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Fifty-year Trends in Minerals Discovery — Commodity and Ore-type Targets

CHRIS BLAIN*Independent Consultant

South Yarra, Victoria 3141, Australia

Received June 7, 2000; accepted August 15, 2000.

Abstract — Based upon an extensive database, this paper analyzes the record of modern mineralexploration success and establishes the 50-year trends in discovery.

The record clearly shows that the overall discovery rate rose during the 1950s and 1960s, peakedin the 1980s, and fell during the 1980s and 1990s. By commodity and ore-type target, the pattern of discovery is not continuous. Typically, it is episodic as a series of waves with minor resurgence. Thewaves reflect the order of the so-called discovery booms, led by uranium, then nickel, and copper,polymetallic base metals and gold. With the possible exception of gold, the discovery booms appearto be independent of metal price, although favorable perceptions of the price outlook may well haveinitiated the boom or led resurgence.

Although difficult to quantify, an emerging trend in modern discovery is the integration of sev-eral detection techniques into the search process. No doubt, this trend will continue as orebodiesbecome more and more difficult to find.

The record of the past two decades shows that greenfield discovery rates have progressively falleneven though the level of investment in exploration has risen to an all-time high. This trend reflectsincreasing discovery risk. Several factors are contributing to this trend. Perhaps the two most impor-tant are: (1) deteriorating economics as increasing real costs and decreasing real prices continue toraise the economic hurdles for minimum acceptable exploration targets, and (2) increasing explo-ration maturity in many search terrains, particularly those in the traditional regions of North Amer-ica and Australasia. To succeed cost-effectively in this new environment of increasing discovery risk will require extraordinary creativity, innovation, and technical skill coupled with commercial disci-pline. © 2001 Canadian Institute of Mining, Metallurgy and Petroleum. All rights reserved.

* Formerly BHP Minerals, Melbourne, Victoria 3000,Australia.**Focus and Comment, Mining Journal, October 1, 1999, p. 267.

Introduction

This paper is based on an address at the Plenary Session

of the North Atlantic Minerals Symposium at Trinity Col-

lege, Dublin, on September 22, 1999. As the address and

Extended Abstract (Blain and Wilde, 1999) have created a

lot of interest** in the minerals exploration community, this

paper expands upon that address and publishes the findings

here in a more readily accessed venue.

This paper takes a long-term view, and examines the

discovery record for the past 50 years. This is the era of

modern exploration following World War II when rapidly

evolving geological concepts and technologies were first

applied to mineral exploration as a commercial endeavor.

How has the industry performed over the past 50years? Where have the discoveries come from? How were

the discoveries made? What do these trends indicate to us

about the future? Are we approaching the end of a golden

era in discovery, or a new beginning? First, let us develop

the context.

Context

Grassroots exploration is the first link in the chain of

minerals supply. It is the route with longest lead time, typi-

cally a decade or more. Consequently, the exploration envi-

ronment is influenced by trends in the minerals industry as a

whole. In the context of this discussion, the most important

trends are:

1. Short-term (typically 4 to 10 years) commodity price

cycles variously affect the profitability of the industry over

time, and, therefore, influence investment patterns in explo-

ration as well as the levels of mine capacity.

2. Superimposed on these are longer-term trends of falling

real prices for most commodities coupled with lowering unit

production costs.3. As a result, industry-wide revenues for most commodities

have levelled out over the past two to three decades

(Doggett, 1999), brought about by increased production,

particularly from the giant resources amenable to expansion

by economies of scale.

1

Explor. Mining Geol., Vol. 9, No. 1, pp. 1–11, 2000© 2001 Canadian Institute of Mining, Metallurgy and Petroleum.

All rights reserved. Printed in Canada.0964-1823/00 $17.00 + .00



Fig. 1. Overall discovery record and trends in discovery by com-modity — data smoothed by five-year rolling average.

4. Consequently, the world is now depleting its mineral

reserves at progressively increasing rates of production.In the face of these trends, it is interesting to ask a hypo-

thetical question: What discovery rates would be required if

the industry had to replace reserves at the current rates of

production by new grassroots discoveries?

A quick calculation reveals some surprising results. The

annual discovery requirements are approximately:• In gold, fifteen 5 Moz Au deposits. (Assuming a

$25/oz discovery cost and a $50/oz development cost,such deposits would need to sustain a production costof <$150/oz).

