The Castle Mountains district is located in the Castle Mountains southwest of White Sulphur Springs. Following the initial discoveries in the mid-1880s, the area boomed. Prospectors located about 1500 claims, of which 15 to 20 became significant producers of primarily lead and silver, with some copper, gold, manganese and iron. The most important, the Cumberland mine, was the state's largest producer of lead in 1891. High transportation costs cut into mine profits, and the financial panic of 1893 dealt the final blow to the isolated district. Most of the mines closed down, never to reopen. Others produced sporadically on a small scale at least through the 1950s (Roby 1950; Winters 1968; Wolle 1963).

The Castle Mountains, named for the striking reddish rock formations near the town of Castle, are "a domal uplift formed by the intrusion of the Castle granite and Robinson diorite into folded Proterozoic (Belt), Paleozoic, [and] Mesozoic strata" (Sahinen 1935). While there is not much metamorphism, "igneous and sedimentary rocks both have been hydrothermally altered by low and medium temperature processes" (Winters 1968).

Ore deposits in the Castle Mountains occur as irregular replacement bodies in sedimentary rocks, either adjacent to or some distance from the intrusive igneous rocks. No ore of economic value is found in the igneous rocks. The ore occurs in bedding plane fractures and joints, as well as in fissure veins (Sahinen 1935; Roby 1950; Winters 1968; Weed and Pirsson 1896).

Most lead-silver ore is found in lower Mississipian limestone (Madison), with a gangue of siliceous jasper. Belt shales contain small, largely unprofitable deposits of copper, gold, and silver. Iron ore occurs as contact replacements in limestone. The manganese deposits are found in lenses along bedding plane faults in the dolomitic limestone; most are along the western edge of the Castle Mountain granite mass (Roby 1950; Weed and Pirsson 1896).

Although accounts differ on the dates and names associated with the first discoveries in the Castle Mountains district, the most credible agree that Hanson H. Barnes, an experienced prospector, probably found the first mineralization. After living in Diamond City for many years, Barnes prospected through the Castle Mountains in 1882 where he staked out, but did not record, the Princess claim. Two years later he located the Maverick. During the same time period, F. L. (Lafe) Hensley had been on a hunting trip far away in the Musselshell River valley where he found a piece of carbonate of iron ore. His extensive mining knowledge led him to search for the source of the ore, a process that took him two years. He staked out the Yellowstone claim in the Castle Mountains in June 1885, returning a year later with his three brothers to record the claim and begin work on the mine (Northwest Magazine 1891; Wolle 1963; Fowlie 1950).

Mining claims multiplied rapidly after this large discovery. The Hensleys were responsible for the two most important mines, the Yellowstone and the Cumberland. In addition, by 1887 they had located the Morning Star, Belle of the Castles, Lamar, Chollar (Collar), Great Western, American, California, Iron Chief, Golden, and Gem. Riley Lewis, C. F. Chapin, and George H. Higgins located the Great Eastern, another top producer, in 1886. Other mines located by these men included the Corliss, Hampden (Hamden), Jumbo, and Ontario. In 1887, Dunn and Donovan found the Hidden Treasure. Other important mines included the Copper Bowl, Copper Kettle, Homestake, and Powderly (Wolle 1963; Northwest Magazine 1891).

Three different towns grew up to service the new mines. The most important was Castle, near the Cumberland, Yellowstone, and Great Eastern mines. At its peak, the town reached 1,500 to 2,000 in population and had a wide variety of stores and services, along with four newspapers. Robinson, named for early prospector George P. Robinson, reached 300 in population. Nearby mines included the Top, North Star, and Silver Star. Blackhawk, known originally as Smith's Camp, was home to 200 people in 1891. The main mines in the Blackhawk camp were the Alice, Altha, Blackhawk, Judge, Legal Tender, Little Casino, and Iron Chief (Wolle 1963).

Outside capital funded development work on the district's main producers. The Hensley brothers bonded the Cumberland to J. R. King of Billings and Thomas Ash of Helena for $50,000 in 1886. The following year they bonded the Yellowstone to Crounse, Hauser, and others for $75,000. The discoverers of the Great Eastern bonded it in 1887 to Woolsten and Hamilton of Helena for $60,000, the same year that the Hidden Treasure was bonded to Hauser and Co. for $40,000 (Wolle 1963).

