aka Mountain Horse aka Burns aka Sarpy Creek

The Prospect Creek mining district (also known as the Mountain House, the Burns or Sarpy Creek district) is located in Sanders County south and west of the town of Thompson Falls and encompasses the Prospect Creek drainage. The southern boundary of the district is the Mineral County line, the western boundary is the Idaho (Shoshone County) line, and the northern boundary is the ridge north of Clear Creek and the Clark Fork River. Prospect Creek rising in the mountains just over the divide from the Coeur d'Alene district of Idaho, enters the Clark Fork at Thompson Falls. Most of the mines in the district are located about 10 miles southwest of Thompson Falls. The Montana Standard mine, located below Crow Creek, was the most productive mine in the Prospect Creek district. It opened around 1898 and operated intermittently until 1957 producing silver, copper, lead, and zinc. The mining district was never highly productive (Sahinen 1935; Crowley 1963).

Thompson Falls and the Thompson River are named for Welsh geographer David Thompson, who traveled in the area in the early 1800s on behalf of the Northwest Fur Company. In 1809 he constructed the Saleesh House trading post and fort on the Clark Fork River in the vicinity of today's Thompson Falls; the post was moved upriver in 1827.

Steamboat navigation on the Clark Fork began in 1865, with the head of navigation at Shannonville, three miles below Thompson Falls on the Clark Fork River. After the Northern Pacific Railroad arrived in 1883, Shannonville declined and the towns of Belknap and Thompson Falls replaced it. Both these towns provided access to the gold strikes in the Coeur d'Alene Mountains of Idaho.

Thompson Falls was the main outfitting point for prospectors and miners heading into Idaho from the Montana side because it had the advantage of having a railroad station (Northern Pacific Railroad) about 30 miles from the gold discovery at Eagle City and Murray. In 1883-84, 10,000 men spent the winter in tents and shacks waiting to head over the range as soon as the weather allowed. The trails to Murray, Idaho were converted to rough wagon roads connecting Thompson Falls with Murray, Idaho (35 miles away).

The trails up Big Beaver Creek from Belknap and up Prospect Creek from Thompson Falls were the main routes to Murray, Idaho (35 miles from Thompson Falls), during the rush of 1882-1887. Two trails crossed the Coeur d'Alene mountains to the mining camps, both following Prospect Creek the 35 miles to Murray. One went over Glidden Pass (to Burke and Wallace), and one led to Murray and Eagle via Thompson Pass. The road up Prospect Creek was built in 1883-1884 as a toll road to the foot of the Montana-Idaho divide (with a foot trail the rest of the way). A way station called Mountain House was located near Evans Creek, but it burned in the late 1800s and was not rebuilt. Farther up Prospect Creek (just above Glidden Creek), another way station was known as Halfway House. Once a road was built to Murray from Wallace, Idaho, the Prospect Creek road was neglected for several decades. A third route to the gold fields of the Coeur d'Alene's went up Trout Creek from the town of that name (Heritage Research Center 1989; Crowley 1963; Calkins and MacDonald 1909; Whisennand 1992; Dufresne 1976).

Besides the roads, or more properly "trails, a diversion ditch approximately four feet wide by four feet deep was dug by Chinese laborers in 1883 to transport water across the state line from Blossom Lake over Thompson Pass to mining operations in Murray, Idaho. It was apparently never used, as the dam at the mouth of Blossom Lake broke in 1887 (Whisennand 1992).

The earliest lode claims in the county and the district may have been staked along Prospect Creek during the rush to Murray, Idaho. Around Mountain House, on the trail from Thompson Falls to Murray, Idaho, there were a dozen patented claims and a small smelter across the creek from the camp ca. 1900. Antimony claims were reported in the drainage opposite Mountain House.

By 1890, the rush to the Coeur d'Alene diggings had ended. Sanders County was created in 1905, with Thompson Falls as the county seat (Wolle 1963; Dufresne 1976; Davis 1958).

A find of rich tellurium float on Prospect and Eddy Creeks twenty miles to the east of Thompson Falls, started a stampede of prospectors into the area in 1906, but nothing further was reported on the telluride finds (Crowley 1963). In 1907 the Blue Slide mine was being developed in the Seepy Creek sub-district near Belknap by the Montana Mammoth Mining Company (Sanders County Ledger 1907). However, there was no further reporting on the Blue Slide, indicating the development was short-lived.

