The quest for metals, both precious and base, has fired Virginians since before the founding of Jamestown.
The Powhatan Indians wore and used copper, traded from as far west as the Great Lakes. The Virginia Company of London, envious of New World riches flowing to Spain, instructed the Jamestown colonists to look for gold.
The colonists at times neglected to plant or tend crops, instead filling barrels with sparkle-flecked earth. But when Christopher Newport turned over the “ore” to metallurgists in England, the sparkle proved merely a gleam in their eyes–pyrite, or fool’s gold.
In fact, the geology of Virginia conceals large quantities of gold, as well as the base metals (that is, neither precious nor iron) copper and zinc, as well as the strange metal uranium. But neither the early English nor the Powhatans had the technological know-how to exploit Virginia’s mineral wealth.
Gold was being mined in Virginia at least as early as 1825. A Mecklenburg County mine was producing copper in 1733. But for every ounce extracted, much more was left in the ground.
Now, with advances in prospecting, a Canadian company called Aston Bay Holdings is taking a second look at minerals in Southside: gold in Buckingham County and copper and zinc in Pittsylvania County.
Whether any large-scale mining will take place is open to question. In 2021 the General Assembly created a work group to assess the desirability of gold mining in Virginia. The Press Pause Coalition is urging caution on copper and zinc mining in Pittsylvania. One of the world’s largest known uranium deposits, at Coles Hill in Pittsylvania, lies undisturbed due to a 1982 state moratorium on uranium mining (upheld by the U.S. Supreme Court in 2019 and a separate Virginia court ruling in 2021).
This is the story, not of the wealth they create, or the environmental or political questions they raise, but of simply how these elements, as ordinary as the copper-plated zinc penny in your pocket, or as potent as the uranium that powers nuclear subs, got mixed up with the rocks underneath the fields and forests of Southside Virginia.
Scientists believe the metallic, heavy elements were created in stellar proceses, supernova explosions, and mergers of neutron stars. A single neutron star merger event is believed to have created gold equivalent to the mass of three to 13 Earths, according to a 2018 report in the Astrophysical Journal. Imagine a solid gold Earth – or 13 of them.
Drifting through space for millions of years, the residues of these titanic events eventually coalesced into our solar system, along with lighter elements, forming the Sun and the planets including Earth with its core, mantle, and crust.
Gold, element 79, has 79 protons in its nucleus. It is denser even than uranium, number 92, because more of it is packed into a unit of volume. Most of the Earth’s primordial gold sank to its core, where it will forever remain beyond acquisitive hands. The gold that is accessible to humans arrived later, in asteroid bombardments, and remains in Earth’s crust.
Gold and copper are native metals, meaning they occur in pure or nearly pure form, and have been mined since ancient times. But usually they are found mixed in an ore. Isolating the pure metal from ore had to wait until humans learned to smelt. Locating and extracting deep underground ores had to wait for the development of modern mining techniques.
Picture a strange planet. This planet is the Earth, long before the time of the dinosaurs. The continents and oceans look nothing like those of today. The land forms are dominated by the supercontinent Rodinia, with part of modern North America at its heart.
Hundreds of millions of years ago, Rodinia began to split, state geologist David Spears wrote in an email. The gap was filled by seawater, the beginnings of the Iapetus (EYE-a-pettus) Ocean. Seawater seeped down into the cracks in the ocean floor, where it was infused with metals and sulfur, forming metallic sulfides. The hot, acidic, metal-rich water was then “exhaled” back up, where it mixed with colder, more alkaline seawater, “causing the metallic sulfides to precipitate onto the seafloor where they became buried in mud derived from the nearby continent,” Spears wrote.
Later, the seafloor rose, shedding its ocean blanket, and parts of it became the dry land of modern Pittsylvania County. “Several other belts of rocks were added to the east during later tectonic events, and that is why the Pittsylvania seafloor deposits are so far inland now,” Spears wrote.
Those metals, including zinc and copper, are still there in the rock under Pittsylvania County, where Aston Bay is searching for them in samples drilled from as deep as 1,000 feet.
To the northeast of Pittsylvania, in Buckingham County, Aston Bay is searching for gold.
The Aston Bay discovery in western Buckingham is also in rocks that formed in a seafloor setting, Spears wrote, but the gold came later, when hot fluid containing gold and quartz seeped into fractures in the rock, forming veins. A vein is a sheet or layer of minerals.
Aston Bay CEO Thomas Ullrich described this as “a single vein about two meters wide… a high-grade vein.” He said he could not disclose the exact location due to a confidentiality agreement with the owners of the property.
“Aston Bay is also drilling farther to the east in Buckingham, in the Virginia Gold-Pyrite Belt, the historic location of most of Virginia’s abandoned gold mines,” Spears wrote.
