UtahRails.net

UtahRails.net

Tintic, Mammoth Mine and Mill

This page was last updated on September 12, 2025.

(Return to Utah Railroads Index Page)

Overview

(The focus of this information is to establish a timeline using sources not previously readily available.)

The Mammoth mine was organized in February 1870 by a group of miners that included Charles Crismon. Supposedly one of that original group of prospectors stated "Boys, she's a mammoth strike! We've got ourselves a mammoth mine." Within a couple years Crismon became the majority owner and in 1873, he exchanged his interest in the mine to Samuel and William McIntyre for cattle that the McIntyre brothers had herded into the Tintic Valley from Texas. One of the first mills in the district, and later a small smelter, was built in 1873 by the Crismon-Mammoth Company out in the valley near the McIntyre's Tintic Ranch, seven miles southwest of the Mammoth mine. The Crismon mill soon became known simply as the "Tintic Mill". The location was chosen to put the mill on land already owned by the McIntyres, and to allow the mill to be near a good source of water. Fuel was another matter, and its high cost would soon be a deciding factor in the mill's closure.

The Mammoth mine is at the head of Mammoth Hollow, also called Mammoth Basin. In 1898, it had been productive from the first, the location having been made on a large, irregular, elliptical-shaped body of ore, which bas been followed continuously from the surface to the bottom of the mine, a vertical distance of 1,600 feet.

The owners of the Mammoth mine were using freight wagons to get the ore down from their mine to the company's new mill, a distance of two miles as the crow flies. The steady stream of wagons moving along the steep road between the mine at Upper Mammoth, and the new mill at Robinson (Mammoth on the railroads), was a cost that the company wanted to avoid. To reduce its costs, the company approached the railroads about building a branch to the mine. Although the Mammoth mine's prospects were bright, both railroads hesitated at building such a steep and difficult line, saying that the mining company would have to pay a large share of the added costs for such a difficult line. To avoid these costs, in January 1894, the mine owners (the McIntyre brothers) organized the East Tintic Railway to build a 2-1/2 mile railroad between a connection with the joint trackage at Mammoth (Robinson), where their mill was, and the mine at the top of Mammoth Hollow. The plans for the new railroad laid dormant after other mining companies along the proposed route expressed an interest in using the new line to haul their ores to the OSL&UN line for eventual movement of their own ores to the Salt Lake Valley smelters. These other mining companies were each located in the upper reaches of Mammoth Hollow, and each had its own mill.

(Read more about the Mammoth mine and its place in the Tintic Mining District)

June 3, 1877
The following description of the Crismon Mammoth mine comes from the June 3, 1877 issue of the Salt Lake Tribune.

The following about the McIntyre Brothers comes from "Pioneers and Prominent Men," published in 1913.

The town of Mammoth was located at the lower end of Mammoth Hollow, with the mine itself being at the top of the Hollow. The town of Mammoth was incorporated in 1910, but due to shrinking population, was disincorporated in 1929.

Mammoth Mine

(The Mammoth mine was separate from the Mammoth Copperopolis, later Ajax, mine.)

(Read more about the Mammoth Copperoplis mine, as the southern extension of the Mammoth Lode; first worked in September 1871, and known as the Ajax mine after 1894.)

November 1871
The Mammoth Lode was being worked by "Mr. Chrissman" (sic: Crismon) on the north and Mr. Armstrong on the south. The Armstrong tunnel was known as the Copperopolis of Utah. (Salt Lake Daily Review, November 1, 1871)

February 9, 1872
"Notice is hereby given, that Thomas Jenkins, H. P. Kimball, Charles Crismon, George Crismon, and Charles Crismon, Jr., do claim 3000 feet by 200 feet on the northern extension of the Mammoth Lode (being a copper and silver bearing vein of rock in place), and the land and premises appertaining to said mine, all situated in the Tintic mining district, county of Juab and Territory of Utah." Containing 13.77 acres. Dated February 9, 1872. Filed with the U. S. Land Office in Salt Lake City on February 15, 1872. (Salt Lake Weekly Tribune, March 23, 1872)

January 25, 1873
"Crisman, Jenkins & Co.'s Mammoth Mine -- Started up to-day with thirty good, practical miners. This is a well developed claim and is supposed to have been sold for 'big money' to an English company." (Salt Lake Weekly Tribune, January 25, 1873)