In 1912 copper ore containing silver and some gold was shipped from one property. One placer miner worked on Prospect Creek in 1914, but there is no record of the amount of gold he recovered or the location of the claim. There was no placer mining reported after that in the area; in fact, only two troy ounces of gold were recovered between 1906 and 1958 (Lyden 1948; Mineral Resources 1913, 1914; Crowley 1963).

The mining camp of Carter was located on the county line between Missoula and Sanders counties. The camp had "a big showing in copper" about 1906. The Carter Mining & Milling company's property was a few miles northwest of the town of Carter. The vein is found in a siliceous, shaley country rock (probably St. Regis of the Coeur d'Alene pre-Cambrian). Much development work had been done at the mine by 1911 (Mineral Resources 1906b; Rowe 1911).

Between 1908 and 1958, the Prospect Creek district produced 3,585 tons of ore yielding 39 ounces gold, 8,348 ounces silver, 1,660 pounds copper, 448,497 pounds lead, and 207,000 pounds zinc. The average value per ton was $26.04. Most of the mines and prospects contained galena and sphalerite and were poor in silver minerals. The lack of abundant silver minerals combined with the abundance of zinc minerals (which were not economical to mine during much of the historic period) help explain why the district did not see large-scale production (Crowley 1963).

The Montana Power Company was organized in 1912 and the Chicago, Milwaukee and St. Paul Railroad was interested in the hydroelectric potential of the Thompson Falls area because of the proximity to the mines and smelters of the Coeur d'Alene mining district in Idaho. In 1912 John D. Ryan (a member of the Milwaukee board of directors) purchased two Thompson Falls sites and began development at the one at Prospect Creek. In 1913 Ryan's Thompson Falls holdings were added to the newly organized Montana Power Company system. In 1915 a plant at Thompson Falls was completed. The availability of power from the plant allowed the electrification of mines and smelters, and aided in the development of electrolytic refining of copper and zinc (Bowers and Hanchette 1982; Wyss and Axline 1991).

The bedrock along the Clark Fork and Flathead River valleys between Ravalli and the Idaho boundary formed during the Precambrian era and is mostly sedimentary (Belt) formations. Much of the rock is of the Prichard formation. Glacial Lake Missoula was created about 15,000 years ago by an ice dam and covered much of the Clark Fork River valley as well as land to the east. The entire flow of the Clark Fork River backed up behind the dam, and the glacial lake reached an elevation of about 4350 feet When the ice dam failed, Glacial Lake Missoula emptied through the Clark Fork Valley in just a few days, releasing the greatest flood of known geologic record. This process occurred repeatedly, each time resulting in colossal floods. The passage of the torrents of water during the flooding scoured the narrow stretches of the valley, especially between Perma and Plains and several miles east of Thompson Falls. Exposed bedrock and sedimentary deposits provide evidence of the long- ago rushing floodwaters through the valley, as do ripple marks in Camas Prairie (Alt and Hyndman 1986).

The valuable minerals in the district are gold, silver, lead, and antimony. Faulting is evident near and in most of the prospects (Crowley 1963). The geology of the district is described as follows:

The country rock is quartzite, slate, and argillite of the Prichard and Ravalli group formations. Ore deposits occur in veins which cut the quartzite or are associated with basic dikes cutting the hardened sediments. A vein along the contact of the dike carries white quartz and galena. Siderite is associated with galena in a cross vein (Sahinen 1935).

Prospect Creek cuts east-west through a nearly north-south trending anticline. Prichard Formation sediments, sericitic grey thin-bedded argillites, are exposed in the center of the anticline with the heterogeneous argillites and quartzites of the Ravalli group formation exposed on either side. On the eastern flank of the anticline the predominantly calcareous argillites of the Wallace Formation are exposed (Crowley 1963).


Rowe (1911, 1941) described the Prospect Creek district as nine miles west of Thompson Falls, as a few miles south of Thompson Falls, and as just across the divide from the Coeur d'Alene.

According to Crowley (1963), the district enclosed the drainage of Prospect Creek and its tributaries, and it was also known as the Burns, and as the Mountain House mining district.

Within the Prospect Creek district is the Seepy Creek or Belknap district. Sahinen (1935) places this small mining area in the vicinity of Belknap, and reported that it had produced a small amount of copper ore from deposits associated with Beltian (Algonkian) sediments.