• In copper, two high-grade, world-class porphyry cop-per deposits containing 5 Mt of recoverable copper.

(These each equate to about 500 Mt of 1.3% Cu inlocations with favorable infrastructure).

• In silver, ten deposits containing 60 Moz Ag.• In diamonds, six deposits containing 20 Mcts.

These benchmarks illustrate the current challenge, which place

the discussion of historic discovery trends in perspective.

What do we know about the long-term mineral discov-

ery record? Surprisingly, it is very poorly documented. Only

recently has grassroots exploration evolved from a local

activity to a global business. The literature is full of case his-

tories that detail individual discoveries. In addition, there are

a handful of papers, (for example, Mackenzie et al., 1997;

Blain, 1992; Sillitoe, 1995), or conference proceedings, thatdescribe the sequence of discovery for a particular region,

commodity or ore-type. However, there is no one reference

in the literature where all this information been compiled.

So BHP Minerals built its own discovery database (Blain

and Wilde, 1999). The database records the details of more

than 500 discoveries during the period 1950-2000. The data-

base is the property of BHP Minerals, and the author is

grateful to BHP for permission to present findings from it

solely for the purpose of discussing long-term, industry-

wide trends in mineral discovery in the traditional search

terrains of the Western World.

The database records information on mineral discover-

ies. A discovery is marked by critical information leading to

the delineation of a mineral occurrence that is (or is likely to

become) economic. To qualify as a discovery, the occur-

rence must contain a measured resource, giving rise to an

estimated amount of contained mineral or metal. Not all dis-

coveries are clearly defined. For example, a new investiga-tion of a known occurrence may lead to a significant expan-

sion of the resource. Where this expansion is judged to be

truly significant (several times the initial content), the new

investigation is deemed to be a new discovery.

Another problem arises in determining whether or not

to assign the full size of the resource to the initial discovery.

It is common industry practice to delineate reserves pro-

gressively ahead of production. Although this is generally a

routine operational function, it often leads to an expansion

of the resource base over time. As discussed later, this

expansion becomes most significant for the so-called giant

orebodies. For consistency in this analysis, unless the expan-

sion results from a new discovery, the full size of the knownresource is ascribed to the initial discovery. There are several

measures of size, such as estimates of ore reserves or con-

tained resources. From a discovery point of view, the size of

the total resource is particularly relevant; this includes his-

torical production as well as the estimated amount of the

resource remaining. For consistency, the size of the resource

is measured as a total mineral or metal content, and cross-

commodity comparisons are made by calculating the in-

ground value of the resource as a proxy for size simply to

facilitate comparison.

One other feature of the record that pertains to this dis-

cussion is where the discoveries occur with respect to exist-

ing mining operations. Where the discoveries result from a

broad-based grassroots exploration program well away from

known orebodies, they are classified as greenfields discover-

ies. Where they are made in the vicinity of an existing mine,

and the economics of development are improved by existing

infrastructure, they are classified as brownfields discoveries.

This is an important distinction in the analysis of discovery

trends even though both types contribute to the rates of pro-

duction (and depletion).

The part of the database most relevant to this paper

draws upon the information classifying the discoveries by

type, time and method, and the resources discovered by

commodity, ore-type and size.

Results and Analysis

Figure 1 shows the overall record of mineral discover-

ies for the fifty-year period, plotting the number of discov-

eries over time by commodity. In this format, the trends are

emphasized by the application of a five-year moving average

to the data. The most important points to note are:

1. Base metal discovery rates peaked in the 1960s to 1970s;

gold peaked in the 1980s.

2 Explor. Mining Geol., Vol. 9, No. 1, 2000



1. The boom in steel-making raw material discovery datesback to the 1950s to 1960s, particularly the giant iron ore

districts in Western Australia and Brazil.

2. Coal discoveries continued to flow through the decades.

3. The period 1950–1970 was the heyday in copper although

discovery continued to the 1980s and beyond.

4. The 1980s and 1990s were the heyday in gold.

5. There are three separate decades of major diamond dis-

coveries: 1950s, 1970s and 1990s.

