What does a Copper Deposit Discovery Look Like?
- Noel Ong
- 5 days ago
- 11 min read
A discovery of a copper deposit usually comes with great excitement and is instinctively followed by narratives of great wealth generation. Over the recent decades, these discoveries are few, and the reality for investors is fueled with disappointments and rhetoric of false narratives from the explorers.
The well-seasoned investors in this sector will know that copper has always been one of those commodities that teases investors with the promise of world-class returns. Yet, very few truly understand what a genuine copper discovery looks like. In my three decades of participating in "The Truman Show", I have seen so many headlines—"major intercepts", "new zones", "high-grade hits"—but as this Samso Insight will reveal, the devil is in the details.
The reality investors need to accept is that real discoveries that lead to an economic deposit are more of a rarity than the perception they create to comfort themselves. It is a fact of self-inflicted false narratives and misunderstanding rather than the misconception of messaging from exploring companies. The most important recognition investors need is to understand what a real discovery looks like, and not leave themselves open to disastrous investment positions.
To add to the complexity of trying to figure out the whole "Economical Deposit" concept, one of the realities investors have to accept is that the depth at which new deposits are being discovered is getting deeper, and that adds to the financial disposition of whether the project will ever become a profit-making business. This thought is well documented in Figure 1, a graphical representation of the major discoveries since 1900 from the BHP website.
Figure 1: As deposits are found deeper underground, accessing these resources becomes more costly and technically complex, ultimately impacting copper prices. To highlight this trend, Visual Capitalist partnered with BHP to show the depths and sizes of major copper discoveries found since 1900. (source: BHP)
If you follow the link to Visual Capitalist, you will get a great write-up on these discoveries, and it is a good source of information to help understand the requirements of the modern-day exploration projects.
Table 1: The 10 largest copper discoveries from 2014 to 2023. (source: S&P Global)
Discovery | Discovery Year | Discovered By | Country | Copper in reserves, resources and past production (metric tonnes) |
Kamoa-Kakula (Kakula) | 2014 | Ivanhoe Mines | DRC | 19,840,147 |
Western Foreland | 2017 | Ivanhoe Mines | DRC | 4,959,000 |
Encierro | 2016 | Antofagasta PLC | Chile | 3,400,000 |
Cachorro | 2015 | Antofagasta PLC | Chile | 3,158,000 |
Winu | 2017 | Rio Tinto | Australia | 2,895,000 |
La Huifa | 2014 | Codelco | Chile | 2,430,000 |
Tatogga (Saddle) | 2017 | GT Gold | Canada | 2,173,159 |
Porvenir | 2019 | SolGold | Ecuador | 1,680,000 |
Llaguen | 2019 | Hudbay Minerals Inc. | Peru | 1,100,000 |
Jebel Ohier | 2013 | Qatar Mining | Sudan | 1,087,200 |
Marimaca | 2016 | Coro Mining 51%; Compa Minera Constanza 49% | Chile | 1,040,960 |
Elida | 2020 | Lundin Mining | Peru | 1,016,586 |
Chapada (Sauva) | 2021 | Lundin Mining | Brazil | 945,000 |
Julimar | 2020 | Chalice Mining Ltd. | Australia | 512,000 |
To add to the confusion and the complexities, the fact that you are featured as part of a list of a large deposit, as in Table 1, does not mean that you are an economical deposit. It is also prudent to remember that the time it takes to be an economical concept from discovery is normally measured in a decade, as a minimum, with some exceptions, and these are normally few and far between drinks (for the cricket fans).
Figure 2: A diagrammatic representation of the copper regions and their share of copper deposits. (source: S&P Global).
There is no doubt that South America is rich in copper deposits, as it is blessed with the perfect geology. The region is considered the King of Copper due to the abundance of naturally large-volume porphyry-style deposits. In terms of tonnage, 55.6%, or 730.9 million metric tons, of the copper in Figure 2 was discovered in Latin America.
