Almaden in San Jose in Santa Clara County, California — The American West (Pacific Coastal)

D Retort and Condensing System

Photographed By Barry Swackhamer, November 17, 2011

1. D Retort and Condensing System Marker

Inscription. The D retort, line the rotary furnace, was used to recover mercury from cinnabar ore. Whereas the rotary furnace was a continuously-operating system, the D retort was loaded with ore, fired for a period of time (usually 8 to 24 hours), then allowed to cool before emptying the burnt ore (calcines) and recharging with more ore. Burning fuel in a fire box under the retort heated [the] ore to dissociation temperature (1095 degrees F). Vapors driven from the ore by heat, including mercury, sulphur [sic], and water vapor, were condensed in external air-cooled or water-cooled metal pipes attached to the top of the retort.

The retort was most often used to process relatively small amounts of ore and to perform a second processing of calcines and dust from the rotary furnace.

This retort and condenser were used in the Guadalupe mine from 194-s until the mine closed in the 1970s. The Guadalupe Rubbish Company donated the D retort to NAQCPA in 1987.

Erected 2011 by the California State Society, Daughters of the American Revolution and New Almaden Quicksilver County Park Association.

Topics and series. This historical marker is listed in these topic lists: Industry & Commerce • Natural Resources

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. In addition, it is included in the Daughters of the American Revolution series list. A significant historical year for this entry is 1987.

Location. 37° 10.402′ N, 121° 49.576′ W. Marker is in San Jose, California, in Santa Clara County. It is in Almaden. Marker can be reached from Almaden Road. The Hacienda Mining Display is a short walk on the Deep Gulch Trail from the Almaden Quicksilver County Park parking lot. Touch for map. Marker is at or near this postal address: 21731 Almaden Road, San Jose CA 95120, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within walking distance of this marker. Shaker-Concentrator (here, next to this marker); Mercury Storage Vault (here, next to this marker); Gould Rotary Furnace and Condensing System (here, next to this marker); Hoeing Table and Cleaning Tank (here, next to this marker); Skip Loader (a few steps from this marker); Cornish Pump (a few steps from this marker); Mine Air Compressors (a few steps from this marker); Hacienda Mining Display (a few steps from this marker). Touch for a list and map of all markers in San Jose.

Photographed By Barry Swackhamer, November 17, 2011

2. D Retort and Condensing System Marker

The D Retort image. Click for full size.

Photographed By Barry Swackhamer, November 17, 2011

3. The D Retort

The Condensing System image. Click for full size.

Photographed By Barry Swackhamer, November 17, 2011

4. The Condensing System

Hacienda Mining Display image. Click for full size.

Photographed By Barry Swackhamer, November 17, 2011

5. Hacienda Mining Display

Credits. This page was last revised on February 7, 2023. It was originally submitted on November 26, 2011, by Barry Swackhamer of Brentwood, California. This page has been viewed 700 times since then and 16 times this year. Photos: 1, 2, 3, 4, 5. submitted on November 26, 2011, by Barry Swackhamer of Brentwood, California. • Syd Whittle was the editor who published this page.