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

Photographed By Barry Swackhamer, January 9, 2012
1. Day Tunnel Marker
Photo captions, top left to bottom right:]
Tunnel entrance, ca 1860
Day Tunnel Planilla (ore sorting shed), ca late 1800s
Sherman Day, an accomplished engineer and graduate of Yale’s Sheffield School of Engineering, was hired as Superintendent and Surveyor of New Almaden’s Quicksilver Mines in 1857. He conceived several ideas that added to the success of mining operations.
Tunnel entrance, ca 1860
Day Tunnel Planilla (ore sorting shed), ca late 1800s
Sherman Day, an accomplished engineer and graduate of Yale’s Sheffield School of Engineering, was hired as Superintendent and Surveyor of New Almaden’s Quicksilver Mines in 1857. He conceived several ideas that added to the success of mining operations.
[Side-bar on left:]
Significant Addition to New Almaden’s Rich Mining Operation
Toxic gases and underground water posed perils and problems for miners in search of valuable cinnabar ore. Under Sherman Day’s suggestion, the “New Tunnel” was dug at the 800 foot level to help ventilate and drain the vast catacombs of underground tunnels and shafts. Later re-named the “Day Tunnel”, this new passage into some of the mountain’s hardest rock proved to be quite profitable. For much of the 1870s, miners hauled nearly all of the company’s cinnabar out through this one opening.
It was also Sherman Day who suggested building a new road (now known as the Randol Trail) for easier access to the mine and tunnel. Although the Day Tunnel entrance and planilla are not visible today, evidence of the tons of rock that passed through them can be seen along and below the trail.
Erected by New Almaden Quicksilver County Park Association.
Topics. This historical marker is listed in these topic lists: Industry & Commerce • Natural Resources.
Location. 37° 10.965′ N, 121° 50.278′ W. Marker is in San Jose, California, in Santa Clara County. The marker is located in Almaden Quicksilver County Park on the Randol Trail near the intersection of the Day Tunnel Trail. Touch for map. Marker is in this post office area: 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. Camp Mt. Madonna (approx. ¼ mile away); Site of English Town ★ CCC Camp Mt. Madonna (approx. ¼ mile away); English Camp School (approx. 0.3 miles away); English Camp (approx. 0.3 miles away); Mining Operations (approx. 0.4 miles away); The Yellow Kid (approx. 0.4 miles away); The Buena Vista (approx. 0.4 miles away); The “Main Tunnel” (approx. half a mile away). Touch for a list and map of all markers in San Jose.
Credits. This page was last revised on June 16, 2016. It was originally submitted on February 18, 2012, by Barry Swackhamer of Brentwood, California. This page has been viewed 626 times since then and 62 times this year. Photos: 1, 2, 3, 4. submitted on February 18, 2012, by Barry Swackhamer of Brentwood, California. • Syd Whittle was the editor who published this page.