The Prospect Creek district is shown on Figure 1 as defined by the AMRB (1994) which includes the Prospect Creek drainage. It is essentially as described by Crowley and Rowe.


Antimony Claims

Numerous claims are located on a group of antimony-bearing quartz veins near the head of Antimony Gulch (parts of Sections 16, 17, 19, 20, 21, 29, and 30 in T21N, R31W). The first discovery of antimony in the area was in 1884 when prospectors were traveling up Prospect Creek to the Coeur d'Alene. Three carloads of assorted crude ore were sold in the East at a small profit, so the owners decided to treat the ore on the site. A small smelter reduced the antimony to an oxide, three cars of which were sold at a good profit. A "considerable" amount of antimony ore was shipped prior to 1906, but no production was reported in recent years. The properties were then idle until World War II. Two mines produced antimony ore in 1940, and in 1941 and 1942 four different mines were producing. Between 1940 and 1953, 532 tons of ore were shipped, containing 137 tons of antimony. The productive mines were the Coeur d'Alene, Eureka & Ellis, Interstate, Stibnite Hill, and others (Crowley 1963; Sahinen 1935; Whisennand 1992; Heritage Research Center 1989; Calkins and MacDonald 1909).


The Apex was located on Prospect Creek 10 miles from Thompson Falls and its last shipment was in 1912. It yielded low-grade ore with values in gold. There was a mill at the site and a 300-foot and a 500-foot tunnel. The mine was operated again in 1939 (Crowley 1963; Weed).


The Arlington was located on Prospect Creek near the Montana-Idaho divide in the NW1/4 of Section 28, T21N, R32W, on the north slope of Glidden Creek. The Arlington mine shipped silver, copper, and lead ore in 1908 and possibly in 1906 (Crowley 1963;

Mineral Resources

1906; WPA 1941).

By 1912 the Arlington Mining Company had developed it with a tunnel 500 feet in length. A five-stamp mill was begun in 1908. The ore carried silver, galena, copper, lead, and gold. According to one source, the Arlington produced copper, lead, and zinc from 1900 to 1911 (Heritage Research Center 1989; Walsh and Orem 1912; Mineral World 1906a).

Blue Slide

The Blue Slide gold mine was described as being in the "Seepy Creek" district. The Montana Mammoth Mining Company was operating the property in 1907. In that year the camp included a bunkhouse and cookhouse, and the company planned to add an assay office and general office (

Sanders County Ledger



The Bullfrog mine is located near the head of a small tributary to Summit Creek, only one-half mile west of the ridge crest separating Sanders County, Montana, and Shoshone County, Idaho. In 1916 the Silver Tip Mining Company had a prospect in this area. Although the mine was developed by a 580-foot adit and the beginnings of another, mineralization in the main adit was reportedly sparse. There is no record of production from the mine (Crowley 1963).

Chipmunk Creek

A mine was located on Chipmunk Creek, tributary to Cooper Gulch near the Idaho line. The operation was apparently active from the turn of the century into the 1920s (Whisennand 1993).

Cooper Creek

The Cooper Creek workings are located high on the divide between Montana and Idaho near the head of Cooper Gulch and about one mile west of Cooper Pass. The adits are in the NE1/4 of Section 5, T20N, R32 W. Three different companies were mentioned in 1928 - 1929 as having a prospect at the head of Cooper Gulch (all with the same persons as officers): Cooper Creek Mining Company, Neglected Mines Company, and Copper Creek Mining Company. According to Crowley, no production was recorded from the area, and the last operation was in 1933. Another source, however, reports that the Cooper Creek mine produced from 1920 to 1933 (Crowley 1963; Heritage Research Center 1989).

Eagle Mountain

The Eagle Mountain mine is located seven miles south of Thompson Falls on Prospect Creek. Around 1912, a 1000-foot tunnel was driven to expose ore bodies carrying lead, silver, and gold. According to a 1928 report, a new development was planned for the Eagle Mountain mine, and more than 2000 feet of development had already been done. The mine was last operated in 1931 (Crowley 1963).


The Gilbert mine is located 7 miles south of Thompson Falls. In 1912 the Denver and Gilbert Mining Company (F. A. Gilbert manager) employed seven men and had developed the mine with tunnels 800 feet long. The ore carried gold and silver (Crowley 1963).