March 15, 1873
"There is no Copperopolis mine - but a Mammoth Copperopolis, and Crismon's Mammoth. These mines are raising almost fabulous quantities of ore, rich in gold, silver and copper. The latter is now on the English market, and experts say that it is well worth the $600,000 the company ask for it." (Salt Lake Weekly Tribune, March 15, 1873)

September 6, 1873
"The Crismon Mammoth mine had its tunnel in four hundred and twenty feet, and it was reported that a vein forty feet in width had been struck." (Utah Mining Gazette, September 6, 1873)

December 22, 1873
"The Crismon and Mammoth mine has only four hands at work, and in all probability will be all the men engaged until next spring." (Deseret News, December 22, 1873)

January 10, 1874
"The Mammoth Copperopolis, and Crismon Mammoth, are still yielding ore in large quantities; it is remarkable how this mine 'holds her own,' and lucky are the stockholders of both companies." (Utah Mining Gazette, January 10, 1874)

August 22, 1874
"North on the same [Mammoth Copperopolis] vein is the Crismon Mammoth, opened by shafts and tunnels. At one place the vein is forty-three feet in width, the ores of the same character as the Mammoth. One selected assay gave $42,000 in gold. It is owned by Crismon Bros." (Utah Mining Gazette, August 22, 1874)

Mammoth Mill

There was an earlier "Mammoth mill" located west of Silver City, near the railroad station of Ironton. By use of the leaching method, the Settle Brothers (John A. Settle & Company) were extracting concentrates from the tailings and from ore received from the Northern Spy mine. By August 1891 they had installed 15 stamps to allow them to process ore from the various mines in the district. By February 1892, the Settles were daily processing 50 tons of ore purchased from the Mammoth mine, with plans in June 1892 to expand to a capacity of 100 tons per day. By September 1893, the "old" Mammoth mill was idle, for lack of a market for their concentrates. The old Mammoth mill, along with Samuel McIntyre's barn and hay supply, was destroyed by fire on September 20, 1895.

June 3, 1877
"The Crismon Mammoth Mill is situated near the Shoebridge in Tintic Valley at the springs on the Old Tanner ranch. It is a small concern, but is neat and does its work decently, considering there is no one in charge who thoroughly understnads the business. It has a twenty-three horsepower engine which furnishes all the pumping and crushing power necessary, and, with its five stamps, has a capacity of five tons daily. Six men do all the work about the mill which is kept running steadily night and day. The Mammoth company were under contract to furnish Col. Locke of the Wyoming mill, their silver ores which ran below $100, but when the rich gold strike was made in the mine, some eight months ago, the company concludes to reduce the gold ore themselves, and for that purpose built the mill. During the past month it has been running constantly, turning out gold bullion." (Salt Lake Daily Tribune, June 3, 1877)

October 28, 1893
Machinery of the new Mammoth mill at the mouth of Mammoth Hollow was under construction. Union Pacific had surveyed a line for a spur to the new mill's location. (Tintic Miner, October 13, 1893; Salt Lake Herald, October 28, 1893)

January 1, 1894
The new 20-stamp combination mill of the Mammoth Company was in operation. "The machinery was set in motion the first day of the year, and has run continuously since without a hitch, crushing and reducing 65 tons per day, which will be gradually increased until the full capacity, 85 tons, is reached." (The Tintic Miner, January 12, 1894)

(George H. Robinson was superintendent of the Mammoth Mining company at the time that the Mammoth mill was built. He and Franklin Farrell purchased controlling interest in the Sioux group of mines in December 1893, and May 11, 1895 Robinson had resigned his position with the Mammoth company to concentrate his efforts at the new Sioux mill and its improved process being promoted by Franklin Farrell.)

(Robinson Town -- George Robinson "had hardly scooped out the first shovel full of earth on the mill site when he laid out a townsite nearby, which he called Robinson, after himself, and gave orders that resulted in the initials GHR appearing on about every property item that went into the mill, from sample sacks in the mill to bed sheets in the sleeping rooms of the mill office." -- History of Juab County, page 220)

(The town of Robinson was also regularly referred to as Lower Mammoth.)

