The problems came to a head in mid-October, when “the Union Tunnel”—a joint adit driven horizontally toward the lode from an entrance farther down the hillside by the Ophir, the Mexican, and the Central not to be confused with the tunnel John Mackay had built for the Union mine the previous winter—approached the vein between 180 feet and 155 feet below the surface. (In addition to being a “union” of their interests, the adit’s name probably reflected the political sentiments of the mine owners—politics had become ubiquitous in the run-up to the most contentious presidential election in the history of the republic.) About thirty feet short of where they anticipated cutting the lode, miners at the working head of the tunnel encountered a wall of the tough, plastic clay whose expansive properties caused such problems in the mines above. They’d had little problem with the influx of water for the whole thousand-foot length of their adit, and they hacked at the clay wall without hesitation, failing to realize that the impermeable wall dammed an enormous reservoir of water inside the lode. They received a harsh education when the wall disintegrated in front of them, unleashing a flood.
According to a letter published in the Sacramento Daily Union, the torrent “discharged so rapidly as to render it prudent for them to leave without standing upon the order of their going.” In short, the crew fled for their lives. The torrent tore up the planking of the wheelbarrow track on the adit floor and flushed it out the tunnel mouth. Fortunately, nobody was seriously injured. (John Mackay may have worked on the Union Tunnel; if not, he certainly knew men who did.) The flood drained off the water plaguing the three mines that shared the Union Tunnel.
Continuing explorations exposed a problem of an entirely different scale. A crosscut across the Ophir’s ore body on the level of the Union Tunnel revealed a sixty-five-foot-wide span of ore. The discovery had staggering implications. Prospecting drifts and crosscuts showed that in the southern slice of the mine on that level, the ore body extended from stake to stake between its boundaries with the Mexican and the Central, the full 200 feet, and it averaged 55 feet in width. Above that 200-foot-by-55-foot rectangular footprint the wedge-shaped triangular prism of the ore body angled up and eastward at a forty-five-degree angle to an apex near the surface. Neither did the ore show any sign of “pinching out” below the floors.
The discovery made front-page news as far away as New Orleans, where the Daily Crescent described Ophir, Mexican, and Central shareholders as “much elated.” If so, they hadn’t pondered the scale of their problem—nothing close to that size had ever been extracted in the entire history of mining. To expand the stopes on the level of the Union Tunnel, in what they called the “Third Gallery” (the two others were in the ore body above), Ophir Superintendent W. L. Dall, formerly a ship captain for the Pacific Mail Steamship Company, directed his miners to join timbers together with iron plates, bands, and bolts in much the same manner as sailors step a topmast above a mainmast. Immense pressures within the mine mangled and snapped the joined timbers like kindling. Caves killed several miners. Others had narrow escapes, and aside from the human toll, the mine lost thousands of tons of ore in the caves, since a collapse rendered the vicinity too dangerous to work. The situation presented no small amount of irony: Surrounded by riches, the owners of the Ophir couldn’t get them out.
A number of mining engineers examined the problem. None of them could figure out how to solve it. Near the end of November, one of the Ophir’s trustees (and substantial owners), William F. Babcock, heard about a twenty-eight-year-old German immigrant named Philipp Deidesheimer superintending a gold mine in El Dorado County who supposedly combined the best aspects of the formal engineering education he’d acquired in the Freiberg mining school with an ability to solve real-world problems. Babcock summoned Deidesheimer to San Francisco and asked him if he’d ever seen or worked a quartz vein sixty feet in width.
Deidesheimer said he’d never heard of anything like it.
Babcock asked if he thought it was possible to work such a vein.
Deidesheimer said he had no way of knowing until he’d seen and studied the mine in question.
The German had given the only true answer. Babcock sent him to Virginia City.
Deidesheimer arrived on November 8. He studied the local geology, the Ophir’s underground topography, the vein, the ore, and the method of its workings, paying particular attention to areas where underground pressures and caves had mangled the existing timbers. No obvious solution leaped to mind. The scope of the problem daunted Deidesheimer. For three more weeks, he engineered his way forward, theorizing, modeling, upsizing, testing, rethinking, tweaking, improving, testing, and retesting before he had what he hoped would be a workable solution. Time would prove it a work of simple, elegant genius.
The internal structure of beehives provided the crucial inspiration. In principle, what became known as Philipp Deidesheimer’s system of “square-set timbering” involved replacing each four-foot-wide, four-foot-deep, seven-foot-tall volume of extracted ore with a strong timber frame, then replacing an adjacent extracted volume with a similar timber frame, and so on and so on as the miners stoped ore until the entire volume of the ore body was replaced by a beehive-like structure of stout rectangular cuboids.
To put it into effect, Deidesheimer ordered his miners to crosscut the vein on the level of the Union adit. To serve as the sill timbers on the floor, he made his timbermen physically wrestle the longest timbers it was possible to maneuver into place up the Union adit. Deidesheimer directed them to install the sills down the sides of the initial crosscut, not across it, then had them mount seven-foot posts on the sills at four-foot intervals and connect them overhead with the four-foot caps. Cross-braces went across the floor and ceiling in line with the posts. Spanning the fifty-five-foot width of the ore body required several sill timbers joined end to end. Finished, a line of upright rectangular cuboids stood on the long sills. Different from traditional mine timbering, the main strength of the reinforcement ran over the sills down the sides of the crosscut, not across its course.