Exploration has primarily focused on Chile and Peru, which together account for 573.9 million metric tons, or 78.5%, of the copper found in Latin America. The top three largest discoveries in our list are from Chile (Collahuasi and Los Bronces Underground) and Peru (Cerro Verde), see Table 2.
Table 2: The 20 largest copper discoveries from 1990 to 2023. (source: S&P Global)
Coming back to our reality, let's have a look at some potential characteristics that are featured in known major copper discoveries. These examples are standout projects, and the idea is to understand what kind of numbers one should be looking for to visualise some form of economical discovery.
The next part for your average investor is to look at the ASX announcements and then wonder if the results are any good. What makes a good result?. I ask that question many times, as nobody is an expert on every commodity or any project. What does a keen investor who has no geological background need to know?
Let's see if we can dissect all those parts in this Samso Insight.
Characteristics of Discovery Drillholes for Large Copper Deposits
One of the most common mistakes that investors make is not understanding the facts that indicate a discovery and the type of information that indicates the possibility of an economic discovery. What is the difference between a drill intercept of 2m @100g/t Au or 100m @ 2g/t Au? Does a single drill, like with great results, a discovery? Or is multiple adjacent lines with good results a discovery?
So let's try and make some sense of all the terminologies and the endless numbers. The following are chapters that will provide quick reference to the discussion.
1.0 Long Intercepts
You often get very thick zones — 100 to 300+ meters — of mineralisation.
The copper grades are relatively consistent over long intervals.
For example, at Kamoa and Kakula (Katanga, DRC):
Some early holes hit over 10% Cu over several meters, within broader zones of 2–3% Cu over hundreds of meters.
The Olympic Dam intercepts are also measured in hundreds of meters.
2.0 High Grades (for Copper)
Grades above 1% Cu over large thicknesses are already considered excellent.
Some Examples:
Kakula discovery hole: 11 meters @ 5.53% Cu within 36 meters @ 3.24% Cu (early drilling).
The discovery Hole DD1450 at the Kamoa deposit intersected 13.05% copper over 22.3 meters (true thickness) at a 2% copper cut-off grade. This intersection included multiple one-meter intervals with copper grades exceeding 20%, with one interval reaching 40% copper. The mineralization begins at a depth of approximately 190 meters below the surface. [source: Mining Review Africa]
The discovery Hole DD1124 at the Kakula deposit intersected 5.83% copper over 8.86 meters at a 2.5% copper cut-off grade, including a 6.14-meter interval at 6.84% copper. This discovery extended the known mineralized system at Kakula by approximately 800 meters, bringing the total strike length to about 11 kilometers. [source: Mining Review Africa]
DKMC_RC159 intersected 12m @1.32% Cu associated with malachite and native copper. [3] (Figure 3)
DKMC_RC177 intersected 6m @5.01% Cu. [3] (Figure 3)
Later holes: 8% Cu over 20–30 meters!
Figure 3: Diamond drill section 8811900N through the Kamoa deposit west of the Kamoa dome, looking north. Note the gently dipping strata, strattiform nature of mineralisation. (source: Broughton and Rogers 2010)
At the Olympic Dam discovery, RD1, drilled in July 1975, intersected 38 m @ 1.05% Cu, 70 ppm U3O8, 0.27 g/t Au, 3.5 g/t Ag at a depth of 353 m beneath the surface (Roberts and Hudson, 1983)
High-grade mineralisation was not intersected again until 15 months after RD1, in drill hole RD10, which intersected 170 m @ 2.09% Cu, 630 kg/t U3O8, 0.65 g/t Au, 3.1 g/t Ag.
In 2009, the Degrussa copper project released the following results,
47m @ 5.3% Cu, 2.01 g/t Ag and 1.0% Zn from 93m (DGRC105)
22m @ 3.6% Cu, 3.8 g/t Au and 13.4 g/t Ag from 96m (DGRC101)
18m @ 2.9% Cu, 13.0 g/t Ag, 2.1% Zn, 1.0 g/t Pd from 126m (DGRC101).