(Within a week of the mill's opening, it was shut down due to the delivery of ore being interrupted by claims of the horse tramway between the mine and mill trespassing over various mining claims and properties. The situation became very temporary after the complaining parties were found to be delinquent in some of their financial activities. -- Salt Lake Herald, January 7, 1894)

May 18, 1894
"Ground was broken for the addition to the Mammoth mill last Friday and Supt. Robinson expects to have it running in a couple of months." (The Tintic Miner, May 18, 1894)

(The Mammoth mill opened in January 1894 with 20 stamps. In December 1894, the second set of 20 stamps began operating, bringing the total to 40 stamps. Work started December 1895 to add a third set of 20 stamps, which began operating in September 1896, having been completed in May 1896, bringing the total to 60 stamps.)

July 13, 1894
The addition was to add 20 stamps, which would double the mill's capacity. The excavations were being made large enough to add still another 20 stamps within a year, bringing the mill to its intended 60 stamps, with three times the current capacity. (Salt Lake Tribune, July 13, 1894)

August 18, 1894
Work was starting on the construction of a water pipeline from Cherry Creek to Mammoth to furnish water for the town, the mill, and the mine. The materials needed were shipped in 20 rail cars and were to arrive within one or two days. The construction crews were already in the field between Cherry Creek and Mammoth preparing the ground to lay the pipeline. (Salt Lake Herald, August 18, 1894)

(The Cherry Creek Aqueduct was completed across the Tintic Valley, due west from Mammoth. The aqueduct was built up Death Creek canyon to Cherry Creek Summit of the Tintic Mountains, a distance of about 12 miles. The aqueduct, in the form of an 8-inch pipeline, originated from the vicinity of today's Devil's Gate near the summit and was fed by a series of naturally flowing springs. Cherry Creek Summit, at an elevation of 6,892 feet, is about a half mile farther west. The reservoir at the Mammoth mill was at an elevation of 6,400 feet, with the low point in the valley being at 5,769 feet. The pump for the aqueduct was installed at the western Cherry Creek end, and the reservoir at the Mammoth end was reported as having a 500,000 gallon capacity. The pipeline was completed by late September 1894, and the "triple-expansion" pump capable of the required 800-foot raise between the head of the system and the mill, was installed in mid December 1894. From the reservoir, water was fed by gravity to mill.)

(As a side note, Cherry Creek Summit was the destination of Rio Grande Western's Nevada Extension west from Silver City in 1891-1892. After reaching Cherry Creek Summit, the planned route was to Fish Springs, then farther west to the Deep Creek Mountains. The extension was surveyed and partially graded, but was not built.)

August 23, 1894
"The Union Pacific management is making a number of permanent improvements on the Salt Lake & Western branch, running from Lehi Junction to Eureka. The bridge across the Jordan river, 160 feet in length, is being renewed throughout. Other bridges on the line are being taken out and the grade filled in over good culvert pipe. A new modern station building is about to be erected at Mammoth and new tracks are being laid to the Mammoth mill. When these tracks are completed they will be used and owned jointly by the Union Pacific and the Rio Grande Western. Two miles of steel are being laid." (Salt Lake Tribune, August 23, 1894)

December 23, 1894
"For the first time in its history the Mammoth mill is now operating forty stamps, its full equipment, the new pump at the Cherry Creek station of the waterworks system recently put in by the company having been started. A great stream of water is being forced over the divide on its way to the mill and town and the reservoir at the plant is now kept full and running over. This increase in the water supply enables the company to operate its mill to the limit. Everything at the pumping station and in the mill is operating smoothly." (Salt Lake Herald, December 23, 1894)

September 19, 1895
The contract had been awarded to add another 20 stamps to the Mammoth mill. The bases for the additional stamps were added at the same time as the 20 stamps that were added in December 1894. With 60 stamps, the Mammoth mill would have the same capacity as the Eureka mill. (Salt Lake Herald, September 19, 1895)

October 12, 1895
The bullion from the Mammoth mill was being shipped to the Kansas City Smelting and Refining Company in Kansas City. (Salt Lake Herald, October 12, 1895)

The contract for the 20 additional stamps for the Mammoth mill was awarded to L.C. Trent & Company, of Salt Lake City.

