by John McPhee
So much for theory. This roadcut contained both extremities of Deffeyes’ wide interests in geology, and his attention was now drawn to a large gap in the sandstone, faulted open probably six or seven million years ago and now filled with rock crumbs, as if a bomb had gone off there in the ground. The material was gradated outward from a very obvious core. In a country full of living hot springs, this was a dead one. Sectioned by the road builders, it remembered in its swirls and convolutions the commotion of water raging hot in rock. The dead hot spring had developed cracks, and they had been filled in by a couple of generations of calcite veins. Deffeyes was busy with his hammer, pinging, chipping samples of the calcite. “This stuff is too handsome to leave out here,” he said, filling a canvas bag. “There was a lot of thermal action here. Most of this material is not even respectable rock anymore. It’s like soil. In 1903, a mining geologist named Waldemar Lindgren found cinnabar in crud like this at Steamboat, near Reno. Cinnabar is mercury sulphide. He also found cinnabar in the fissures through which water had come up from deep in the crust. He thought, Aha! Mercury deposits are hot-spring deposits! And he applied that idea to ore deposits generally. He started classifying them according to the temperature of the water from which they were deposited—warm, hot, hotter, and so on. We know now that not all metal deposits are hydrothermal in origin, but more than half of them are. As you know, the hot water, circulating deep, picks up whatever is there—gold, silver, molybdenum, mercury, tin, uranium—and brings it up and precipitates it out near the surface. A vein of ore is the filling of a fissure. A map of former hot springs is remarkably close to a map of metal discoveries. Old hot springs like this one brought up the silver of Nevada. It would do my heart good to find silver right here in this roadcut and put it to the local highway engineer.”
He took some samples, which eventually proved to be innocent of silver, and we got back into the pickup. We soon left the interstate for a secondary road heading north—up a pastel valley, tan, with a pale-green river course, fields of cattle and hay. It was a valley that had been as special to the Paiutes as the Black Hills were to the Sioux. The Paiutes gave it up slowly, killing whites in desperation to keep it, and thus bringing death on themselves. The first pioneers to settle in this “desert” were farmers—an indication of how lush and beautiful the basin must have appeared to them, ten miles wide and seventy miles long, framed in serrated ridges of north-south-trending mountains: range, basin, range. Magpies, looking like scale-model jets, kept rising into flight from the side of the road and gaining altitude over the hood of the pickup. Deffeyes said they were underdeveloped and reminded him of Archaeopteryx, the Jurassic bird. We crossed cattle guards that were nothing more than stripes painted on the road, indicating that Nevada cattle may be underdeveloped, too, with I.Q.s in one digit, slightly lower than the national norm.
For eight million years, Deffeyes was saying, as the crustal blocks inexorably pulled apart here and springs boiled up along the faults, silver had been deposited throughout the Basin and Range. The continually growing mountains sometimes fractured their own ore deposits, greatly complicating the sequence of events and confusing the picture for anyone who might come prospecting for ores. There was another phenomenon, however, that had once made prospecting dead simple. Erosion, breaking into hot-spring and vein deposits, concentrated the silver. Rainwater converted silver sulphides to silver chloride, heavy stuff that stayed right where it was and—through thousands of millennia—increased in concentration as more rain fell. These were the deposits, richer than an Aztec dream, that were known to geologists as supergene enrichments. Miners called them surface bonanzas. In the eighteen-sixties, and particularly in the eighteen-seventies, they were discovered in range after range. A big supergene enrichment might be tens of yards wide and a mile long, lying at or near the surface. Instant cities appeared beside them, with false-front saloons and tent ghettos, houses of sod, shanties made of barrels. The records of these communities suggest uneven success in the settling of disputes between partners over claims: “Davison shot Butler through the left elbow, breaking the bone, and in turn had one of his toes cut off with an axe.” They were places with names like Hardscrabble, Gouge Eye, Battle Mountain, Treasure Hill. By the eighteen-nineties, the boom was largely over and gone. During those thirty years, there were more communities in Nevada than there are now. “Silver is our most depleted resource, because it gave itself away,” said Deffeyes, looking mournful. “You didn’t need a Ph.D. in geology to find a supergene enrichment.”