Transportation problems plagued the mines in the Castle Mountains district from the start. In the spring of 1888, the first ore from the Cumberland mine was hauled by wagons to Livingston, nearly 75 miles away, and then shipped by rail to the Chicago & Aurora Smelting Company in Chicago. This first shipment of less than 21,000 lbs. of ore yielded 11,331 pounds of lead and 285.72 ounces of silver. Later ore was sent to smelters in Denver and Omaha (Roby 1950; MacKnight 1892).

Despite the richness of the ore, excessive transportation costs cut into profits considerably. To resolve the situation, investors erected two smelters in the district. The Yellowstone smelter was a 42-ton plant located on Alabaugh Creek to process ore from the Yellowstone mine. The $20,000 unit produced its first lead bullion in August 1888. The 40-ton Cumberland smelter, built for $25,000, started operations in May 1891. In addition, the Cumberland mine operated three calciners, capable of handling 30 tons of ore a day. The Cumberland smelter's brief run ended less than a year later in March 1892, about the same time the other smelter ceased operations. The primary problems were high shipping costs, both for hauling supplies in and bullion out. In addition, Winters (1968) reported that the nature of the ore changed to sulphide as the mines deepened, making it hard for the local smelters to treat (Winters 1968; Roby 1950; MacKnight 1892; Northwest Magazine 1891).

By 1892, district production dropped with the closure of the smelters, and mine owners looked to a railroad to save the district. Richard A. Harlow, a young lawyer, envisioned a branch line east from Helena to Lewistown, with a temporary line from Loweth to Leadboro, just below Castle. He hired an engineer to plan the route in 1891, lined up considerable financial backing, and started construction in 1893. The nationwide financial panic that year brought his plans to a temporary halt, however, and the Montana Railroad was not completed to Lewistown until 1903 (Wolle 1963; Baker 1990).

The promise of a rail line failed to save Castle, however. The drop in the price of silver and the ensuing financial depression in 1893 closed most of the mines in the Castle Mountains district. By the time the railroad arrived in 1896, there was very little activity in the camp. Harlow hauled ore from the Cumberland mine dump to the American Smelting and Refining Company smelter in East Helena, and soon afterward, he removed the once coveted rail link (Baker 1990; Winters 1968; Roby 1950).

Although the boom in Castle was over by 1893, a number of the mines continued with small-scale production for many years. The two largest, the Cumberland and Yellowstone, both began regular production again after 1957. Total district production up to 1968 was 27,940,466 pounds of lead, 2,147,752 ounces of silver, and 146,803 pounds of zinc (Winters 1968).

The Castle Mountain district also includes the northwestern slope of the mountain range, an area with very little mining when compared with the richness of the discoveries near Castle. Prospectors located the Alabama and Cleveland claims southeast of White Sulphur Springs around 1888, and operators worked them off and on for a number of decades. Nearby, the Willow Creek-Ringling mine on Willow Creek was discovered in 1919 and produced iron ore briefly during the 1920's (Roby 1950).


Roby (1950) describes the Castle Mountain district as including all of the Castle Mountains, approximately 80 square miles. The most important mines cluster on the southeastern slope near the old towns of Castle, Robinson, and Blackhawk, between 6,000-7,000 feet in elevation in upper drainages of Alabaugh, Robinson, Slauther House and Bonanza Creek (Roby 1950). The AMRB (1994) has defined the district similar to Roby's definition.



The Alabama-Cleveland consists of two unpatented claims near the base of the western slope of the Castle Mountains, about 5 miles southeast of White Sulphur Springs. The claims, located around 1888, have been mined for lead, silver, and manganese. Operators shipped a few tons of manganese from the Cleveland in 1917. Eight years later, E. B. Hubbard of Helena organized the Castle Mountain Co. Employees drove an adit in the search for lead and silver, but there is no record of production. Later, in 1944, a lessee had a contract for 500 tons of manganese ore, but there is no record of production. The workings consist of two adits, one on each claim (Roby 1950).


