aka Lothrop


The Petty Creek mining district (also known as the Lothrop) is located in Missoula County west of the city of Missoula. Petty Creek empties into the Clark Fork River about two miles east of Alberton, near Lothrop. The district had some placer mines and ore deposits containing copper, none of which were very productive.

The district is part of a great anticline of quartzites and shale, with several porphyritic dikes on both sides of the best deposits. The ore is mostly chalcopyrite in stringers. A small vein near Lothrop contains considerable barite and yielded some gold (Rowe 1911).

In 1860 Frank Worden and C. P. Higgins established a trading post at Hell's Gate, which formed the nucleus of a small village on the Mullan Road. Built 1859-62, the Mullan Road connected Fort Benton and Walla Walla and indirectly made possible the mining development of western Montana because of increased ease of access via the road and because large numbers of men came into the area during the construction of the Mullan Road and the Jocko Agency. Prospectors were drawn through the Missoula valley and Hells' Gate on their way to the mines at Wild Horse Creek in British Columbia.

The town of Missoula was established in the winter of 1864-65 by the building of a sawmill and grist mill and business house by Worden & Co. Frenchtown was established in 1864. In response to the market for food in the placer gold mining camps in the 1860s in Montana and in Idaho, the Missoula Valley was developed for agriculture. Drifters began to settle in the Missoula area and in the Bitterroot valley. Missoula became a distribution center for goods since it was at the junction of five valleys (Leeson 1885; Coon 1926).

Placer mining in the Petty Creek district was minimal, but some gold was recovered from the gravels of Petty Creek. During eight seasons between 1904 and 1946 the total annual recovery was generally less than 10 ounces of gold (Lyden 1948; Sahinen 1935; Sahinen 1957).

As of 1935, no production from lode or placer mines had been reported from the district for many years (Sahinen 1935).


Sahinen (1957) reported on placer mines on Petty Creek as being in the Ninemile area, but noted that the creek was not in the Ninemile basin but flowed into the Clark Fork River south of the Ninemile district. Rowe (1911) called the Petty Creek district the Lothrop mining district and said it was located southwest of Lothrop.

Figure 1 shows the district as defined by the AMRB (1994) with a small area delineated which conforms with the vague descriptions given by Rowe (1911) and Sahinen (1935).



The Copper-Smith (or Coppersmith) mine was located on Ed's Creek about a mile from its junction with Petty Creek in Section 3, T13N, R23W. In 1910 the Coppersmith Mining and Milling Company was developing the mine. The veins contained copper oxides, chalcopyrite, and some nickel. The mineral zone is composed of a lime quartzite with occasional intrusions of diorite. There is no known record of production (Sahinen 1935).


The copper deposits in the Hailstorm mine were being worked in 1910 (Rowe 1911).


The Inverness mine was located three miles northeast of the Copper-smith, on the east side of Petty Creek. In 1910 the Inverness was also owned by the Coppersmith Mining and Milling Company (Sahinen 1935).


Abandoned Mine Reclamation Bureau (AMRB)

1994 Mining districts of Montana. Maps 1:100,000 and Map #94-NRIS-129. Compiled and edited by Joel Chavez. Prepared by Montana State Library Natural Resource Information System (NRIS) for Montana Department of State Lands. Helena

Coon, Shirley Jay

1926 "The Economic Development of Missoula, Montana." University of Chicago Ph. D. thesis.

Leeson, Michael A., ed.

1885 History of Montana, 1739-1885. Warner, Beers & Co., Chicago.

Lyden, Charles J.

1948 "The Gold Placers of Montana", Montana Bureau of Mines and Geology, Memoir no. 26.

Moore, Harry A.

1910 "Coppersmith Mineral Zone, Montana", Min. World, Vol. 33, No. 1, p. 19.

Rowe, Jesse Perry

1911 "Gold Quartz Mining in Western Montana", Min. World, Vol. 34, No. 20, pp. 1033-1034.

1911 "Mines of Missoula County, Montana." Mines and Minerals. vol. 31, May. pp. 581-584.

Sahinen, Uuno Mathias

1935 "Mining Districts of Montana", M. S. thesis, Montana School of Mines.

1957 "Mines and Mineral Deposits, Missoula and Ravalli Counties, Montana", Bulletin 8, Montana Bureau of Mines and Geology.