Geological Survey Bulletin 707 Guidebook of the Western United States: Part E. The Denver & Rio Grande Western Route

BINGHAM, THE GREAT COPPER CAMP.

A visit to Bingham can hardly fail to interest the traveler, for almost everyone enjoys seeing the wonderful things man is accomplishing, even though he may not be interested in them financially or professionally, and nothing more spectacular than the mining in Bingham Gulch can be imagined. In a visit to most mining districts the traveler actually sees little of real interest. He may be told that this or that mine has produced so many millions of dollars, but great dump heaps and mine buildings are about all he sees, and he generally leaves the camp with a very hazy idea of what actually takes place in the mine, for he can not see the work that is being done; but in Bingham it is different. Here he can see the work actually in progress, and he can almost watch the movement of the ore from the time it is gathered up by the giant steam shovels until it is delivered to the smelter. It is a wonderful sight that can be rivaled only at some of the great iron-ore mines of Minnesota.

In order to reach Bingham the traveler has the choice of three routes: He may go by train on the Denver & Rio Grande Western Railroad or the Los Angeles & Salt Lake Railroad, or he may go by automobile stage or private conveyance. As the camp should be approached by the route that will give the best view with the least effort, for the sake of first impressions, the writer would recommend that the traveler take the Los Angeles & Salt Lake route, and then he may return if he wishes by any other of the routes mentioned.

In going to Bingham by way of the Los Angeles & Salt Lake Railroad the traveler goes to Garfield on the main line toward Los Angeles. In this part of his journey he has a good opportunity to see the great flat plain at about the level of the lake, which stretches from Salt Lake City to Garfield, a distance of 15 miles. Near Garfield he may see on the north (right) the pavilion at Saltair and some of the salt-manufacturing plants in the vicinity, but they are so far away that he may not be able to distinguish details. He sees little or nothing of the lake, for it is far to the north. The town of Garfield was built to accommodate the workers in the Garfield smelter, which was put in operation in 1906. The smelter is not visible from the train, but the high stack rises from behind the sharp point of rocks on the right as the train makes the curve into Garfield. As few travelers are familiar with the smelting of ores, a brief description of the work carried on in the Garfield smelter, as well as in those seen at other places along the railroad, is given by C. N. Gerry in the footnote.⁸⁶

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⁸⁶A smelter is an establishment where ores are reduced to the metallic state or to matte (pronounced mat; crude metal containing sulphur, which needs further purification) by melting in a furnace. This statement is simple, but the actual working out of the process is often lengthy and complex. There are many kinds of smelters—iron, zinc, copper, and lead smelters in the East and principally copper and lead smelters in the West. Some plants are equipped for smelting both lead and copper and for producing at the same time gold and silver and perhaps the rarer metals in the base bullion. The smelter at Garfield, Utah, produces blister copper (crude pig copper, so called from gas blisters that form on the surface while cooling), from which gold, silver, and copper are afterward refined. The dust from the furnaces is also saved, and from it are obtained gold, silver, and lead. The smelter at Murray produces principally lead bullion containing a small percentage of silver and gold, a matte containing copper as well as the precious metals, and arsenic from the flue dust. At the Midvale smelter the products are much the same as those of the Murray smelter, but in addition the metal cadmium is obtained. Some smelters operate concentration mills in conjunction with the furnaces, in order to make a higher grade of ore by rejecting a part that is worthless or to separate one kind of ore from another.

