The Tarong high-grade thermal coal deposit, in the South Burnett area of Queensland 180km NW of the State Capital Brisbane, was discovered in 1968 by a geological team from Conzinc Rio Tinto of Australia (CRA).

In the remainder of this essay, I will refer to the company as Rio Tinto [1].

Rio Tinto did not waste time. By 1970, following a massive drilling campaign of mostly vertical open drill holes, they had proven 163 million tons of coal within an open pit mine profile with low stripping ratio [2]. Much, much more has been discovered since in the immediate area (see: South Burnett Coal Reserves 2015). They named their discovery after the Tarong pastoral station in which it was located.

The deposit is now owned by the Queensland State Government utility, Stanwell Corporation. Coal has been continuously extracted from Tarong since 1984 through the open cast Meandu Mine. The mine’s entire output of 2 million tpa is sent by conveyor belt to the adjacent, Government owned, Tarong Power Station, which burns it to produce 1.4 GW p.a. of electricity, fed directly into the Australian East Coast Grid [3]. Tarong does not just contribute electrons to the ECG. As with all turbine systems, it contributes critical grid stability (firming) at no extra cost.

With present known reserves and present consumption rate it will be at least 250 years before the Tarong Power station runs out of coal.

With the closures and projected closures of coal mines across Australia [4], the price of electricity from Tarong is set to become the lowest in Australia [5].

About the geology

The Tarong deposit is located within a north-trending, 60x10km, outlier of thick Late Triassic sediments. The outlier is now called the Tarong Basin [6]. The Basin is fault bounded within Early Paleozoic metasediments and assorted intrusives that make up the Australian east-coastal Tasman Orogenic Belt of the Great Dividing Range. Major steep dipping, north-trending faults divide the Belt into elongate tectonic slices called “blocks”. It is probable that the Tarong Basin is a pull-apart basin caused by a late Triassic strike-slip re-activation along one or more of these faults. The sediments that fill the basin were laid down in a swampy environment of slow meandering streams, shallow lakes and, most importantly in this context, a riot of tropical vegetation whose remains locally accumulated to fossilise as coal.

Rio Tinto (and I) appear on the scene

In 1964, Rio Tinto discovered the giant copper-gold deposit of Panguna in Bougainville Island, Papua New Guinea. By 1968, they were advanced in the process of developing a major mine there. They hoped to find a similar deposit in Eastern Australia. Stream-sediment geochemistry – then a new exploration technique – had worked well for them in the islands but had not previously been employed at scale in Australia. It was a smart exploration play.

In the early months of 1968, as a junior geologist with Rio Tinto Exploration, I was transferred from the Northern Territory to work on base metal exploration in the Lower Paleozoic rocks of the Queensland coastal ranges. Geologist W H Johnstone (hereinafter, Bill) and I were tasked with collecting stream sediment samples from across an approximate 100km by 30km area between the regional inland centers of Towoomba and Kingaroy. Bill had been working in the area for some months prior to my arrival and was much more experienced than I. He mentored me in the techniques of stream sediment sampling.

The area is dominated by forested north-trending ranges, the intervening valleys partially cleared for grazing and for horticulture on the rich alluvial flats. Access was generally good: paved roads and farm tracks in the valleys, logging tracks through the intervening hills. Some of the most beautiful country in eastern Australia, baking under the hot summer sun.

We based ourselves at the Grand Hotel (today, the Grand Old Crow Hotel) in the small agricultural town of Crows Nest (pop. around 1000), central to the area. I was based there for over three months. One of the best exploration bases I ever had.

Rural Town Interlude

On weeknights there was little entertainment to be had in Crows Nest (no rural TV in 1968). We spent our evenings in a shared room at the Grand (bathroom at the end of the corridor, telephone in the public bar downstairs), sorting samples, writing up notes, planning next day’s activities. I did not own a camera back then so attempted to record my day’s experiences in a sketch book.

Long summer weeknights in the Grand Hotel, Crows Nest

But on Saturday the town was busy, even roisterous, as the farmers came into town for shopping, a meal at The Grand and to socialise after a hard-working week…

Saturday night in the Ladies Lounge at the Grand Hotel. 

Back to the Story

Early in our acquaintance, Bill told me that sometime previously when he was staying in a hotel at Nanango (50km north of Crows Nest), he was approached by a local man called Nobby [7], who owned and ran a contract water drilling service for farmers. Nobby had told Bill that around the headwaters of the Yarraman and Meandu Creeks (30km north of Crows Nest) many of his boreholes had encountered seams of coal. At that time, drilling for agricultural water was subsidised by the State Government, but drillers had to inform the Department of their results and provide a geological log for each hole.

Bill decided to go to the State capital Brisbane to check this information at the Department of Agriculture. He would not have done this without the permission of our immediate supervisor, Gladstone-based geologist Ian Witcher. It turned out that, over the general area described by Nobby, almost every water bore sunk over a period of many decades had recorded coal in their logs (even rural water drillers had little problem identifying that black stuff in their cuttings). By contouring the results, an area prospective for coal mining in the southern Tarong Basin was outlined. Although many other coal occurrences were known in Queensland at that time, the attraction of Tarong was its good existing infrastructure and proximity to the population centers of SE Queensland.

Me (smoking a pipe), Nobby [but see footnote 8] and Bill Johnstone in the front bar of a Nanango Hotel

Ian Witcher notified the Head Office of Rio Tinto Exploration in Melbourne. The company’s Exploration Manager – the legendary Australian mining Geologist Haddon F King – made the strategic decision to pivot exploration in the South Burnett area from base metal to coal. The first diamond drill hole to test the coal potential of the Tarong area was planned for the center of the best legacy water bore results.

For whatever reason (I was the most junior geologist on site), I was asked to geologically log this hole [9]. It was collared on the top of a low hill in the Meandu Creek area: a hill clothed in dry grass, scrub and stands of Eucalypt trees with some clearing for pasture on its lower slopes; now long swallowed up by the later mine.

Prior to drilling, although outcrop was poor, I attempted to make a geology map. A conglomerate was exposed on the hilltop – an outlier of the basal unit of a late, overstepping formation. On the lower slopes, some surface float of sandstone. Along the new drill access, track the dozer blade had exposed outcrop of a soft, rubbly, buff-coloured rock. I confidently identified this as mudstone. All units were flat lying.

The 200m vertical drill hole presented the easiest logging exercise of any I have ever attempted. Layer cake stratigraphy; well-bedded sedimentary lithologies dominated by sandstone, siltstone, mudstone and coal; sharp contacts between units; little post-depositional deformation. In first 100m, the drill hole encountered at least five coal seams ranging from 1 to 25 meters thick, the first seam only 20m below surface.

After the ancient metamorphic rocks of the Territory, I thought coal geology a piece of cake. But the “mudstone” I had observed at surface turned out to be heavily weathered coal. So much for my surface rock recognition skills.

My association with the Tarong project ceased at this point as I was transferred to another project in Papua New Guinea (see HERE). Someone else was brought in to replace me. Hopefully someone with more knowledge and experience of coal exploration than I.

The Moral of my Story

The discovery of Tarong is a good example of a general principal for the exploration geologist: when you are exploring an area, always seek out local knowledge. If someone, knowing a company geologist is in town, approaches you with an interesting rock specimen he has found, treat him (it’s always a him) with respect. Listen to his story and make sure you protect his interests if you or your company follows up on any new knowledge or insight he has brought you.

In 1962, Lang Hancock, a cattle station owner in the Hamersley Ranges in the remote northwest of Western Australia, brought the iron ore potential of the area to the attention to Rio Tinto. He was rewarded with a generous ongoing royalty from Rio’s subsequent, hugely profitable iron ore mines. Hancock died in 1992, but the royalty stream continued. Hancock’s only child Gina Reinhart, who had grown up on her father’s Mulga Downs station, leveraged her small inherited fortune into a much greater one to become today Australia’s richest person with over $46 billion (US$32 billion) in assets.

Lang Hancock and his daughter Gina, circa 1980. Photo by the Sydney Morning Herald.

It seems to me likely that the well-publicized story of Lang Hancock’s new-found wealth prompted a Nanango resident called Nobby to approach a Rio Tinto geologist in a pub in late ’67 or early ’68.

Bill Johnstone’s decision to follow up on his local knowledge was the key to the discovery of the Tarong coal deposit.

Epilogue

After I left Queensland, Bill’s career and mine took different paths and we never met again.  Much later, I was told by a mutual acquaintance that when Rio lodged a Mining Lease over the Tarong coal deposit, Nobby was given a similar royalty deal to that of Lang Hancock on any future coal sales by Rio Tinto in the South Burnett Region. I was also told that Bill subsequently married one of Nobby’s daughters. Although I have no independent verification for any of that, if it is true, good luck to them both. They deserve it.

The post The Power of Local Knowledge: the discovery of the Tarong coal deposit: appeared first on Roger Marjoribanks.

In any given set of large (i.e. spanning several orders of magnitude) random numbers, one might expect that all the digits from 1 to 9 should appear, statistically, at each position in the number sequence around 11% (100/9) of the time[1].

In 1881 Canadian astronomer Simon Newcomb, and again independently in 1938 American physicist Frank Benford, noticed that, in sets of large numbers obtained by measuring natural physical phenomena, digit 1 appears as the first digit of the number on average 30% of the time, 2 appears in this position 26% of the time and so on through to digit 9, which appears in the first position a mere 5% of the time. Benford called this the “Law of Anomalous Numbers” or the “Law of First Digits”, but it has today come to be known as the Newcomb-Benford Law or, more commonly, just Benford’s Law[2]. Benford’s Law is a statistical effect, so our set of measured numbers must contain many examples before the effect can be conclusively demonstrated.

