mining for meteors
Billboards
Route 66 is often viewed through the lens of its billboards. The Jack Rabbit Trading Post, a small store a few miles out of Joseph City, would hardly be remembered were it not for its billboards spanning four states. The tradition of far-advance billboards is still observed today. Albuquerque's roadside stop operator Bowlin puts billboards six hours and two freeway exchanges out from its combined gas station-Dairy Queens. One can ponder the mystery of "The Thing" (near Benson, Arizona) throughout nearly the entire state of New Mexico.
So, if you have driven anywhere over a several-hundred-mile span of Interstate 40 (the modern-day successor to Route 66 in this area), you are probably aware of the Meteor Crater [1]. At Meteor, Arizona, between Flagstaff and Winslow, the Meteor Crater earns its nonspecific name: it was the first crater definitely shown to have been the result of a meteor impact. It is a spectacular sight, almost 4,000 feet wide and 600 feet deep. It is also known by another name: Barringer Crater, for the family that has owned it for over one hundred years.
Today, Meteor Crater is one of the few traditional Route 66 roadside attractions to have held on to much of its vitality. A steady flow of visitors pay admission to see the crater and its attached visitors center, somewhat ostentatiously styled as the Barringer Space Museum. The museum focuses on the crater's two major connections to space: first, that it was formed by a meteor that came from there. Second, and most importantly, that the crater has been used as a training site for astronauts since the Apollo era.
I assume it has been calculated that these are the two topics that draw visitors, because the museum devotes almost no space at all to what I consider the most fascinating of the crater's many stories: that the crater was a mine. Forget space; the Meteor Crater is the greatest artifact of a fascinating, but brief, chapter of American mining history.
Meteorites
But first, as dismissive as I may be, we must talk a bit about space. During the 19th century, detailed observations of meteor showers established that the bright trails of light seen in the night sky---previously assumed to be some atmospheric phenomenon---must in fact be the collision of objects from space with the atmosphere. The idea that rocks or something were flying out of space and into the upper reaches of our world naturally suggests that some of them might make it all the way down. Indeed, as early as 1803 such a meteorite [2] had been found on the ground in France following a meteor shower, although the idea that it had fallen from above was not universally accepted until much later.
Chemists analyzed a number of meteorites recovered during that era and found that almost all of them contained significant amounts of iron, and their geological oddities (such as the inclusion of spherical globules of metal) supported the idea that they had formed in space. By the turn of the 20th century, it was generally understood that meteors were chunks of mostly iron that came from somewhere out there and collided with our planet, and that some of them made it all the way to the ground.
What was not well understood by that time was the fate of those meteorites. Since the 17th century it was known that there were craters on the moon, and the idea that they had been formed by impacts is nearly that old as well. Even three hundred years later, though, it was far from a settled matter. Volcanic activity was also a promising explanation, and one that many felt to be more comfortably within the bounds of reason. In the year 1900, many astronomers would have been quite dismissive of the moon-meteorite theory, as the opinion of the day favored a moon with an active volcanic core.
The idea that impacts had formed vast craters on Earth must have been even more far-fetched. Besides, the known meteorites were quite small, more prone to knocking holes in roofs than in the very desert. It was in this context that the Meteor Crater was first examined.
Okay, we're done with that boring space stuff. Let's talk about mines!
In 1891, a small mining firm based out of Albuquerque received a sample from a prospector in Arizona. The prospector had found an ore vein in a remote part of that territory that he believed to be quite valuable. Indeed, an assayer put the included sample at a remarkable 77% iron, with a bit of lead, silver, and gold to boot. Observing its purity and unusual structure, the assayer figured that it had been melted in a furnace.
The mining firm, amazed by this new ore and skeptical of the assayer's attribution to a furnace, circulated parts of their sample among a number of business leaders---men who might put up the money for a large-scale mining operation. One of them, James Williamson of Civil War fame and by then an executive the Atlantic and Pacific Railroad, sent his sample to mineralogist Albert E. Foote of Philadelphia for his thoughts on its commercial value and exploitability. Foote, recognizing the sample's unusual structure, knew immediately that the prospectors claim of a vein two miles long and up to forty yards wide could not be entirely true [3]. It was a meteorite.