In the early days some of the mines were equipped with small furnaces, but as these were generally crude the losses in slag and fumes were great. Mine smelters have been generally abandoned, and now it is more economical and convenient to ship the ore to a centrally located custom plant, where it is smelted with ores from other mines or even other districts. The ore when received is usually crushed and carefully mixed, and a small sample is taken that will represent the entire lot. This sample is "assayed" both by the mining company and the smelting company. That is, it is tested to ascertain how much of each of the metals it contains. The assay at the smelter is often watched by representatives of the mining companies called "moochers." If the assays of the owner and of the smelter do not agree closely an umpire assayer is called upon to analyze a third sample, and the differences are adjusted by arbitration. The ore is then paid for according to current metal prices less fixed deductions for losses in the process, penalties for objectionable ingredients, and a definite charge for smelting—all these items being frequently covered by contract. The ores that reach a custom smelter differ greatly in their composition; some contain lead or copper as sulphides with gold and silver; others are oxides or carbonates that have lost the sulphur. Pyritic or iron sulphide ores often contain gold and silver, and a familiar ore is one that contains much silica or quartz with gold and silver. The western sulphide ores frequently contain much zinc, which is objectionable in lead smelting and is ordinarily penalized by the smelters when above a certain percentage. If the ore contains much sulphur, as it commonly does, it receives a preliminary treatment in roasters. Some of these roasters are circular, about 22 feet in diameter, and have a number of hearths on which the ore is slowly "rabbled" or raked by arms that extend from the center. After entering at the top and passing over the hearths it has been relieved of most of its sulphur and is then dumped into cars. Another type of roaster produces a coherent mass called sinter, which naturally makes a less dusty charge for the blast furnace. In some places a series of pots are used in which the sulphur is burned off by the aid of a blast after the introduction of burning coal. Years ago at Butte, Mont., the ore was roasted in the open air on piles of cordwood, but the farmers objected to a process which permitted the escaping gases to destroy vegetation. In most places, therefore, the smoke and gases are now carefully diverted and treated. The result is that farms now thrive close to smelter stacks, and the smelters make a much better saving of metal.

The blast furnace in common use is upright and has a rectangular cross section. It is cooled by a water jacket, and the charge on the hearth receives an air blast, as its name implies. For the best results the charge must be carefully calculated and weighed. It usually consists of about 75 per cent of ore that has been previously roasted, mixed with coke, limestone, and old scrap iron or slag. After smelting has been in progress several hours lead bullion forms in the crucible, if the charge consisted of lead ores, and slag and matte flow into special cars. The bullion is skimmed to remove the dross or impurities and then cast into bars, which are shipped to refineries where the gold, silver, and lead are separated. The slag, which contains iron, silica, and other substances, is discarded, and the matte, which contains gold, silver, copper, and lead, is either crushed and returned to the blast furnace or shipped to a refinery. Some plants use reverbatory furnaces in smelting lead ores that contain little silica. These furnaces are horizontal and combine roasting with reduction. The product is lead bullion and a residue which may be treated in a blast furnace. In all these operations, but especially in the operation of the blast furnace, the draft of air takes up small particles of ore, and the intense heat volatilizes some of the metals, such as lead, zinc, and arsenic. The fumes are therefore turned down into long semicircular flues, where the dust particles collect, or they are cooled and condensed to solids in chambers. In some plants the particles are collected by being passed through pipes fitted with a central insulated wire, the pipe and wire forming the two poles of a high-tension electric field. The dust becomes charged with electrostatic energy and is driven to one pole of the field, where it accumulates and is periodically collected. Arsenic is also saved by passing the fumes through thousands of woolen bags treated with zinc oxide or lime. At present many plants use the fumes in the manufacture of sulphuric acid, which is again utilized in the leaching of copper ores. These devices have brought a great change in smelting. Many years ago a dense volume of smoke marked the position of the smelter stack, but now the smoke nuisance is largely abated.

Copper smelting to a certain extent is similar to lead smelting, but the products must be treated somewhat differently. Roasters, reverberatories, and blast furnaces are used, but the operation of the blast furnace, instead of making copper bullion, results in copper matte, a product that contains copper, sulphur, and iron. This matte is again treated in converters which have an opening in the top to dispose of the fumes and to receive the matte when the converter is charged. An intense blast of air is forced in from the sides, allowing oxygen to combine with the sulphur and form sulphurous gases which are led away from the top, and after about 2 hours the matte is "blown" into the product known as blister copper, which contains about 98 per cent of pure copper. If much gold and silver is present the blister copper is further refined.

A large copper smelter in operation is a most impressive sight. It consists of a row of blast furnaces belching forth white-hot slag. Strings of cars take the fiery material to the slag dump, and glowing streams of the melted matte flow from the furnaces into large kettles. Traveling cranes pick up the kettles and pour the molten matte into the converters, where, with an intense light, the work of "blowing" begins, which changes the matte to blister copper.