All you needed was Silver Jim. Silver Jim was a Paiute, and he, or a facsimile, took you up some valley or range and showed you grayish rock with touches of green that had a dull waxy lustre like the shine on the horn of a cow. Horn silver. It was just lying there, difficult to lift. Silver Jim could show you horn silver worth twenty-seven thousand dollars a ton. Those were eighteen-sixties dollars and an uninflatable ton. You could fill a wheelbarrow and go down the hill with five thousand dollars’ worth of silver. Three or four years ago, a miner friend of Deffeyes who lives in Tombstone, Arizona, happened to find on his own property an overlooked fragment of a supergene enrichment, a narrow band no more than a few inches thick, six feet below the cactus. Knocking off some volcanic overburden with a front-end loader, the miner went after this nineteenth-century antique and fondly dug it out by hand. He said to his children, “Pay attention to what I’m doing here. Look closely at the rock. We will never see this stuff again.” In a couple of hours of a weekend afternoon, he took twenty thousand dollars from the ground.
We were off on dirt roads now with a cone of dust behind us, which Deffeyes characterized as the local doorbell. He preferred not to ring it. This talkative and generous professor—who ordinarily shares his ideas as rapidly as they come to him, spilling them out in bunches like grapes—was narrow-eyed with secrecy today. He had stopped at a courthouse briefly, and—an antic figure, with his bagging sweater and his Beethoven hair—had revealed three digits to a county clerk in requesting to see a registry of claims. The claims were coded in six digits. Deffeyes kept the fourth, fifth, and sixth to himself like cards face down on a table. He found what he sought in the book of claims. Now, fifty miles up the valley, we had long since left behind us its only town, with its Odd Fellows Hall, its mercantile company, its cottonwoods and Lombardy poplars; and there were no houses, no structures, no cones of dust anywhere around us. The valley was narrowing. It ended where ranges joined. Some thousands of feet up the high face of a distant and treeless mountain we saw an unnaturally level line.
“Is that a road?” I asked him.
“That’s where we’re going,” he said, and I wished he hadn’t told me.
Looking up there, I took comfort in the reflection that I would scarcely be the first journalist to crawl out on a ledge in the hope of seeing someone else get rich. In 1869, the editor of the New York Herald, looking over his pool of available reporters, must have had no difficulty in choosing Tom Cash to report on supergene enrichments. Cash roved Nevada. He reported from one place that he took out his pocketknife and cut into the wall of a shaft, removing an ore of such obviously high assay that he could roll it in his fingers and it would not crumble. Cash told the mine owner that he feared being accused of exaggeration—“of making false statements, puffing”—with resulting damage to his journalistic reputation. There was a way to avoid this, he confided to the miner. “I would like to take a sample with me of some of the richest portions.” The miner handed him a fourteen-pound rock containing about a hundred and fifty troy ounces of silver (seventy-three per cent). In the same year, Albert S. Evans, writing in the San Francisco Alta California, described a visit with a couple of bankers and a geologist to a claim in Nevada where he was lowered on a rope into a mine. “The light of our candles disclosed great black sparkling masses of silver on every side. The walls were of silver, the roof over our heads was of silver, and the very dust that filled our lungs and covered our boots and clothing with a gray coating
was of fine silver. We were told that in this chamber a million dollars’ worth of silver lies exposed to the naked eye and our observations confirm the statement. How much lies back of it, Heaven only knows.”
Heaven knew exactly. For while the supergene enrichments—in their prodigal dispersal through the Basin and Range—were some of the richest silver deposits ever discovered in the world, they were also the shallowest. There was just so much lying there, and it was truly bonanzan—to print money would take more time than to pick up this silver—but when it was gone it was gone, and it went quickly. Sometimes—as in the Comstock Lode in Virginia City—there were “true veins” in fissures below, containing silver of considerable value if more modest assay, but more often than not there was nothing below the enrichment. Mining and milling towns developed and died in less than a decade.