The American mine is on Alabaugh Creek, about one mile west of the town of Castle. Located by the Hensley brothers around 1886, the American, Collar, and Vera were worked as a group. By 1891 there were three shafts descending 35, 50, and 65 feet, with a 200-foot tunnel on the Collar claim. Structures included shaft houses, boarding houses, and other mine buildings. The Hensleys made several shipments of high grade ore in the 1890's. Assays showed yields of $10-50 in silver and $2.50 to $7.50 in gold in 1891 (Northwest Magazine 1891; Winters 1968; Wolle 1963).

Blackhawk and Alice

These two mines, which followed the same vein of ore, were part of a group of five patented claims near the town of Blackhawk. Owners in 1891 estimated that the Blackhawk could produce 25 tons of manganese ore each day from an ore body that was 100 feet wide. The ore was considered good as a smelter flux. The Alice, idle in 1891 while awaiting new machinery, had shipped 400 tons of ore. The Blackhawk shaft reached 130 feet while the Alice was 85-93 feet deep. Underground workings totaled 300 feet of tunnels and drifts (Northwest Magazine 1891; Roby 1950; Winters 1968).


The California mine, located west of Robinson, adjoins the Iron Chief on the south. By 1891 the main shaft was down 150 feet and miners were following two leads. One was manganese iron ore that was used as a flux, while the other contained gold with assay values ranging widely from $6 to $2,000 a ton. Lessees operated the mine in 1897 but became discouraged with flooding problems (Northwest Magazine 1891; Roby 1950; Winters 1968).

Copper Bowl and Copper Kettle

These two mines consist of four unpatented claims on Hensley Creek about one mile northwest of Robinson. Despite the names, the ore contained primarily iron, assaying at 53-61 percent iron and 2.3 percent copper. Mine operators shipped 2000 tons of the ore in 1902 to be used as smelter flux. The claims are developed with two adits and two pits (Winters 1968).


Located by the Hensley brothers in November 1886, the Cumberland mine became the largest in the Castle Mountains district. The mine encompassed four or five claims and two mill sites, less than one mile above the town of Castle in Section 14, T8N, R8E. It was bonded to Thomas S. Ash and John R. King, who organized the Cumberland Mining and Smelting Co. in September 1887; company reorganization a year later added three other owners (MacKnight 1892; Northwest Magazine 1891).

The Cumberland shipped its first lead-silver ore in May 1888, receiving favorable returns. The 20,742 pounds of ore yielded 11,331 pounds of lead (60.7 percent) and 285.72 ounces of silver. The high costs of transportation to outside smelters encouraged construction of two smelters in the district. The Yellowstone smelter processed 2000 tons of ore from the Cumberland in 1889, yielding $90,000 in bullion. The Cumberland smelter, purchased for $25,000 from the Chicago Iron Works, produced its first bullion in May 1891. Although it shut down ten months later, the smelter reduced 13,000 tons of ore during its brief run, yielding $494,906.44 in bullion (Swallow and Trevarthen 1889; MacKnight 1892; Roby 1950).

The Cumberland was the state's largest producer of lead in 1891, turning out 5 million pounds of bullion. That year, 70 men worked in the mine, but employment dropped to 45 a year later. The main shaft reached 700 feet, with development on eight levels within the mine. The 500-foot level included 2,500 feet of tunnels and drifting. The hoist, a Corliss double-cylinder engine, had steam clutches as safety features (Hogan and Oliver 1891; Hogan and Oliver 1892; MacKnight 1892; Weed and Pirsson 1896).

J. Kennedy Tod of New York City and Charles Severance took control of the Cumberland and reorganized the company in February 1892. After investing considerable money in exploration and development work, they closed the mine to await the arrival of the railroad. Following the financial panic in 1893, the mine remained closed for a long time. R. A. Harlow, president of the Montana Railroad, purchased the ore on the Cumberland dump in 1896, and he hauled it to East Helena once his temporary branch line terminated near Castle (MacKnight 1892; Roby 1950).

