Everything You Need to Know About Copper Porphyries - Infographic
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Everything You Need to Know About Copper Porphyries

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Everything You Need to Know About Copper Porphyries

Everything You Need to Know About Copper Porphyries

Presented by Entrée Gold

What is a Porphyry?

Porphyry deposits are very large, polymetallic systems that typically contain copper along with other important metals. Much of today’s mineral production depends on porphyries: 60% of copper, 95% of molbdenum, and 20% of gold comes from this deposit type.

Where and How are Porphyries Formed?

Porphyries are most commonly found along the west coast of North and South America, as well as in the Southwest Pacific.

Porphyries are formed in tectonic plate convergent zones where oceanic crust has subducted beneath the continental crust, and in some cases the oceanic crust. As the plate subducts, the overlying upper mantle partially melts and the liquid magma rises to the surface. Hot fluids rise to the surface by flowing through cracks and fissures. Metals precipitate out of the solution as fluid cools and moves away from the heat source and pressure.

Mineralization

In porphyry mineralization, there are many economic minerals that can be found: copper, gold, molybdenum, silver, lead, zinc, tin, and tungsten. There are also associated mineral deposits that can form that depend on the host rock and the distance from the heat source. These include skarn, epithermal, and breccia type deposits.

Four Things to Know on Porphyries

  1. Polymetallic nature – Each porphyry is unique and holds different concentrations of minerals. Some deposits have such high concentrations of gold that they may be considered gold deposits rather than copper deposits. Others have barely any gold at all but may have plenty of molybdenum.
  2. Large Size, Low Grade – Porphyries typically have 100 million to 5 billion tonnes of ore with a lower grade (0.2% to >1% copper). It is the size of these deposits that allow for bulk mining and economies of scale.
  3. Long Mine Life – The size of porphyry systems usually mean that the life of the mine can be multi-decades long. This means that these deposits last through multiple market cycles, and are thus not as vulnerable to challenging market environments compared to other smaller mines.
  4. Infrastructure is Key – In order to process large amounts of ore, infrastructure can be a large part of initial capital expenditures (CAPEX). Access to power and water are key issues as large amounts of both are needed to process ore. The footprint of the mine and volume of tailings disposal can also make porphyries more challenging to permit.

Example Porphyry

Each year the Bingham Canyon Mine, located in Utah and owned by Rio Tinto and in production since 1906, produces approximately:

  • 300,000 tons of copper
  • 400,000 oz of gold
  • 4,000,000 oz of silver
  • 30,000,000 lbs of molybdenum

The value of the resources extracted to date from the Bingham Canyon Mine is greater than the Comstock Lode, Klondike, and California gold rush mining regions combined.

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Energy

Visualizing U.S. Consumption of Fuel and Materials per Capita

Wealthy countries consume large amounts of natural resources per capita, and the U.S. is no exception. See how much is used per person.

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Visualizing U.S. Consumption of Fuel and Materials per Capita

This was originally posted on Elements. Sign up to the free mailing list to get beautiful visualizations on natural resource megatrends in your email every week.

Wealthy countries consume massive amounts of natural resources per capita, and the United States is no exception.

According to data from the National Mining Association, each American needs more than 39,000 pounds (17,700 kg) of minerals and fossil fuels annually to maintain their standard of living.

Materials We Need to Build

Every building around us and every sidewalk we walk on is made of sand, steel, and cement.

As a result, these materials lead consumption per capita in the United States. On average, each person in America drives the demand of over 10,000 lbs of stone and around 7,000 lbs of sand and gravel per year.

Material/Fossil FuelPounds Per Person
Stone10,643
Natural Gas9,456
Sand, Gravel7,088
Petroleum Products 6,527
Coal 3,290
Cement724
Other Nonmetals569
Salt359
Iron Ore239
Phosphate Rock 166
Sulfur66
Potash49
Soda Ash36
Bauxite (Aluminum)24
Other Metals 21
Copper13
Lead11
Zinc6
Manganese4
Total 39,291

The construction industry is a major contributor to the U.S. economy.

Crushed stone, sand, gravel, and other construction aggregates represent half of the industrial minerals produced in the country, resulting in $29 billion in revenue per year.

Also on the list are crucial hard metals such as copper, aluminum, iron ore, and of course many rarer metals used in smaller quantities each year. These rarer metals can make a big economic difference even when their uses are more concentrated and isolated—for example, palladium (primarily used in catalytic converters) costs $54 million per tonne.

Fuels Powering our Lives

Despite ongoing efforts to fight climate change and reduce carbon emissions, each person in the U.S. uses over 19,000 lbs of fossil fuels per year.

U.S. primary energy consumption by energy source, 2021

Gasoline is the most consumed petroleum product in the United States.

In 2021, finished motor gasoline consumption averaged about 369 million gallons per day, equal to about 44% of total U.S. petroleum use. Distillate fuel oil (20%), hydrocarbon gas liquids (17%), and jet fuel (7%) were the next most important uses.

Reliance on Other Countries

Over the past three decades, the United States has become reliant on foreign sources to meet domestic demand for minerals and fossil fuels. Today, the country is 100% import-reliant for 17 mineral commodities and at least 50% for 30 others.

In order to reduce the dependency on other countries, namely China, the Biden administration has been working to diversify supply chains in critical minerals. This includes strengthening alliances with other countries such as Australia, India, and Japan.

However, questions still remain about how soon these policies can make an impact, and the degree to which they can ultimately help localize and diversify supply chains.

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