The next series of figures plots the annual discovery

rate, by commodity, against commodity price in dollars

of the day in order to review the relationships between

2. The patterns of discovery are not continuous; they areeither episodic or cyclical.

3. The patterns are those of a series of waves or booms, each

portraying a cycle and resurgence.

4. The booms reflect a broad sequence: uranium, nickel,

copper, polymetallic base and precious metals, and

gold.

5. The overall discovery rate rose throughout the 1950s and

1960s, peaked in the late 1970s and fell during the 1980s

and 1990s.

Figure 2 shows the discovery record by commodity in

decade blocks. Note:

Fifty-year Trends in Minerals Discovery • C. BLAIN 3

Fig. 2. Number of discoveries each decade, grouped by commodity.




Fig. 3. Number of copper deposits discovered each year and trendsin copper price.

Fig. 4. Number of nickel deposits discovered each year and trendsin nickel price.

Fig. 5. Number of lead-zinc deposits discovered each year andtrends in lead price.

Fig. 6. Number of gold deposits discovered each year and trends ingold price.

Fig. 7. Number of discoveries by ore-type model and their size distribution measured by in-ground value.



For gold (Fig. 6), the discovery rate boomed during theperiod 1980–1994. Gold provides the clearest example of

a price-led discovery boom. However, success was sus-

tained at rates of eight to ten discoveries per year because

the new heap leach-CIP-CIL technologies lowered the cost

thresholds sufficiently that orebodies were relatively easy

to find.

It is instructive to look at discovery patterns by ore-

type, rather than by commodity, because ore-type models

are the drivers of modern mineral exploration. The ore-type

model not only defines the style of orebody but it controls

the selection of the search terrain.

periods of prolific discovery and historical commodityprices.

For copper (Fig. 3), the periods 1955–1971 and

1977–1981 represent the most prolific when discovery rates

ran from four to ten per year. In 1981, the industry discov-

ery rate fell and has not since risen above two discoveries

per year.

For nickel (Fig. 4), most discoveries came in the period

1954–1980 at a discovery rate of one to four per year.

For lead-zinc (Fig. 5), most discoveries came in the

period 1962–1982 at a discovery rate of two to three per

year.


Fig. 8. Time trends in discovery by ore-type model.



Figure 7 shows the number of discoveries classified by

ore-type model and their size distribution measured by in-

ground value. In base and precious metals, the most fre-

quently discovered class by far was porphyry copper fol-

lowed by volcanic-hosted massive sulfide, SEDEX/BHT

lead-zinc, stratiform copper, epithermal gold and magmatic

nickel-copper sulfide.Comparison of the discoveries shows that each ore-type

class has a distinct size distribution. For example, the

SEDEX/BHT class contains a greater proportion of large

(>$10 Bn in-ground value) discoveries than porphyry cop-

per. This comparison reflects differing discovery risk pro-

files between classes, where the discovery risk profile

reflects the proportion of high-value deposits to the total

number of discoveries.

Figure 8 shows the discovery time trends by ore-type

model. The discovery sequence for the differing deposit-

styles also tends to occur in waves. The waves typically last

for five to ten years then taper off to a trickle of discoveries.

For most ore-type classes, there are new waves but seldom

do the later waves eclipse the first.

Figure 9 shows the discoveries grouped by age of ter-

rain. Interestingly, the cumulative in-ground value of the

discoveries is greatest for the Mesozoic-Cenozoic terrains

and decreases progressively with increasing geological ageof the search terrains. This trend mainly reflects the rela-

tive value of the porphyry copper and epithermal gold

deposits in the younger terrains, coal and base metals in

the Paleozoic, base metals (particularly SEDEX/BHT lead-

zinc) in the Proterozoic, and precious metals in the

Archean terrains.

Figure 10 shows the cumulative in-ground value of dis-

coveries in greenfields and brownfields search terrains. Over

the fifty-year time period, the greenfields discoveries have

the greatest in-ground value. As the search terrains of the

world progressively reach maturity, it would be expected

that brownfields discoveries will become more important,

particularly for those deposit-styles that tend to cluster. If this is to become an emerging trend, it will become an

increasingly important factor favoring continuing explo-

ration in the vicinity of the mineral districts around the giant

orebodies; this theme is discussed again below.

Discovery Techniques — Discussion

How have the discoveries been made? Figures 11 and

12 show the results of a cursory review of the case histories

that classify the discoveries by primary method or approach.