Lessees worked the mine for a few years during the 1940's. Work increased during the 1950's when HOCO, Inc. took over operations. The mine produced 25-50 tons of ore each month after 1959, with values averaging 19.6 percent lead and 6 ounces of silver per ton (Roby 1950; Winters 1968).

The ore zone in the Cumberland was just eight feet wide at the surface but widened to 75 feet on the 500 foot level. Most of the ore was argentiferous galena and cerussite, with small amounts of iron pyrite, set in a gangue of jasper. The ore decreased in value below the 500-foot level. Total production for the mine was 18 to 20 million pounds of lead and 615,000 ounces of silver (Roby 1950; Winters 1968).

Great Eastern and Great Western

The Great Eastern and Great Western consist of four patented claims on a ridge between Hensley and Hamilton creeks. The claims are close to or adjoin the Yellowstone mine. Riley Lewis, C. F. Chapin, and George H. Higgins located the Great Eastern in 1886, and the Hensley brothers located the Great Western. Ore shipped in 1890 from the initial exploration work had a value of $60 per ton. A year later, the Great Eastern employed 16 men and had three shafts ranging from 35 to 200 feet deep. By 1892, the Great Eastern had shipped 500 tons of ore, while little development work had been done on the Great Western. The main shaft eventually reached 300 feet and provided access to three levels with 825 feet of drifts and crosscuts. Ore was raised with a horse whim hoist. Following the closure of most mines in the Castle Mountain district in 1893, the Great Eastern was back in operation in 1897, employing 25 miners and 9 topmen; ore was sent to the smelter in East Helena. There is little information on the mine after this date (Northwest Magazine 1891; MacKnight 1892; Weed and Pirsson 1896; Byrne and Hunter 1897; Roby 1950; Winters 1968; Wolle 1963).

Hidden Treasure

Dunn and Donovan located the Hidden Treasure in 1887, near the top of the ridge dividing Hensley and Robinson creeks. Today the road between Castle and Robinson runs just south of the claim. The mine began operations in 1888, and within three years crews had a working shaft down 180 feet and an inclined shaft down 120 feet; both were connected on the 100-foot level. The main shaft eventually went another 20 feet, with a horse whim to operate the hoist. Although there are no production records available, an ore sample sent to Omaha in 1888 assayed 70 ounces of silver, $8 in gold, and 59 percent lead (Northwest Magazine 1891; Weed and Pirsson 1896; Roby 1950; Wolle 1963).


The Homestake Mining Co. owned four claims in 1891, abutting the Great Eastern on the ridge between Hamilton and Hensley creeks. Several shafts ranged in depth from 10 to 70 feet, and underground workings included nearly 300 feet of tunnels. Despite considerable work, no valuable ore bodies were found. Operators shipped a small quantity of lead-silver ore in 1925 (Northwest Magazine 1891; Roby 1950).

Iron Chief

The Hensley brothers located the Iron Chief in 1887 on the west side of Robinson Creek, about one half mile south of the Robinson townsite. Work began the following year. In 1890, operators put in a new shaft, shaft house, and equipment. The shaft, which eventually reached 250-270 feet, ran through a 70-foot vein of carbonate ore. There is no record of lead-silver production, but a sample of ore assayed at 50 percent lead and 20 to 30 ounces of silver per ton. Mine owners also bought the nearby Top Lode and put in a shaft until they ran into problems with water. By 1891 they planned to work the Top Lode through the Iron Chief shaft. In addition to the lead-silver ore, operators mined iron ore from an open cut, sending it to the Cumberland smelter for flux (Northwest Magazine 1891; Weed and Pirsson 1896; Roby 1950; Winters 1968; Wolle 1963).


The Judge was one of a group of mines near Blackhawk that included the Legal Tender, Iron Chief, Blackhawk, Alice and others. It is located on a ridge top about one quarter of a mile northeast of the townsite. The two compartment main shaft, sunk in 1891, eventually reached 230-240 feet. Just two men worked the mine in 1896, raising the ore in a bucket hoist and then sorting, sacking, and shipping it to White Sulphur Springs. Employment was up to 10 the following year, with the ore being sent to East Helena for smelting (Weed and Pirsson 1896; Byrne and Hunter 1897; Roby 1950; Winters 1968).