In truth, the "ore" was one of a number of small fragments (where "small" still often surpassed 100 pounds) that could be found over a large area near Cañon Diablo and a feature known to locals as "Crater Mountain." Foote described the "so-called 'crater'", "the sides of which are so steep that animals that have descended into it have been unable to escape and have left their bleached bones at the bottom." Foote carefully searched the rim, but found no evidence of volcanic activity, leaving the crater's origin a mystery. Foote's blindness to the crater's connection with the meteorite fragments is almost hard to believe, but he seems to have taken it as a coincidence.
The remarkable quantity of oxidized black fragmental material that was found at those points where the greatest number of small fragments of meteoric iron were found, would seem to indicate that an extraordinarily large mass of probably 500 or 600 pounds had become oxidized while passing through the air and was so weakened in its internal structure that it had burst into pieces not long before reaching the earth.
Indeed, that same year, the chief geologist of the USGS visited the crater and reached the same conclusion. The crater's proximity to the meteorites seemed to be chance. The crater itself must be the result of a vast steam explosion, which was, after all, not an unknown phenomenon in that part of the Arizona territory.
The late 19th century saw the formation of the Division of Forestry (of the Department of Agriculture) and a related reorganization of the General Land Office, precursors to today's Forest Service and Bureau of Land Management. Large areas of public land would be withdrawn from the GLO's management (which consisted mostly of sale to private owners) and reserved as National Forests. In eastern Arizona, this controversial task fell on GLO agent S. J. Holsinger. He traveled the region extensively in studying forest issues and establishing the boundaries of what would become the Coconino National Forest. Although he never saw it for himself, he heard stories of an enormous crater, near what he called Coon Mountain or Coon Butte. The stories held that fragments of iron, from a meteor, had been found within and around it.
The record is unclear on where or how, but one day in October of 1902, Holsinger found himself in a casual conversation with a mine engineer by the name of Daniel Barringer. Perhaps they sat by each other in a saloon or a train station. Perhaps Barringer told Holsinger that he worked in iron mining, and Holsinger said something along the lines of "I'll tell you about some iron." In any case, Holsinger described the meteorites, and the crater---as they had been described to him. Some of the locals, Holsinger said, had a theory: that the crater had actually been formed by the meteorites. That a single meteorite larger than ever seen before had crashed into the earth, burying itself far below, and leaving behind the feature known as Coon Mountain, or Crater Mountain, or Sunset Knoll as the USGS had labeled it on maps.
Barringer was hooked. He wrote back to Holsinger for more information, he researched the area, and he involved his friend Benjamin Tilghman, the inventor of sandblasting and a general scientific type in the pattern of the era, in the pursuit. They became convinced that the USGS had been wrong, and the locals right: that it was not just a crater, but a Meteor Crater. So, they bought it.
Iron
Although Barringer was well-qualified as a geologist and was clearly fascinated by the crater, his interest in it was not purely scientific. In a 1905 paper making his argument for its meteoritic origin, Barringer reports that the iron fragments from the meteorite had already been commercially exploited. A nearby merchant had hired laborers to search the area around the crater for the "iron ore," and they had found some pieces as heavy as 1,000 pounds. Of the smaller pieces that they collected, the merchant estimated that between his efforts and those of another businessman, perhaps 15 tons of the iron-rich material had been shipped away for smelting.
Barringer and his business partners had found thousands of fragments, ranging from over 200 pounds to less than an ounce. These "Cañon Diablo siderites" could be over 90% iron, the rest being mostly nickel.
Among the evidence he cites for the meteoritic theory, Barringer observes that every single one of these fragments had been found immediately on the surface, and only a handfull had ever been found inside of the crater. They were not themselves buried by impact; they seemed to be found right where they lay after they were ejected from the crater with great force.
Barringer's tone in the 1905 paper is, well, critical, particularly where it comes to the USGS geologist who had declared the crater a product of a steam explosion, Gilbert. Barringer suggests that Gilbert's rejection of the meteoritic theory could only be the result of a profound failure to notice geological inconsistencies that ought to have been obvious. The presence of a great amount of fine silica in every direction from the crater (sometimes called "rock flour," this very fine sand is the result of impact forces instantaneously shattering a large area of bedrock), the distribution of iron fragments neatly centered on the crater, and the upturned and sideways geological layers found in the rim all indicated that the rim had been "heaved out" of the crater itself by a great force.