The light bulb moment for Newcomb came when he noticed that the first few pages of his book of logarithmic tables (covering numbers 1,2 & 3) were much more thumbed and dog-eared than the final few pages covering numbers 7, 8 & 9 [3].

Counterintuitively, Benford’s Law holds true even for systems which we might expect to be randomly distributed, for example: the lengths of the hundred longest rivers in the world. It holds true no matter what physical characteristic of a system (mass, length, volume, radiation, dollars etc..) is being measured. The Law also holds true irrespective of the units being used (SI v Imperial, meters v kilometers, grams v tonnes, light years v parsecs) provided that the units employed give sufficiently large numbers for the thing being measured. The numbers can be to base 10 (our normal system of counting), base 60 (as used by the ancient Babylonians) or base 2 (as used by computers). It does not, however, hold true for artificially restricted numbers (telephone numbers, for example).

Why is this so? Clever mathematicians and statisticians have pondered this question and, although I do not fully understand all their explanations, the one answer that I do understand seems to lie in the positional number system that we use to represent large numbers.

In the following, remember that we read large numbers from left to right, but add to them (count) from right to left.

With our numbering system, we unconsciously use logarithms almost every day. The system is a not-so-secret code which specifies that a in a number expressed as a linear sequence of digits, the digits are arranged logarithmically. Each number position (slot) contains an order of magnitude more digits than the position immediately to its right. Thus, the five-position number 76543, when we break the code, represents (7×10000) +(6×1000) +(5×100) +(4×10) +3.

When we are counting with this system, each added unit goes into right-hand position of our growing number. When that position is filled, the units are converted to a 1 which is then transferred to the second position from the right.  Adding units steadily to the right-hand slot, it will take ten times as long to fill the second slot as it does to fill the first, and ten times as long again to fill the third slot as it does the second, and so on. When we stop counting, it is therefore much more likely the slot on the right will contain a 9 than any position to its left. Turning the argument around, it is likely that when counting stops, the left-hand position of our large number – the last slot to be filled – will contain a 1 than any slot to its right. The same argument can be made for all the other digits from 2 to 8.

Benford’s Law has found many practical applications in the detection of fraud. It cannot prove a fraud, but it can quantify a “that does look right” moment and so focus further investigation. Crooked accountants inventing false company profits. Bureaucrats working for corrupt Governments producing false GDP figures. Scientists publishing fake data. Fishermen lowering the weight of their annual haul to meet Government catch limits. Taxpayers doing their annual returns. In all such cases, liars are likely to produce numbers that do not correspond the Benford’s Law. The reason is that creators of large false numbers will instinctively seek to distribute their digits randomly along the sequence.

A good example (I take this from the statology.org website) is the collapse of the giant US energy company Enron in 2001. Forensic accountants, applying Benford’s Law to Enron’s public accounts, showed that they did not satisfy the Law. This could have, and should have, raised suspicions about Enron’s viability if said forensic accountants had carried out their work before the company collapse, rather than after. Enron’s auditor for many years – Arthur Andersen LLP, one of the world’s largest accounting firms with over 84,000 employees – deservedly followed Enron into receivership in 2003. Note that number 84000 – although large, it has only two significant figures.

The average crook

Law enforcement relies on being smarter than the average crook. That, unfortunately, is not always the case. More sophisticated liars can research Benford’s Law – as I have done – and make sure that their numbers pass this test.

Can Benford’s Law be applied to the mining industry? Mining and exploration companies can falsify their financial accounts like any other company. However, when they announce their resource figures these do not normally contain enough significant digits. No company ever presents their metal resource to the nearest ounce of gold or ton of base metal – a large element of rounding is always used, reflecting the inherent uncertainty of such calculations. A knowledgeable person would not need Benford to recognise BS when they see it.

Take the biggest mining fraud in history – the Busang scandal of the mid to late-1990s (for full details and analysis on the Busang fraud see my previous posts HERE and HERE).

In this fraud, a small group of contract Filipino geologists working for the Canadian junior exploration company Bre-X, added purchased alluvial gold to drill samples from the Busang gold project, located in the remote jungle of Central Borneo, in the Indonesian province of Kalimantan. The crushed and mixed samples were then sent to an independent laboratory to be assayed. From thousands of assays results reported regularly to the Toronto stock exchange over a three-year period, expert analysts calculated that the Busang deposit contained over 70 million ounces of gold. Hyperbolic, overexcited, financial journalists enthused over a potential for 200 million ounces. At its peak, the penny stock Bre-X soared to CAN$286.50, valuing the company at CAN$6 billion. The fraudsters made cash by trading in company stock.

But 70 million ounces is a round figure. All one can say is that it is a very big number for a single gold deposit. There is nothing for Benford to work on here. And the Borneo fraudsters were sophisticated; they did not just add a pinch of gold dust to each of around 10,000 drill samples (my estimate). Operating over several years in a secret jungle laboratory, they carefully weighed calculated amounts of gold to each sample to precisely create desired assay numbers compatible with a real hard-rock epithermal gold system.

The deception continued for several years. Geologists who knew the Indonesian exploration scene and fancied themselves knowledgeable in gold exploration (I was one) did not suspect fraud even though there were some puzzling aspects to the steady stream of data provided by Bre-X. The sheer scale, duration and sophistication of the fraud that would have been necessary was beyond our experience and our imagination.

The criminality was finally exposed in 1997 by the arrival of a geological team at Busang from the American mining company Freeport-McMoRan – the first outside experts to be allowed on site. They were there to carry out a due diligence study prior to Freeport making a takeover offer for Bre-X. But the unmasking of the fraud was too late for the thousands of Canadian mum-and-dad and corporate investors who collectively lost 6 billion dollars when Bre-X was delisted. No one was ever charged with the crime [4].

The post Benford’s Law (1) appeared first on Roger Marjoribanks.

Experimental science is focused observation guided by emergent theory. Geologists exploring for minerals are experimental scientists. They study rocks in the field with a series of experiments to test their ideas about the occurrence of metallic concentrations. But many exploration programs today deny these simple truths and believe the exploration geologist’s role is mindless acquisition of mass data as feed for computer programs. Given sufficiently large data sets (the organisers of such programs reason) the might of the micro-chip is all that is required to find an orebody.

Speak to exploration geologists and you will find two opposing views about how to observe outcrop or drill core.  Some seek merely to be unbiased objective recorders of what they see.  Others observe the rock in the wider context of their theories about region or prospect geology and ask questions of the exposure to help choose between these theories.

I characterize these two approaches with the metaphors of geologist-as-camera, and geologist-as-interrogator.

The Geologist as camera

I arrive at the exploration site to find a team of three young geologists engaged in making a geological map of their large exploration acreage. Using GPS, they walk predetermined traverses spaced 2-400m apart. Each aim to average 8km a day and between them, by taking alternate lines, they cover a large swathe of country before their next field break. Observations on each geological feature along the line of march are logged into a field-hardened tablet computers by going through a series of pull-down menus and checking boxes on pre-determined questions. The geologists have only the vaguest ideas about the geology of the property they are mapping. Two of them have never thought much about this: the brightest of the three specifically rejects the notion of understanding her observations: she sees herself as an unprejudiced objective observer: confirmation bias is not for her. Eventually all this data is computer-plotted to 2D images as linear sequences of point observation.  Another more senior geologist might eventually produce a 2D geological map by joining the dots. Probably there is a software program that can do much of this task for him (or her) and thus obviate the need for too much thought or hard work.

I travel to an exploration site on the other side of the country. Here, a much larger company have been drill testing a substantial metal deposit for several years. Four diamond rigs are going 24/7 and have drilled well over 300 holes. Stacked on pallets, several kilometers of core are waiting to be logged. Four geologists are hard at work logging core laid out in the open on long racks. It seldom happens that any one hole is logged in its entirety by the same person. Logging is done on to spread sheets in laptop computers using alpha-numeric codes on pre-determined menu options. There are more than 50 columns on their spreadsheet and the same digital form has been used since hole one. The geologists have never seen a drill section of the prospect (there are none). There are no detailed maps or level plans either. The geological model, such as it is, was produced a year before by an outside consultant who spent ten days on site. Back in the head office, a specialist Ore Reserve Geologist ignores 95% of the vast data base and calculates a resource based on assay numbers, virtual reality 3D string models and geostatistics. For the young geologists at point, labouring in the core yard, their job is 100-meter-a-day, core-logging automata is mind-numbingly boring. They count the days till their next field break, or until they have earned enough money to be able to resign and find some other more intellectually stimulating employment. Taxi driving, anyone?

After a long day core logging, Susan contemplates a career change.

These are anonymized projects, extreme examples perhaps, but based on observations of many actual projects, with many companies in many different countries over many years. Not all exploration projects are conducted like this of course, but I am sure readers will recognize the method of doing geology that I describe.

The geologists themselves are not to blame. In many cases it is their first job, they are on short-term contracts, and they are doing what their employer asks and expects of them. They probably wonder what the point was of much of the time they spent learning geological theory and critical thinking at university and have come to believe that the essence of their job as exploration geologists is to convert light signals from their eyes into digital computer feed according to pre-set formulae. A kind of biological digital camera.  Without a pre-existing context in their brain, each observation they make has equal importance, each pixel equal weight.

There is a better way.