Over the fifty-year period, traditional prospecting has

given rise to many discoveries, presumably reflecting the

fact that many of the orebodies actually cropped out at the

surface. Similarly, geology combined with geochemistry

has led to many discoveries, particularly in base metals and


Fig. 9. In-ground value of discoveries grouped by the age of thesearch terrains.

Fig. 10. In-ground value of discoveries grouped by search terrainclassification — greenfields and brownfields.

Fig. 11. In-ground value of discoveries grouped by primary dis-covery technique.



As the prime search terrain was completely covered by up to200 m of younger sediments, the next step was to define tar-

gets by geological interpretation of high-resolution aero-

magnetic surveys. The discovery came on testing the third

target in the first regional drilling program. Similarly, the

search for Ekati integrates several themes (Fipke et al.,

1995a). The exploration project started in Superior Oil-

Minerals Division with the application of diamond-indicator

mineral surveys in British Columbia (Dummett, pers.

comm.). The critical component in this phase was the inte-

gration of pioneering studies into the significance of G10

garnet geochemistry by John Gurney, which indicated that

gold. As a direct method, geophysics was most successfulin uranium.

As orebodies have become harder to find, a trend has

emerged whereby several approaches and techniques are

integrated throughout the discovery pursuit. Cannington Ag-

Pb-Zn and Ekati diamonds are excellent examples. The

search for Cannington (Skrzeczynski, 1998) started with re-

interpretation of the Broken Hill block and the formulation

of a new ore-type model. It then took several years of geo-

logical and geochemical application to screen the potential

of all the Australian Proterozoic terrains before BHP Miner-

als homed in on the Eastern Succession of the Mt. Isa block.


Fig. 12. Time trends in discovery — primary discovery technique.



unique mineral suites were derived from diamondiferous

kimberlites (Fipke et al., 1995b). The Superior Oil-Minerals

Division work also showed that the diamond indicators were

derived from the Shield to the east (Dummett, pers. comm.).

When Superior Oil exited, Fipke used carefully controlled

geochemical sampling and analysis techniques to chase theindicator trains 1100 km eastward to the source region.

When BHP joined the search, it was the development and

application of high-resolution airborne and ground geo-

physics that generated targets for drill testing. Since then,

BHP has found and tested more than 100 kimberlites. Both

these case histories illustrate the importance of integrating

several approaches and techniques as the search evolves.

There is little doubt that this will be a way to future success

in discovery.

Economic Trends

Economic trends also impact upon the rates of discov-

ery. Figure 13 illustrates cost and price trends in the mining

industry over the past fifty years (S. Lewis, pers. comm.).

The construction cost index shows the trend in unit cost of

constructing mining facilities and infrastructure. This index,

derived from data collected by Engineering News Record*,

is calculated by pricing a bundle of 200 hours of labor, plus

appropriate amounts of structural steel, cement and lumber.

Similarly, the mining machinery and equipment index,

derived from data collected by the US Bureau of Labor Sta-

tistics, compares costs over time of a consistent set of sur-

face and underground mining equipment: for example, 40 to75 ton capacity trucks. This index does not measure changes

in capital efficiency in the sense that newer designs of the

same truck last longer and require less maintenance; but it

does reflect changes in price per unit capacity. As such, it is

a useful proxy for the real price trend in mining equipment.

The mineral commodity price index (also derived from data

collected by the US Bureau of Labor Statistics) plots the

price of a set bundle of mineral commodities; it is the

unweighted average of the price indices for iron ore, bitu-

minous coal and nonferrous metals, converted to real terms

using the US producer price index — all commodities. All

these indices are US based, but no matter what data sets one

uses, the trends are very clear and illustrative of the issue.

The conclusion is inescapable: in the mid-1970s, there was

a decoupling between unit capital costs and the prices of most mineral commodities.

The significance of this decoupling becomes clear when

the unit capital cost and price trends are compared in real

terms. Figure 14 shows the change in the real value of the

capital costs of extracting mineral commodities and the

value of the commodities produced. To an extent, rising unit

capital costs have been offset by productivity gains and thus

falling unit operating costs. However, the combined effect of

rising capital costs and falling prices does illustrate a long-

term deterioration in the economic fundamentals of the min-

erals industry. This phenomenon is widely recognized

emprically by financial analysts in the mining sector

because modelling commonly shows that development of

many past producers, particularly the smaller orebodies,

would not be economically viable at current outlook condi-

tions. There are many theories as to why this is happening.