January 28, 1896
"L. C. Trent visited Mammoth during the week, to look after the placing of twenty additional stamps at the Mammoth mill. He reports the new Sioux mill doing splendid service and handling about eighty tons per day. This plant was designed by L. C. Trent & Co., who also furnished a portion of the machinery." (Inter-Mountain Mining Review, January 28, 1896)

May 16, 1896
"Work is progressing nicely in grading for the broad-gauge track between Mammoth mill and the Mammoth mine. The distance by wagon road is only one and a quarter miles, while the railroad will be over two miles, being elongated by several zigzags made necessary to overcome the heavy grade. J. A. Cunningham is building this road and will operate it for a term of several years under a contract to haul ore from the mine to the mill and take up all supplies, machinery, fuel, etc,, required at either the mine or mill. Broad-gauge cars and a thirty-ton Shay engine will be used. At the mine one track will run to the new 1700-ton ore house, having four loading chutes, while another track will reach the tunned level much higher for taking in fuel, timber, etc., for use at the mine. An important change is to be made in handling ore. Two Blake crushers will be moved from the mill to the ore house and all the rock-breaking will he done there. Of course an engine will be put in for that purpose. This will do away with crushing at the mill and permit the construction there of storage bins to aid in accumulating surplus ore to draw from and not have to shut down the mill, as has sometimes been the case, from teams being unable to furnish ore because of bad roads. Then it does away with the crushers now used at the top of the mill. Altogether this is going to be an important improvement for the Mammoth company." (Salt Lake Tribune, May 16, 1896)

May 25, 1896
The newly installed 20 stamps were completed at the Mammoth mill, but were not yet in service. The new stamps would not be used until the railroad was completed between the mine and mill. (Deseret News, May 25, 1896)

(No reference has been found in available online newspapers for the arrival of the New East Tintic's new locomotive, but with the date that it left the factory in Ohio on June 6th, the locomotive likely arrived in Utah in late June or early July 1896.)

September 8, 1896
"The New East Tintic railway, connecting Mammoth Junction on the Union Pacific with the Mammoth mining property, has been finished and although only a few miles in length, the road has some heavy grades." (Salt Lake Tribune, September 8, 1896)

September 25, 1896
The New East Tintic railroad sent its first four cars of concentrate from the Mammoth mill to market on Sunday September 20th, then two more cars of concentrate on Monday September 21st, then two more cars on Thursday September 24th. (Salt Lake Daily Tribune, September 25, 1896)

October 19, 1896
The Mammoth mill went into full production, using the full battery of all 60 stamps for the first time on October 19, 1896. The New East Tintic railroad was delivering 225 tons per day to the Mammoth mill. (Salt Lake Tribune, October 25, 1896)

(Although the installation of the last 20 stamps at the mill was completed in late May, the full use of all 60 stamps was delayed until the railroad was completed, which allowed a reliable supply of ore, compared to the previous method of using wagons.)

(From this point, the weekly reports of shipments from the Tintic District showed a considerable increase in production from the Mammoth mill, including both car loads of concentrate, and bars of bullion.)

April 17, 1897
"The ore treatment, as exemplified at the Mammoth mill, consists of crushing and battery, from which the material is discharged through a 40-mesh screen [40 openings per inch] upon copper plates. The tailings run automatically from there to Frue vanners, where the baser materials are concentrated. The tailings from the vanners drop to the pan floor and there the pulp is put through the amalgamation process in the regular way. In this mill two-thirds of the values saved are from the amalgam plates, while one-third is in the form of concentrates. This two-thirds saved in bullion comes from 90 per cent of the ore tonnage, and the one-third saved in concentrates comes from the other 10 per cent of the ore tonnage. The Mammoth mill's output, divided up, is 75 per cent gold, 23 per cent silver and 2 per cent base metal." (The Argus [Salt Lake City], April 17, 1897)

May 28, 1897
The Mammoth mill shut down due to low metal prices. Other mills that shut down also were the Bullion-Beck and the Eureka Hill. (Salt Lake Tribune, May 28, 1897)

June 8, 1899
The assay building adjacent to the Mammoth mill caught fire and was totally destroyed, causing an estimated $10,000 damage. (Salt Lake Herald, June 9, 1899, "yesterday")

