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August 2006


4KCy + 2Au + O + H2O = 2KAuCy2 + 2KHO

Cyaniding at Bodie


Michael H. Piatt


A new recovery process introduced in 1890 transformed the world of precious metals mining so successfully that variations of the method are still used today.  Based on the well-established fact that gold and silver dissolve in a solution of potassium cyanide, the “cyanide process” brought new life and profits to tired old mining camps, first as a treatment for discarded mill tailings, then for processing low-grade ore from the mines.


            Cyanide’s usefulness as a gold solvent had been recorded through a century of advances and a proliferation of patents since the 1790s.  The first commercial use of cyanide in the metal trades occurred in 1840, when English gilding shops electroplated dissolved gold onto other metallic surfaces.  An 1843 discovery in Russia demonstrated that solid gold could be precipitated from a liquid containing cyanide in which the metal had been dissolved.  Discoveries in Germany the following year showed that cyanide also acted on silver, and that the presence of oxygen accelerated its behavior.  Taking advantage of these characteristics, a number of English patents for electroplating with cyanide were granted during the early 1850s.  Two Americans published a scientific paper in 1866 concluding that cyanide could be used for removing gold and silver from ore, but they failed to advance the idea further.  Their insight led to a flurry of inventions in America and abroad, each trumpeted as a practical industrial-scale ore treating process, but none of them developed into a commercial success.


            Beginning in October 1887, metallurgical chemist John MacArthur and two physicians, Robert and William Forrest, secured a series of cyanide-related patents for the Cassel Gold Extraction Company of Glasgow, Scotland, a firm well-known for advances in chlorination, a chemical ore treating process.  Improving upon the work of Cassel’s previous owner, the three men built a test plant and experimented on ores from around the globe.  Beginning in 1889 they established cyanide plants in three of the British Empire’s major mining centers to demonstrate and market their technique.  The first plant was built in New Zealand, the second in Australia, and the third South Africa.  Successes at the South Africa facility mark 1890 as the year when the “MacArthur-Forrest Process” was introduced and shown to be practical for production-level mining.(1)


            Mining men in America scrutinized Cassel’s progress.  A December 1889 issue of New York-based Engineering and Mining Journal described the still-unproven process in detail, after which Cassel’s general manager arrived at Denver, Colorado, during an April 1890 promotional tour.  “Our process, which has been in practical use but little over a year,” exclaimed the company official, “is one which will reduce the most refractory ores and decrease the cost [of milling] from the present cost of $15 to $20 per ton to $5 per ton. . . .  The process will revolutionize the present system of reducing ores, and is no longer an experiment.”  (Mining and Scientific Press 1 March 1890, 146)  At the Crestone Mine, some 125 miles southwest of Denver, he proved the method’s commercial feasibility in this country by launching construction of the first American plant to use the MacArthur-Forrest Process.


            In an age and industry where wonderfully impractical ideas were pitched daily, the MacArthur-Forrest Process received a fair share of skepticism.  One “practical miner” expressed doubt:


California is spotted with the wrecks of crank mills and processes that were going to revolutionize the business – going to, but didn’t.  The fact is, these patent processes ... put money in the pockets of iinventors, and still more

[in the pockets] of promoters.  When they show me an honest miner who has got rich through this cyanide

process, I may take some stock in it.  (Mining and ScientificPress 21 May 1892, 376)


            Expecting to profit by collecting royalties from authorized users, the Gold and Silver Extraction Company of America purchased for $2,000,000 the rights to market the process in the United States.  Organized in 1890 with foreign capital, the company opened an office and laboratory at Denver.  This was followed in 1891 by a plant at the Mercur Mine in the Floyd District, Utah, and another at the Calumet Mine, Shasta County, California.(2)


            Throughout 1891 and early 1892, assertions made for the process were challenged and defended in scientific and trade journals across the country.  Not until summer 1892 did doubts subside in the face of persistent success stories.  The first cyanide plant in Nevada was built in October 1892 in the Tuscarora District, Elko County.  About this time, amid litigation initiated by holders of earlier patents and those who claimed rights for improvements, MacArthur-Forrest disappeared from the vernacular, and the process became known as the “cyanide process.”


