Free copper, in the form of nuggets, has never been abundant. Therefore, obtaining copper was not an easy task for the ancients. After cleaning the surface of earth and rock, rough tools were used to smash and pulverize minerals containing copper. Then the ore had to be smelted to separate and recover the metallic copper.
Until the 20th century, natives of Shaba in the Republic of Congo, they mined and smelted copper from a green gem-like mineral called malachite. In the 19th century, different tribes produced ten to fifteen tons of copper per year, all by hand. Let's take a look at how these people got the copper.
Native extraction and blending
The three main copper mining tribes were the Bayeke in the east, the Basangas in the central area and the Baluba in the west. The exploitation of copper for these peoples was a sacred profession. A wizard directed the work. Each mining group had its own professional secrets, traditions and superstitious rituals.
In May, at the onset of the drought, mining operations began. At this point, the harvest was ready, so that the important growing and harvesting of food would not be disturbed. The village chief signaled the start of the year's copper campaign by calling it “Tuye tukadie mukuba”, literally “We eat copper”. It actually meant: "We will enrich ourselves to support our lives."
As the village prepared to move to a temporary camp near the malachite deposits, the women prepared food. Axes and picks were collected, as well as baskets to carry bellows made of malachite and antelope skin to increase the heat of the furnace. When the caravan left, the wizards and rulers summoned the spirits to succeed.
As the deposits approached, and preferably near a river, grass huts were erected. Then, as the women and children scooped up malachite from the surface, the men went to work in the open air. Other people prepared charcoal for the ovens by cooking firewood in a pile of mud.
As men worked year after year in open pits, they reached 15 meters or more in depth and over 50 meters in diameter. And, imagine, those huge mining pits were dug by hand! After the ore was collected, it was pulverized and washed in reed baskets in the nearby river. Now was the time to melt the mineral.
The barrel-shaped ovens were built using mounds of mud and termites, the clay of which is particularly resistant to heat. The oven was usually a meter or more in length. Small holes were drilled in the sides and antelope skin bellows inserted into the holes provided a draft. The furnace was then lit with coal and other combustible materials. About one hundred kilograms of malachite ore were added.
Imagine the scene as the oven heats up. The foundry master added pieces of sacred bark or sprinkled ritual water into the oven. The two men operating the manual bellows worked feverishly to raise the fire until it was scorching. The spectators sang and danced to encourage their efforts and to summon the spirits.
Now, green flames have started to rise from the cauldron, announcing a heat close to 1,083 ° C, in which the copper melts. On the side of the furnace, a hole leading to a clay mold was ready to reveal the molten copper. Hence, the seemingly miraculous transformation has taken place. Once green, the malachite flowed like molten copper. It was considered the work of the spirits.
The merger continued in the field from mid-August to October. The villagers then set up a camp and returned home, where the copper was again smelted for refinement. Then it was molded into pots, pans, bowls and spoons. The warriors were equipped with helmets and shields made of copper. In addition, X-shaped copper crosses were used as currency, exchanged for desired goods.
Another way to model copper was wire. A bar of raw copper was hammered out over a large stone anvil. The stretching and thinning process continued to reach an even smaller anvil. The rod was then pulled over a small diameter wire with several ingenious methods. A copper ingot, less than six inches long, was drawn to a length of almost fifty feet with a diameter of only 0.02 inch! The thread was used to make bracelets.
It is not known to what extent copper-working activities in African tribes date back earlier. But the industry has developed so much that the tribes in this part of Africa produced some 700 tons of copper in the second half of the 19th century. Around that time, however, Belgian settlers arrived and indigenous extraction and smelting methods gave way to modern methods.
Current copper production
Today, large government-controlled companies oversee and operate the mines, as well as the necessary smelting plants. Some surface mines have turned into large stepped canyons, more than half a mile deep!
Instead of men working with picks and axes, explosives remove mineral deposits. Then, gigantic electric shovels gobble up up to 15.5 cubic meters of ore at a time and throw that "bite" into dump trucks capable of loading hundreds of tons of rock at a time.
The mineral is processed by washing it with water, spraying it and sieving it until the desired grain size is obtained. Copper ores generally contain less than 4% copper, but five tons of ore can produce only twenty pounds of copper. However, each year more than 5,750,000 tons of copper are produced worldwide. Modern large furnaces and an electrolytic recovery process separate copper much more quickly and efficiently than previous methods.
Today copper serves man in a thousand ways. Since copper is the best low-cost conductor of electricity, about half of the copper produced is used in the electrical industry. At home it is usually the basic material for locks, pipes, faucets, handles, chandeliers and lamps.
Therefore, from the days of Tubal-Cain, more than 5000 years ago, to the present day, copper has been a very useful servant to man.
Copper serves man in many ways