The geologist as interrogator

All observation is made in a particular context. The context which should guide the exploration geologist is a matrix of different competing theories about the true nature of the geology being observed. This context provides the questions that must be asked of each outcrop or each piece of drill core. It defines the strategy to be followed in the search for those critical observations that allow selection between multiple working hypotheses. The idea of multiple working hypotheses was first propounded by 19th Century USGS geologist Thomas Crowther Chamberlin ⁽¹⁾. It is a methodology now used in all fields of science research ⁽²⁾, but geologists can be proud that the first clear statement and naming of this procedure came from their own profession.

Critical observations are those that fit into a pre-existing context or, just as importantly, those that do not. These are prioritized and not lost in a sea of trivial observation.

The method does not guarantee that you will arrive at the correct solution. Your evidence may be less than ideal, the expression in the rocks of geological events may be atypical.  Nature can be chaotic and unpredictable: the true hypothesis you should be testing may be the one that you – or perhaps no one else – have/has yet thought of. In all science, and especially geological science, neat, clean results where all observations slot in exactly to a model are rare and, when this happens, should be regarded with some skepticism. But despite all that, the method of multiple working hypotheses is still the best-known procedure for navigating apparent (or real) chaos and approaching the truth.

After a morning of fieldwork, Robert interrogates his lunchtime sandwich using the method of Multiple Working Hypotheses.

All geologists have biases. These were imprinted through university training and reinforced by early-career mentoring and reading geological literature relevant to the job.  Collecting data to choose between these hypotheses or to help formulate new ones is biased observation. But this bias is a good thing where it is up-front, acknowledged and constantly revised and re-focused in the face of evidence. Without bias, there is no way of separating signal from noise. This is a totally different kind of bias from the one that uncritically accepts only evidence that confirms a single pre-existing theory – one you might have fallen in love with – and ignores, or explains away, evidence which does not. That is Confirmation Bias, rightly condemned.

All scientists have a point of view. All views must have come from somewhere. Anyone who claims to make unbiased observation merely lacks self-awareness. Their biases are unconscious or lie in the biases of whoever drew up the detailed procedure manual which they follow.

The metaphor I use for this approach is the geologist as an interrogator of each rock exposure or core piece, asking a series of relevant questions that come from a range of competing views his as to what might be happening, with each question determined by the answer to the previous question.

Interrogating drill core.

The Scientific Method

The true nature of scientific investigation is focused observation guided by emergent theory. This is a long established and respectable idea and contrasts with seeking to find your theory in your data after you have completed your observations.

Collecting data should not be a fishing expedition that hopes to fortuitously hook new understanding or ideas on its line.  Its purpose should be to provide evidence to choose between a wide range of pre-existing hypotheses.  It therefore follows that the hypotheses must come first.

Seeking your hypothesis in your results is an acknowledged error in many scientific disciplines. So much so that it been given its own acronym – HARKing (Hypothesizing After Results are Known ⁽³⁾). In statistics-based research the same error is known as p-hacking ⁽⁴⁾.  Both techniques have been, and undoubtedly still are, widely used in science ⁽⁵⁾.

The parable of the Texas Sharpshooter provides a dramatic example of the HARKing method at work. As the cited Nature article ⁽⁵⁾ explains:

The Texan directs multiple shots at a barn door. He then selects the closest grouping of the random impacts and draws a target around them. A carefully cropped photograph is then used to establish his sharpshooting credentials.

The Texas Sharpshooter

The idea that theories should precede observation is the exact opposite of what is popularly believed, including by many scientists. Sherlock Holmes, for example, is usually quoted approvingly:

It is a capital mistake to theorize before one has data.

But Sherlock’s patronizing throw-away line to Watson could not be more wrong. Contrast it with these quotes from real scientists – as opposed to a fictional one.

In Biology:

How odd it is that anyone should not see that all observations must be for or against some view if it is to be of any service.  Charles Darwin, letter to Henry Fawcett September 1861.

In Physics:

We never draw inferences from observations alone, but observations can become significant when they reveal deficiencies in some of the contending explanations. David Deutsch, The Fabric of Reality, 1998.

“If (your hypothesis) disagrees with experiment, it’s wrong. And that simple statement is the key to science. Richard Feynman, 1964

In the Philosophy of Science:

Half of Science is asking the right questions. Roger Bacon (1219-1292).

The facts that we measure or perceive never just speak for themselves but must be interpreted through the colored lens of ideas…. We can no more separate our theories and concepts from our data than we can find a true Archimedean viewpoint – a God’s eye view – of ourselves and the world. Michael Schermer, Scientific American, 2007

In Medical Research:

…you cannot find your hypothesis in your results. Before you go to your data…you have to have a specific hypothesis to check. If your hypothesis comes from analyzing your data, then there is no sense in analyzing the same data again to confirm it.  Ben Goldacre, Bad Medicine, 2008.

In Psychology:

I am more and more convinced that the only way to obtain clear answers from Nature is to ask her clear questions. Eric-Jan Wagenmakers, Professor of Neuro-Cognitive Modelling, University of Amsterdam, 2014.

 Final words

But despite this, it is my observation that the geologist-as-camera view is becoming increasingly common in exploration geology.  This slows down the acquisition of knowledge and can be disastrous for understanding.

One should always remember the quatrain:

Data is not information

Information is not knowledge

Knowledge is not understanding

Understanding is not wisdom ⁽⁷⁾

Without geological understanding, drill holes can be put in the wrong place, or ten are drilled where one would have sufficed. Without good geological models that reflect reality, the certainty required to convert an Ore Resource into a bankable Proven Reserve cannot be easily or cheaply achieved.

No one – beyond its most starry-eyed proponents – believe that AI will one day be able to fill in all the steps that lie between data and wisdom.

I cannot resist a final quote, this one from Albert Einstein:

Knowledge is knowing it’s a one-way street. Wisdom is looking both ways when you cross.

 ******

This is an updated and amended version of a previous post entitled The Camera and the Interrogator

(1) Revisiting Chamberlin: Multiple Working Hypotheses for the 21st Century. LP Elliot & BW Brook. BioScience 57 (7), 608-614  https://doi.org/10/10.1641/B570708

(2) The method of multiple working hypotheses. Thomas Crowther Chamberlin 1890 Science 15 92-96 (reprinted in Science 148, 754-759, 1965). https://doi:10.1126/science.ns-15.366.92

(3) HARKing - an acronym for Hypothesizing After Results are Known.  

(4) p-hacking - carrying out multiple sets of analysis on massive multivariate data sets until the one analysis is found that has “statistical significance” (i.e., p ≥ 0.05, meaning: 5 or fewer chances in a hundred that the result – or indeed any publishable result – was generated by pure chance. The “negative” or “null” analyses go to the filing cabinet or trash can): the “positive” result is published. This leads to what is known publication bias – see footnotes 5 and 6.

 (5) How scientists fool themselves – and how they can stop. 2015 paper by Regina Nuzzo. Nature 526,182-185; https://doi.org/10.1038/52618a

(6) The cumulative effect of reporting and citation biases. 2018 by Y.A. De Vries (and five co-authors). Psychological Medicine 48, 2453-2455  https://doi.org/10.1017/S0033291718001873

(7) These oft-quoted lines, which are usually attributed to American physicist Clifford Stoll or rock poet Frank Zappa, almost certainly were inspired by the 1934 T S Elliot poem, The Rock:

Where is the wisdom we have lost in knowledge?

 Where is the knowledge we have lost in information?

The post The Scientific Method and the Practice of Mineral Exploration appeared first on Roger Marjoribanks.

In 1997, the mining world was rocked by the dramatic exposure of a $6 billion gold salting scandal. From 1994, a crew of corrupt Filipino geologists, working in a remote jungle location in eastern Borneo for a small Canadian mining company called Bre-X, had undertaken industrial-scale salting of a gold prospect called Busang. This was at such a scale, and continued over such a time, as to convince hardheaded global mining companies as well as Mum and Dad Canadian investors that Bre-X had discovered the largest gold mine in the world. Some analysts, working from Bre-X stock exchange reports, estimated well over 200 t of economically recoverable gold.  The resulting 3-year frenzy of greed caused the penny stock Bre-X soar to over $285, valuing the company at over $6 billion. It also exposed corruption at the highest level in Indonesia and lack of oversight by regulators in Canada. When qualified external assessors finally got access to the remote location the fraudsters knew the game was up. Bre-X Chief Geologist Michael De Guzman, on his way back to site to face the music, fell (or did he jump, or was he pushed, or was he even there?) from a helicopter. His body (or at any rate, someone’s body) was recovered on the jungle floor four days later, partially eaten by pigs. The corpse was identified by one of his colleagues from the Busang site before he, and the remaining Filipino members of the crew, flew back to the anonymity of Manila.

Apart from De Guzman, no one was ever named, and no one convicted of crime either in Indonesia or Canada. The Bre-X stock price collapsed overnight, and the company quickly went into receivership. David Walsh, the President and Chief Executive of Bre-X, and his Vice-President of Exploration John Felderhof, retreated to their respective villas on the Cayman Islands.

The whole story revolves around the actions of De Guzman. Bizarrely, although the podcast describes in gruesome detail what De Guzman’s (supposed) corpse (what was left of it) looked like, none of the interviewees describe the living man in any detail, and none give his background or evaluate his character. He remains a shadowy figure. What the witnesses give is a cardboard villain, a toothless, bespectacled, gold-bedecked conman drinking and whoring his way through the fleshpots of Jakarta, Samarinda and Toronto. But De Guzman must have had some impressive qualities to fool so many for so long.