MacArthur-Forrest Process.  Although originally envisioned as an ore treating process, cyaniding found early worldwide acceptance for re-working old tailings.  It promised to recover 70% to 80% of the gold and silver from the sandy waste material by using chemicals that cost only about $1.00 per ton of tailings.  At Bodie, where tailings assayed around $5.00 per ton, there existed a good margin for profit.


            Several district enterprises built cyanide plants to process tailings from old mill sites.  After completing its first plant in September 1894, the Standard Company conducted Bodie’s most extensive and longest lasting tailings recovery operation.  Standard Tailings Plant No. 1 sat atop the Bulwer Tunnel’s dump, strategically situated between the Standard mill’s tailings pond and a tailings pond below the recently-dismantled Bulwer-Standard mill.  Horses and mules pulled plows and harrows to loosen dried tailings that had accumulated during nearly 30 years of mining.  Draft animals also dragged wheelless scrapers called “fresnos,” similar to those employed in road and canal construction, through the sandy material to scoop it up and carry it away.  A long handle cantilevered rearward allowed the driver to control the depth of cut and flip the fresno forward to dump it.  Ramps and bridges carried loaded fresnos over waiting wagons or mine cars, which received tailings dumped through grated bridge decks.  Specially built “tailings wagons,” whose bottoms were made of removable transverse slats hauled the sandy cargo to the cyanide plant, where workers with pry bars dislodged the slats, one by one, allowing the contents to spill through the wagon’s running gear and the bridge’s open deck.  Mules or horses also pulled side-dump mine cars on tracks to the plant, where a winch hoisted the loaded cars up an incline to be dumped.


            Leaching Vats. The process inventors originally contemplated large tanks with revolving arms to agitate a mixture of crushed ore and cyanide solution.  This called for substantial motive power, and proved impractical in districts where fuel costs were high.  Instead, Bodie’s early plants adopted a modified process that soaked granular tailings in wooden “leaching vats” and required only enough power to run several pumps.  The vats were usually about 5 or 6 feet deep and 10 to 20 feet in diameter, each fitted with a false bottom made of porous textiles.  A “filter bottom” consisted of layered wool packing, cocoa-matting, canvas, and burlap supported by wooden slats.(3)


            At Tailings Plant No. 1, the horse-drawn equipment required about nine hours to fill one vat with 75 tons of dried tailings.  A “strong” solution of cyanide and water flooded the charge from a pipe in the vat’s bottom.  Although referred to as a strong solution, it contained less than 1% cyanide to minimize its action on base metals, such as lead, iron, and copper.  Filling a vat with liquid consumed about four hours.  The saturated tailings soaked for another four hours.  Moisture from the tailings diluted the solution, so after soaking, the weakened solution was drained through the filter bottom (often with the aid of a suction pump), and displaced by strong solution until the ratio of cyanide was corrected.  Periodic testing of the outflow determined when the liquid in the vat had reached the proper strength.  Changing the solution and correcting its strength continued over the next 20 hours, during which each drawdown allowed air to infiltrate the porous charge with oxygen that hastened the action.  When finally saturated with strong solution, the charge soaked another 20 hours.  After the solution drained, a weak solution of about 1/2% cyanide filled the vat and soaked another 29 hours.  That solution was drained and replaced with wash water to recover any remaining cyanide, requiring 13 more hours.(4)


All cyanide liquid drawn through the filter bottoms carried dissolved gold and silver, and was saved for further processing.  Finally, a discharge gate opened on the vat’s side, and shoveling assisted by high-pressure water from a hose flushed the spent residue through sluices back into the tailings ponds.  Emptying the vat took three hours.  In total, each vat at the Standard plant required 102 hours, or about four days to treat one charge.  The plant’s four 75-ton vats worked in rotation, one per day.  Since one vat treated its charge every day, the plant was rated at 75 tons per day.(5)


            Zinc Precipitation Boxes.  The final steps in cyaniding removed solid gold and silver from the cyanide solution and melted them into bullion.  Clear solution from the filter bottoms entered long wooden boxes divided into about 12 compartments.  Partitions forced the liquid into each compartment from below, passing upward through perforated trays containing zinc shavings.  Dropping as a gray-black powder, solid gold and silver particles precipitated when solution came in contact with the metallic zinc.  The Standard’s plant employed five zinc precipitation boxes, three for the strong solution, two for weak solution.  After giving up their precious metals, the liquids were stored for reuse in separate tanks, where additional cyanide corrected their strengths.  The process consumed twenty pounds of zinc shavings daily, more than the amount of gold and silver recovered.  The Standard mill’s lathe turned zinc discs to produce replacement shavings.