We were on our way to a nineteenth-century mine, and were now turning switchbacks and climbing the high mountainside. Deffeyes, in order to consult maps, had turned over the wheel to me. He said his interest in the secondary recovery of silver had been one result of certain computer models that had been given wide circulation in the early nineteen-seventies, using differential equations to link such things as world population, pollution, resources, and food, and allow them to swim forward through time, with a resulting prediction that the world was more or less going to come to an end by the year 2000, because it would run out of resources. “We have found all obvious deposits, and, true enough, we’ve got to pay the price,” he said. “But they did not take into account reserves or future discoveries or picking over once again what the old-timers left behind.” Seeking commissions from, for example, the Department of Energy, he began doing studies of expectable discoveries of petroleum and uranium. He sort of slid inadvertently from uranium into silver after a syndicate of New York businessmen came to him to ask for his help in their quest for gold. The group was called Eocene and was interested in scavenging old mines. Deffeyes pointed out to them that while new gold strikes were still occurring in the world and new gold mines were still being developed, no major silver mine had been discovered since 1915. The pressure for silver was immense. Dentistry and photography used two-thirds of what there was, and there were no commercial substitutes. “We’ve been wiped out. We’ve gone through it, just as we have gone through magnesium and bromine. You can raise the price of silver all you want to but you won’t have a new mine.” He predicted that as prices went up silver would probably outperform gold. The potentialities in the secondary recovery of silver appeared to him to be a lot more alluring than working through tailings for gold. Eocene engaged him as a consultant, to help them scavenge silver.
Now far above the basin, we were on the thin line we had seen from below, a track no wider than the truck itself, crossing the face of the mountain. It curved into reentrants and out around noses and back into reentrants and out to more noses. I was on the inboard side, and every once in a while as we went around a nose I looked across the hood and saw nothing but sky—sky and the summits of a distant range. We could see sixty, seventy miles down the valley and three thousand feet down the mountain. The declivity was by no means sheer, just steep—a steepness, I judged, that would have caused the vehicle, had it slipped off the road, to go end over end enveloped in flame at a hundred yards a bounce. My hands slid on the wheel. They were filmed in their own grease.
The equanimous Deffeyes seemed to be enjoying the view. He said, “Where did you learn to drive a truck?”
“Not that it’s so god-damned difficult,” I told him, “but this is about the first time.”
Before 1900, the method used in this country to extract silver from most ores was to stamp the rock to powder in small stamp mills, then stir the powder into hot salt water and mercury, and, after the mercury had attracted the silver, distill the mercury. In 1887, a more thorough extraction process had been developed in England whereby silver ores were dissolved in cyanide. The method moved quickly to South Africa and eventually to the United States. An obvious application was to run cyanide through old tailings piles to see what others had missed, and a fair amount of such work was done, in particular during the Depression. There had been so many nineteenth-century mines in Nevada, however, that Deffeyes was sure that some had been ignored. He meant to look for them, and the first basin he prospected was the C Floor of Firestone Library, up the hill from his office in Princeton. There he ran through books and journals and began compiling a catalogue of mines and mills in the Basin and Range that had produced more than a certain number of dollars’ worth of silver between 1860 and 1900. He prefers not to bandy the number. He found them in many places, from barrelcactus country near the Colorado River to ranges near the Oregon line, from the Oquirrh Mountains of Utah to the eastern rampart of the Sierra Nevada. In all, he listed twenty-five. The larger ones, like the Comstock, had been worked and reworked and cyanided to death, and “tourists were all over them like ants.” A scavenger had best consider lesser mines, out-of-the-way mines—the quick-shot enrichments, the small-fissure lodes, where towns grew and died in six years. He figured that any mine worth, say, a million dollars a hundred years ago would still be worth a million dollars, because the old mills at best extracted ninety per cent of the silver in the ores, and the ten per cent remaining would be worth about what the ninety per cent had been worth then. Pulling more books and journals off the shelves, he sought to learn if and where attention had been paid to various old mines in the nineteen-thirties, and wherever he discovered activity at that time he crossed off those mines.
