The Rabbit Hole Sulphur Mines are located in northwestern Humboldt County, Nevada, on the border of the Black Rock desert. The deposit was located in 1875 and mining continued until the 1950’s.

Early History

As early as 1869, efforts were made to exploit sulfur deposits in Humboldt County, Nevada. In that year, Chinese immigrants launched an unsuccessful effort to mine sulfur from an inactive (“fossil”) solfatara near Humboldt House, a station of the Southern Pacific Railroad (Valentine, 2002; Raymond 1870).

In early 1875, J W Rover and F J McWorthy arrived in Humboldt County in search of a rumored sulfur deposit. This site proved to have limited economic potential. However, they were told that a local Native American knew of a large sulfur deposit further northwest at Rabbit Hole Springs, at the base of the Kamma Mountains on the edge of the Black Rock Desert. Induced by the promise of a horse and saddle (which according to local lore he never received) the Native American showed Rover and McWorthy the locality of the sulfur deposit (Adams, 1903).

Despite the fact that the lack of transportation was a major impediment (the nearest rail head was located 35 miles to the southeast at Humboldt House, Nevada) Rover and McWorthy felt that the deposit had economic potential, and filed a claim to the area circa April, 1875.

A few months later, Charles Wright and L. H. Egbert staked a claim to a second sulfur mining site roughly a mile south of McWorthy’s mine. They took in Theodore Hale as partner and formed the Humboldt Sulphur Company to prosecute the work. The mining camp became known as “Inferno,” a singularly appropriate choice of name for a brimstone mining operation at the edge of a forsaken stretch of scorched Nevada desert.

The business partnership of McWorthy and Rover was to be short of duration. Rover was accused of murdering I. N. Sharp, a business associate, in mid 1875. He was found guilty and, after several retrails, was hanged on 19 February 1878. Rover protested his innocence until his dying day. Local legend claims that McWorthy – who had been the single witness at Rover's trial – had murdered Sharp, and pinned the blame on his partner to gain sole ownership of the mine.

The McWorthy Sulphur Mine and the Humboldt Sulphur Company property were merged into a single operation in 1879 (Valentine, 2002).

Mining and Extraction

In 1882, Israel C. Russell submitted a paper to the New York Academy of Science describing the Rabbit Hole Mine and giving a general overview of the geology of the site. He stated that at that time, the mine was producing about 6 tons of raw “ore” a day, and that work was prosecuted by a day shift of 17 men.

Adams (1903) describes the mining operations at Rabbit Hole circa 1900 as consisting of “open pits, tunnels and underground chambers,” and also mentions that local timber resources were being exploited to provide “timbers for the mines,” but fails to provide further technical details on mine design, layout or operations. Lincoln (1923) states that the site consisted of “300 sulphur deposits distributed over an area of about 1,200 acres”.

The sulfur-bearing rock was cobbed and sorted at the mines and then transported a short distance to the company’s mill. After passing through a grizzly to remove any oversized rock, the sulfur-bearing rock was placed into two “upright cast-iron retorts, having a general resemblance to the common form of blast furnace,” each capable of handling a charge of approximately 2½ tons (Russell 1882).

After the retorts are charged, they are closed, and live steam is turned into them at a pressure of about 70 pounds to the square inch, but as the sulphur melts the pressure is decreased somewhat – to about 60 or even 50 pounds. The melted sulphur sinks through a grate into the kettle-like bottom of the retort. From the retort it is drawn off into a settling pan, in which it is kept at a temperature sufficiently high to maintain it in a liquid condition. From the settling pan the sulphur is run into cast-iron molds, which have a capacity of about 250 pounds each, and are in the form of a frustrum of a cone. In these molds the sulphur is allowed to stand from thirty-six to forty-eight hours. (Adams, 1903)

Firewood cut from the nearby mountainsides was used as fuel for the extraction process. No local source of coal was available.

After the sulfur cooled, the sulfur cones were knocked out of the molds and broken up into small pieces. It was then run through a crusher and reduced to pea-sized lumps (“Pea Sulfur”). A portion of the sulfur was further comminuted by grinding between buhr-stones to produce “Flour Sulfur” (which should not be confused with “Flowers of Sulfur” produced by sublimation of sulfur). “Pea Sulfur” was bagged into sacks of 100 pounds, and “Flour Sulfur” was bagged in sacks of 110 pounds, for shipment to market. The sulfur was sold in San Francisco for about $45 per ton.

The bagged sulfur was then transported overland by mule teams to Humboldt House to be shipped to California via the Southern Pacific Railroad. As early as 1875, the Humboldt Sulphur Co. at employed seven 8- to 12-mule teams to cart sulphur to the rail depot. In 1878 the company experimented with using a 7-ton steam wagon invented by R. R. Doan to haul sulphur to the depot (Marden, 1988, cited in Valentine, 2002), but apparently abandoned the concept because of the paucity of firewood to stoke the steam engine. (Valentine, 2002). Transportation issues were somewhat alleviated when the Western Pacific Railroad was completed in 1909 (Myrick, 1990), establishing the town of Sulphur.