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From Garfield the route lies almost south along the eastern foot of the Oquirrh Range. At Arthur and Magna there are large mills for crushing and concentrating the copper ores of the Bingham district. The Magna plant (see Pl. XCVI, A) has a capacity of 14,000 tons daily of low-grade ore, and the Arthur plant of 10,000 tons. From Magna southward the train runs over the tracks of the Bingham & Garfield Railway, which was built in 1911 for the sole purpose of transporting ore from Bingham to Garfield. This road is said to handle a greater tonnage of freight to the mile than any other railroad in the United States.

After leaving Magna the track winds up the slopes of the mountain, but as it traverses mainly the sand and gravel deposited in ancient Lake Bonneville, there are few rock cuts. In this interval the traveler has several excellent views of the terraces of Lake Bonneville (see Pl. XCVI, B), and as the track enters the mouth of Bingham Canyon the road has attained about the level of the highest or Bonneville shore line.

By climbing steadily from Garfield the railroad is here about 200 feet above the bottom of the canyon, and the traveler may look down on the left and note all the activities of a mining town. (See Pl. XCV, A.) The canyon is very narrow, and the town consists of a single street with scarcely room enough for houses on both sides. The view from the train would be fine were it not that the road is chiefly carved through the mountains. From time to time the train emerges from the portal of a tunnel and crosses one of the side canyons on a steel trestle 200 feet or more high. The traveler may then have a good view of the canyon, but the mines are mostly above the town, so that they are not visible until the train stops.

PLATE XCV. A (top). BINGHAM CANYON. View of the canyon above the mouth of Carrs Fork from the station of the Los Angeles & Salt Lake Railroad. The copper ore is mined by steam shovels and loaded directly into railroad cars, which are run on all the levels. It is then taken to the mills for concentration, and the concentrate goes to Garfield for smelting. Photograph by Shiplers, Salt Lake City. B (bottom). BINGHAM MINE OF UTAH COPPER CO. Near view of the copper mine, showing most of the 24 levels upon which excavating work is going on. The levels extend from the bottom to the top of the canyon wall, a vertical distance of about 1,600 feet. About 21,009 tons of material is handled daily in this mine. Photograph by Shiplers, Salt Lake City.

When the traveler alights from the train he finds himself high up on the side of the canyon and at its largest fork. He may well stop here to look at the surroundings, for it is doubtful if he will find as good a viewpoint without considerable climbing. He may look in vain for the mines, but instead he will see the wall of the canyon before him creased with horizontal benches and on each of these benches an enormous steam shovel lifting the ore and its overburden upon waiting cars.⁸⁷ (See Pl. XCV, B.) When the cars are full they are drawn away and made up into trains to be sent to the concentrators at Magna and Arthur. The side of the canyon in front of the traveler is 1,600 feet high, and it is divided into 24 steam-shovel levels, on each of which is a railroad track. At present about 60,000 tons of material is being handled daily, of which 38,000 tons is cap rock and 22,000 tons ore.

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⁸⁷C. N. Gerry gives the following account of the development of the mines at Bingham and the wonderful work that is now being done there.

About 25 miles southwest of Salt Lake City, in a narrow canyon, is the town of Bingham which has been a mining center since 1865. Recently the camp has assumed great importance, and at the present time it is unique among producing regions in that it has the largest single copper mine in the United States. Up to 1900 the camp had been producing metals valued at more than a million dollars a year, and that was regarded as a large output. The production jumped to $3,000,000 in 1901, to $39,000,000 in 1915, and to $72,000,000 in 1917. In 1918 it fell to $62,800,000, in 1919 to $27,900,000, and in 1920 to $27,500,000. As a spot of beauty or a model of cleanliness the place is not worth noting, but its gigantic mining operations are certainly impressive.

The history of the first mineral discovery is unusual, for ore was found in 1863 by soldier prospectors under Gen. P. B. Connor, who was stationed at Fort Douglas. While the Indians were quietly hunting and the Mormons were peacefully pursuing agriculture and irrigation, the soldiers, who were from California, were engaged in the search for mineral wealth.