Discovered in 1886, the Jumbo mine includes eight claims just northeast of the Cumberland mine. Following incorporation of the Jumbo Mining Co. in July 1890, operators began major work on the mine, sinking two shafts and connecting them on the 100-foot level. Twenty men worked in the mine in 1891. A year later the main shaft was down to 200 feet, opening onto two levels. Following the closure of most mines at Castle, lessees worked the Jumbo in 1898 and production continued on for many years, making it one of the longest operating mines in the district. The geology of the Jumbo was similar to that of the Cumberland, with ore bodies found in Madison limestone at or near the contact with quartz porphyry. Over the years, the Jumbo produced at least $80,000 in lead and silver. Ore values dropped in deposits below the 100-foot level (Northwest Magazine 1891; MacKnight 1892; Roby 1950; Winters 1968).


The Powderly, also known as the Silver Dollar, Silver Spoon, and currently the Lucky Dollar, is located on the east side of Robinson Creek, about one half mile south of the townsite of Robinson, in the NE 1/4 of Section 12, T8N, R8E. The mine was discovered in 1887 and continued to be worked long after most of the other district mines closed in 1893. The workings include a shaft and an adit (Roby 1950; Winters 1968; Newton 1993).

Willow Creek-Ringling

The Willow Creek-Ringling is one of only two mines mentioned on the western slope of the Castle Mountains. It is located just east of Willow Creek, about five miles southeast of White Sulphur Springs. Discovered in 1919, the mine's brief production was concentrated in the early 1920's. After R. T. Ringling purchased the property in 1920, he contracted to provide 5,000 tons of iron ore for flux to the American Smelting and Refining Co. of East Helena. The ore was removed from an open stope and trammed through an adit fifty feet below. A lower adit produced little or no ore. There was no further production from the mine (Roby 1950).


The Yellowstone was the second most important mine in the Castle Mountains district, ranking just behind the Cumberland. F. L. Hensley found the outcrop on a ridge between Hensley and Hamilton creeks in June 1885, but did not officially locate it until the next year when he returned with his three brothers. Work progressed rapidly on the mine, with the discovery shaft sunk to 250 feet. After the discovery of two other important ore shoots, operators sank two more shafts, and by 1892, the main shaft was down 415 feet (MacKnight 1892; Roby 1950; Winters 1968).

The owners constructed a 42-ton smelter in 1888 to process ore from the discovery shaft. A run of 1,000 tons of ore during the summer of 1890 showed values of $45-50 per ton. Company equipment included a 20-horsepower hoist, two boilers, and a large pump, while the physical plant contained offices, boarding houses, and other structures (Northwest Magazine 1891; Weed and Pirsson 1896; Winters 1968).

Although the mine closed in 1893, various lessees operated it sporadically over the years. Ten miners and three topmen worked in the Yellowstone in 1897, and a year later the employment was up to fifteen. In 1926-1927, 3,800 tons of slag from the smelter dump were shipped out. Ten years later, operators shipped 48 tons of ore which yielded one ounce of gold, 193 ounces of silver, 15,000 pounds of lead, and 1,500 pounds of zinc. Both the Yellowstone and the Cumberland became active once again after 1957. The total production for the Yellowstone over the years probably amounted to a minimum of 1,500 tons of ore (Byrne and Hunter 1897; Calderhead and Holmes 1898; Roby 1950).


Other mines of lesser importance include the Antelope, Armada, Baltimore, Belle of the Castles, Bondholder, Broadway, California, Cleopatra, Etta, Felix-Crescent, Golden Eagle, Grand Central, Graphic, Grasshopper, Hamden, Helena, Hendricks, Homestead, Legal Tender, Merrimac, Milwaukee, Mohawk, P and K, Potomac, Princess, Queen-Hensley, Ruby Adit, Skidoo, Silver Belt, Silver Star, Snowdrift, Solid Silver, Top Lode, Vandar, and Wee Wee (Roby 1950; Winters 1968).


Abandoned Mine Reclamation Bureau (AMRB)

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