I listened to the podcast in one marathon session and thought it brilliant. The depth of research by the team of journalists working for the BBC and CBC, and their ability, after a 25-year gap, to ferret out and interview key witnesses, was impressive. I have no doubt that this podcast will become the definitive account of the Bre-X scandal. New revelations are unlikely, but who knows? There is still time for an aged de Guzman to reappear from the shadows and tell his side of the tale.

There are numerous unresolved questions, but three major ones stand out:

1. The involvement of Indonesian President Suharto’s family and close associates in the bidding war to gain control of the promised riches of the Busang mine and the actions they may have taken when the extent of the fraud first became apparent.

2. The true involvement of the pilot, the only person in the helicopter besides De Guzman at the time of the incident. He was/is an Indonesian Army Airforce officer and provided the only account of the incident, then was made unavailable for further comment by Government authorities. And what was in the large “box” that witnesses saw being loaded into his Squirrel helicopter at Samarinda airport in Kalimantan immediately prior to the fatal flight? And what credence should we give to the unconfirmed report that a corpse from the Samarinda morgue mysteriously went missing at around that time?

3.  The extent to which David Walsh and John Felderhof were involved in the fraud. Walsh, the President of Bre-X, was an entrepreneur with little previous mining background who would have relied on his Vice President of Exploration, Dutch Canadian geologist Felderhof, for all technical advice.  At the height of the Bre-X boom both Walsh and Felderhof made tens of millions of dollars selling Bre-X stock. After the scandal broke, Felderhof was charged with insider trading by the Toronto Stock Exchange. He pleaded that he was just another innocent, albeit naive, dupe of the fraudsters and, after more than ten years in litigation, was acquitted of the charge. Both Walsh and Felderhof are now dead.

As a geologist, I did much work in Indonesia throughout the 1990’s and have a personal view on many of these matters (see HERE). In my opinion, Felderhof (whom I met and worked with in the field) was a good geologist who, at a critical juncture, allowed desire for fame and riches to overwhelm his professional judgement.

Contract Filipino geologists were much favored for field work throughout SE Asia at that time. All those I worked with were honest, dependable and great companions in the field. They could blend with the local population, were acclimatized to tropical conditions, technically competent and hardworking. But from the point of view of Western mining companies they were, above all, cheap. They were in fact being exploited, and they knew it.

With hindsight, I think it foolish of Bre-X to have offered their site crew extra remuneration in the way of stock options. This was meant to buy loyalty, but once the low-paid field geologists realised that adding $10 worth of locally purchased alluvial gold to a single drill sample could add $100,000 to their potential net worth, the temptation to do just that must have been great. By succumbing, they unwittingly stepped onto an ever faster moving treadmill that could only result in dramatic consequences for all when it finally stopped. It was a classic Ponzi scheme.

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A moment of fierce joy

In a near 60-year career this experience has only happened to me three times. Two of these discovery outcrops eventually led to operating mines, the third, after years of exploration and drill testing, failed to make the cut (I still think it will be a mine someday, so I will say no more on that one)).  I take only modest credit for these discoveries. I was first on the ground and got the naming rights for the prospect and subsequent mines, but was part of a team, and a large element of luck was involved. All this happened 30-50 years ago when not all the low-hanging fruit had been plucked. Prospecting discovery of significant outcropping mineralisation  happens increasingly less these days. Maybe in a remote and under-prospected third world country? If there are any such left in this globalised world.

The Greenfields (1) gold deposit near Coolgardie in Western Australia, which I identified in the course of 1:5000 scale geological mapping, was named for the field below which it lay – full of Spring grass and wildflowers and big eucalypt trees when I first came upon it in 1984. I hoped that the name would preserve the memory of this pleasant little valley long after the bulldozers had moved in. Greenfields open cut mine is long exhausted, but the Greenfields Mill still operates today as a Toll facility for other gold mines in the district.

The Magellan Pb deposit near Wiluna in Western Australia was an entirely serendipitous discovery of high-grade (2) outcropping mineralisation which I made in in 1991 in the course of checking old gold claims in nearby rocks. That day was the first time that I had used a GPS unit in the field. This was a hand-held instrument made by a company called Magellan and the size and weight of a house brick, but a revelation and a boon. I thought it a cool name so gave it to my discovery. Magellan was the first discovery in a new and unique lead province. Later prospects in the area followed the same theme and named for 15th Century Spanish and Portuguese explorers. The Magellan lead mine is still in operation today although environmental restrictions have severely restricted its operations.

Discovery of outcropping mineralisation is invariably followed by collecting rock samples for assay.  The different types of rock chip sampling and how to collect them are detailed in an earlier blog post here.

 (1) The name I gave was actually Greenfield, but the company later added the final “s”, probably because they wanted investors to think they had more than one.

 (2) The first suite of rock chip samples from Magellan, collected from over 5km of strike, came back 5%-35% Pb. Near pure cerussite.

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Scientific knowledge is a body of statements of varying degrees of uncertainty – some most unsure, some nearly sure, none absolutely certain.” – Richard Feynman, Theoretical Physicist and Nobel Laureate.

 “The unknown is the dark matter of all things, the greater part of the universe.” Geoffrey Weiss, 2021

Fact and Truth

At the most fundamental level, the idea of a fact, and the related but more morally portentous concept of truth, are ideal philosophical concepts that we seek but can never be certain to have achieved.

In one of his Dialogues (The Republic, Book VII) the 5th century BC Greek philosopher Plato compares the physical world that we see and measure to shadows on the wall of a cave made by something “out there”, beyond our direct vision. In this allegory, the cave is our skull, imprisoning our brain: the “something out there” is an external reality of fact and truth. We are condemned to remain forever in our cave, observing, and analyzing the shadows on the wall and speculating as to what they might mean.

“Fact” and “truth” are loaded words all too often used as a means of asserting authority and pre-empting debate. When you say, “this is a fact” or “the reality is” or “the truth of the matter is”, you are saying in effect, “you may not dispute this”. They are polite ways of saying that those who disagree with you are deniers, heretics, contrarians, ignoramuses or just plain stupid.

Recall, from your own experience, how often in debate these phrases are used to introduce a controversial statement that the speaker knows you might well not accept and wants to ring-fence in advance against your anticipated scepticism. Phrases such as “in fact…” or “the truth is…” are rhetorical figures of speech that we all use in conversation as a means of emphasizing the strength of our belief.  Nothing wrong with that, they are useful for casual conversations. In fact, and in that context, I use them too, but you are entitled to respond: “that’s not a fact, it’s just your opinion” – or – “where’s your evidence?”.

Quoting “fact” and “truth” are always to weaponize these words in pursuit of an agenda: to persuade, to win an argument, to convince a doubter, to change an opinion. Evidence for this abounds in all fields of communication: the words “fact” and “truth” are stock phrases used in advertisements to convince you to buy a product; they populate the language of journalists and of politicians [1] trying to convince their readers or influence their electorate.

 Claims of absolute fact and enduring truth properly belong to the realms of faith and belief. Scientific Knowledge is not based on faith or belief but on physical evidence and deductive reasoning: its conclusions are always provisional and subject to the next observation, of which the best we can ever say is that the new data has failed to falsify the original observation or idea. Failure to falsify gives you the confidence to think that you might be on the right track, but it does not constitute proof. At any rate, that is the ideal and is the process which has underpinned the advance of scientific knowledge, created its successes and given it authority to speak on the natural world. Evidence (and its digital version, data) is not the same as fact, though the two ideas are often conflated. “Alternative evidence” is a valid subject for discourse and argument, but “alternative fact” is an oxymoron (2).

There is only ever one way that an observation or an idea can be true, but there is a very large number of ways in which they can be false, including the multiple ways that neither you nor anyone else has yet thought of. All else being equal, the more ways that an observation or a theory can be false, (and you have no idea how many ways there are) the more the likelihood is that it will be false. Black Swan Events happen all the time.

Old Legal joke)

I Digress here to the Law

Or, more specifically, to Criminal Jurisprudence. This subject provides a good way of illustrating the difference between fact and evidence, truth, and opinion.  Lawyers prosecuting or defending a person accused of crime get equal time to present evidence – which is often conflicting – to an experienced judge or a randomly-selected 12-person Jury of their peers. It is then the job of the Judge or the Jury, having heard all the evidence and all the arguments, to determine “fact” by giving a guilty-not guilty verdict. Unless and until a guilty verdict is given, the null position (i.e. that the accused is innocent) is held to be true. But the legal definition of “fact” and “truth” to which the Jurors must adhere is limited and qualified.  It is an opinion with which all 12 Jurors must agree and which they consider to be “beyond all reasonable doubt”, with the implied assumption that what is “reasonable” is available to all. And yet, despite this laborious, time-consuming and expensive process – the best that centuries of jurisprudence have yet devised – criminal courts often get it wrong (3).

Juries and Judges are human beings and not always rational or reasonable. They are subject to error, misunderstanding, ignorance, emotion, group think, peer pressure, societal prejudice, fashionable opinion, deference to authority and uncritical acceptance of expert opinion. And that list applies to journalists, politicians and scientists too.

“..one has to remember that the probable need not necessarily be the truth and the truth not always probable.” – Sigmund Freud

Returning to Science

At least the Lawyers have a definition, albeit limited and subjective, for what they mean by “fact” and “truth”.  Many scientists, on the other hand, use these words to mean, like Humpty Dumpty in Alice in Wonderland, whatever they want them to mean.

