The Permanente Quarry and cement plant is in an unincorporated area of Santa Clara County, California, just west of Cupertino. The limestone and aggregate mining operation and cement plant is owned by Lehigh Southwest Cement, a subsidiary of Heidelberg Cement. Limestone was mined beginning in 1902 but remained a small operation until 1939 when it was purchased by Henry J. Kaiser to supply the 5.5 million barrels of cement to build Shasta Dam. With increased production Kaiser supplied all of the cement used by the Navy in the Pacific Theater of World War II. At 7 million barrels, it was more cement than the Shasta Dam project. Roughly 70 percent of the cement used in the communities of Santa Clara County was acquired from the cement plant. Located in the foothills above Cupertino on the northeast slopes of Black Mountain, the quarry runs east–west parallel to the upper watershed of Permanente Creek to the south and to Permanente Ridge and Rancho San Antonio Open Space Preserve to the north. The limestone rock found in the Permanente Creek valley and on the summit of Black Mountain is relatively unique in the Bay Area. Microfossils in the limestone deposits suggest that the mountain originated as a seamount at 22 degrees north in the tropical Pacific about 100 million years ago and was transported to Los Altos by the Pacific Plate. These rocks occur as jagged gray boulders and outcrops just southwest of the radio towers on the summit of Black Mountain, as well as in the Permanente Quarry.
Initial operations In the 1890s, R. A Swayne purchased 160 acres of land at the headwaters of Permanente Creek. He planted vineyards, built a winery and other buildings, expending about $25,000 in the process. When that venture failed, Swayne sold the property for $1500. Granite Rock Company of Watsonville bought it from the subsequent owner for $2500 to mine the limestone. In 1902, the Alvarado Sugar Company contracted with Granite Rock to produce 5,000 tons of limestone to be shipped at the rate of two carloads per day. The Alvarado (now Newark, CA) plant was the first sugar beet factory in the country. A state mining report in 1906 lists it as the El Dorado Sugar Company Quarry, located in Section 18 of Township 7 S, Range 2 W. That location is approximately 1.8 miles west of the end of Stevens Creek Boulevard. The rock was transported nine miles by wagon to Mountain View, where it was then loaded onto Southern Pacific Railroad trains at a rate of 30-60 tons per day in the dry season. The rock was taken to the sugar factory in Alviso where it was burned into quicklime and used to refine sugar. The stone was described as, "being good road material as it was in small pieces that would not require further grinding". In 1906, the sugar refining industry was using much of the limestone quarried in California and only a small amount was used in road construction. Large amounts were also used for the manufacture of Portland cement. In 1908, Southern Pacific Railroad completed the Mayfield Cutoff which ran from Mayfield (now part of Palo Alto), along the west side of the Santa Clara Valley to Los Gatos. There was a stop at Monta Vista where the tracks crossed Stevens Creek Boulevard. This eliminated the nine-mile wagon journey between the quarry and the railroad. The operation continued intermittently until 1934.
Early Kaiser Era
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