The Bilger Quarry operated, with some periods of inactivity, between 1870 and 1946. It was originally developed by the Oakland Paving Company, which mined sandstone and quartz diorite of the Franciscan Complex, crushed it and shipped the finished product by rail to various users. Later the quarry was operated by Blake & Bilger Company. For many years it was the largest rock quarry in Alameda County. Most of the early paved streets in North and West Oakland were originally built by the macadam method using crushed rock from this quarry. Crushed rock was also used in building foundations, roadbeds for railroads and streetcar lines, and aggregate in the manufacture of concrete.
After a long period of neglect, the abandoned quarry was redeveloped into the Rockridge Shopping Center. The quarry walls were groomed again and reinforced in places during the construction of the current commercial complex centered on a Safeway store. At that time too a historical exhibit was placed at the edge of the water-filled pit, which displays some good examples of the rock that was produced there and the people who worked there.
The pond at the east end of the former quarry is now filled with groundwater and perennial flow from the Rockridge branch of Glen Echo Creek and is owned by the Claremont Country Club, which uses the water for irrigating its golf course. Over the years, there has been at least one drowning. On March 31, 1955, 7 year old Gary Schaffer and two friends climbed over a broken part of the fence and went 'exploring'. Gary slipped from a rope, fell into the water, and drowned. It took divers all night to find his body, caught in a tangle of branches. 3 A more recent drowning occurred in November 2012 when a man searching for his cat fell from the cliff adjoining St. Mary's Cemetery.
There is some uncertainty about the rail line that served the quarry. Some believe that between 1873 and 1923 a 3' gauge steam railroad ran between the Bilger Quarry and the rock crushing plant. After the quarry was abandoned in 1923 houses were constructed on the former railway. This 1912 ad suggests that the Key System acquired the right of way as part of a plan for a long-distance line across Piedmont and the East Bay, but this line was never built.
"Blake & Bilger Company's Quarry (formerly the Oakland Paving Company's quarry); F. W. Bilger, secretary and treasurer, Central Bank Building, Fourteenth and Broadway, Oakland. Located on McAdam street, just off Broadway. It was opened about 1870, and has been operated almost constantly since. It is the largest quarry in Alameda County. The rock is typical 'blue rock,' as termed by the trade, and is a metamorphosed sandstone, with lime carbonate in seams. It is used for macadam, concrete, and gutter rock. Two Gates crushers handle all the rock. Two steam percussion drills are in operation. From 60 to 80 quarrymen are employed." 2 (From The Structural and Industrial Materials of California, Bulletin No. 38, California State Mining Bureau, San Francisco, 1906, p. 312.)
Links and References
- Rockridge Shopping Center quarry Oakland Geology