The famous bio-statistician Sir Ronald Fisher (1890-1962) gave his definition of scientific fact in 1926, when he wrote (in that well-known publication, the Journal of the Ministry of Agriculture of Great Britain, 33, p 504):

 “A scientific fact should be regarded as experimentally established only if a properly designed experiment rarely fails to give this level of significance..”

By “this level of significance”, Sir Ronald meant that the probability (known as p) that pure random noise in your data would yield your result is 0.05 or less (written p ≤ 0.05: meaning five or fewer chances in a hundred). If such a number can be calculated then, according to Fisher, a p≤0.05 enables you to call your result “statistically significant” and thus “a scientific fact”.  But if p=0.05 is considered significant, what then do we call a p=0.06?  And if we conclude (as we must) that number is also significant, what then of p=0.07 ? And so on. In other words, what is the logic of imposing an arbitrary cut-off in a continuum of potential results? This is not science, but simply a way of putting an illusion of quantitative rigor on fuzzy qualitative numbers. In fairness to Sir Ronald, he may have had in mind to define a “scientific fact”, in the manner of the Lawyers, as an inferior and qualified version of an actual fact. If that was his purpose, it was an insult to both Science and the English language.

By many accounts (4), for almost the last 100 years, researchers in statistic or mostly statistic-based sciences like Social Science, Political Science, Environmental Science, Climate Science, Medical Science – (5) – Psychology and Economics had to make sure they met Fisher’s arbitrary “wee pee” criterion if they wanted their work to be published in scientific journals (and negative results failing to make the cut left languishing in dusty file or trash can). But in recent years there has been a strong pushback against this misuse of statistics (6). I doubt that many scientists today would consider statistical significance to be synonymous with fact.  However, most would consider a 95% or better chance that their research was on the right track to be the basis for a good working hypothesis, although they would never bet their lives on it.

None of the above is to dispute that an observation (evidence) can be so well established by universal experience that for all practical, everyday purposes it can be called a “fact” that few rational people would dispute without being dismissed as a nut case or, at best, a boring pedant (maybe you have already fitted me with one of these hats?). That the sun rises in the east or that the earth is round are all, by this definition, statements of fact (7). In my own profession, when a geologist produces a large-scale outcrop map and calls it a “fact map”, or refers to his field observations “ground truth”, I do not think we have to accept that his or her lines on a piece of paper can be described, even on this colloquial definition, with the same level of certainty (see my earlier Post on this subject: Is there such a thing as a geological fact map?).

Qualifications and Caveats

You may think from the above that I have strayed into the area of post-modern philosophy called Relativism (not be confused with Relativity). Relativism denies that there is any objective truth out there: the shadows on the walls of our caves are illusions. From this idea follows that all systems of knowledge are social constructs, and all such constructs, from Astronomy to Astrology, Dark Matter to the Dreamtime, Quantum Mechanics to Queer Theory, Relativity to Relativism, String Theory to Shamanism, have equal validity and truth (or lack thereof). The concept was widely disseminated in the late 20th century through, among others, by the works of French philosopher Jacques Derrida and his well-known phrase: “There is nothing out of context” or, in another translation: “There is nothing but words” (8).

That is not my opinion. That is the not the point I wish to make. The moon in the sky and the tree in the forest exist, even when no one is looking.

The Takeaway Message from my Essay is… 

In their professional communications, Scientists should never use the words “fact” and “truth” and accept that their observations and theories are always subject to scrutiny, qualification, replication, skepticism and, potentially, retraction.

The purpose of scientific endeavor is to seek Truth, not proclaim it.

*****

 Footnotes 

(1) There are two good contemporary examples of the misuse of the concepts of Truth and Fact in popular media. The 2006 disaster movie “An inconvenient Truth” by Al Gore (a failed politician) and the 2019 BBC TV documentary “Climate Change: The Facts” by Sir David Attenborough (a TV journalist).  Their technique was highly effective. Al Gore got a share of the 2007 Nobel Peace Prize for his efforts: Sir David got his second Knighthood (in 2022) for his.

(2) When Donald Trump’s campaign manager Kellyanne Conway used the phrase “alternative fact” in a 2017 interview she was widely ridiculed. “Alternative facts are not facts” spluttered her interviewer “They’re falsehoods”. And he was right. Kellyanne would have avoided the ridicule and subsequent pile-on, and been better able to argue her case, if she had used the word “evidence” rather than “fact”.

(3)  As of 2023, in the USA alone, over 3200 convicted persons have been exonerated over the past 40 years as a result of the application of new forensic technologies, or through the debunking of previously accepted technologies. The number of innocent people still in jail must be far larger than those already exonerated (source:  www.innocenseproject.org). For other egregious examples of miscarriages of Justice, Google the four women in the list below. In separate cases, in three different countries, these women were convicted of multiple infanticides and jailed on the testimony of scientists whose confident “expert” opinions were later proven to be false.

Lindy Chamberlin (convicted in Darwin 1982, pardoned 1988, exonerated 1989, compensated 1992);

Sally Clark (convicted London 1999, freed on appeal 2003, committed suicide 2007);

Lucia de Berk (convicted at the Hague 2003, freed on appeal 2010); 

Kathleen Folbigg,  Sydney 2003 sentenced to 40 years jail, pardoned and exonerated 2023, compensated 2026).  

(4) See, Stuart Ritchie 2020: “Science Fictions: exposing fraud, bias, negligence and hype in science”. Penguin-Random House 353p.  

(5) “…never trust a science with an adjective in front of it..” – anonymous internet blogger, 2019

(6) Valentin Amrheim et al., 2019: “Scientists rise up against statistical significance”. Nature 567, No 7748, pp305-307 https://doi.org/10.1038/d41586-019-00857-9 and: John Ioannidis, 2005; “Why most published research findings are false”. PLoS Medicine.  https://doi:10.1371/journal.pmed.0020124 This is one of the most downloaded papers in the 20-year history of PLoS (Public Library of Science)

(7) The sun does not “rise”, this is an optical illusion: it is the earth that moves. (“Eppure si muove” – yet it moves – Galileo muttered as the Inquisition led him away). But the illusion fooled the best brains of humankind for countless millennia and is still built into the structure of our language. And the earth is not round: this is a convenient simplification, good enough for everyday discourse. Our planet is actually an asymmetric oblate spheroid – and a slightly lumpen one at that. 

(8)  What Jacques Derida actually wrote was: “Il n’y a pas de hors-texte”.  

 *****

 This post incorporates some material from earlier post entitled Is there such a thing as a geological fact map? Roger Marjoribanks. First posted December 2022. Updated 2023 & 2026

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Speak to exploration geologists and you will find two opposing views about what a geologist should do when observing outcrop or drill core in the field.  Some seek merely to be unbiased objective recorders of what they see.  Others observe the rock in the wider context of their theories about region or prospect geology and ask questions of the exposure to help choose between them. I characterize these two approaches with the metaphors of  geologist-as-camera, and geologist-as-interrogator.

Geologist as camera – 1

I arrive at the exploration site to find a team of three young geologists engaged in making a geological map of their large property. Using GPS, they walk predetermined traverses spaced 400m apart. They each aim to average 8km in a day and, between them, by taking alternate lines, they cover a large swathe of country before their next field break. Observations on each geological feature along the line of march are logged into a field-hardened tablet computers by going through a series of pull-down menus and checking boxes on pre-determined questions. The geologists have only the vaguest ideas about the geology of the property they are mapping. Two of them have never thought much about this: the brightest of the three specifically rejects the notion of understanding her observations: she sees herself as an unprejudiced, objective observer – confirmation bias is not for her. Eventually all this data is computer-plotted to 2D images as a linear sequences of point observation.  Another, more senior geologist, might eventually produce a geological map by joining the dots. Probably there is a software program that can do much of this task for him (or her) and thus obviate the need for too much thought or hard work.

Geologist as Camera – 2

I travel to an exploration site on the other side of the country. Here, a much larger company is at the final stage of drill testing a substantial metal deposit. Four diamond drill rigs are going 24/7 and have reached hole number 300 and something. Stacked on pallets, kilometers of core are waiting to be logged. Four geologists are hard at work logging core laid out on long racks in a big shed. As geologists come and go on field break, or come and go through resignations and new hires, it seldom happens that any one hole is logged in its entirety by the same person. They log on to analytical spread sheets in laptop computers using pre-determined menu options – there are more than 50 columns on their spreadsheet. The same log form has been used since DDH 001. The geologists have never seen a drill section of the prospect (there are none). There are no detailed maps or level plans either. The geological model, such as it is, was produced a year before by an outside consultant who spent ten days on site. Back in the head office a specialist Ore Reserve Geologist ignores most of the vast data base of geological observations and calculates a resource based on assay numbers, virtual reality 3D string models and geostatistical techniques. For the geologists at point, slaving in the core yard, their job as 100-meter-a-day, core-logging automata is mind-numbingly boring. They count the days till their next field break, or until they have earned enough money to find some other more intellectually stimulating employment.

After a day data logging, Susan contemplates a career change. Picture by author.

These are anonymized projects, extreme examples perhaps, but based on my observations of many actual projects, with many companies in different countries over many years. Not all exploration projects are conducted like this, but I am sure that readers will recognize the method of doing geology that I describe. The geologists are not to blame. In many cases it is their first job, they are on short-term contracts, and they are doing what their employer asks and expects of them. They probably wonder what the point was of much of the time they spent learning at university and have come to believe that the essence of their job as exploration geologists is to convert light signals from their eyes into digital computer feed according to pre-set formulae. A kind of biological digital camera.  Without a pre-existing context in their brain, each observation they make has equal importance, each pixel equal weight.