The Mammoth mill remained closed while the assay office was rebuilt and re-equipped. The mill management took the opportunity to perform some needed repairs, upgrades and additional clean-up, all prior to a planned re-opening after the July 4th holiday. This later opening was to allow employees a chance to celebrate the holiday. The rumors of a more permanent closure of both mine and mill stemmed from the sudden resignation of James Earle, superintendent of the Mammoth mine. The mill re-opened on July 11th, with the delay being changes in the operation of the mine to reduce handling of the ore. This change at the mine was reported as being the reason for James Earle's departure, which preceded termination of his employment by the board of directors. (Salt Lake Tribune, July 2, 1899; Salt Lake Herald, July 5, 1899; July 12, 1899, "yesterday")

The difference in mine operation between the old management and the new management was a change in policy, from sending as much ore to the mill as possible, to completing more assay work at the mine to allow better quality ore to be sent to the mill, thereby improving the mill's output. Better assay work would also allow more direct shipments to smelters, avoiding the cost of milling. This change also required more prospecting and new ore bodies to be opened on new levels within the mine, along with increasing the payroll from 125 men to 160 men. The changes were the result of William McIntyre retiring from the Mammoth company, and overall management of mine and mill being put into the hands of Samuel McIntyre and his son, Samuel McIntyre, Jr. A dividend was declared for stockholders. (Salt Lake Herald, July 19, 1899; July 29, 1899)

(The newspapers and their sources appear to have been outside the ore milling community. The newspapers continually reported that the Mammoth mill, possibly for good. When, in fact, the mill shut down regularly, almost on a monthly basis, to do a "clean-up," which was cleaning all the stamps and machinery within the mill between runs of different grades of ore. The purpose being to prevent cross-contamination between runs of ore, thereby affecting the value of each ore run.)

(The constant rumors of the mill's closure were also the result of James A. Cunningham wanting to either lease or purchase the Mammoth mill, preferably the latter, so that he could convert it to a custom mill, which would allow accepting ore from other mines in the district. These rumors started in early March 1899 and continued well into August. The changes in processing ore that started in July resulted in the Mammoth company placing a higher value on the mill, thereby increasing their asking price from Cunningham. Samuel McIntyre, Jr., was quoted on July 18th, saying about Mr. Cunningham, "he does not seem to esteem it with the same valuation as the Mammoth company does." -- Salt Lake Herald, July 19, 1899; August 31, 1899)

After restarting on September 11, 1899, the new processes in use at the Mammoth mill were proving to be most gratifying, delivering "earnings at a better figure, it is claimed, than at any time in several years." Samuel McIntyre, Jr., had taken over as superintendent of the Mammoth mill. (Salt Lake Herald, September 11, 1899; Salt Lake Tribune, October 26, 1899)

November 12, 1899
The Mammoth mill was closed due to the Shay engine of the New East Tintic railway suffering a burned boiler crown sheet. The railroad borrowed Salt Lake & Mercur Shay No. 1, but it was barely powerful enough to move a half-car of coal up to the mine, and one car of smelter ore down to Mammoth station. It was completely unable to pull a single car of concentrates from the mill, forcing the mill to close. The New East Tintic's Shay would be out of service for two weeks while the boiler was repaired, with the railroad taking the opportunity to install new cog gears on the locomotive. The railroad was able to deliver one car of milling ore at a time using the Mercur engine, severely reducing the output of the mill. The locomotive was returned to service on November 23rd, and all was well for the Mammoth. (Salt Lake Herald, November 13, 1899; November 15, 1899; November 20, 1899; Salt Lake Tribune, November 24, 1899; Deseret News, November 24, 1899)

(During January 1902, the Mammoth mill tested 500 tons of milling ore from the Star Consolidated mine. There were numerous newspaper reports, first about the possibility, then the arrangements, then the actual test. The actual tests results were announced in early February, after three cars of Star concentrates were shipped to Salt Lake City. The actual returns from the final sale did not carry the profit as originally thought, and to increase returns, the Star would have to pay to have a dedicated crusher installed for its ore at the Mammoth mill. The ore from the Mammoth mine did not need to be crushed because it passed through a crusher at the mine prior to being shipped to the mill. In May 1902, the Star mine decided to market its ore to the Bingham Consolidated smelter, rather than having the Mammoth mill market the Star ore through its own marketing system that included the Asarco smelter, which had refused the Star ore.)