To definitively prove his theory, though, Barringer relied on trenches in search of buried fragments. If Barringer was correct, there should be fragments of the meteorite mixed randomly within the other ejecta of the crater. It took some effort, but eventually Barringer reported clear cases, including a large iron fragment found underneath a slab of sandstone that must have come from 400 feet below the surface.
Still, Barringer had bigger plans: he intended to find the original meteorite itself--the core from all of the fragments had broken. With a horse-driven drill, his employees sunk numerous shafts from 200 to over 1,000 feet deep. Many seemed to strike iron material, but Barringer believed them to be mere fragments, not the great cluster of broken iron that must be present somewhere beneath the crater.
His belief in this huge iron core explains the mining patent he took out on the behalf of his company, Standard Iron. He planned to find it and sell it. By his estimate, based on a crude analysis he developed, it would have a market value in the range of one billion dollars.
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Shafts
Barringer was enthusiastic about his meteor theory in a charmingly turn-of-the-century way. He had invented, he said, the field of "meteoritics," or the study of meteors. A central concern of meteoritics was the ballistics of a meteorite: what happened when a meteorite struck the ground.
Today, thanks in large part to World War II munitions research and the nuclear weapons program, we have considerable theoretical and experimental information on how solid objects penetrate soil and rock---a topic that Sandia Laboratory, operating with similar zeal for the new frontiers of science, dubbed "terradynamics." This work began in the 1930s; Barringer was too early to benefit. He had to develop a similar theory on his own.
Understanding the geology of the crater involved a huge effort, particularly in such a remote location. Barringer had to build out a considerable operation, and he had to do so by remote. He was already a known figure in Arizona, having launched a particularly successful mine, and he worried that anyone that got word of his interest in the crater would attempt to jump his claim. Instead of traveling to Arizona, be brought in relatives and friends as business partners and even hired Holsinger away from the Division of Forestry to act as land manager. Barringer and Holsinger chartered a railroad to the site, established mill sites on the Little Colorado River and Oak Creek, and constructed a water reservoir. A camp was established at the base of the rim, and an expanding workforce started on holes, trenches, and a shaft straight down in the center of the crater.
Barringer first reached the crater in 1904, where he learned that the central shaft had been abandoned at 200 feet of depth due to the fine silica forming a quicksand that quickly filled the excavation. He opted for a different approach, buying a 4" drill and sinking five smaller shafts in the crater floor. Most of these shafts ended when they struck meteorite fragments too hard for the drill. One, managing to dodge any large pieces of iron, found no new meteoritic material after 550 feet, and reached intact bedrock at 1000 feet. These observations lead Barringer to conclude that the crater had originally been deeper but had been partially filled back in by the material that was thrown into the air.
Barringer thought that a steam hoist might allow them to excavate the quicksand more quickly than it filled, allowing progress on the larger shaft in the crater's center. Barringer called off the drilling effort and shifted focus once again to the shaft, spending 1905 excavating a larger clean shaft to the level of the quicksand. In 1906, the race against the soil was attempted, but failed. The next year, drilling resumed at an accelerated pace, with sixteen new boreholes completed in 1907.
Each bore found meteor fragments down to nearly 600 feet, but there was no evidence of the meteorite itself. Barringer began to develop a new theory: the meteorite was not directly below the crater.
He conducted a series of simple ballistic experiments: he shot a rifle into the ground. The impact of the bullet into the desert soil, he reasoned, would behave similarly to the impact of a meteorite into the same. His easy target shooting lead to an interesting finding. Regardless of the angle at which he shot the ground, the resulting hole appeared round. The meteor, he realized, likely didn't come straight down; it struck at an angle.
Analyzing the rim, he came to believe that the meteorite would be found somewhere beneath the south rim. More fragments were found to the north, and the south rim had been lifted higher than in other directions. He had a new target, but there was a problem... he was out of money. Barringer had started the project with considerable wealth and several partners, but he had spent $100,000 searching and Tilghman, his friend and investor in the project, decided to back out.