In the author’s opinion, several key contributing factors are:• Since World War II, the period of modern mineral dis-

covery has had unprecedented success, resulting in asurfeit of new orebodies for development.

• Market economies have become increasingly preva-lent, resulting in a freer flow of capital, informationand technology, in effect lowering the barriers to entryfor the development of new mineral projects.

• The productivity gains from new technology in miningand processing have largely been taken up by fallingprices in highly competitive markets, rather than con-tributing to long-run profitability.

Whatever the causes, the main consequence is that

many of the traditional profit-making opportunities either no

longer exist or their margins have closed rapidly. The only

real lasting profit-making opportunity stems from resource

quality — those giant high-grade orebodies that sit at the

bottom of the cost curve. These are the resources that are

amenable to successive capital expansion projects capturing

efficiencies and economies of scale. Because such resources


*The data can be accessed at www.enr.com.

Fig. 13. Economic trends in the unit cost of construction and min-ing equipment vs the unit price of mineral commodities.

Fig. 14. Economic trends in the relative real cost of producing min-eral commodities vs the real value of commodities produced.



1 300 000 tons of copper per annum. Such orebodies are rare

geological occurrences. For this reason, it is interesting to

see what the discovery record tells about the timing and fre-

quency of their discovery.

The most reliable criterion to classify orebodies as

giants (or non-giants), and to analyze this aspect of discovery

trends between ore-type classes, would be net present value.

In view of the impracticality of applying financial modelling

to the entire database, however, in-ground value is used here

as a more easily measured approximation of size. In-ground

value is simply the product of the total contained mineral (or

metal) and the current price. Giant orebodies are defined here

by the arbitrary but consistently applied criterion of having

an in-ground value greater than US$10 Bn.

Figure 16 plots the in-ground value of all discoveries,

year by year. It shows a trend that rises to the greatest value

in the 1960s and then progressively falls.

Figure 17, which plots the in-ground value of only thegiant (>$10 Bn in-ground value) discoveries, has a remark-

ably similar trend.

Figure 18 shows a direct comparison between the over-

all discovery rate and that of the giants alone. The data show

that the frequency of discovery of the giant deposits mim-

micks that of the overall discovery rate.

Despite the clear economic imperative, no one yet has

successfully devised a discovery strategy specific only to

giant orebodies. This remains one of the great geological

discovery challenges of the future. The long-term (25

years), industry-wide trends of rising rates of production,

significantly influence or control the economics of produc-

tion, they are the prime targets for growth-oriented resource

companies. So what are the implications of these economic

trends for discovery?

Figure 15, based on data compiled by Annette McIlroy

(1999), illustrates the point. It plots orebodies for two

deposit-styles by recoverable in situ value per tonne of ore

versus recoverable reserves. It also shows contours of net

present value derived from generic financial models. With

trends of decreasing real prices and increasing capital costs,

the economic threshold contour progressively migrates to

the upper right of the diagram over time. The giant high-

grade orebodies are the only ones that can sustain long-term

profitability. Every time the economic threshold bar is

raised, so too is discovery risk.

Giant Orebodies — Discussion

In view of these trends of increasing real unit capital

costs and falling real prices and operating costs, it is clear

that the giant orebodies are the key to the future because the

giant orebodies have the reserve base capable of capturing

economies of scale by increasing capacity. Orebodies such

as Escondida illustrate the point. Initial production was

planned at the rate of 150 000 tons of copper per annum but

then through expansion projects, phase 2, 3, and 3.5, pro-

duction rapidly rose above 800 000 tons per annum. If phase

4 expansion reaches fruition, production will peak at over


Fig. 15. Economic target thresholds for minerals discovery. Note that MTGC denotes the minimum tonnage andgrade curve for orebodies having an estimated net present value greater than US$1 billion.



increasing exploration expenditures, significantly falling

rates of discovery, and increasing economic target thresh-

olds suggest that, sooner or later, scarcity will become a

force acting on real price. At that point, the trend in realprice decline may reverse, creating a more favorable envi-

ronment for investment in exploration. Meanwhile, we

must find new ways to succeed in a world of increasing dis-

covery risk.

