File:Mine shaft (Orphan Girl Mine, Butte, Montana, USA) 5.jpg

English: The town of Butte, Montana (pronounced “byoot”) is known as the “Richest Hill on Earth” and "The Mining City". The Butte Mining District has produced gold, silver, copper, molybdenum, manganese, and other metals.

The area's bedrock consists of the Butte Quartz Monzonite (a.k.a. Butte Pluton), which is part of the Boulder Batholith. The Butte Quartz Monzonite ("BQM") formed 76.3 million years ago, during the mid-Campanian Stage in the Late Cretaceous. BQM rocks have been intruded and altered by hydrothermal veins containing valuable metallic minerals - principally sulfides. The copper mineralization has been dated to 62-66 million years ago, during the latest Maastrichtian Stage (latest Cretaceous) and Danian Stage (Early Paleocene). In the supergene enrichment zone of the area, the original sulfide mineralogy has been altered.

This is the Orphan Girl Mine, on the western side of Montana Tech campus in Butte. The site is now a museum. The grounds include the original headframe of the Orphan Girl Mine, so named because it was so far away from other Butte mines - it was alone. The mine operated from 1875 to 1957. It was a zinc-lead-silver mine, but principally a zinc mine. The 90 feet tall headframe and the hoist house are original.

The photo shows the mine shaft at the 65 feet level, which is underground.

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Info. from onsite-signage:

ORPHAN GIRL MINE

From the time it was located in 1875 until it was purchased by Marcus Daly and associates in 1879, ownership and fractional shares in the Orphan Girl Mine changed hands faster than the ante in a poker game. The Orphan Girl eventually operated to a depth of over 3,000 feet. While not a huge producer according to Butte standards, by 1944 hardrock miners had removed a respectable 7,626,540 ounces of silver as well as lead and zinc from her depths. Cool temperatures between 55 and 65 degrees made the Orphan Girl - affectionately nicknamed "Orphan Annie" or "the Girl" - a desirable place to work, unlike some "hot boxes" where temperatures could top 100 degrees. By the end of the 1920s, the Anaconda Company owned the Girl which operated until the 1950s. In 1965, the Girl became the site of the World Museum of Mining.

HEADFRAME

With typical dark humor, mines often called headframes "gallus", or gallows, frames - because they seemed likely places to hang a man and because the threat of death was ever present in the mines. The headframe supported the sheave wheels, around which wrapped the cables tht pulled the cages up and down the mineshafts.

The cables attached to both the cages and the hoists. Located in the hoist house the main engine powering the hoist is a 450 horsepower double drum unit manufatured by Nordberg in 1923 and assembled in 1925. It was small compared to the electric and compressed air hoists used in the largest mines on Butte Hill, which were generally 2,000 to 3,000 horsepower. Nevertheless, it regularly lifted three cages stacked one atop the other. Together, these cages weighed over ten and one half tons when all three were loaded with ore. The ore was hoisted at 1,550 feet per minute. Men only traveled at 800 feet per minute, but that was still at stomach-jolting ride (passenger elevators generally travel at less than 450 feet per minute).

Headframes were designed to be dismantled and moved when a mine played out. The Orphan Girl received its main headframe in 1925 from the Colorado Mine in East Butte. Later, the mine added the steel legs on the west side. These legs held the sheave wheel for the chippy hoist, located in front of the hoist house. The chippy hoist hauled men and material when the main cages were filled with ore.

SHAFT, CHIPPY HOIST, AND TURNSHEETS

The Orphan Girl's shaft has four compartments. The smallest (west) compartment is the "manway", which held the mine's pipes and electrical cables and ladders for service work and emergencies. The "chippy hoist" serviced the next compartment to the right, hauling cages filled with men and material when the larger cages were filled with rock. The function of the chippy hoist - to "service" the men - may have given it its name; chippy is slang for a loose woman, or prostitute. A slightly different theory [sic] holds that the hoist was so-named because the cage it powered "ran around", making many more trips than the main cages.

The main hoist serviced cages in the two compartments on the right. As the hoist pulled up cages loaded with ore, waste rock, or men, cages in the other compartment descended as a counterbalance.

The head of the shaft is called the collar. Abutting the collar are large metal plates known as "turnsheets", steel plates that allowed men to slide the cards to turn them so they could be loaded into the cages.

CAGES

"As the warning bell sounded, the cage dropped into the dark shaft. The only light came from the lanterns affixed to the cage itself and from those passed on the way down. Likened by some miners to being buried alive, the fall produced only muted sounds . . . then from the pit of the stomach came the sinking feeling that accompanied the rapid fall." -- Ronald C. Brown, Hardrock Miners (1979)

The Orphan Girl shaft descends 2,731 feet below the surface. The first "level" or "station", is about 90 feet down, with another level placed every 100 to 200 feet after that. Six to seven miners packed tightly into "cages" (elevators) to reach the levels where they spent their shifts mining ore from the rich veins that threaded below Butte. Anxious to get home, miners coming off shift would crowd as many as ten skinny men into each cage. The cages were also used to hoist ore and waste rock. All the rock from the Orphan Girl, probably around a million tons, was hoisted one car at a time in the cages.

In the 1880s, hoisting accidents accounted for approximately 33% of mining deaths. An 1889 law improved cage safety by requiring mines to install iron bonnets (roofs) to protect miners from falling rock. The same law required safety gates, to keep the men from plummeting down the shaft to their deaths. In 1916, despite many technological improvements, hoist accidents still accounted for approximately 5% of mine fatalities.

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Locality: Orphan Girl Mine, Butte Mining District, northeastern Silver Bow County, southwestern Montana, USA