Progress at Meteor Crater was slow for the next decade as Barringer marketed the project to prospective investors. It was not until 1918 that he signed up a new partner, the United States Smelting and Refining Company. USSRC signed up to put $75,000 into exploratory drilling, but $60,000 was spent installing supporting infrastructure, including a ten mile water pipe, before drilling began from near the top of the south rim.
Progress was slow, and stopped entirely at 282 feet when the drill became jammed and the $75,000 exhausted. Barringer seems to have pulled off some feat of salesmanship by convincing USSRC to continue to support the project, and in 1921 a horizontal tunnel was dug from the interior of the crater to the end of the drill, revealing the two iron balls that had stopped the work. While the tunnel plan was innovative, it was not particularly effective, as the bore turned out to be in poor shape and difficult to continue.
Drilling practically started over again, reaching 600 feet at the end of 1921. Barringer's theory appeared to pan out: at 1,100 feet, well below the crater floor, meteor fragments started to appear. The drill stuck again at 1,300 feet, but not before finding dense a span dense with iron fragments. Drilling to that depth had cost $200,000, and while promising, none of the material recovered had been of any significant value. USSRC pulled out.
Barringer was back to fundraising, courting various mining companies including one, United Verde Extension, who rejected the project based on their conclusion that the crater was the result not of a meteor, but of a steam explosion. You see, even in 1924, Barringer's theory of the crater's origin came off as crackpot. The steam explosion theory was still the accepted one, and the crater had attracted surprisingly little attention from professional scientists. Barringer's abrasive response to the USGS survey was no doubt a factor; a USGS geologist by the name of N. H. Darton who had worked for Gilbert during the original survey took the cause to heart.
Throughout Barringer's mineral exploration of the crater, Darton published papers arguing for a steam explosion and dismissing the meteorite theory. He refused to change the name of the site on USGS maps away from Coon Butte until 1916, when he begrudgingly accepted "Crater Mound." Barringer's son, Brandon Barringer, wrote that a USGS geologist once told him that he thought the meteor theory to be correct but "it would cost me my job if I was heard saying so."
Drilling resumed again that year, the effort of a new stockholder corporation that leased the crater from Standard iron and worked on the advice of Barringer. This corporation, the Meteor Crater Exploration and Mining Company, was backed in part by Boston business magnate Quincy Adams Shaw. Shaw would bring about Barringer's vindication, and his downfall.
One of Daniel Barringer's sons, Daniel Barringer Jr., followed his father into the study of meteoritics. He would make a discovery similar to his fathers: a letter to a mining journal described the discovery, in 1921, of a large iron meteorite near a hole in the area of Odessa, Texas.
Barringer Jr. arranged a deal with G. M. Colvocoresses, a smelter executive and one of the investors in the Exploration Company, to inspect a set of mines in Texas on his behalf. This provided a convenient excuse to travel through Odessa, where he examined the area and found signs much like those near Cañon Diablo. In 1926, he discovered the world's second known meteor impact crater, the Odessa Crater.
Incidentally, something else had been discovered near Odessa: oil. The Odessa Crater turned out to be owned by an oil interest, which was not interested in selling.
Fragments
According to a pattern, the Exploration company completed a new shaft near the USSRC effort, which struck water at 600 feet and about $200,000 in expense. Shaw, beginning to question the project, engaged the services of an expert: astronomer Forest Ray Moulton. Moulton was a distinguished scientist, a professor at the University of Chicago, and even better, an expert in ballistics, having been in charge of ballistics research at the Aberdeen Proving Ground during the First World War.
Moulton seemed to accept the meteorite theory from the start. After all, despite the objections of the USGS, General Electric cofounder and MIT president Elihu Thomson had visited the crater and reached the same conclusion. Still, it gives some of the flavor of the debate that Barringer sometimes referred to his scientific supporters as "converts."
Moulton's report, published in 1929, was a mixed result for Barringer. He concluded that the crater was indeed the result of an impact by a meteorite, perhaps 50,000 to 3,000,000 tons. He also concluded that the meteorite would never be found. The impact energy was more than enough to vaporize it entirely, leaving only the fragments scattered across the plain.