            Acid Bath and Retort.  Every other week or so, a cleanup recovered the precious metals from the zinc precipitation boxes.  Trays were shaken or stirred to loosen precipitate from the shavings, and a stream of fresh water flushed deposited gold and silver particulates from the chambers.  Filtering and decanting removed excess liquid, leaving valuable solids that resembled a dark slimy powder.  A sulfuric acid bath consumed any clinging zinc fragments, before more rinsing and decanting prepared the powdery gold and silver for drying in a special furnace equipped with an exhaust hood that carried away sulfur fumes and vaporized mercury residue from the stamp mill.  Thereafter, careful handling prevented a gust of wind from blowing away the dried powder.  Finally, a furnace exceeding 2,000 degrees Fahrenheit melted the precious powder in crucibles, from which molten metal poured into molds formed bars of bullion.(6)


            Bodie’s pioneering cyanide plants were built near old mill sites to take advantage of tailings that had accumulated during and after the district’s boom years:  The Bodie Tunnel plant, near the Bodie Tunnel mill, presumably Bodie’s first--construction date unknown; Standard Tailings Plant No. 1, near the ruins of the Bulwer-Standard mill, 1894; Parr and Tyack’s plant, at the Syndicate mill, 1894; and the South-End cyanide plant, above Booker Flat, where the Noonday, Spaulding, and Silver Hill mills deposited their tailings, 1895.  Cyanide plants along Bodie Creek treated tailings that had washed downstream:  Standard Tailings Plant No. 2, located 3.3 miles below Bodie, 1896; University plant, 4 miles, 1896; Victor plant, 2.6 miles below town, across from the stone tollhouse, about 1897; Sunshine plant, 7.2 miles at the California-Nevada state line, 1898; the Baldwin plant, 14 miles down Bodie Creek at Fletcher, 1898; the Del Monte plant, 10.5 miles at the site of Aurora’s old Del Monte mill, 1899; and the Green plant, 18 miles from Bodie at the confluence of Bodie and Rough Creeks near Nine-Mile, 1900.  The Standard Company’s third cyanide plant, built adjacent to the Standard mill in 1898, treated tailings directly from the mill as part of a combined ore milling and cyaniding operation.


            Although remarkable for delivering profits, the cyanide process worked better on Bodie’s old tailings than it did on ore from the Standard Mine, which usually contained coarse gold, silver sulphurets, and slimes.  Coarse gold particles required extended time to dissolve, slowing the process, so amalgamating plates in the Standard mill removed as much gold as possible.  The mill’s mechanical concentrators then recovered the silver sulphurets, those vexing compounds that confounded most attempts to redeem their values, even with cyanide.  Extended time in a separate pan and settler treated concentrates with a stronger than normal cyanide solution.  Slimes, the very fine particles in tailings, complicated matters in other ways.  Most apparent was their propensity to clog filter bottoms.  They also tended to pack together in the vats, impeding percolation and sometimes forming impervious layers that brought filling and draining to a halt.  These difficulties could be overcome to some degree by mixing slimes with granular tailings.  The proportions had to be carefully controlled so that the blend remained porous.  The precise ratio, however, accommodated only a small quantity of slimes, leaving many tons of the gold- and silver-bearing material in the ponds to torment experts who sought a method to profit from them.