“There is an old mine that was exploited up until 1850 or so,” Ullrich said. “It was an underground mine. They originally mined about 125 feet down. The reason they stopped mining was they didn’t have the technology to go any deeper.”
The Gold-Pyrite Belt is the remnant of a volcanic arc that formed along the eastern edge of North America, Spears wrote. A volcanic arc is a chain of volcanoes that forms an arc shape.
Geologists believe that sections of the earth’s crust, called plates, float on the semi-solid mantle.
“Volcanic arcs of this sort form where oceanic plates are colliding, and one plate is being subducted [pulled] beneath another oceanic plate,” Spears wrote. “The downgoing plate contains cold, wet seafloor sediments, but as it is driven downward, it becomes hot…this volatile mixture then rises through the crust…the hot fluids also carry metals and sulfur, which become interlayered with the volcanic rocks as they are deposited.”
And there they remain, until further geological processes disturb them — or human beings come along.
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In a nondescript former school building on Douglas Avenue in Martinsville, stacked up on shelves, stored in pizza-sized boxes of cardboard and wood, lie thousands of rock cylinders. Each is a section of a core drilling. “They use a hollow drill stem with a diamond face and it cuts its way down while it’s being lubricated with fluids,” said Bill Henika, a research associate with the Virginia Museum of Natural History, which maintains the storage facility.
Accounts vary of how Pittsylvania County’s uranium was discovered. A 2010 article in New Republic states that a geologist named Byrd Berman, prospecting for Marline Uranium, was driving along a rural road in 1979 when the scintillometer sitting on his dashboard began to beep. A scintillometer is similar to a Geiger counter. On the other hand, Robert Bodnar, a Virginia Tech professor of geochemistry who has studied the Pittsylvania uranium, heard that it was discovered by a man working for the National Uranium Resource Evaluation project.
Marline became interested in the area due to its geological similarities to Canada’s Athabasca Basin, location of a large uranium deposit, Bodnar said. Definitive documentation came during an aerial survey.
Regardless of who discovered it, sources agree that the deposit, located at Coles Hill, northeast of Chatham, is one of the biggest in the world. Bodnar puts it at around 113 million pounds of uranium. This does not mean the ore is high-grade–in fact, Bodnar said, the concentration of uranium oxide in the deposit is very low. But there is a huge amount of ore, some 119 million tons.
How much energy is in the uranium under Coles Hill?
The uranium nucleus is packed with 92 positively-charged protons, which repel each other. When hit by a precisely aimed neutron of the correct energy, the nucleus splits in two. The energy released when a single uranium nucleus splits is enough to make a grain of sand visibly jump. (Conditions must be right; there is zero chance of a natural deposit like Coles Hill exploding.)
Where does that energy come from? When the uranium atom splits, the mass of the two fragments combined is less than the mass of the original atom. The missing mass is converted to energy. The equation relating mass and energy is one that everyone knows:
e = mc2
where e = energy, m = mass, and c is the speed of light. The speed of light is a huge number, 186,000 miles per second. Square that number and even a tiny amount of mass is converted into a staggering amount of energy.
How did the uranium get in Coles Hill? “That of course is the million dollar question,” said Bodnar, comparing it to the police investigation that follows the discovery of a dead body.
During the Triassic era, which saw the rise of the dinosaurs, the North American continental plate was attached to the African plate. When the plates started to separate, rifts developed at and around the line of separation, and started to fill with rainwater runoff and sediment. The biggest rift became the Atlantic Ocean. Other adjacent rifts remain under the dry land of Virginia. These rifts are called, somewhat misleadingly, Triassic Basins. The “basin” that cuts through Pittsylvania, appearing as a blue-green strip on some geology maps, is shaped like an irregular ditch, not a bowl.
Over tens of millions of years, water carrying tiny amounts of uranium flowed west through Pittsylvania’s Triassic Basin, Bodnar said. Along the basin’s western edge, called the Chatham Fault, the uranium-carrying water encountered chemically different rocks. “They changed the chemistry such that the solubility of the uranium decreased dramatically,” Bodnar said. “That then caused all the uranium that was being transported in the fluids to be deposited in the rocks that make up the current Coles Hill deposit.”
That, at least, is Bodnar’s best guess. He said that the truth about Coles Hill would only be known if the deposit were opened to mining–a process he compared to a forensic autopsy.
Whether Virginia will ever see uranium mining, or large-scale gold mining, will be decided by politicians. The gold mining study group must report its findings to the General Assembly by Dec. 1, 2022. But regardless of events in the political world, geologists will always be interested in processes that dwarf the human time scale.
Bill Henika, the geologist with the Virginia Museum of Natural History, was walking through the museum’s parking lot on the way to visit the core storage building. Chatting about a certain geological event, he said: “It was very, very quick, only about a million years or so.”