Escondida Porphyry Copper Deposit, Atacama Desert, Northern Chile
First hole, RDH-6, on the northern slopes of the Cerro Colorado, intersected 241 m of strongly leached capping before passing through 51 m of supergene chalcocite averaging 1.51% Cu, underlain by an additional 0.68% Cu enrichment zone and into a high pyrite/chalcopyrite primary zone.
The second hole, RDH-7, on the southern slopes of the hill passed through 137 m of leached cap, and then into 73 m of secondary chalcocite averaging 0.68% Cu, 55 m at 1.52% Cu and 37 m of 0.68% Cu.
The third hole, RDH-8 was further south again and over the best of the surface leached capping indications. It detected a 22 m thick interval of copper oxides assaying 0.8% Cu and an underlying 25 m of 0.67% supergene copper sulphide.
The final hole in this program, between RDH-6 and 7, and a little further east, penetrated 365 m of intensely leached capping, before intersecting 91 m of supergene sulphides averaging 1.30% Cu.
3.0 Shallow Depth - Maybe Not so now post 2025
Ideally, in the past, discovery holes should have found mineralization near surface or within 300m downhole, although this may be a characteristic of a few decades ago. The analogy in Figure 1 is now more the normality than not.
The idea of having a shallow deposit was that it would be cheaper to mine; however, as I have mentioned, this is now more about the grade and the length of interception.
4.0 Visual Cues in Core
Copper sulphides dominate, especially minerals like:
Chalcocite (Cu₂S) — bright steel-grey colour, very high copper content (~80% Cu).
Bornite (Cu₅FeS₄) — purple to iridescent colours ("peacock ore").
Chalcopyrite (CuFeS₂) — brassy yellow colour.
Massive or semi-massive textures — meaning much of the rock is made up of copper minerals.
Veinlets, replacements, disseminations are also common.
5.0 Good Geological Context
The discovery holes usually intersect:
Favourable stratigraphy (certain sedimentary layers).
Structural traps (like folds or faults).
Strong alteration (silica, carbonate, chlorite) surrounding mineralisation.
6.0 What Does The Drill Core from a Major Copper Discovery Look Like?
In early discovery holes from Kamoa-Kakula (and similar deposits):
You’d see thick sections of core looking dark and metallic from the chalcocite or bornite.
Figure 4: A sample of core from Sandfire Resources Limited (source: Sandfire Resources Limited )
Veins and massive sulphide zones can be several centimeters to tens of centimeters thick (Figure 4).
High copper content zones often look "heavy," reflective, and may even leave a metallic mark on your fingers when handling the core.
7.0 An Example of a Good Copper Discovery.
7.1 The Kamoa-Kakula deposit in the Democratic Republic of Congo (DRC)
One of the most significant copper discoveries in the past 30 years is the Kamoa-Kakula deposit in the Democratic Republic of Congo (DRC). Discovered by Ivanhoe Mines in 2014, Kakula is recognized as the largest copper find of the past decade, containing approximately 19.8 million tonnes (Mt) of copper with an exceptionally high grade of 2.58%. Combined with the earlier Kamoa discovery in 2008, which holds about 25 Mt of copper, the Kamoa-Kakula project ranks among the world's largest undeveloped copper resources.
The Kamoa-Kakula mine commenced production in 2021 and is projected to become the world's second-largest copper mine upon full expansion, with peak annual output exceeding 700,000 tonnes of copper. Its high-grade ore and shallow depth make it one of the most economically attractive copper mining projects globally.
These discoveries have significantly contributed to global copper resources, addressing the increasing demand driven by technological advancements and the transition to renewable energy.
7.1.1 Interesting Notes
Kamoa Deposit (2008): Discovered by Ivanhoe Mines' geologists, the Kamoa deposit is a near-surface, flat-lying, stratiform copper deposit. At the time of discovery, it was considered the largest high-grade copper discovery in Africa and the world's largest undeveloped high-grade copper deposit.
