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.
Afon Clun
Lead mines were opened in Mwyndy (between Llantrisant and Groesfaen) in the "Parke of Cloune" in May 1531 CE. By August 1531 iron ore was being mined there. Iron smelting began nearby during the summer of 1532, with one bloomery furnace site at Mwyndy, and (probably) another smaller smelting site at Rhiwsaeson, employing 4 blowers/hewars, with three blowers operating the bellows at any one time. They produced up to two blooms, of 50 kg per bloom per day, from 150 kg of ore, taking 6 to 7 hours each to produce. Charcoal to heat the furnaces was probably derived locally, from "Cloune Park" — mention is made by Rice Lewis in his 'A breviat of Glamorgan' (1595 and 1600) of the destruction of the forests of Garth Maelog and Allt Griffith because of the ironworks. The iron mines were leased by the crown in 1539, granting rights to mine and make iron and to build water powered ironworks within three miles of Cloune Park for 21 years. There is no evidence to suggest that either iron mining or smelting continued in the area after the 16th century.