Humans Meet Metal

Between seven and ten thousand years ago, our early ancestors discovered that copper is malleable, holds a sharp edge, and could be fashioned into tools, ornaments, and weapons more easily than stone, a discovery that would change humanity forever. This meeting of humans and metals would be the first step out of the Stone Age and into the ages of metals: the Bronze and Iron Ages. Thus began the increased movement of elements and minerals out of their parent geological formations and into the air, soil, water, and living organisms by way of smelters, furnaces and mine tailings.

The first several thousand years of copper production contributed little to global or even local pollution. Copper is not very toxic in comparison to other metals and early humans used too little of it to begin concentrating it in soil, air, or water to the extent that it would affect human health or ecosystems. It appears that during the first few thousand years of its use, humans experiment with and learned techniques to utilize copper. As they got better at working with it, civilizations became more complex, which in turn often enabled better copper-working technology. With this came expanded use of copper and a greater movement of copper into our everyday environment.

Metallurgy is Born

Gold is believed to have been used earlier than copper, though its softness and scarcity made it impractical for widespread use, whereas copper is harder and found in pure form (“native copper”) in many parts of the world. (Gold and copper’s distinct colors and existence in pure form made it easy for our early ancestors to distinguish the two metals from other minerals and stones they came across.)

There is disagreement among archaeologists about the exact date and location of the first utilization of copper by humans. Archaeological evidence suggests that copper was first used between 8,000 and 5,000 B.C., most likely in the regions known now as Turkey, Iran, Iraq and — toward the end of that period — the Indian subcontinent. Archeologists have also found evidence of mining and annealing of the abundant native copper in the Upper Peninsula of Michigan in the United States dating back to 5,000 B.C.

Native copper was likely used first, as it did not require any process to purify it. It could have been hammered into shapes although it would have been very brittle. Annealing was the first step toward true metallurgy, when people discovered that copper became more flexible and easy to work with when it was heated before hammering. Next, casting of molten copper into molds was developed. At some point humans discovered copper ore and — possibly by accident — that the ore could be heated to very high temperatures in a low-oxygen environment to melt out the pure copper, a process known as smelting. This lent more flexibility to copper crafting; no longer was native copper the only kind of useful copper if copper could be extracted from ores.

Innovative Egyptians

By comparing the purity of copper artifacts from both Mesopotamia and Egypt, scientists have determined that the Egyptians improved upon the smelting methods of their northern neighbors in Mesopotamia. Most copper items in Egypt were produced by casting molten copper in molds. The Egyptians appear to have been one of several groups that independently developed the “lost-wax” method of casting, which is still used today. (Put simply, wax is formed into the shape of the end product, then covered in clay. The wax is melted out leaving a clay mold, which is then filled with molten copper. The mold is broken off when the metal is cool.)

Bronze is Better

The Egyptians may have been the first group to discover that mixing copper with arsenic or tin made a stronger, harder metal better suited for weapons and tools and more easily cast in molds than pure copper. (Since copper ore often contains arsenic, this may have been the unintentional result of smelting copper ore that included naturally occurring arsenic.) This alloy of copper with arsenic or tin is called bronze, and there is archeological evidence that the Egyptians first produced bronze in 4,000 B.C. Bronze may have also been developed independently in other parts of the Middle East and other parts of the world. Regardless of where it originated, bronze metallurgy soon overtook copper in many parts of the globe, thus ushering in the Bronze Age. (In parts of the world that lacked deposits of tin, copper was used alone or alloyed with other metals until iron was introduced.)

The smelting process for bronze made with arsenic would have produced poisonous fumes. People may have preferred tin-based bronze or found that it was easier to control the amounts of tin added to copper than it was to control the amount of arsenic, which often occurred naturally in copper ore. Whatever the reason, bronze made with tin soon became the bronze of choice throughout the Middle East.

Tin deposits were more confined to certain geographical areas than copper, which was readily available in many parts of the Middle East as well as other parts of the world. As people began using bronze instead of pure copper to make weapons and tools, trade in tin developed. The availability of bronze led to more advanced tool and weapon making, and with better weapons, armies could better conquer neighboring societies (and plunder their tin and copper resources).

Copper Crafting and Spirituality

As copper helped humans to advance warfare, it also has played a role in the religious and spiritual life of people around the world through time. Hathor, Egyptian goddess of the sky, music, dance and art, was also the patron of Sinai, the major copper mining region of the Egyptians; she was often referred to as “Lady of Malachite.”

To the people of the Andes in South America, who developed the most advanced metallurgy in pre-Columbian America, copper metallurgy was more than a secular craft for producing tools. Using native copper, Andean artisans made religious items from pounded copper foil and gilded copper.

Copper also plays a role today in many New Age beliefs. In some modern religions, it is seen as having healing powers, both spiritually and physically. Some people wear copper to help alleviate the symptoms of arthritis.

Bronze Buddhas and Copper “Cash”

Copper was first used in China around 2500 BC. The Chinese quickly began using bronze as well, and used different percentages of tin in bronze for different purposes. They used copper and bronze extensively for coinage. During the flourishing economic activity and expanded foreign trade in the Sung dynasty, circa 900 to 1100 AD, the use of cash—round copper coins with a square hole in the middle—exploded. Copper production was now reaching almost industrial proportions in some civilizations, though probably nowhere more than in ancient Rome.

The Romans: Precocious Polluters

Although iron and lead were in use by the era of the ancient Romans, copper, bronze, and brass (an alloy of copper and zinc) were used by the Romans for coins, aspects of architecture such as doors, and some parts of their extensive plumbing system (although pipes were made of lead). They also developed pipe organs made with copper pipes.

