Terra Cotta, California
Coal, along with clay deposits, was found on the site by John D. Huff in the late 1880s, and the Southern California Coal and Clay Company was formed to mine them. The town site of Terra Cotta was laid out and was given a post office on October 26, 1887. In May 1893 its post office was closed and moved to Lake Elsinore. A plant for the manufacture of sewer and water pipes was built using the coal to fire ceramic pipes in the four kilns. The finished product had to be shipped by wagon six miles through Lake Elsinore to the La Laguna rail station at the mouth of Railroad Canyon until 1896 when a spur line was built through Lake Elsinore and Terra Cotta to the new clay deposits in Alberhill. The coal mined was also used locally as fuel for the stamping mill at the Good Hope Mine and was shipped elsewhere in the state.
Conservation and restoration of ceramic objects
Additionally the type of ceramic will affect how it will break down. Unfired clay, like mud and clay adobe, is clay that is fired under 1000 °C or 1832 °F. This type of clay is water-soluble and unstable. Earthenware is clay that has been fired between 1000-1200 °C or 1832°-2192 °F. The firing makes the clay water insoluble but does not allow the formation of an extensive glassy or vitreous within the body. Although water-insoluble, the porous body of earthenware allows water to penetrate. A glaze can be applied that will protect the vessel from water. Due to its porosity, earthenware is susceptible to moisture and creates problems including cracks, breaks and mold growth. Porcelain and stoneware is fired at the highest temperatures between 1200-1400 °C or 2192-2552 °F. Porcelain clay mixtures are fired to create a non-porous and very hard surface. However, the materials also create a very brittle surface which increases the potential for chips, cracks and breaks.