Although the district was never famous as a source of free gold, considerable placer mining was done about 1865 in the vicinity of the present town of Bingham and for several miles, east along the canyon. The first shipment of copper ore, which was made in 1868, was hauled to a station on the Union Pacific Railroad and was shipped to Baltimore. Not until 1873 did railroad connection with the outside world give an impetus to genuine development. About this time the adverse attitude of the Mormons changed, and the church began to encourage the mining industry. Then followed a period of lead mining, which was fairly successful while the oxidized zone was being exploited. In the early eighties several stamp mills were erected to treat oxidized gold ore. Then other lead carbonate bodies containing silver were successfully mined until the decline in the price of silver in 1893. This period was followed by the development of the heavy copper and iron sulphide ore, which is a conspicuous ore of the camp even at the present time. It contains about 30 per cent of iron, 30 per cent of sulphur, and a few per cent of copper. The problem of economically treating it was not solved until 1899, when efficient smelting plants were constructed. Most of these plants were built in the Salt Lake Valley east of Bingham. As the lead mines became deeper sulphide ore began to appear, which added other difficulties to be overcome. Some of this ore was sufficiently rich to be shipped at a profit, but much of it required concentration, so plants using crushers, rolls, jigs, and concentration tables were erected. Several times these plants, as well as dwellings, have met with disaster when a large boulder or even a derailed engine rolled down the steep hillside. When much zinc sulphide occurred with the lead the smelters imposed a penalty, but later, when the zinc was separated, it became a valuable product. Not until 1909, however, was the zinc product sold. At present the entire output of the district is shipped and concentrated, or separated, and smelted. So the camp has had a great variety of ores, from simple free-gold ore and oxidized copper and lead ores to difficult sulphides of iron, lead, copper, and zinc, even down to the famous low-grade disseminated ore containing specks of copper sulphide that constitutes the bulk of the copper ore mined at the present time.

The treatment of the ore has kept pace with discovery, gradually developing from the panning of placer gold and the amalgamation and cyanidation of gold and silver ores to the concentration and separation of copper, lead, and zinc ores. The smelting has grown from the old furnace that looked like a stove to a plant that covers hundreds of acres.

About 1900 events of real importance to Bingham's growth began to occur. In that year the output of gold, silver, copper, and lead had a value of over $1,500,000, and there was a general consolidation of mining property in order to effect economy in operation, and the building of large smelting plants to treat these ores began.

In 1902 the United States Smelting & Refining Co. constructed a plant at Midvale, east of Bingham, to treat 1,000 tons of copper ore a day, and later the company built a lead plant to treat 400 tons a day. At present this plant has developed into one that treats 1,500 tons a day, and the copper furnaces are idle. A copper plant was also erected in the Salt Lake Valley by the Bingham Copper & Gold Co., which owned large interests at Bingham. The Highland Boy mine developed so extensive a body of copper ore that a smelting plant was built near Murray. Both these plants operated for years but were afterward dismantled. Ore from the Yampa mine was treated in a copper plant in the canyon below the town. The American Smelting & Refining Co.'s lead plant at Murray, with eight blast furnaces, was erected in 1901; it had much to do with the exploitation of lead ores from Bingham. There have been several concentration mills close to the mines, such as the Utah, Apex, Bingham, New Haven, and custom mills, but a considerable proportion of the lead-zinc ore is now shipped to Midvale, where it is concentrated and separated into lead and zinc products.

The operation of these mines created a maze of underground workings, miles in extent. Without a map or guide traveling in the tunnels is dangerous. Some years ago a Mexican criminal, by his knowledge of the workings of the Apex mine, succeeded in eluding the sheriff who was pursuing him. How he got out and where he went is one of the mysteries of Bingham.

In 1905 the 21 mines in operation produced more than a million tons of ore, which was valued at nearly $10,000,000. As many of the mines are several miles from the railroad terminus, it was necessary to haul the ore by teams or to use transportation tunnels or aerial tramways. Several tramways lead down the canyon or over the crest of the range to the International smelter at Tooele (too-ell'y), which in October, 1916, was treating 1,200 tons of copper charge and 1,500 tons of lead charge daily.

Although the ores mentioned have played an important part in the past development of Bingham, they are now of less relative value, for the great work of to-day is the mining, concentrating, and smelting of copper ore, which averages about 1.5 per cent of metallic copper. This ore occurs as grains of copper sulphide disseminated in a large mass of monzonite.

From 1993 to 1909 the Boston Consolidated Mining Co., which operated on part of this ground, used steam shovels and produced over 43,000,000 pounds of copper. The ore averaged 1.65 per cent copper, or only 33 pounds of copper in 2,000 pounds of ore. The loss in milling reduced this figure to 23 pounds actually recovered.

In 1904 the Utah Copper Co. built the Copperton mill for experimental work in the lower canyon. As the work progressed the mill was increased in size until it could treat 900 tons of ore a day. At the same time underground development was proceeding, and in 1906 it amounted to nearly 18 miles. The plan was to extract ore by the caving system, but when some idea was gained of the extent of the ore body and the amount that would be required to make a sufficient tonnage of commercial concentrate, steam shovels were put to work. These shovels have been used ever since, partly to load ores on cars for milling and partly to remove the top or cap of the deposit, a brown oxidized material from which part of the copper has been removed by natural leaching. A photograph taken in 1906 shows only one steam shovel, and that one was at work on the capping. Trees still grew on the hillside, where apparently slight change had been made on the surface.

In 1909 the property of the Boston Co. was consolidated with that of the Utah Copper Co., which thus acquired 740 acres of mineralized territory, most of which is north and west of the main canyon. When the first mill at Copperton proved that the ore could be successfully treated the Magna mill (Pl. XCVI, A), 15 miles north of Bingham, was constructed, section by section, until its capacity was 4,000 tons of material a day. The ore was concentrated at the ratio of 20 tons of ore containing less than 2 per cent to 1 ton of concentrate containing about 25 per cent copper, leaving 95 per cent of the original material to be discarded as tailing. The development proceeded so rapidly that the company was reorganized many times. In 1904 it was capitalized at $4,500,000, and in 1910 its capitalization reached $25,000,000. To increase the extraction of ore the only thing necessary was more steam shovels. The solitary shovel of 1906 had 22 companions in 1910. But transportation and milling had to keep pace with mining. The Garfield branch of the Denver & Rio Grande Railroad hauled an immense tonnage, but in 1911 the Utah Copper Co. constructed a railroad from Bingham to Garfield, a distance of 20 miles, in order to meet its needs.

PLATE XCVI. A (top). MAGNA MILL OF THE UTAH COPPER CO. The Magna mill, at the north end of the Oquirrh Mountains, was built to concentrate a part of the copper ore mined at Bingham. It treats more than 10,000 tons of ore daily. Above the mill may be seen some of the terraces of old Lake Bonneville; the uppermost is the Bonneville shore line. Photograph by Shiplers, Salt Lake City. B (bottom). BONNEVILLE SHORE LINE ON WASATCH MOUNTAINS. Near view of the west face of the Wasatch Mountains showing the horizontal band across the mountain front that looks like a well-graded road. This is the beach cut by the waves of Lake Bonneville when it stood 1,000 feet higher than the water stands to-day in Great Salt Lake. Photograph by Shiplers, Salt Lake City.

After the property of the Boston Consolidated Co. was taken over the 3,000-ton mill near Garfield was remodeled and enlarged. This mill was later called the Arthur plant. It treated 8,000 tons of ore a day in 1910 and 15,000 tons in 1918; the Magna mill treated 10,000 tons of ore a day in 1910 and 18,000 tons in 1918. The Magna plant was shut down in February, 1919. In 1920 the Arthur plant treated 5,500,000 tons of ore. A mill treating 500 tons is considered a fair-sized plant, but these mills require 12 trains a day hauling 40 cars of 50 tons of ore each. The Magna plant alone covers 20 acres, and the company owns an immense acreage for the disposal of the tailings. Like most plants of this character, it is built on a hillside so that the ore may pass by gravity from one process to another. The ore is ground very fine. After the material has been well classified it reaches tables and vanners. The table has a plane surface, which is tilted at an angle and partly covered with riffles or strips of wood. As the machine is agitated the water carries the lighter gangue or waste material over the edge, separating it from the heavier copper and iron minerals held by the riffles. A well-managed table will sometimes distinctly show three different minerals, such as lead, zinc, and iron sulphides, which have been separated because of their difference in weight. This machine applies the principle of wet concentration. The principle of flotation is the direct opposite of this principle, for the heavy metallic particles in the flotation process float on a froth after the finely crushed ore is mixed with oil and air. Experiments with flotation are going on at Magna and Arthur, and if this system is used in conjunction with wet concentration the saving from losses in tailing will probably be increased about 20 per cent. At present the mills save 63 per cent, or about 18 out of 28 pounds of copper. A ton of the ore treated would make a cube about 28 inches on a side, but the copper recovered would be only about a 4-inch cube. An additional 5 pounds to the ton amounts to a large increase in production if 8,000,000 tons are treated each year. If flotation can make a better saving on the sulphide ore and the leaching process can be used in treating the oxidized portion the future will be bright, especially as the company estimates the life of the mine at over 60 years. When copper is 25 cents a pound ore is worth over $4 a ton at the present rate of saving, and all costs of mining and treatment are less than $1.

The great work of mining may be observed from the station of the Bingham & Garfield Railroad. In the view looking south, as shown in Plate XCV, B, the Denver & Rio Grande Western tracks circle the hills on several levels. The northern side of the canyon is served by the Bingham & Garfield road. The work of the steam shovels can be seen to better advantage if one walks along the main canyon. The ore body is about a mile in length and approximately 1,500 feet above the level of the road. Over 43,000,000 tons has already been removed from the mine, and drilling in various parts of the area has shown that a total of 390,000,000 tons is available. Steam shovels (Pl. XCV, B) operate on a great many levels, from the base of the hill up to the very summit, where the cap is being removed and dumped near the old Jordan mine. In each scoopful the steam shovel lifts 4 tons of the ore into cars. The mining, handling, and concentrating on a large scale by the Utah Copper Co. of this great mass of low-grade ore, which for a long time was considered too poor to be of value, has revolutionized Bingham. The output of the Utah Copper Co. has grown from 3,000,000 pounds of copper in 1903 to a maximum of 206,000,000 pounds in 1917; in 1920 it was 106,600,000 pounds. The aggregate production for the district to the end of 1920 has been 2,100,000,000 pounds. In 1915 the gold and silver were about ten times, the lead twenty times, and the copper thirty times the output in 1900. Bingham should have celebrated its fiftieth anniversary in 1915, but the date was forgotten in the anxiety to add to a record of metal output valued at nearly $280,000,000 in 50 years. The total value at the end of 1920 was $538,000,000.

Several large low-grade deposits are worked in other States—at Ely, Nev.; Ray and Miami, Ariz.; and Chino, N. Mex.—but these do not compare in size or output with the mine of the Utah Copper Co. Credit for the great achievement must be given to many. Col. E. A. Wall always had implicit faith that this grade of mineral would eventually become commercial ore. The Boston Consolidated Co., with Mr. J. A. Bettles, worked out many of the mining and milling difficulties, and credit for organization and financing is due to Col. D. C. Jackling.

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As seen from the station of the Bingham & Garfield Railway the canyon resembles a fairy scene. Here and there on the mountain side gnomes and dwarfs are digging their way along its front. Puffs of steam show the location of tiny steam shovels laboring away to help tear down the mountain. Locomotives with long lines of ore cars shuttle back and forth across the face of the mountain, at times directly above the spectator, then again far below. It seems to be pandemonium let loose, but out of it comes the ore in a steady stream that makes the spectator wonder.

The town of Bingham may be as interesting to the traveler as the great mines that give it life. Through force of circumstances it is a one-street town, and this street winds and twists with the winding and twisting of the narrow canyon. The street is so narrow that the traffic is accommodated with difficulty. By patience teams and wagons are maneuvered so as to allow automobiles to pass, but even these autocrats of the highway are sometimes involved in an almost hopeless tangle. Residences have been built wherever there was space; if this space was on level ground so much the better, but it was not left vacant even if it was on the steep mountain side. People live almost in the midst of the great excavation, and they soon become accustomed to the rumble of the train above, below, around, and in fact on all sides.

When the traveler has satisfied his curiosity regarding both the mine and the town he can return by way of the Denver & Rio Grande Western Railroad, which runs in the bottom of the canyon, to Salt Lake City to resume his westward journey, if he has not reached the end of his route.