There is a better way.

The geologist as interrogator

All observation is made in a particular context. The context which should guide the exploration geologist is a matrix of different competing theories about the true nature of the geology being observed. This context provides the questions that must be asked of each outcrop or each piece of drill core. It defines the strategy to be followed in the search for those critical observations that allow selection between multiple working hypotheses (1), (2). The idea of multiple working hypotheses was first propounded by 19th Century US Geological Survey geologist Thomas Crowther Chamberlin. It is a methodology now used in all fields of science research, but geologists can be proud that the first clear statement of the idea came from their profession.

Critical observations are those that fit into a pre-existing context or, just as importantly, those that do not. These are prioritized and not lost in a sea of trivial observation. The method does not guarantee the you will arrive at the correct solution. Your evidence may be less than ideal, the expression in the rocks of geological events may be atypical.  Nature can be chaotic and unpredictable: the true hypothesis you should be testing  may be a Black Swan – the one you have never thought of. In Geology – indeed in all science – neat, clean results where all the data slots in exactly are rare and should be always regarded with some skepticism. But in spite of all that, the method of multiple working hypotheses is the best known procedure for approaching the truth.

After a morning of fieldwork, Robert interrogates his lunchtime sandwich using the method of multiple working hypotheses. Picture by author.

Collecting data to test hypotheses in this way is biased observation. All geologists have cognitive biases which were imprinted when they were taught to be geologists at University, and reinforced by early-career mentoring and  reading geological literature relevant to the job.  But this bias is a good thing where it is up-front, acknowledged and constantly revised and re-focused in the face of evidence. Without bias, there is no way of separating signal from noise – not even by the most sophisticated of statistical procedures. This is a quite different kind of bias from the one that uncritically accepts evidence that confirms a single pre-existing theory, or a theory you have fallen in love with,  and ignores, or explains away, evidence which does not. That is Confirmation Bias and is rightly condemned.

All scientists have a point of view and all views must have come from somewhere. Anyone who claims to make unbiased observations merely lacks self-awareness. Their biases are unconscious or lie in the biases of whoever drew up the detailed procedure manual which they follow.

The metaphor I use for this approach is the geologist as an interrogator of each rock exposure or core piece, asking a series of relevant questions that come from his or her views as to what might be happening, with each question determined by the answer to the previous question.

RM ’14

In a previous post I explore how using the technique of multiple working hypotheses can be used when constructing a geological map (LINK)

The wider context

The true nature of scientific investigation is focused observation guided by emergent theory. This is a long established and respectable idea and contrasts with seeking to find your theory in your data after you have completed your observations.

Collecting data should not be a fishing expedition that hopes to fortuitously entangle a new understanding or ideas on its line.  Its purpose should be to provide evidence to choose between a range of pre-existing hypotheses.  It therefore follows that the hypotheses must come first.

Seeking your hypothesis in your results is such a widespread and acknowledged error in many scientific disciplines that it has been given its own acronym - HARKing[3] (Hypothesizing After Results are Known). In statistics-based research the same error is known as p-hacking [4].  Both techniques have been, and undoubtedly still are, widely used in so called science [6].

The parable of the Texas Sharpshooter provides a good example of the HARKing technique at work [5] (6):

“The Texan directs sixty shots at a barn door. He then selects the best grouping of the random impacts and draws a target around them. A carefully cropped photograph is then used to establish his sharpshooting credentials.”

The Texas Sharpshooter – Picture by author. 

This idea that theories should precede observation is the exact opposite of what is popularly believed. Sherlock Holmes, for example, is often quoted approvingly:

“It is a capital mistake to theorize before one has data”.

But Sherlock’s patronizing throw-away line to Watson could not be more wrong. Contrast it with these quotes from real scientists – as opposed to a fictional one.

In Biology:

“How odd it is that anyone should not see that all observations must be for or against some view if it is to be of any service.”  Charles Darwin.

In Fundamental Physics:

“We never draw inferences from observations alone, but observations can become significant when they reveal deficiencies in some of the contending explanations.” David Deutsch, The Fabric of Reality, 1998.

In the Philosophy of Science:

“The facts that we measure or perceive never just speak for themselves but must be interpreted through the coloured lens of ideas…. We can no more separate our theories and concepts from our data than we can find a true Archimedean viewpoint – a God’s eye view – of ourselves and the world”. Michael Schermer, Scientific American, 2007

In Medical Research:

“…you cannot find your hypothesis in your results. Before you go to your data…you have to have a specific hypothesis to check. If your hypothesis comes from analysing your data, then there is no sense in analysing the same data again to confirm it.”  Ben Goldacre, Bad Medicine, 2008.

In Psychology

“I am more and more convinced that the only way to obtain clear answers from Nature is to ask her clear questions.” Eric-Jan Wagenmakers, Professor of Neuro-Cognitive Modelling, University of Amsterdam, 2014. 

 Final words

But in spite of this, it is my observation that the geologist-as-camera view is becoming increasingly common in our profession.  This slows down the acquisition of geological knowledge and can be disastrous for understanding.

Data is not information

Information is not knowledge

Knowledge is not understanding

Understanding is not wisdom (8)

Without geological understanding, drill holes are put in the wrong place, or ten are drilled where one would have sufficed. Without good geological models that reflect reality, the certainty required to convert an Ore Resource into a bankable Proven Reserve cannot be easily or cheaply achieved.

This is a modified and updated version of an essay first posted in 2014

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Diamond drilling is always undertaken for the needs of the moment. But fresh-cut rock, in most cases, will last hundreds, if not thousands, of years. Drill core is a resource which can keep on giving as we go back to it again and again with fresh ideas, questions, techniques or agendas. This could be by you or your company, or by other geologists and other companies as the years go by. However, core can only provide this continuing value if indexing and storage systems match the longevity of the core itself.

Roy Woodall, former Exploration Director for Western Mining Corporation said in 1995: “We have re-logged the core from Kambalda (West Australian Ni/Au Camp) three times, and each time we do it, we find a new ore body”. 

Drill core is an expensive product providing direct physical sample of the subsurface and will always be an invaluable and irreplaceable resource. As a condition of granting a Mining Lease or Licence to Explore the State should should specify strict enforceable requirements for permanent indexing and storage of core. That core will have cost between $100 – $500 per metre to acquire, so it is not too much to ask that a company spend around $1-$5 per metre extra to properly index and store their product. That company or that geologist might one day themselves be the beneficiaries of similar forethought.

You could be one of them.

I certainly was.

In the mid-1970s, as part of a structural re-assessment of the giant Broken Hill  Pb/Zn/Ag mining camp in New South Wales, I had to re-log a number of holes that had been drilled in the 1920s and 1930s. This core was the product of one of the first major diamond drilling campaigns be undertaken in Australia. It was stored in the long-abandoned Consolidated Zinc core yard – an acre of ground on the line-of-lode, sandwiched between old head frames, abandoned machinery and infrastructure, mullock and tailings heaps.  The core had been stored in wooden trays laid out in long lines on the ground. Tens of kilometres of core carpeting the entire yard. At the head of each core run a steel stake had been driven into the ground with the  hole ID traced on it with solder. Even more importantly, the drillers’ original wooden depth markers had been replaced by small rectangular zinc tags on each of which the hole number and down-hole depth had been stamped by a steel punch.

…in the sea of sand the steel stakes still stood proud…

During a heavy downpour in the 1940s, a nearby fines dump had collapsed and tailings had flowed outwards to cover the yard in fine white sand to depths of up to 50 cm. But in the sea of sand the steel stakes still stood proud, and although not a trace of the original wooden trays remained, with some excavation (you could call it industrial archaeology: the Mining company provided the labour) the core was soon exposed in its original neat parallel rows, as fresh and easy-to-be examined as it had been fifty years before. I mentally thanked the foresight of the long-forgotten project geologist, and remembered the first occasion, seven years before, when I had been given the task of re-logging legacy core.

Rum Jungle, 1967.  A mine operated by a subsidiary of Rio Tinto in Australia’s Northern Territory. They were engaged in mining and processing uranium and copper ores from a series of open cuts in the surrounding district . Re-logging old drill core was deemed a suitable task for a rookie geologist. The core had been drilled 5 to 6 years previously and stored in wooden trays stacked over 10 high at the back of an old shed behind the mill. Around 3 kilometres of it. When I pulled back the doors of the shed to let the light in, I found a slope-sided mountain of broken and disorganized core pieces out of which a few bits of rotten, termite-gnawed wood still projected.  We organised a front-end loader and quickly transferred the lot to the nearest mullock heap.

…a slope-sided mountain of broken and disoriented core pieces out of which a few bits of rotten, termite-gnawed wood projected…

A few years later, during the nickel exploration boom in Western Australia (1968-71), I frequently scouted old exploration properties abandoned by their former owners. Diamond drill core was left abandoned in the bush, sometimes in their original stacks and sometimes tipped into the nearest gully. The galvanized metal core trays then used were immune to termite attack, but even when stacked, the core was almost as useless as the Northern Territory core described above. The trays were typically in random order, and neither geologist nor driller seemed to have realised (or more likely did not care) that felt or fibre tipped ink marking pens, or painted lines, are not permanently legible, despite what the labeling on the product might say. Exposed to baking heat, rain, UV light and the passage of time, numbers fade and become illegible in a period that can be as short as a few months.

