History of 3M Corona
The 3M Corona plant is located on a site that is rich in history for our local community. Historically, the Butterfield Overland Stagecoach passed near the site on its route to deliver the mail between San Francisco and St Louis.
This location has been an active mine site for over 100 years. Temescal Rock Company operated the site at the turn of the 20th century, producing ballast rock for building railroads. It was then purchased by Blue Diamond Company which operated a quarry that produced concrete aggregate until the plant was destroyed by fire in 1928. In 1924 the property was the site of the largest non-accident explosion in the world up to that point in time. 3M acquired the site in 1941 and began operations to produce roofing granules in 1948.
The rock quarried at this site is a hard trap rock which is blue-black in color flecked with white. It has the toughness and durability to withstand maximum weathering effects.
View of the 3M Corona Plant in 1948