A detail of Philipp Deidesheimer’s cuboids.
The importance of that distinction didn’t become apparent until Deidesheimer had his workmen begin installing additional rows of “square sets” on each side of the first. The main strength of the system wasn’t designed to support a single crosscut. As the systematic beehive structure of the square-set timbers grew, its main strength formed over the sill timbers, across the ore body, oriented to support the extraction of the entire thing. Timbermen installed a plank floor over the sills and built wooden tracks on the floor, a miniature railroad along which they ran ore cars. While one crew of miners steadily advanced four feet into the ore body on one side of the original crosscut, timbermen replacing each volume of extracted ore with a square-set until they’d completed an entire row, another crew did the same thing on the opposite side. Once they’d advanced several rows in both directions, a third gang began mining overhead, hacking ore from the ceiling into ore cars positioned beneath. When the overhead gang had removed sufficient volume, timbermen shored the void with a square-set built atop the bottom row. When the overhead miners completed a full line across the vein, they, too, turned and advanced into the ore body in both directions a few rows of square-sets behind the crews still advancing on the first floor. When the bottom two floors had “worked out” a sufficient volume, more miners began opening a third-floor overhead. Thus, the stopes advanced into the ore body on both sides of the original crosscut like the leading edges of two wedges pushing out from a central point, adding another level to the overhead work whenever sufficient space opened above. The distance between the sill timbers and the miners working overhead quickly grew to the point that falls from above presented a serious hazard—of people, of objects they might drop, and of rocks and other debris falling from the ceiling. To improve safety and aid their working, miners working overhead built plank floors. Thus, “the rats of the lower galleries” safely extracted huge volumes of ore at a
velocity hitherto unknown in mining.
Few lodes orient perfectly vertical. Like the Comstock, most angle or “dip” one way or another, which gives them a high side and a low side. Miners consider the “hanging wall” to be the country rock above the lode and the “footwall” to be the country rock below, and as the square-set lattice expanded inside the ore body, it was an easy matter for timbermen to add one square-set on the footwall side of the vein and subtract one against the hanging wall to account for the lode’s dip. Directly against the footwall and hanging wall on both edges of the ore body, timbermen installed “wall plates” similar to the long floor sills, then created resisting force between the wall plates with timber “angle braces” installed diagonally across the whole volume of square-sets that created solid lines of resistance between the weight of the hanging wall pressing down from above and the support of the footwall below.
Deidesheimer’s square-set timbering system was pure engineering genius, plain and simple and in retrospect obvious, easy to comprehend, install, and adapt to changing underground circumstances. A man who inspected the Ophir the following year described the “strong, heavy timbers, braced and counterbraced . . . like the trestle-work of a railroad bridge.” Another noted the “striking contrast” Deidesheimer’s system made to “the slovenly timbering” in the neighboring Mexican mine, and an 1862 visitor from Marysville emerged from the Ophir much impressed by the “ingenious frames of massive timber of great strength” holding open stopes that climbed from several hundred feet underground to within thirty feet of the surface. And although phenomenally expensive due to the vast quantity of timber required, Philipp Deidesheimer’s novel square-set timbering system made it possible to extract the Ophir’s immense ore body. Along with the California stamp mill and the “Washoe Pan Process” Almarin Paul developed earlier in the year, Philipp Deidesheimer’s square-set timbering system formed the third leg of the great trifecta of American contributions to the art and science of mining, worldwide. Miners today use evolutions of all three systems 150 years after the Comstock heyday.
Opening a gallery approximately one hundred feet below the square-set matrix revealed the final genius of Deidesheimer’s system. Surveyors carefully aligned the huge sill timbers in the lower level with the ones already installed above. Since each long sill spanned several square-sets, the miners working up from below with the identical system could directly connect from the uppermost line of square-sets—albeit one at a time and very carefully—to the long sills above, which allowed the miners to extract every last ton of the ore body.
Not only did Deidesheimer’s square-sets make practicable the extraction of the Comstock’s enormous ore bodies, its employment greatly accelerated the entire mining process. Using Deidesheimer’s system, a single man could mine from five to ten tons of ore per shift. The Ophir stoped out ore at a rate that would have astonished previous generations of miners.
And in mining, speed mattered. A competent, well-planned, well-executed, rapid mining operation raised a given quantity of ore with less cost. Speedy extraction minimized the total time needed to exhaust a mine, and therefore lessened the amount of fuel required to fire the engines that drove the pumps and hoists, and with mine workers paid per day, “snaking out the ore” at an efficient clip lowered total labor costs. And since even the most perfectly installed square-sets lasted only a finite time—timbers rotted, decayed, and compressed—rapid prosecution of the work extracted the ore before the expensive timbers needed replacement. Most important of all, a fast-working mine was safer. Speed minimized the total time crews spent exposed to the myriad hazards of working underground.