            Before Bodie’s pioneering cyanide plants were built, the Washoe Process had been the Standard mill’s primary ore treating method, until superseded in 1890 by amalgamating plates and mechanical concentrators.  After cyaniding proved successful, General Manager Robert Gilman Brown abandoned the old pans and settlers in 1897 by linking the mill directly to the distant cyanide plant, where cyanide would recover gold and silver that had escaped amalgamation and concentration.  Eliminating the expense of digging tailings from the ponds then transporting them to the cyanide plant, a bucket elevator raised the slurry above the mill, so that gravity carried it through a flume 1,800 feet to the cyanide plant.  The flume was also expected to do away with winter shutdowns, when frozen ponds halted the horse-drawn excavating equipment.  Cyanide would now become an integral part of treating mined ore, promising extraction rates between 80% and 90% of the assayed value--comparable to chlorination, smelting, or processes requiring roasting--but much cheaper.  Cyanide was especially suited to districts like Bodie, where high transportation and fuel costs had forced miners to leave behind tons of poor ore that would have cost more to mine and mill than it was worth.  Miners returned to the stopes to remove low-grade that now meant big profits.


            Bodie’s first attempt to link milling with cyaniding, known as “direct treatment,” was a dismal failure.  The flume, built in 1897, tying the mill to the cyanide plant frequently plugged with the gritty effluent and froze in winter.  It was abandoned the following year, when the Standard Company built a cyanide plant adjoining its mill.  Built for direct treatment, the plant may not have been operational before an 1898 fire destroyed nearby the mill.(7)  The cyanide plant survived the fire, but was torn down in 1902 and its parts used to double the capacity of Tailings Plant No. 1.


Moore Slimes Process.  One nagging drawback that plagued the cyanide process as introduced by MacArthur and the Forrest brothers was an inability to recover gold and silver from slimes, the very fine particles that clogged filter bottoms and packed together in layers impervious to the liquid cyanide.  Slimes also held the solution like a sponge and refused to release it within time constraints.  Mill operators and experts struggled for more than a decade with what they called “the problem of slimes.”  A related problem also challenged them:  how to increase particle surface area by fine grinding while leaving the material granular enough to percolate.


            In 1903 George Moore obtained an American patent for a suction filtration system that dealt with the conundrum.  Suction pumps drew valuable cyanide liquid through specially built filters that cleaned themselves.  An enormous improvement over primitive filter bottoms, Moore’s filters recovered values from slimes that heretofore had been lost.


After months of research and testing, the Standard Company under Assistant Manager Theodore Hoover converted its enlarged cyanide plant in 1904 to the “Moore Slimes Process,” which promised to improve yields from slimes and tailings lying in the ponds.  It would also increase extraction rates from crushed ore sent from the Standard Company’s new 20-stamp mill, built in 1899 to replace the mill destroyed by fire.  An improved wooden flume, four inches wide by nine inches deep, carried pulp to the remodeled cyanide plant on a steeper downward grade than its failed predecessor.  Four Frenier pumps, capable of withstanding the abrasive effects of finely crushed ore, pushed the pulp in stages 63 feet above the new mill’s floor through a vertical pipe, where it entered the flume.  Trestlework behind the mill supported the flume as it angled downward toward the hill, then turned northward and descended to the cyanide plant 1,800 feet away.(8)  Cyanide had again become the final stage of the milling process.  To distinguish between tailings from the mill and tailings excavated from the ponds, the gritty product leaving the mill through the flume was referred to as “pulp.”  “Tailings” and “slimes” described waste material excavated from the ponds.


            Tube Mill.  Settling tanks inside the rebuilt Standard cyanide plant mixed pulp (flumed from the mill) with tailings and slimes (excavated from the ponds) and removed the coarse sands, which entered one end of a “tube mill” that ground the granular particles to the consistency of slimes.  Introduced to metallurgy in 1894, tube mills were the most recent grinding machines descending from Mexican arrastras and Washoe pans.


Essentially a large horizontal cylinder revolving on its longitudinal axis, the tube mill tumbled very hard flint pebbles or iron balls against the sand to be ground.  Greenland flints were initially used at Bodie, later replaced with iron balls.  The grinding action was twofold:  abrasion occurred as the hard flint stones and sand jostled against each other in the revolving cylinder, and as the flint stones rode up the cylinder’s wall, then dropped into the churning mixture below.  The cylinder’s speed had to be precise, otherwise the pebbles slid back down or traveled all the way around.  The Standard’s tube mill measured 5 feet in diameter, 22 feet in length, and revolved at 26 rpm.  It held 12 tons of coarse pulp and tailings, and every 24 hours ground 60 tons finer than 200 mesh (0.003 inch), the equivalent of talcum powder.  Because everything treated at the plant was either slimes to begin with or was ground to slimes, the Standard Company’s remodeled cyanide plant became known as the “Standard slimes plant.”