Kakula Deposit (2016): Approximately 5 km southwest of the Kamoa deposit, the Kakula deposit was discovered. It is characterized by its ultra-high-grade, shallow, and flat-lying stratiform copper mineralization, making it ideal for low-cost mechanized mining.
8.0 Other Notable Copper Deposits
Resolution Copper (USA): Discovered in 2002 in Arizona, this deep underground deposit is expected to supply up to 25% of U.S. copper demand over a 40-year lifespan. It holds an estimated 27 MMt of copper but faces environmental and regulatory challenges.
Oyu Tolgoi (Mongolia): Discovered in 2001, this mine is one of the largest copper and gold deposits globally, with an estimated 2.7 MMt of copper. It began production in 2013 and is a joint venture between Rio Tinto and the Mongolian government.
Timok (Serbia): Discovered in 2012, the Timok deposit contains approximately 16 MMt of copper and is notable for its high-grade ore and potential for rapid development.
9.0 Concluding comments from Samso.
The discovery of a copper deposit is without doubt a great prize for any company, and with a global narrative calling for more copper, this is as close you can come to finding the holy grail of mineral exploration. I have tried to keep my blog as simple as possible and used examples that are as definitive to being a world-class discovery.
The Kamoa-Kakula example serves as the benchmark of what defines a copper discovery in the modern age. The discovery of Escondida serves to show that a "low-grade" copper deposit mixed with the right ingredients is just as appetising.
It is never just about a single high-grade drillhole—it’s about continuity, scale, context, and the right rocks. Long intercepts with consistent grade, strong geological frameworks, and the ability to deliver economic extraction are what separates geological noise from genuine discovery.
As investors, the message is clear: be wary of the hype and be smarter with due diligence. The path from drillhole to production is long, complex, and often paved with many false dawns. Learn to read between the lines and recognise the signs of a true discovery. After all, in a world where copper is the bloodline of electrification, the rewards for getting it right are significant—but only if you can tell signal from noise.
One must always know and accept that copper is not a hidden treasure; it is one that teases investors with its geological charm and financial seduction (Check out Hot Chili Limited (ASX: HCH). Yet, what this Samso Insight reinforces is the clear distinction between a “drill hit” and a genuine discovery. Too often, market excitement is drawn from shallow headlines and not the substance of what makes a mineral system truly economic.
The takeaway here is simple — discoveries like Kamoa-Kakula, Olympic Dam, or DeGrussa did not emerge overnight, nor were they proven by one drill hole. They were built on consistent data, long intercepts, grade continuity, and most importantly, strong geological context. That is the bar. If an investor wants to understand copper exploration, they must become comfortable with the language of geology, not just the excitement of assay results.
Samso always reminds the market that exploration is a process, not a product. Discovery is the start of a journey, not the end. If you are investing based on a headline, step back and ask: Does it resemble what a real copper discovery has historically looked like? If not, you may be funding a drill program, not a mine.
10.0 Reference
Kinkela, Jai & Ziramov, Sasha & Dzunic, Aleksandar & Urosevic, Milovan & Hilliard, Paul. (2014). Seismic Exploration for Volcanogenic Massive Sulphides - The DeGrussa Copper-gold Mine, Western Australia. ASEG Extended Abstracts. 2015. 10.3997/2214-4609.20140503.
Hawke, Margaret & Davidson, Garry & Meffre, Sebastien & Hilliard, Paul & Large, Ross & Gemmell, Bruce. (2015). Geological Evolution of the DeGrussa Cu-Au-Ag volcanic-hosted massive sulfide deposit, Western Australia.
D. W. Broughton, T. Rogers, 2010. "Discovery of the Kamoa Copper Deposit, Central African Copperbelt, D.R.C.", The Challenge of Finding New Mineral Resources: Global Metallogeny, Innovative Exploration, and New Discoveries, Richard J. Goldfarb, Erin E. Marsh, Thomas Monecke
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