The Romans controlled extensive copper deposits throughout their empire. Scientists analyzing copper isotopes and trace metals present in Roman copper coins have determined that Rio Tinto, Spain (still a working copper mine), Cyprus, and to a lesser extent Tuscany, Sicily, Britain, France, Germany and other parts of Europe and the Middle East were sources of copper for the Empire. Increased purity of Roman copper coins over time also shows that their smelting methods improved quickly.

The Romans in their heyday produced nearly 17,000 tons of copper annually, more than would be produced again until the Industrial Revolution in Europe. With this enormous output of copper came pollution that would be unsurpassed for almost two thousand years when the Industrial Revolution began. Did polluted air from early copper smelting affect the health of humans living in ancient times? Probably. Early smelting methods at that time were crude and inefficient by the standards of today. Copper smelting and to a lesser degree copper mining produced ultra-fine particle dust that was carried into the atmosphere on air currents created by the intense heat from smelting operations. Most of the pollution would have fallen near the smelting sites, causing health problems and contaminating soil and water.

The copper pollution of the Roman days still haunts us today. One former Roman copper mine and smelting site in Wadi Faynan, Jordan is still — two thousand years after it ceased operations — a toxic wasteland littered with slag from copper smelting. Researchers have discovered that vegetation and livestock in Wadi Faynan today have high copper levels in their tissue.

The Industrial Revolution: Picking up Where the Romans Left Off

Beginning in the late 1600s, copper smelting became a major industry in Great Britain. Copper ore from Cornwall and other areas and coal deposits throughout the country fueled the smelting of copper. An abundance of coal in Swansea, Wales made this coastal town a prime location for Britain’s copper smelting activities beginning in early 1700s. The copper industry drove the economy of this town. Wealthy English people often owned smelters, while local Welsh people worked as laborers in the industry. Just as in ancient Rome, copper smelting had its price. The town and once lush countryside surrounding Swansea was stripped of vegetation by noxious copper smoke that billowed from the smelter stacks and settled on the surrounding town and fields. Topsoil on denuded hillsides succumbed to erosion. Livestock developed strange new ailments like swollen joints and rotten teeth. Farmers blamed the smoke. The smoke also reportedly caused shortness of breath, decreased appetite, and other complaints in humans.

The Cornish copper ore purified in the Swansea smelters was high in arsenic, sulfur, and fluorspar (a compound of the element fluorine). The smelters emitted fumes from these compounds along with exhaust from the coal that fired the operations. The sulfur and fluorspar from the smoke mixed with water and oxygen in the atmosphere to produce sulfurous, sulfuric and hydrofluoric acids which rained down on Swansea as acid rain. Copper slag and other waste covered the landscape near the smelters.

Eleven years later, a group of Welsh farmers from outside Swansea sued one of the major smelter owners for public nuisance, claiming that the smelter smoke was damaging their farms. The owner of the copper smelter hired one of the best lawyers in the country, who fought the plaintiffs on the basis that the town depended on the copper industry for its economic survival and that the crop failures and sick livestock were the result of the Welsh people’s backward farming methods and the disagreeable Welsh weather. The farmers lost the suit.

Conductive Copper

Copper played a central role in the technologies developed during the industrial revolution. One of the most important uses of copper at that time was in electrical engineering. Early scientists experimenting with electricity chose copper as a transmitter because it is highly conductive (can transmit electrical current easily). The electrical engineering industry today is the second largest consumer of copper.

The Price of Industrialization

Although production methods have improved since the time of the Romans and the Industrial Revolution, today copper production makes a hefty contribution to global pollution.

Butte, Montana is home of an abandoned copper mine once owned by the now defunct Anaconda Copper Mining Company, established in Butte in 1895. Until the major Butte mine operations closed in the 1980s, the mine produced 20 billion pounds of copper. Until the 1950’s, it produced one third of the country’s copper and was an important supplier for the nation during the two World Wars. The former mine is now the largest Superfund site in the country. The main open pit has filled with water since the termination of mining activities, forming a 600-acre lake. Copper, lead, cadmium and arsenic contaminate the huge pit, which is recharged with water every day from an aquifer below—making the toxic lake nearly impossible to clean up. Sulfur, a mineral that is commonly a component of copper ore, reacts with air and water, producing sulfuric acid, which fills the pit. Mine runoff and fallout from the smelter once owned by Anaconda cover the landscape. A 1,000-acre tailings pond sits near the main pit.

The Anaconda Company also owned a massive copper mine in Chuquicamata, Chile that operated from the 1920s to the 1970s. Chilean mine laborers lived in tiny company-owned apartments with minimal plumbing facilities. Wives and family of miners waited in lines daily for access to the meager provisions at the company store designated to the lowest class of mine employees. Their employment status also dictated which schools their children could attend. Strikes were also a regular part of life for miners and their families. Ethnographer and Butte, Montana native Janet Finn writes, “In establishing labor, community, and government relations in Chuquicamata, the company turned to tried and true methods practiced in Butte: blacklists, bribery, and occasional brute force tempered with amusements that embraced both vice and virtue.”

Anaconda Company’s Chuquicamata mine was closed in 1971 after the Chilean government nationalized the country’s copper resources. However, copper mining is still a major industry in Chile. A University of Chile study in 1999 showed that copper mining, smelting, and refining accounts for a significant portion of the greenhouse gas production and other air pollution in that country and accounts for the largest consumption of fossil fuels in Chile as well as a significant amount of electricity. This contributes to global carbon dioxide levels, which contribute to global warming. Additionally, during the smelting process, large quantities of sulfur dioxide (SO2), a precursor to acid precipitation, are released from the sulfide ores, the most commonly mined copper ores in Chile.

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