            The tube mill’s product and slimes were mixed with cyanide liquid, then conveyed to one of nine wooden settling vats, each requiring about six hours to fill.  After 28 hours of settling, clear cyanide solution, now rich in gold and silver, was drawn off the surface and run through zinc precipitation boxes for another eight hours to remove the precious metals.  Pumps transferred the murky residue from the settling tanks into vats, where Moore vacuum filters would remove more cyanide solution.


            Moore Vacuum Filters.  Moore’s filters consisted of two canvas sheets, 5 feet tall, 16 feet long, sewn back to back with vertical stitching every four inches.  The parallel stitching created channels each of which contained a suction pipe.  The unit was called a filter “plate,” and 49 of them hung four inches apart, resembling pages of a book suspended by its spine.  This assembly with its supporting steel framework, about 16 feet square in plan, was called a “basket.”  Each basket’s filtering surface represented 7,840 square feet.  Two gantry cranes in the Standard plant traveled on overhead tracks, each carrying a basket suspended below.  One observer described the operation in 1905:


The filter is lowered in the slimes and the vacuum pump started, the slimes being agitated to prevent settling.

The suction is continued until a coating of slimes is formed on all parts of the filtering surfaceto a depth of from 3/4 to  1 inch.  During this time the pump is continuously discharging the clear gold solution. The crane then carries the basket to the ... wash water, the vacuum preventing the cakes from dropping off during the transfer.  (Mining and Scientific Press 23 September 1905, 214)


Each gantry crane immersed its basket in the slurry for about 3-1/2 hours, while a vacuum drew cyanide solution through the hanging filter plates, accreting 18 tons of caked slimes.  It was important that the cakes remained thin enough to allow cyanide solution to pass through.  The gantry lifted the basket from the vat while vacuum held the cakes fast to the canvas.  Encased with solids, the filters were conveyed to a wash water vat then submerged for another three hours.  Vacuum drew fresh water through the cakes, recovering any cyanide solution still permeating the clinging colloids.  After the filters were withdrawn from the wash water, 30 minutes of suction held the cakes in place and dried them, all the while recovering more liquid.  Now cleansed of cyanide, the filters traveled to a discharge hopper, where the vacuum pump stopped and successive blasts of air from within dislodged the dried slimes, dropping them from the canvas.  The entire sequence required eight hours for each basket.  Throughout filtering, washing, and drying, all recovered liquid passed through zinc precipitation boxes that recovered the gold and silver.


            The distant Standard mill received several modifications to accommodate the Moore system.  Cyanide solution was introduced in the stamp batteries, increasing the ore’s exposure to the chemical, which remained in contact with the pulp until removed by the cyanide plant.  Behind the mill, a 3,100-cubic foot storage tank supplied the stamps with solution that circulated between the mill and plant.(9)


            Ore from deep inside the Standard Mine now took a serpentine route before it became bullion ready for shipment to the mint.  From the stopes, it traveled in mine cars through drifts and crosscuts to the shaft, where it was either hoisted or lowered to the Bulwer Tunnel and dumped into two underground storage bins.  Mules pulled the ore in cars 1,860 feet through the tunnel, then 1,200 feet southward along the base of High Peak on snowshed-covered tracks.  A winch pulled the cars, one at a time, up an incline into the Standard mill, where the ore dropped through a grizzly into bins.  After a rock breaker fractured oversized rocks, and stamps crushed the ore and mixed it with cyanide solution, amalgamating plates and concentrators removed the coarse gold and silver sulphurets.  The pulp and cyanide mixture reversed direction, flowing through the flume 1,800 feet to the Standard cyanide plant near the Bulwer Tunnel, where fine grinding then filtering captured the remaining gold and silver.


            Inside the cyanide plant, workers had carefully marked cyanide pipes to prevent inadvertent poisoning of personnel.  Despite all precautions, Theodore Hoover recalled nearly dying from accidentally drinking the deadly chemical.  He had been hard at work on the remodeled plant, when he drank from a freshwater faucet.


