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California \ Iron Mountain Railway
Reference Data.
July 17, 1895

Corporate Ownership.
Mountain Mines Syndicate LTD
1895 - 1896
Mountain Copper Company
1896 - 1927

Rail Weight.
40 lb

Last Updated: Sept. 12, 2015

Iron Mountain Railway.

By Greg Maxwell.

I n the early 1860s William McGee and Charles Camden secured a claim on an iron deposit on Iron Mountain, nine miles north-west of Redding, California. In 1879 silver was discovered on an adjacent claim by James Sallee who then formed a partnership with McGee and Camden. The combined property was leased in 1886 to a party who erected a 20 stamp mill. It was found that the silver ore contained too much base metal to be worked profitably and the operation folded. The silver mine on Iron Mountain was eventually sold in 1894 to a group of English metal brokers who incorporated as the Mountain Mines Syndicate, LTD in 1895.

While doing exploration work, the English company discovered a large body of sulphide copper ore. The ore assayed 7% copper and had gold and silver values of two to three dollars per ton. To exploit the discovery, plans were made for a narrow gauge railroad to run between the mine on Iron Mountain and Keswick (m.p. 265) on the Southern Pacific. A smelter site was prepared 1.2 miles up Spring Creek from Keswick station.

The Iron Mountain Railway was incorporated on July 17, 1895. The company was capitalized at $100,000 with Louis B. Parrot named as President. The railroad was constructed between August, 1895 and February, 1896 by railroad contractor J.A. McLean under the direction of engineer Michael M. O’Shaughnessy. O’Shaughnessy would go on to gain wider fame as the builder of San Francisco’s Hetch Hetchy water project.

The route laid out by O’Shaughnessy was something of an engineering marvel. To reach the company’s mine; the Iron Mountain Railway had to climb 1,850 feet in 10.65 miles. To keep the maximum grade under 3.75%; O’Shaughnessy utilized a switchback, a 163’ tunnel, two partial loops and one complete loop with a maximum curvature of 34°. The longest piece of straight track on the entire railroad was only 655’ in length. There were 25 trestles, the longest of which was the 255’ crossing at the Spring Creek loop. The 1.2 mile portion of the line between Keswick and the smelter was dual gauge and was laid with 56# and 80# rail. The balance of the rail was 40#. The first revenue run over the Iron Mountain Railway was made on February 1, 1896.

Motive power for the Iron Mountain Railway was provided by five H.K. Porter 0-4-4 tank engines, numbered #1-#5. All of the Porter locomotives, ordered between 1895 and 1899 were delivered as wood-burners but were converted to burn oil in 1901. The line’s rolling stock consisted of 72 ore cars, 22 flat cars and two cabooses.

The Mountain Copper Company’s smelter opened in March, 1896. Copper ore from the Iron Mountain mine contained, on average, 45% sulfur and required extensive roasting before it could be smelted. Like most of the smelters in the Shasta copper belt, ore at Keswick was roasted in the open causing a great deal of environmental damage. The narrow gauge delivered ore directly to the roasting stalls from an adjacent elevated trestle. Once sintered, the ore went to the smelter which produced matte copper that was sent to New Jersey for refining.

On December 1, 1896 the Mountain Copper Company LTD was incorporated in London for the purpose of acquiring the Mountain Mines Syndicate’s Shasta County properties which included: the Iron Mountain Railway, the mine and Keswick smelter. The purchase was consummated on January 1, 1897. Mountain Copper’s production steadily increased. By 1904 the capacity of the Keswick smelter had been expanded to 1,000 tons per day, with four furnaces in operation. On a typical day, the Iron Mountain Railway would run five trains consisting of 10 to 17 cars. Although the Iron Mountain Railway was a common carrier, the line charged a minimal amount for ore movements to its parent company and showed a deficit in all but three of the years the line was operated.

Beginning in 1900, the Mountain Copper Company faced litigation from both the federal government and private parties. The suites were brought to recover damages caused by sulfur dioxide emissions resulting from the company’s ore roasting practices. About the same time, the Mountain Copper Company began to supply the Pacific Coast Oil Company at Richmond, California with sulphide ore for the purpose of manufacturing Sulfuric Acid. Under this arrangement, once the oil company had roasted off the sulfur, the residual ore had to be returned to Keswick for smelting. As the demand for sulfuric acid by California oil refineries was on the rise, it was decided to move the Mountain Copper Company’s smelting operations to the San Francisco Bay area. There, the company could fully utilize the sulfur by-product for acid production and also reduce transportation costs.

The company purchased an 80 acre tract at Bulls Head Point on the Carquinez Straits, near Martinez. In 1905, three furnaces were removed from the Keswick smelter and moved to the new site named Mococo. Also at Mococo were facilities for manufacturing sulfuric acid and fertilizer. A dual-gauge switching railroad was built to serve the new works and two of the Iron Mountain Railway’s Porters, #1 and #5 were transferred to Mococo.

The last furnace at Keswick went cold in 1907. Large ore bins had been erected at the smelter site and ore came direct from the mine and was transferred to standard gauge cars for shipment to Mococo. As the company’s focus changed to chemical manufacturing, mining operations began to shift to the Hornet mine, as ore from that mine had higher sulfur content. Ore was hauled from the Hornet mine, located a mile northeast of Iron Mountain, by way of an incline tram down to the narrow gauge in Boulder Creek Canyon. At the end of the Boulder Creek loop, a spur was extended 600’ up the creek to reach the ore bins at the base of the tram. In 1912 the Mountain Copper Company began to switch to geared locomotives. That year the first of three new Lima Shay engines that were to operate on the Iron Mountain Railway was purchased.