…exposed to baking heat, rain, UV light and the passage of time, numbers quickly fade and become illegible…

Nobody seemed to care that this expensively-acquired product would soon become virtually useless.  Or perhaps they did, but reasoned that once they had extracted all the value they could from their one-off pass, no one else – not even themselves -  should be given another opportunity. A true dog-in-the-manger attitude.

How not to store drill core. In fairness to Rio Tinto, their Hidden Valley project was heroic exploration in an extreme environment near the crest of the Owen Stanley Range. The only access was by helicopter in the brief intervals when the clouds parted and the rain stopped. In the 1990s, after a series of extraordinary force majeur events (Bougainville, Wafi, Mt Kare), Rio took the decision to walk away from all their Papua Nugini operations.

Best practice core storage and labeling. This is core was acquired by the Homestake company from their Trilogy Pb/Zn/Au project in Western Australia. Trays are permanently labelled with riveted metal markers and placed in racks that allow easy individual tray extraction.

I have emphasized how durable diamond drill core is. But sometimes that is not the case..

In the West Java province of Banten, the epithermal gold prospect of Cibaliung was explored with a major diamond drilling program by a junior Australian company during the late 1990s. Many of the rocks on the footwall of the ore body consisted of crumbly acidic clays which swelled to two or three times their volume when exposed to air and moisture. Needless to say, core recovery through these units was poor.  I undertook a major re-logging exercise on drill core that was up to 3 years old in order to resolve structure. The core had been stored, according to then best practice, in steel racks under cover, but in a tropical environment it is very difficult to exclude moisture. In the critical section below the ore body, core had expanded to a spongy mass – a gross acidic efflorescence that dissolved the base of the galvanized iron trays cementing them together into an inchoate mass. Pity the poor geologist who had to try to make sense of this stuff (and pity the poor miners who were proposing to develop an underground access decline through it).

…a gross efflorescence had cemented many of the trays together into an inchoate mass…

But you might say, what could anyone do to recover and store drill core from refractory rocks such as these, especially in the heat and humidity of a tropical environment.

Well, there is a way…

2007, Central Thailand. I consulted for the Australian mining company Oxiana (now OZ Minerals) at their Wang Pong epithermal gold exploration project. Oxiana was (and, for all I know, may still be) one of the most technically competent explorers that I have come across .

…one of the most technically competent explorers that I have come across…

Parts of the prospect consisted of swelling acidic clays similar to the problematic rocks that the Indonesian explorers had to deal with. To drill this successfully, Oxiana employed the following strategies:

• Large diameter core (HQ and PQ)
• Triple tube drilling
• Split inner tube for core extraction.
• Wrapping core in clear plastic (industrial strength cling film) to exclude air (see photo)
• Use of plastic core trays (now thankfully becoming an industry standard)
• Long term storage of severely affected sections in sealed shipping containers with nitrogen atmosphere

Note: core wrapped in clear plastic to exclude air and moisture. Twelve metre long racks allow re-assembly of broken core pieces from up to 2 core runs – this facilitates accurate depth measurement and placement of  long-core orientation lines

The moral to be taken from the examples above is should be sufficiently obvious.

The post Look after your Drill Core: it’s a resource that keeps on giving appeared first on Roger Marjoribanks.

In my previous post I described my encounter in 1984 with claim salting (or at least, alleged salting). These were early days, the late 20^th Century gold boom was still young, and claim salting considered a rather amusing but small-scale misdemeanor practiced by dishonest small-time prospectors – easily spotted by the sophisticated explorer.

KARPA SPRINGS

Two major multimillion-dollar scandals, in 1990 at Karpa Springs in Western Australia and in 1997 at Busang in Indonesia, ended this age of innocence. Although well known, the stories are worth re-telling, and as I had some peripheral first-hand knowledge of both scandals, I might be able to add some additional insights.

Here is the Karpa Springs story, as I understand it from information given to the press at the time and from talking to people involved. It begins with three wheat farmers (Clark Easterhay and the brothers Len and Dean Ireland), filling in time before the harvest, who pegged a Lease on the nearest available ground to Mount Gibson in the West Australian Yilgarn.  Mount Gibson was then a hot “address” following nearby well-publicized gold discoveries.  The ground acquired by the three wannabe prospectors was available for pegging because it was underlain by granite. Granite terranes in the West Australian goldfields have historically produced only insignificant amounts of gold compared to the adjacent, basalt-dominated, greenstone belts – hence usually ignored by experienced prospectors.   Having acquired a RC[1] drill rig, the trio then proceeded to drill a number (around 9, from memory) of random, 60m deep, vertical holes along the line of an old track that traversed the sandy soil and thick scrub of the property.  As an exploration strategy this was hardly sophisticated, but the trio’s next step showed more cunning: they added fine gold grains – acquired from somewhere else – to the drill cuttings.  On assay, all holes were mineralised, one of them yielding an intersection of 38m at 34 g/t Au. The fraudsters then contacted a mining consultancy group called the Aracus Syndicate that included entrepreneur Mike Novotny and geologist Laurie Whitehouse[2].  Whitehouse travelled to the site and supervised the prospectors while they drilled a duplicate set of holes on each of the original sites. He then sampled the cuttings and was able to replicate the earlier assays.  Convinced they had a major new discovery, the Syndicate then promoted the property around  Mining Companies in Western Australia, one of which was my then employer Renison Goldfields Corp. (RGC). My colleague Keith Watkins visited the site and panned RC cuttings from the holes which were lying on the ground. Keith told me he recovered gold that was clearly alluvial and not consistent with the granite bedrocks being drilled: on Keith’s recommendation and suspecting fraud, RGC declined to become involved. However, an Australian Junior company called Perilya, along with their Canadian partner Noranda (a major player with deep pockets), were less discriminating: Perilya optioned the property and made a first payment of Aus$6.5 million to the fraudsters (reports at the time said the Aracus Syndicate were to receive a 5% Royalty on the profits from any subsequent mine). But in the absence of the merry farmers (they were in Perth, cashing their cheque) and their magic drill rig, all Perilya’s subsequent test holes were duds. To cut a long story short: Perilya stopped payment on the cheque and the police were informed.  The West Australian Department of Mines then got involved and, under police supervision, drilled a fresh set of holes on all the earlier sites. No gold was found. At this stage there were now four closely grouped holes on each of the nine original sites. The first of each set were those drilled and sampled by the prospectors. The second were drilled by the prospectors under the supervision of, and sampled by, the Aracus Syndicate. The third drilled by Perilya using their own contract drilling team.  The fourth by the Mines Department in the process of collecting evidence for criminal prosecution. Clearly, the prospectors had salted the second round of holes in full view of Laurie Whitehouse, but this was probably not too difficult for them – in these innocent days he would not have been expecting fraud, and it is easy to be wise after the event. Eventually, the prospectors were charged, found guilty of fraud and served 13 months in jail. But see footnote [3].

BUSANG

Karpa Springs was serious fraud – an attempt to steal $6.5 million – but it was very small beer compared to what happened a few years later (1995-98) in Central Kalimantan on the island of Borneo. A group of Filipino contract geologists, working for a Canadian Junior Mining Company called Bre-X, salted diamond drill cuttings from a genuine (albeit, as much later established, sub-economic) epithermal hard-rock gold prospect known as Busang. The resulting assay results, consistent over almost 300 diamond drill holes, caused the penny-stock Bre-X to soar to over Can$285 on the Toronto Stock Exchange, valuing the company at over $6 billion. The site geologists, and Bre-X Vice-President of Exploration John Felderhof, reportedly sold their stock at the inflated values: Felderhof reputedly making over $80 million, and in 1997 awarded the title “Prospector of the Year” by PDAC – the Prospectors and Developers Association of Canada (4).

Over a period of several years, the conspirators had operated a secret jungle laboratory where carefully calculated and measured amounts fine gold were added to literally thousands of drill samples from hundreds of holes. An astonishing, sustained, industrial-scale operation. The doctored samples were then dispatched to an outside laboratory for assay. Such was the scale of the deception it is estimated that well over $30,000 worth of alluvial gold must have been used in the deception. External ore reserve geologists (working from data provided by Bre-X in their reports to the Toronto Stock Exchange) estimated an 80 million oz. gold resource (well over $160 billion at today’s prices).  No outside experts were allowed in to visit the property. However, international investors and stockbrokers (money men, who would not know an epithermal from an epitaph) were given site tours and produced uncritical, glowing reports. With hindsight these were all warning signs, but at the time no one seriously considered fraud. Where that thought occurred, the sheer scale, technical difficulty and effrontery of the effort that would have been required led to the idea being dismissed.

But in 1998 the Bre-X bubble was to burst, as all bubbles do. The events took place rapidly, and I am not clear on all the details (perhaps no one is) but here is my understanding..