In about five minutes I began to feel queer, but thought it was fatigue and loss of sleep.  A minute or two later, I looked up, thinking that all the machinery had stopped, as everything was silent.  The machinery was all running, but I had lost my hearing.  Then my hearing came back, all right again with a bang.  In a few minutes hearing was gone again, also sense of touch, and also, I suppose, taste and smell.  By this time I was becoming excited, and my mind was working rapidly to fathom the cause. ...  The cycles of lost hearing and touch were recurring regularly about every six minutes. (Hoover 1939, 136-137)


A quick laboratory test of a sample from the spring-water tap revealed cyanide.  “After the first flush of fright, however, I felt that, as I had lived the better part of half an hour since drinking, the chances were that the poison would not get me that time.”  Hoover survived the episode, but an investigation revealed that a machinist had inadvertently connected a fresh water pipe to a cyanide pump, and poisonous solution had infiltrated the drinking water.  Luckily, the concentration was diluted when Hoover drank from the tap.  “If it had not been discovered in time many men might have been killed.”  (Hoover 1939, 136-137)  The outcome of another cyanide poisoning incident was not so fortunate.  Robert Bell recalled his young cousin, whose father worked at the Baldwin Plant:  “One day he came home from work without changing his clothes and must have got some cyanide on his shoes.  He probably walked through some of it when they were dumping it out.  She thought it was sugar and ate it.  When they found her, she was already dead.”  (R. T. Bell:  Telephone interview, June 21, 1998)


Butters Slimes Process.  Shortly after Moore marketed his slimes filtering process, Charles Butters developed a similar method that proved more practical for treating large volumes of low-grade ore.  Butters’ system employed filter plates that remained fixed, while the various liquids (cyanide solution followed by wash water) flowed in and out of each vat.  In 1910 the Standard Company converted its slimes plant to the Butters system, a simpler, automated method that required motive power only in the form of pumps.


            Finely ground pulp and tailings from the tube mill were mixed with slimes and agitated in a cyanide solution storage tank, where ample time allowed the gold and silver to dissolve.  The mixture was pumped from the tank into a rectilinear vat containing nearly 100 hanging filter plates.  After the rising slurry had engulfed the plates, a vacuum pump drew the valuable liquid through the filters.  Additional mixture had to be added as the liquid was removed.  After 3-1/2 hours, caked colloids enveloped the filters.  Suction held the cakes in place while the tank drained and the pulp returned to the storage tank.  Wash water then filled the vat and was sucked through the filters, displacing cyanide solution saturating the cakes.  After as much cyanide solution as possible had been removed from the clinging solids, the vat drained to a level immediately below the filters and the vacuum pump stopped.  Blasts of compressed air from within dislodged the spent slimes, which fell into the water to be discharged as tailings.  Economies of scale applied readily to Butters’ system, allowing large-scale operations with only one long vat.  The Standard Company, however, realized little benefit from the improvement.  Its mine closed in 1913, just three years after installing the Butters system.





1.   Chlorination’s popularity was short-lived.  Requiring large-capacity airtight tanks, expensive chemicals, and poisonous chlorine gas, the process recovered base metals more readily than gold and silver.


2.   The new company found that collecting royalties was not easy, a problem that led to its downfall.  Former MacArthur-Forrest employees who understood the process presented themselves as “experts,” selling their knowledge to mine owners seeking to avoid paying royalties by building cyanide plants on the sly.  An intriguing silence from regional newspapers and the lack of other documentation suggests a clandestine origin for Bodie’s first cyanide plant, presumably near the Bodie Tunnel mill, whose construction date remains a mystery.  Sixty years later, Ella Cain described her father-in-law’s interest.  “When the cyanide process was discovered, J. S. Cain and A. J. McCone . . . hired an expert from New Zealand, who was familiar with the process, to build the first plant and work the tailings.  His salary was $1,000 a month, which included a horse and buggy for his use.  This was an unheard of salary in those days, but Cain and McCone figured he was worth it.”  (Cain 1956, 82-83)  Warren Loose recalled interviewing a Bodie pioneer and former Syndicate mill foreman.  “John Parr once laughingly described to me how he and other curious Bodie mining men on many occasions (during the secret construction of Bodie’s first cyanide plant) slipped out at night to glue their eyes to a handy knothole or a crack in the siding to try and see what in thunder was going on behind the locked doors.  Parr said that he had the process almost figured out by the time McCone and Cain’s plant began its operations.”  (Loose 1971, 211)