His next move was to buy aerial photographs from the United States Geological Survey. The pictures were in overlapping pairs, and each pair covered sixteen square miles. “You look at them with stereo equipment and you are a giant with eyeballs a mile apart and forty thousand feet in the air. God, do you have stereovision! Things jump off the earth. You look for tailings. You look for dumps. You look for the faint scars of roads. The environmentalists are right. A scar in this climate will last. It takes a long time for the terrain to erase a road. You try to reason like a miner. If this was a mine, now where would I go for water? If this was a mill here, by this stream, then where is the mine? I was looking for mines that were not marked on maps. I could see dumps in some places. They stood out light gray. The old miners made dumps of rock that either contained no silver at all or did not contain enough silver to be worth their while at the time. I tried to guess roughly the volume of the dumps. Mill tailings made unnatural light-gray smudges on the pictures. Some of the tailings and dumps I found in these mountains appear on no maps I’ve seen.”
He flew to Nevada, chartered a light plane, and went over the country a thousand feet above the ground, taking fresh private pictures with a telephoto lens. When he flew over places where other scavengers looked up and waved, he crossed those places off his list. He went in on the ground then, to a number of sites, and collected samples. He had machines at home that could deal with the samples in ways unheard of just a few years before, let alone in the nineteenth century. Kicking at old timbers, he looked at the nails. Wire nails came into use in 1900 and are convenient index fossils of the Age of Cyanide. He hoped for square nails.
Deffeyes was on his own now. His relationship with Eocene had faded out after they had chosen, on various points, to follow counsel other than his, and they transferred their scrutiny to Arizona, preferring not to cope with winter. One day in Princeton, his wife, Nancy Deffeyes, was looking through a stack of hundred-year-old Engineering & Mining Journals when she found a two-line reference to certain mining efforts in the eighteen-seventies that eventually assumed prominence on her husband’s list, and that was what had brought him here and why we were crawling like a Japanese beetle across the face of this mountain.
We turned a last corner, with our inner wheels resting firmly on the road and the two others supported by Deffeyes’ expectations. Now we were moving along one wall of a big V-shaped canyon that eventually became a gulch, a draw, a crease in
the country, under cottonwoods. In the upper canyon, some hundreds of acres of very steep mountainside were filled with holes and shafts, hand-forged ore buckets, and old dry timbers. There were square nails in the timbers. An ore bucket was filled with square nails. “Good litter,” Deffeyes said, and we walked uphill past the mine and along a small stream into the cottonwoods. The stream was nearly dry. Under the cottonwoods were the outlines of cabins almost a century gone. Here at seven thousand feet in this narrow mountain draw had lived a hundred people, who had held their last election a hundred years earlier. They had a restaurant, a brewery, a bookstore. They had seven saloons. And now there was not so much as one dilapidated structure. There were only the old unhappy cottonwoods, looking alien and discontented over the moist bed of the creek. Sixteen stood there, twisted, surviving—most of them over four feet thick. “Those cottonwoods try an environmentalist’s soul,” Deffeyes said. “They transpire water like running fountains. If you were to cut them down, the creek would run. Cottonwoods drink the Humboldt. Some of the tension in this country is that miners need water. Getting rid of trees would preserve water. By the old brine-and-mercury method, it took three tons of water to mill one ton of ore. There was nothing like that in this creek. They had to take the ore from here to a big enough stream, and that, as it happens, was a twelve-mile journey using mules. They would have gone out of here with only the very best ore. There was probably a supergene enrichment here over a pretty good set of veins. They took what they took and were gone in six years.”