In 1997, at the height of the stock market bubble, major North American gold mining companies, including Barrick, Placer and Freeport, became involved in a bidding war for the Busang property.  Each sought advantage by signing up various members of President Suharto’s family or his close confidants. Freeport won this war, but before committing to a large up-front cash payment (which would have been in excess of $100 million), sent a team of geologists to the Busang site in Kalimantan to conduct a forensic examination of the drilling, sampling and assay methodologies employed by Bre-X, and re-drilling and sampling a number of check holes. This was standard due diligence: the Freeport geologists were not expecting fraud. The Filipino site team, and especially Chief Project geologist Michael de Gusman, must have realised that the game was up. While this was going on, there was a dramatic development: Michael de Guzman, returning to site from the Toronto PDAC meeting, had fallen from a helicopter (or did he jump, or was he pushed?) and his body (or at any rate, someone’s body) found in the jungle four days later, partially eaten by pigs. A few weeks later, Freeport announced their conclusion that the core they had drilled at Busang contained only insignificant amounts of gold, and that the core previously drilled from the same sites by De Gusman’s team had been doctored with added alluvial gold. The Bre-X stock price collapsed, the company was de-listed and went bankrupt. Vice-President of Exploration John Felderhof (who after his triumph at the Toronto PDAC meeting had retired to his new villa on the Cayman Islands: David Walsh had retired to his in the Bahamas) was put on trial in Toronto for insider trading. That was the best the Canadians could do as the physical crime of salting drill core had taken place in a foreign jurisdiction. Felderhof’s defense was that he too had been duped and all his actions were made in good faith. Felderhof’s trial lasted for years and, although he was ultimately acquitted, he was reportedly bankrupted by his legal fees. He was still in litigation in 2011. Only the (now conveniently dead) De Guzman is known to have been certainly involved in the fraud. Other participants (and there must have been many) in the biggest mining fraud in history simply disappeared into the barrios of Manila, never named or charged.

The crime took place in the jurisdiction of the Indonesian Government, but in view of the involvement of the President Suharto’s family (and the mysterious Indonesian Air Force helicopter pilot that featured in early press reports, then mentioned no more), it is perhaps not surprising that their investigation was cursory and inconclusive. The de-helicopterisation of de-Gusman remains a mystery.

CONCLUSIONS

During the 1990s, I knew John Felderhof, Mike Novotny and Laurie Whitehouse. They were part of an informal syndicate or network of geologists, assay chemists and general “fixers” who offered services to mining/exploration companies in the fields of target generation, land acquisition, government liaison and ready-made contract geological teams (5). They had long experience in Australia and Indonesia and provided useful services for incoming players to these countries. Novotny- no scientist – was an old Indonesia Hand who spoke fluent Bahasa and knew how to navigate the Byzantine Jakarta bureaucracy. I thought Felderhof and Whitehouse were able, honest and hard-working geologists. After the events at Busang, I have come to believe that gold fever and desire for riches and fame led Felderhof at Busang to suspend oversight and critical judgement and become a dupe for an unscrupulous group of technically clever on-site Filipino fraudsters. But I might be wrong.

Would I have been any smarter had I ever been in a similar situation? I like to think that I would. You may judge that is just my conceit, and there, but for the grace of God…..

MORAL

If something is too good to be true, it most likely is.

Caveat Emptor

The post How to salt a gold claim – Part 2, Karpa Springs and Busang appeared first on Roger Marjoribanks.

It is always better to know the orientation of planar structures at the time of logging rather than at some later date when the structure that was measured is long forgotten and the core returned to its stack in the yard.

The six rules are mostly common sense. With a little thought, and the help of an actual piece of core to play with, you could work them out for yourself. But employing them will greatly speed up the process of understanding the attitude of planar structure in oriented drill core at the time of logging.

Measurement of planar structures – such as bedding, veins or cleavage – in oriented diamond drill core can be done in two ways. The simplest way is to set up the core in its original orientation by means of a core frame and then measure structures within it using a geologists’ compass.  The second way is to measure the angles which the plane makes with lines of known orientation in the core and then, knowing the hole orientation, use these angles to calculate the strike, dip and dip direction. This is called the internal core angles method. I described these methods in some detail in an earlier blog post and discussed the advantages and disadvantages of the two methods (Measuring structures in oriented core, Oct 19 2013). 

But there is a third way: just eyeball the data and work it out for yourself. My six rules show you how to do this.

Before I present the rules, I will quickly recap the internal core angles method. The orientation of a planar surface intersected by drill core can be defined by two angles called alpha (α) and beta (β). The definition of these angles is shown in the diagram below: 

To be geologically useful, these alpha and beta numbers for a plane have to be converted into the more meaningful dip and dip directions. This conversion is usually accomplished by mathematical calculation (computer software) or less frequently by graphical means (i.e. a stereonet). How to use a stereonet to reduce alpha/beta angles is detailed in my blog post here.

In the discussion of Rules 1-6 that follow, note that no alpha or beta measurements made in core can ever be considered accurate to more than +/- 2 degrees.  Therefore for 180° you should read 178° – 182°, for 0° read 358°-002° and for 90° read 88°-90°. If the alpha and beta angles are more than +/- 2 degrees away from the key numbers of 0, 90, or 180,  the more we are into the area covered by Rule 1 – estimating approximate values for dip and dip direction. The further measured alpha and beta are from 0, 90 & 180, the more approximate that estimation will be.

 Rule 1

When logging oriented core it is a simple matter to hold a piece of core in your hand and roughly orient it to its original in-ground attitude – your hand acting as a crude core frame. Most experienced geologists logging structure in core would do this automatically. By doing this one can eye-ball any planar structure in the core and quickly estimate its dip and dip direction. However, very often structures are analyzed ex post-factum on the basis of recorded observations long after the original structure is forgotten. All there is to work on is the record in the structure log. This is not an ideal situation, but all is not lost. We can recover the same quick qualitative assessment of dip and dip direction by visualizing the core in its original orientation and peopling it with a plane which would give the recorded measurements.

But why would you want an approximate dip and dip direction when you can use a computer program to calculate an exact one? A good question, but there are at least four  good answers:

1. The process is quick.

2. An approximate answer may be all that you need to answer your structural question.

3. If mass data has been entered into a spread sheet for computer processing, knowing the approximate solution for any given measurement provides a quick way of checking the accuracy of the computer output (or more particularly of the data entry process, where errors are most likely to have occurred). This step is the essential one of quality control and validation.

4. For particular values of alpha and beta (as explained in Rules 2, 3,4 & 5) simple mental calculation involving adding or subtracting two-digit numbers can provide an accurate dip and dip direction.

Except in the few specific cases referred to in Answer 4 above, it is impossible for any normal person to mentally calculate an exact dip and dip direction from alpha and beta angles.  However, by visualizing the angles on a mental image of the core, it is usually possible to produce an approximate estimate of the dip and dip direction of the plane – one good enough to be in the right ball park (1). I illustrate this with a random example (one sent to me by a reader):

a hole drilled at -44⁰ (dip below horizontal known as hole inclination In) to 031⁰ (the direction of drilling known as Azimuth  Az) ; a plane in the core with internal angles alpha 09⁰ and beta 227⁰. 

With just introspection it is possible to say that the plane must dip  broadly to the east (the beta number tells you that) with a dip that is a bit steeper than the hole inclination (the alpha number tells you that).

The exact answer (which I calculated using a stereonet): is 54⁰ to 094⁰

If my calculation of had come up with a plane dipping at, say, a low angle to the NE, I would have instantly known that this was BS and I had made a gross error in my stereonet manipulation.

RULE 2

If β = 180º, then you are drilling at right angles to strike of the plane and in the direction of its dip. In this case… 

                                    Dip direction = Az

                                    Dip =  In – α    

Rule 3          

 If β = 180° and angle α = In, then..

 Dip = 0° (i.e. horizontal)

No strike can be defined (see footnote 1)

 Rule 4        

 If   β = 0º, then the hole is drilled at right angles to the strike of the beds. There are 3 possibilities for the dip:

 (a)Where In + α < (is less than) 90º

                                           Dip Direction = Az

                                           Dip = In + α 

  (b)  Where In + α > (is greater than) 90º, then…. 

                                           Dip Direction = Az + 180º

                                           Dip = 180 – α - In

   (c)  Where In + α = 90º, then… 

                                          Strike = Az + 90º (Note: no dip direction can be assigned)

                                          Dip =90º             (i.e. Vertical) 

 Rule 5    

 If α = 90º, then the hole is drilled at right angles to the strike of the plane in a direction that is opposed to the dip of the beds. There is no useful definable beta angle (if you think you can measure a beta angle then the number you get is meaningless – see Rule 6). The relationships are these: 

                                                Dip direction = Az + 180º

                                               Dip = 90º – In    

 Rule 6                       

As the angle alpha approaches 90°, the intersection ellipse on the core surface approaches an intersection circle on which no unique long axis can be defined (see Rule 5). For large α angles it is therefore not possible to define the point E (or E’) on the core surface with sufficient accuracy to enable an accurate measurement of the beta angle to be made.  Small errors in measuring beta can produce large errors in the calculated strike and dip for that bed. How large does alpha have to be make errors in the corresponding beta angle unacceptable?  There is no fixed cut-off point: every increase in alpha above 50° causes potential measurement  error in beta to rise exponentially. Experience suggests any alpha angle greater than 65º is large - but how much error you are prepared to tolerate is a matter for judgement and is to some extent dependent upon how well the plane is defined in core and how many parallel planes of that orientation are present.

 Where large alpha angles are encountered the alpha/beta method should not be used and core should be set up in a core frame and the surface measured with a geologists’ compass.

***** ****

(1) Computer software will calculate an exact strike (or dip direction) for a plane, even if the difference between the alpha angle and the hole inclination is a fraction of a degree. However, if the difference between these two angles is 10 degrees or less, the calculated dip direction is essentially meaningless, since even the smallest error in measuring either α or In will lead to an order of magnitude greater error in the calculated strike. This is the same problem as trying to measure the strike of near-horizontal beds exposed at surface: but the problem is much more acute in drill core because of the small area of exposed surface.

******

Please note that this blog no longer accepts comments (there was too much spam coming in!) However, I welcome your opinions, comments even criticisms.  You can contact me direct through the email form on the Contacts Tab.

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