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    1995 Mining History Association Tour

    North Star Gold Mine Powerhouse Museum,
    Grass Valley, CA and
    Malakoff Diggins SHP, North Broomfield, CA

    Allegheny, California

    June 3, 1995

     

    Grass Valley was home to two of California’s most famous underground gold mines, the North Star, visited on this MHA field tour, and the Empire, now a State Historic Park, visited on another tour. The North Star was discovered in 1851 and operated over the years by several different owners. It eventually became Grass Valley’s deepest mine at 4000 feet. In 1929, Newmont Mining purchased the North Star and the Empire mines and consolidated them. Mining ceased during World War II but resumed afterward until the mines were closed in 1956.

    The area was settled by many Cornish miners who brought their exceptional mining skills with them from the Old Country. The Cornish influence is still alive during annual heritage festivals. The MHAers enjoyed authentic Cornish pasties during the conference.


    PHOTO GALLERY

    CLICK ON A PHOTO TO DISPLAY A LARGER IMAGE

    The North Star Mine was one of the most important gold mines in Grass Valley.  The North Star Powerhouse, built in 1895, has been converted into a mining museum.

    The grounds of the North Star Museum contain an array of historic pieces of mining and mineral processing equipment.

    Pelton Wheels such as the ones shown above and at the right used high-pressure jets of water to spin the wheel which would then power various types of mining equipment.

    The 30-foot diameter Pelton Wheel in the museum towers over the MHAers on the tour.  It originally powered compressors for the mine.  Pelton wheels are used to demonstrate the operation of some of the museum exhibits.

    (Above) A bob with a counterweight is part of this display of a Cornish pumping apparatus.  As the bob moved back and forth, the reciprocating rod at the right would drive an attached lift pump in the mine shaft.

     

    (Right) This ten-stamp mill battery was used for crushing quartz ore to free the gold (Mark Langenfeld and Mark Vendl for scale).  Water would convey the crushed ore from the stamps across a copper amalgamation plate coated with mercury.  The gold would adhere to the mercury while the fine quartz particles would be washed away.  The gold-mercury amalgam would be periodically scraped off the plates, the mercury distilled and reused, and the gold recovered.

     

     

    The Assayer’s Shop exhibit includes scales (left), ore crushers (floor and right), and crucibles (right rear) used in the assaying furnace.

    This exhibit includes an assay furnace (left), mercury distillation tube (back wall), refining furnace (right), and molds for gold bars (floor).


    The Malakoff Diggins State Historic Park preserves the last of the large-scale hydraulic gold mining locations.  The restored village interprets the life of the miners and their families in the 1870s.

    MHAers learn about the history of the “diggins” from a costumed reenactor (center).  In the 1850s, prospectors discovered gold in Humbug Creek, a tributary of the South Yuba River.  Placer mining quickly gave way to hydraulic mining using monitors (water cannons) to loosen gold bearing gravels which could then be directed to sluice boxes and the gold recovered.


    Hydraulic mining caused large volumes of silt to flow down the river all the way to San Francisco Bay.  Navigation and agriculture were greatly impaired.  The environmental impacts are still visible.
    In 1884, a court decision prohibited the North Bloomfield Mining and Gravel Company from dumping tailings into the river.  This ended the hydraulic mining era.

     

     

    Photo Credits: Mike Langenfeld and Mike Kaas

     

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