the golden age – forced the industry to change – driving exploration deeper, and making it increasingly more technologically focused and expensive to pursue. Today rather than combing the backwoods, Beverly Hillbillies style, for “a-bubbling crude”, serious exploration takes place on the back of comprehensive geological and geophysical evaluation of sedimentary basin histories and predictive modeling of petroleum evolution and migration, carried out to identify prospective search domains and provide the confidence required for the multi-million-dollar investment decision to mobilize a drill rig and sink an exploratory hole.
Okay, no more swaggering heroes and rugged individualists to lionize in cinematic tributes – no-one’s going to remake the 1943 John Wayne vehicle “War of the Wildcats” updated for the modern era as “Co-operative Joint Venture of the Balanced Risk Portfolio Exploration Drillers” any time soon – but the industry as a whole has been incredibly successful in meeting global resource needs over this period of change. And turning a more than tidy profit.
Rather than putting in more streetlamps then, the better solution to the dark frontier of mineral exploration under cover may be to follow the example of the petroleum industry here and think more carefully about where we aim the light sources we already have.