Happy Boy

The Happy Boy prospect is located in the NW1/4 of Section 33, T21N, R31W. Two adits were driven into the quartz veins, 275 and 150 feet long (Crowley 1963).

Iron Daisy

The Iron Daisy mine is located on Daisy Creek about one mile south of Prospect Creek and 11 miles from Thompson Falls. The Iron Daisy produced gold, silver, zinc and lead intermittently from about 1894 to 1936. The Iron Daisy Mining and Milling Company owned the mine beginning in 1919. In 1927 the Princess Gold Mining Company took the mine over on lease and shipped ore containing gold, silver, lead and zinc to a smelter. In 1928 a mill was built at the site. Assays on ore samples ran $18 to $52 per ton in metals. By 1931, 3,000 feet of tunnels had been built, and the depth of workings was 100 feet In 1936 the Thompson Falls Mining Company was reported ready to resume work on the Iron Daisy. The production of valuable metals from the Iron Daisy mine in the years 1923, 1926, and 1930 totaled 7 ounces of gold, 120 ounces of silver, 60 pounds of copper, and 3,223 pounds of lead (Crowley 1963; Heritage Research Center 1989).

Jim Fisk

In approximately 1906 George Thayer of the Ponderay Smelting Company at Sand Point bonded the Jim Fisk mine on Prospect Creek from George Burson and others (

Mineral Resources


Montana Standard

The Montana Standard group of four claims was located about 11 miles above the mouth of Prospect Creek in Sections 25 and 35, T21N, R31W. The vein was "associated with a massive basic dike which cuts a country rock of the Burke formation." An adit on the east contact of the dike showed white quartz carrying galena. A cross-lead carried galena and siderite. According to a 1906 report, the veins at the mine were transverse fissure fillings that cut quartzites and argillites of the Ravalli Formation (Crowley 1963; Calkins and MacDonald 1909).

The Montana Standard mine was first mentioned in 1905, when a flume was built to carry water from Crow Creek to the mine and a 1400-foot crosscut tunnel was driven. There is no record of production until 1939, but 5 carloads of ore were reportedly shipped to the Tacoma smelter in 1910 or 1911. Between 1911 and 1937 the mine was apparently shut down. In 1953 the Montana Standard Mining Company reopened the mine, and production was reported until 1957. The three adits developing the mine are 1800, 600, and 100 feet long. The total production from the mine in the years 1939-1940 and 1954-1957 was 4 ounces of gold, 7,563 ounces of silver, 1,600 pounds of copper, 444,129 pounds of lead, and 208,000 pounds of zinc. Lessors were operating the mine in 1960 (Crowley 1963; Mining World 1906a).


In 1906 the Rosebud Mining Company was exploring several claims near the mouth of Rosebud Creek (a small tributary that enters Prospect Creek about 9 miles above its mouth). The company found a vein of white quartz in the upper part of the Prichard formation that reportedly carried some silver chloride and over $100 per ton in gold in the weathered zone at the surface. In 1911 the company was still developing several claims (Rowe 1911; Crowley 1963; Calkins and MacDonald 1909).


The Shamrock mine is located in the N1/2 of Section 25, T21N, R31W, on the ridge west of Shamrock gulch, a tributary gulch to Prospect Creek. The Shamrock produced gold, silver, and lead between 1906 and 1912 (Heritage Research Center 1989; Crowley 1963).

By 1906 the Shamrock mine had been developed by a series of tunnels, the longest over 1000 feet in length (350 feet were built in 1906). The ore carried gold and silver. The owners were the Shamrock Gold Mining & Milling Company, and they employed 15 men in 1906. By 1906 a 5-stamp mill had been erected to concentrate the gold-bearing sulfide ores, and by 1911 a reduction mill was operating at the mine. That year, 300 tons of ore were shipped that yielded 20 ounces of gold, 176 ounces of silver, and 165 pounds of lead (Walsh and Orem 1906; Crowley 1963; Mineral Resources 1906; Hall 1910).

In 1912 the mine was owned by the Florence Mine & Developing Company. The longest tunnel was 1000 feet, with 350 feet of it on the vein. The property was being operated at intervals, making mill tests to determine the best method of saving the values in the ore (Walsh and Orem 1912).

In the early 1960s the foundations of the mill were visible at the mouth of the gulch north of the road (Crowley 1963).


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