3.   Some vats in South Africa were enormous, reaching diameters of more than 40 feet with a 14-foot depth.


4.   Lime added to the vats helped check natural deterioration of the solution as it acted upon gold and silver.  Lime also reduced cyanide weakening caused by organic plant matter dug up with tailings from creek beds and the banks of tailings ponds.  A kiln near Mono Lake supplied the lime.  A decade earlier the kiln had produced lime for mortar to construct Bodie’s brick buildings.


5.   A strange contrast occurred between stamp mills and cyanide plants.  Solids contained the values in stamp mills, and water was discarded.  Liquid, however, carried the gold and silver in cyanide plants, and the solids were discarded.  Stamp mills were classified by the number of stamps, cyanide plants by their capacity in tons per day.


6.   For detailed descriptions of Bodie’s four pioneering cyanide plants in 1898, Standard Tailings Plant No. 1, Standard Tailings Plant No. 2, South End plant, and the Victor plant, see:  Francis L. Bosqui, Practical Notes on the Cyanide Process  (New York, NY:  Scientific Publishing Company, 1899), 36-192.


7.   It is unclear if the Standard’s new mill was connected to the adjoining cyanide plant.


8.   An iron pipe replaced the wooden box flume in 1909, and more substantial trestlework improved flow by straightening the pipe’s alignment.


9.   For additional details on the Moore Process at the Standard cyanide plant, see Robert Gilman Brown, “Cyanide Practice with the Moore Filter.”  In Recent Cyanide Practice, ed. T. A. Rickard (San Francisco, CA:  Mining and Scientific Press, 1907), 92-109.  For a later account, see S. F. Shaw, “The Standard Consolidated Cyanide Mill,”  Engineering and Mining Journal  (New York, NY), 6 March 1909:  487-489.





Bosqui, Francis L.  Practical Notes on the Cyanide Process.  New York, NY:  Scientific Publishing Company, 1899.


Brown, Robert Gilman.  “Cyanide Practice with the Moore Filter.”  In Recent Cyanide Practice, ed. T. A. Rickard, San Francisco, CA:  Mining and Scientific Press, 1907:  Part 1, 92-97; Part 2, 98-109.


Cain, Ella M.  The Story of Bodie.  San Francisco, CA:  Fearon Publishers, 1956.


“The Cassel Gold-Extracting Process.”  Mining and Scientific Press  (San Francisco, CA), 1 March 1890:  146.


“The Cyanide Process.”  Mining and Scientific Press  (San Francisco, CA), 2 July 1892:  3-13.


“The Cyanide Process.”  Mining and Scientific Press  (San Francisco, CA), Part 1, 27 May 1905:  337-338; Part 2, 3 June 1905:  356-357.


Eakle, Arthur S., Emile Huguenin, and R. P. McLaughlin.  Mines and Mineral Resources of Alpine County, Inyo County, and Mono County.  Sacramento, CA: 

ia State Printing Office, 1917.


“History of Cyanidation.”  Mining and Scientific Press  (San Francisco, CA), Part 1, 23 November 1907:  655-657; Part 2, 30 November 1907:  682-685.


Hoover, Theodore J.  “Memoranda:  Being a Statement by an Engineer”  (Typescript)  Hoover Institution Archives, Stanford University, 1939.


Loose, Warren.  Bodie Bonanza:  The True Story of a Flamboyant Past.  New York, NY:  Exposition Press, 1971.


Scheidel, A.  California State Mining Bureau Bulletin No. 5, October 1894, The Cyanide Process; Its Practical Application and Economic Results.  Sacramento, CA:  Superintendent of State Printing, 1894.


Shaw, S. F.  “The Standard Consolidated Cyanide Plant.”  Engineering and Mining Journal  (New York, NY), 6 March 1909:  487-489.