Deidesheimer’s square-set timbering system had one drawback—its phenomenal cost. Some mines balked at the expense. Most cut corners wherever possible. One of them was the Ophir’s neighbor, the Mexican. Rather than investing in square-sets, it used old Mexican mining techniques. The Mexican mined on the dip of the vein via an incline shaft, shoring its workings as needed with traditional timbering techniques, as had originally been done in the Ophir. Using steps hacked into the floor of the slope, the mine’s predominantly Mexican workforce lugged enormous loads of ore to the surface in rawhide baskets held against a man’s back with a tumpline around his forehead. The mine took the incline shaft down forty or fifty feet, then drifted north and south across the full hundred-foot length of the claim. At regular intervals along the drift, they sank “winzes” deeper into the ore body, still following the lode’s dip. (In technical parlance, a “winze” was a mine working made driving down; one worked upward from a lower level was called an “upraise” or “raise.”) Another long drift connected the bottoms of the winzes. Below the bottom drift, miners sank another series of winzes and connected their sumps with an even lower drift. And so on they descended on the dip of the lode, leaving the grid of ore pillars between the drifts and winzes in place to support the mine. The technique saved a great portion of the timbering expense required to mine with Deidesheimer’s square-set system, and it had another advantage, since unlike timber, ore left in situ didn’t rot and decay. Proper use of the technique in solid ground rendered mines permanently secure. The idea was to use the system to reach the bottom of the ore body, then mine out the supporting ore pillars, starting at the bottom, and allow the mine to fall in on itself one level at a time. Silver miners in Mexico and Spanish America had used the strategy to hold mines open for centuries.
John Mackay was underground through all of it, watching with his eyes and doing with his hands. Deidesheimer’s new square-set timbering technique perfectly complemented Mackay’s skills. For a miner at the end of 1860 and the start of 1861, there was no better place in the world to learn mining techniques both new and old than in the mine workings beginning to open below the young towns of Virginia City and Gold Hill.
• • •
Sources don’t reveal much about John Mackay in 1861. We do know that he worked through the whole year on the tunnel he’d agreed to build for the Buck Ledge back in March 1860, the contract that required him to “run said tunnel five days in every week till his contract is completed.” Mackay wouldn’t finish that project for another twenty-three months, but when he did, mining district records noted the “full satisfaction thereof.” With that job set to pay him in feet, he had to continue earning coin in the same way he had since the first day he set foot in Washoe—working for wages in the mines. Although the words of a Daily Alta California correspondent described “everyone” in Washoe “in a fret because he has made his fortune, or because he has not made it,” virtually everyone would have been a more accurate assessment. Thirty-year-old John Mackay chose an entirely different course than the get-rich-quick schemes that fired the imaginations of so many men on the mining frontier. Lacking capital, he worked to earn it, saving every penny. Lacking knowledge, he worked to gain it, never overlooking a learning opportunity. He worked for wages in the Central-Ophir-Mexican bonanza, in other mines in the Gold Hill and Virginia districts, and on his own account in the tunnel he was building for the Buck Ledge on the slopes of Mount Davidson above the Chollar and the Potosi. An immensely practical man, Mackay started at the bottom and worked his way up, educating himself in every facet of Comstock mining by doing it himself, trying to peer ahead, both into the rock and into the future, to figure out how he might win his own share of the riches that surrounded him every day. Slowly, diligently, with constant endeavor, Mackay learned the characteristics of the vein, of the country rock that surrounded it, of the clay sheets that held the ore bodies—or underground floods—of the “pitch” and “dip” of the ore bodies, and of the ore itself, silver sulphurets and chlorides, pregnant with royal metals. He drove through the “horses” of worthless matter that disappointed miners where they’d otherwise expected good pay. In the dangerous, valuable labyrinth growing underneath the two camps, Mackay acquired a reputation for exacting competence. He took pride in honest toil. To him, all work was honorable, and a job was sacred. What he did, h
e did right, and he impressed men with his upright manner and steady judgment. His peers soon counted him among the lode’s best timbermen for shoring caving ground.
• • •
Meanwhile, during the winter of 1860–61, San Francisco citizens flocked to the South Beach salesrooms of the Union Reduction Works to take a close look at what had everyone so excited—a display of $9,000 worth of Washoe bullion, a fraction of the roughly $1 million worth of gold and silver disgorged by the Comstock mines that year. Except in those few places where the casting mold had roughened the surface, the Daily Alta California described the huge bricks gleaming “pure silver white and bright as a new coin.” Composed of two-thirds silver and one-third gold and certified by assayers as 997 fine, lacking only three parts per thousand of gold and silver, the bullion bars sat on the countertops “freely exposed to public inspection.” The proprietors felt no worry about theft due to the immense weight of the ingots, each heavier than a man “could comfortably lug a hundred yards.”
The successes in the new mineral territories of western Utah were welcome news in California, for the opening of new mining frontiers in the Great Basin portended well for the state’s economy. News from the East provided a counterbalance. Lincoln’s election had caused the gravitation that held the United States together to fail. People on the Pacific Slope awaited the arrival of the Pony Express with “breathless anxiety” and “every word on the subject of secession [was] read and discussed by all.”
The Bonanza King Page 15