Three months later, Daniel Barringer died.
His dreams of one billion dollars of iron and nickel buried beneath the crater died with him. While his family carried on the effort, the Great Depression ensured that only two further shafts would be drilled, after which mining exploration ended.
By 1930, the passage of time, the discovery of the Odessa Crater, and Moulton's report had solidified the meteorite theory to such a degree that the Meteor Crater became generally accepted as just that. Meteor mining, though, was over before it had started.
Billboards
If not valuable, meteor craters remain unique and fascinating geological features. The Odessa Crater was leased by Ector County as a tourist site, and efforts by various parties including the Texas Memorial Museum lead to the discovery of a six-ton meteorite at the bottom of a second, smaller crater nearby. Efforts by the Works Progress Administration and later the Barringer Family to locate the meteorite that formed the larger main crater failed, leaving a covered shaft still visible today.
At Meteor Crater itself, the mission has changed in a classic Route 66 fashion: from mining to tourism. In 1953, the Standard Iron Company renamed itself to the Barringer Crater Company. The Company continues to operate Meteor Crater as a tourist attraction and scientific resource, hosting NASA training efforts and geological experiments. Ongoing research at Meteor Crater produced many conclusions about meteorites and impact events, including extensive research by Eugene Shoemaker.
It was Shoemaker who directed NASA to the site for training purposes: he had been considered as an astronaut himself, but excluded for medical reasons. Instead, he took to Meteor Crater as a moon of his own. It is due in large part to Shoemaker's comparisons between Meteor Crater and the lunar surface that we now know the the craters of the Moon to be a result of meteorites as well.
Today, Meteor Crater appears as a roadside stop, not that different from Jack Rabbit or "The Thing." Billboards precede it by hours, ignored by their audience of long-haul truckers. It is dusty, and minimally staffed, and has the feeling of a forgotten place; a spacesuited mannequin and a 4D Experience only add to the impression of a tourist trap with a brighter past. The museum, with so much focus on the only tangentially related Apollo program, forms a stark contrast with brass plaques devoted to a hagiography of the Barringers. They bring you out to see the crater, but then they say very little about what is in the crater. You have to read between the lines to find the reason why: Barringer never found what he was looking for.
Still, there are things that you cannot see anywhere else. The crater itself, bigger than the Sedan Crater excavated by a nuclear weapon, can only hint at the unthinkable energy released some 50,000 years ago. A huge fragment of the meteorite, weighing 3/4 ton and named for Holsinger, is prominently displayed in the museum. Apartments built for staff remind us of just how remote "between Flagstaff and Winslow" once was.
Barringer's obsession with meteorites was sincere. Based on his writings, it predated the discovery of the Meteor Crater, and he devoted as much of his life to better understanding the crater as he did to mining it. His family and the Barringer Crater Company continue to make grants in meteoritics research, and each year they give the Barringer Medal. Its first honoree was Shoemaker, its most recent Canadian geology professor John Spray, who studies deformation and friction at extreme speeds and pressures.
Like so much of Route 66, it feels dated, and more than a little tacky. And like Route 66 as well, it is a fascinating chapter in the story of the American West. An eastern businessman, as eccentric as he was passionate, left for Arizona in pursuit of a wild idea. He was only half right.
[1] Curiously, the most recent billboards for Meteor Crater mainly feature an anthropomorphic rabbit, apparently a character designed for a "4D experience" at the museum. The connection between the rabbit and the crater is left unexplained; an odd mascot that you might be tempted to ascribe to furries except that if the furries were in charge it would have looked better. I cautiously speculate that it may have been intended as a reference to the Jack Rabbit.
[2] A meteor is seen in the sky, a meteoroid is the actual object that burned up to be seen as a meteor, and a meteorite hits the ground. It is said that you can remember this by recalling that meteorites are "right" in that they successfully made it all the way. As with so many memory devices, I think you could also argue this one the other way, so it's not really that helpful.
[3] Foote's paper to the AAAS about the discovery makes it clear that this kind of wild exaggeration was not unusual when coming from prospectors. "There were some remarkable mineralogical and geological features which together with the character of the iron itself, would allow of a good deal of self-deception in a man who wanted to sell a mine."