By 1914 hi-grade ore in the Iron Mountain Mine had become exhausted. The Mountain Copper Company built a $500,000 flotation mill halfway between Keswick and Iron Mountain at Minnesota Flat to concentrate the lower grade ores that remained. During the metal mining boom brought on by World War One, the Iron Mountain mine made daily ore shipments of 300 tons to the Minnesota Flat mill by way of the narrow gauge. The concentrates, called copper cement were then hauled to Keswick for transshipment. Another 500 tons of ore was sent from the Hornet Mine to Keswick and on to Mococo for processing.

Copper prices fell at the end of the First World War causing the flotation mill at Minnesota Flat to be closed in 1919. In 1921 the Mountain Copper Company discontinued mining at Iron Mountain and moved all operations to the Hornet Mine. Through the war years the Iron Mountain Railway had been allowed to deteriorate. To avoid spending the large sum of money needed to rehabilitate the narrow gauge, a 12,500’ aerial tramway was built connecting the Hornet Mine to Matheson siding (m.p. 267.2) on the SP. Also in 1921, the machine shop and other railroad facilities, formerly at the smelter site near Keswick, were moved to the Hornet spur location. The Iron Mountain Railway was kept in limited operation as far as the Hornet spur primarily to transport supplies for the Hornet Mine and to serve the Pittsburgh-Mt Shasta Mining Company’s “Little Nellie” mine on Boulder Creek.

The Iron Mountain Railway saw sporadic use through the 1920s. When the Pittsburgh-Mt Shasta operation closed down, the Mountain Copper Company decided that it would no longer be of any benefit to operate the Iron Mountain Railway as a common carrier. The company applied to the California Railroad Commission for permission to abandon service over the narrow gauge and consent was received on February 5, 1927. At that time, the remaining locomotives, with the exception of Shay #8, were moved to Matheson where they were eventually sold or scrapped. The Minnesota Flat mill reopened for a time in 1928 and the line may have been used as late as 1929 to haul materials for the construction of a cyanide plant on Iron Mountain. The Iron Mountain Railway’s fixed plant remained in place until the early 1930s.

As an aside; circa 1918 the Pittsburgh-Mount Shasta Mining Company acquired a Shay locomotive from the Dairy Farm Mining Company. The Shay may have been used on the Iron Mountain Railway or possibly the Pittsburgh-Mount Shasta Mining Company had a rail line to connect their mine and mill, a short distance up Boulder Creek from Hornet siding.

Today you can drive on the Iron Mountain Railway’s roadbed between Minnesota Flat and Iron Mountain on Iron Mountain Road. Both the Iron Mountain Mine location and the Minnesota Flat mill site are marked by large remediation projects, to treat toxic run off from the Mountain Copper Company’s former operations. A handful of small buildings and the mill foundation at Minnesota Flat are the only evidence of what was once California’s largest copper producer.

Revised: May 31, 2017
Aubury, Lewis E., The Copper Resources of California, San Francisco, CA: California State Mining Bureau, 1908.
Borden, Stanly T., The Iron Mountain Railway, The Western Railroader, Vol 34, issue 1, January, 1964.
Diller, J.S., Copper Deposits of the Redding Region, California, Bulletin 213, United States Geological Survey, 1903.
Hilton, George W., American Narrow Gauge Railroads, Stanford, CA: Stanford University Press, 1990. ISBN: 0-8047-2369-9
Kett, William, Fifty years of Operation by the Mountain Copper Company LTD in Shasta County, California, California Journal of Mines and Geology, Vol 43, San Francisco CA: California State Printing Office, 1947.
Mines and Mineral Resources of Shasta County, Siskiyou County, Trinity County California, (reprint of California State Mining Bureau Report, 1915), Josephine County, OR: Gold Rush Books, 2014, ISBN: 9-781497-541399
Polkinghorn, R.S., Pino Grande, Logging Railroads of the Michigan-California Lumber Company, Berkley, CA: Howell-North Books, 1966.
Porter Steam Locomotives, Light & Heavy, Chattanooga, TN: NMRA 2001. ISBN: 0-9647050-3-6
Signor, John R., SP’s Shasta Division, Wilton and Berkley, CA: Signature Press, 2000. ISBN: 1-930013-02-7
Spohr, David, Narrow Gauge to Van Trent, Western Railroader, Fall, 1990,
Weed, Walter H. ed., The Mines Handbook, 1922. Tuckahoe, NY: Mines Handbook Company, 1922.
California Railroad Commission: Report of Value of the Iron Mountain Railway, September 15, 1912.
California Railroad Commission: Profile and alignment maps of the Iron Mountain Railway, June 20, 1912.
Mineral Wealth, Redding, CA, Vol 8, Number 20, January 1, 1907.
Red Bluff Daily News, Red Bluff, CA, various issues.
Salt Lake Mining Review, Salt Lake City, UT, various issues.

Reference Material Available Online:

Equipment Rosters.

Iron Mountain Railway Equipment Roster by Greg Maxwell.


Collected Iron Mountain Railway Photographs.
Images collected from private collections, libraries and historical societies.

California \ Iron Mountain Railway
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