In 1900, the Rabbit Hole Sulfur Mine were acquired by the Nevada Sulphur Company of San Francisco, CA. (Lincoln, 1923) In a Congressional hearing requesting protectionist tariffs for a number of commodities, the Nevada Sulphur Co stated that their production of sulfur for the period 1905 to 1908 was as follows:

Partial Sulfur Production Data

Year Tons 1905 2,248 1906 1,782 1907 1,417 1908 773

The company's president, Louis Rosenfeld, offered a breakdown of the costs of sulfur production in 1905:

Cost of sulfur production per ton, 1905 dollars

Candles 0.128 Fuel 1.420 General Expense 2.316 Hauling 5.066 Mine and Milling Expense 0.496 Mine and Milling Supplies 0.337 Powder, Fuse and Caps 0.339 Sacks and Twine 1.341 Insurance 0.378 Total Cost at Shipping Point: 20.348

The Nevada Sulphur Company produced at lease three grades of sulfur circa 1908; two were marketed under the “Horse Head” brand (pea sulfur and powdered sulphur), and their premium grade sulfur powder which was marked under the “Crown Sublime” brand. An analysis of all three grades was conducted by George E Colby of the University of California's College of Agriculture and Agricultural Station, who determined that they (unlike the Sicilian and Japanese sulfur being marketed in California) were uncontaminated with residual sulfuric, sulfurous, or arsenious acids. (Committee on Ways and Means, 1909)

The Nevada Sulphur Co. still owned the mines in 1923, at which time sulfur production had been increased to approximately 12 tons per day. The mine superintendant was I. C. Crowley. Operations appear to have terminated on the site in the 1950's.

Minerals

Alunite – derived by the chemical alteration of country rock by the action of acidic, sulfur-containing waters and gases, alunite occurs in a “considerable amount” as white powdery fillings in cavities in the country rock adjacent to the sulfur.

Cinnabar – a small amount of cinnabar giving the crystallized sulfur “a reddish tinge” was observed by Adams, who also described the cinnabar as being “deposited on the surface” of the sulfur – possibly indicating that the cinnabar represented a late-stage mineral .

Gypsum – Adams noted that “some crystals of gypsum were seen in the mines” but failed to provide further details on size and morphology.

Opal var. “Hyalite” – “Globular masses” and coatings of hyalite on country rock adjacent to the sulfur were reported by Adams.

Sulfur – The primary form in which sulfur occurs at the Rabbit Hole Mines is as dark, resinous yellow massive sulfur that “has the appearance of a flow of molten sulfur”and “it contains occasional fragments of rocks, but is remarkably pure” (Adams 1903). Russell (1882) noted that sulfur sometimes lines large cavities with layers of crystals five to six feet in thickness,” to which Adams added that the sulfur occurs as “masses of crystals” hanging from irregular cavities and encrusting open surfaces of the country rock and sulfur. “It has the beautiful yellow color of crystallized sulfur, with here and there a reddish tinge due to the occurrence of a small amount of cinnabar deposited on its surface” (Adams 1903). The Salt Lake Mining Review (1909) commented "It is no uncommon sight to see deposits containing many tons of sulphur in clusters of crystals almost like yellow glass."

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Bibliography:

Adams, George I.
The Rabbit Hole Sulphur Mines Near Humboldt House, Nev.
In: Contributions to Economic Geology 1903
United States Geological Survey Bulletin 225
Government Printing Office, Washington DC 1904

Anonymous (1909)
"Humboldt Sulphur and Antimony"
Salt Lake Mining Review 30 April 1909 p26

Committee of Ways and Means
Tariff Hearings Before the Committee of Ways and Means of the House of Representatives, Sixtieth Congress
Volume 1 Washingtton DC Government Printing Office 1909 pp 535-541

Lincoln, Francis Church
Mining Districts and Mineral Sources of Nevada
Nevada State Bureau of Mines 1923 p. 103

Marden, Jay P.
The Sulphur Mine Steam Wagon. Humboldt County’s Historical Legacy. Manuscript
on file, Humboldt County Library, Winnemucca, Nevada. 1988

Myrick, David F.
Railroads of Nevada and Eastern California. Volume 1: The Northern Roads.
University of Nevada Press, Reno and Las Vegas. 1990

Raymond, Rossiter W.
Statistics of Mines and Mining in the States and Territories West of the Rocky Mountains.
Government Printing Office, Washington, D.C. 1870

Valentine, David
“Ask Not For Whom The Toll Bills . . .”
In-Situ: Newsletter of the Nevada Archaeological Association
Winter 2002

Russell, Israel C.
Sulphur Deposits in Utah and Nevada
Transactions of the New York Academy of Sciences 1882

Completed: 11 October 2008
Revised: