Lehigh Southwest Cement

The ‘70s ushered in a new attitude, a changing climate for business and home alike.

Pressure from both within and outside of the cement industry combined to dictate changes: increased power and fuel costs, a saturated cement market, economic recessions, rampant inflation, government price controls, and public demands for an increased commitment to the environment.

With the wet “slurry” process used at Permanente, more than 25 million cubic feet of costly and scarce natural gas were needed to produce one day’s output of cement. This was equivalent to supplying the heating requirements of approximately 140,000 homes.

Responding to public and government concerns, more and more resources were dedicated to restoring and protecting the environment while the company searched for a more cost-effective method of producing cement.

Meanwhile, on Permanente’s doorstep, the semi-conductor industry was changing the world with its technological innovations and transforming Santa Clara Valley into Silicon Valley. Local cities exploded with growth, creating a huge market for Permanente’s products.

Cement, a primary building material throughout the ages, was once again answering the call—this time by the newest of industries.

For forty years, the kilns at Permanente had used the wet-process method to produce clinker. One-half million gallons of water a day carried the limestone, clay and iron ore in a slurry to the kilns, where the mixture was calcined. In the aftermath of the 1973 oil embargo, the fuel for heating the water, along with the minerals, was now too costly.

Although a dry-process had been used before, it wasn’t until the late ‘70s that technology came together to make it truly cost-effective. By combining a precalciner with a preheater to reclaim heat from a single kiln, energy use could be cut dramatically. A $112 million program was launched in 1977 to replace Permanente’s six kilns with a single dry-process one. It would be equipped to burn coal as well as fuel oil and natural gas.

Clockwise: Raw Mill Gear, Kiln Sections/Clinker Silo Foundation, Double-Rotator Raw Mills, Delivery of Kiln Sections

Overlooking the pre-blend dome.