Conclusions

1. The overall discovery rate rose throughout the 1950s

and 1960s, peaked in the late 1970s, and evidently fell dur-

ing the 1980s and 1990s. During this time, there were a

series of discovery booms by commodity and ore-type

model. Base metal discovery rates peaked in the 1960s and

1970s; gold peaked in the 1980s.

2. Apart from gold, those peak discovery rates have not

been sustained for several decades. As production rates con-

tinue to increase, it is interesting to speculate whether eco-nomic scarcity will become a real force in the long term.

3. Meanwhile, the giant orebodies that came out of

those discovery booms now control or significantly influ-

ence the economics of production because the giant deposits

are amenable to capital expansion projects that capture

economies of scale.

4. Economic trends are making conditions tougher for

the exploration industry overall by raising target hurdles and

thereby increasing discovery risk. Coupled with increasing

exploration maturity in many mineral provinces, mineral

explorers must find new ways to succeed in a world of

increased discovery risk.


Fig. 16. Time trends in discovery — in-ground value of all discov-eries.

Fig. 18. Comparison of the discovery frequencies — overall discoveries vs giants.

Fig. 17. Time trends in discovery — in-ground value of the giantdiscoveries.



BLAIN, C.F. and WILDE, A.R., 1999. Trends in discovery:Commodity and ore-type targets. Extended Abstracts Vol-ume, North Atlantic Minerals Symposium.

DOGGETT, M., 1999. Exploration trends in the next century.Extended Abstracts Volume, North Atlantic Minerals Sym-posium, Trinity College, Dublin, Ireland.

FIPKE, C.E., DUMMETT, H.T., MOORE, R.O., CARLSON,J.A., ASHLEY, R.M., GURNEY, J.J. and KIRKLEY,M.B., 1995a. History of the discovery of diamondiferouskimberlites in the Northwest Territories, Canada. Proceed-ings, Sixth International Kimberlite Conference, p. 158-160.

FIPKE, C.E., GURNEY, J.J. and MOORE, R.O., 1995b. Dia-mond exploration techniques emphasizing indicator min-eral chemistry and Canadian examples. Geological Surveyof Canada Bulletin 423.

MACKENZIE, B.W., DOGGETT, M.D. and THOMPSON,M.J., 1997. Economic Potential of Mineral Exploration inAustralia: Evidence from the Historical Record — 1955-91. Centre for Resource Studies, Queen’s University,

217 p.McILROY, A.R., 1999. The Return from Exploration Success:

Relating Economic Quality to Geological Quality. Ph.D.thesis, Queen’s University, Kingston, Ontario.

SILLITOE, R.H., 1995. Exploration and discovery of base- andprecious-metal deposits in the Circum-Pacific Region dur-ing the last 25 years. Resource Geology Special Issue, 19,199 p.

SKRZECZYNSKI, R., 1998. The discovery of the CanningtonAg-Pb-Zn deposit, Mt. Isa Inlier, NW Queensland, Aus-tralia. In Pathways 98. Extended Abstracts Volume, SEGInc.

5. As in the past, there will be successful companies

who can discover or otherwise access giant orebodies

cheaply. It is likely that the successful companies will con-

sistently outperform the industry as a whole. The successful

companies will require a superb quality technical team oper-

ating with commercial skill and business discipline.

To succeed in this environment is a great challenge. Itwill require an integrated team with technical and business

skill, optimism, commitment and determination, a sense of

humor, and above all, abilities to learn. It is a real challenge

but that is what will make it all worthwhile.

Acknowledgments

This paper is based upon an address delivered at the

Plenary Session of the North Atlantic Minerals Symposium

on September 22, 1999. I would like to express my gratitude

to BHP Minerals for encouragement and support to investi-

gate this subject, and permission to publish these findings.The views expressed in this paper, however, are the views of

the author, not necessarily those of BHP Minerals. Special

thanks go to Dr. Andrew Wilde for his help in constructing

the database and to Stan Lewis for his help in developing the

economic analysis of capital expenditure.

References

BLAIN, C.F., 1992. Is Exploration Becoming More Cost Effec-tive? Minerals Exploration Symposium, ABARE Outlook Conference.


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