March 4, 1902
The Mammoth mill was closed pending a decision on new methods to mill the second-class copper, silver and lead milling ore currently blocked out at the mine. The work force at the mine was greatly reduced, with the few remaining men extracting only high-grade smelting ore. The work force at the mill was laid off entirely. "Mr. McIntyre stated that the change would cost not more than $10,000 to $15,000, and consisted of replacing the amalgam treatment with tanks for a cyanide solution." The stamps and vanners were to be retained. The mill re-opened on April 24th, after being "thoroughly overhauled." (Salt Lake Herald, March 4, 1902; Salt Lake Tribune, April 25, 1902)

(Throughout this period of uncertainty, from March 1902 and continuing into December, and according to the weekly newspaper reports, the Mammoth mill continued to ship one or two cars of concentrates and one or two bars of gold and silver bullion, in varying combinations of each.)

December 19, 1903
For the entire year of 1902, the Mammoth mill shipped 47 cars of concentrates, forming a major part of the 119 cars shipped from the entire Tintic District. During 1903, the Mammoth did not ship any cars of concentrates, with a total of 23 cars shipped from the entire district. The change was said to be the changing market for second-class milling ore. The Mammoth mine shipped 316 cars of ore (7,900 tons) during 1902, and 392 cars (11,6760 tons) during 1903. These figures indicate the trend of the smelters buying both first-class smelting ore and second-class milling ore. (Deseret News, December 19, 1903)

(The last report of the Mammoth mill shipping cars of concentrates was in December 1902, and the last report of the Mammoth mill shipping bullion bars was in January 1903.)

After the Sioux mill was sold for salvage in May 1903, there was speculation that the nearby Mammoth mill would soon follow in its demise, since the smelters had improved their rate for low-grade ore. The low-grade silicate ore so prominent in all Tintic mines was now in demand by the smelters to balance the treatment of other ores from other mining districts.

September 26, 1904
The Mammoth mill was restarted, testing a new process promoted by a "Prof. Carmichaels of Boston." The new method would process ore that was sitting in the ore bins at the mill. The initial startup used 30 stamps, then another 20 stamps were added the next day, then the final 10 stamps the following day, meaning that the mill was again in full production. The mill was to process 3000 tons sitting in the ore bins, with an average assay value of $12 to $15 per ton. The mill's capacity was 125 tons per day. The first car of concentrates was shipped on October 16th, with one bar of gold and silver bullion being shipped a few days before. A second bar of bullion was shipped on October 27th. (Salt Lake Tribune, September 29, 1904; Deseret News, September 29, 1904; September 30, 1904; Salt Lake Telegram, October 17, 1904; October 28, 1904)

November 19, 1904
"Unable to make satisfactory recovery from the class of ore of which about 3000 tons were put through the crushers, the management of the Mammoth mill at Robinson has hung up its stamps indefinitely, or until there is a change in the composition of the rock." The second class ore was then to be shipped directly to the valley smelter. (Salt Lake Tribune, November 19, 1904)

November 28, 1904
The following comes from the November 28, 1904 issue of the Salt Lake Herald.

December 3, 1904
During the last week of November 1904, the Mammoth mine shipped 10 cars of ore, both first-class and second-class. (Salt Lake Herald, December 3, 1904)

(All of this ore was moved by way of the New East Tintic Railway, with its 6 percent grades, very sharp 30-degre curves and switchback. The New East Tintic company by this time was owned by the San Pedro, Los Angeles & Salt Lake Railroad, having been purchased in July 1903 from the Oregon Short Line Railroad, which in-turn had purchased the New East Tintic company in November 1900. The extreme high value of the Mammoth ore being shipped being the major motivation.)

(Shipments of concentrates from the Mammoth mill continued through the last week of December 1904, with six cars of concentrates being shipped. After that period, there were limited shipments of the mill's tailings to persons and companies who were testing various concentration methods.)

More Information

New East Tintic Railway -- Built by the Mammoth Mining company to haul their ore from the mine down to the town of Mammoth, and interchange with Union Pacific's Oregon Short Line subsidiary.

Railroads and Mining at Tintic -- A history of railroads and mining in the Tintic Mining District (Updated and expanded from an article in The Streamliner, published by the Union Pacific Historical Society)

###