The Pacific Coast Borax Company (PCB) was a United States mining company founded in 1890 by the American borax magnate Francis Smith, the "Borax King".
The roots of the Pacific Coast Borax Company lie in Mineral County, Nevada, east of Mono Lake, where Smith, while contracting to provide firewood to a small borax operation at nearby Columbus Marsh, spotted Teels Marsh while looking westward from the upper slopes of Miller Mountain where the only nearby trees were growing. Eventually, to satisfy his curiosity, Smith and two assistants visited Teels Marsh and collected samples, that proved to assay higher than any known sources for borate. Returning to Teels Marsh, Smith and his helpers staked claims and laid the foundation for his career as a borax miner.
With the help of his older brother, Julius, who came west from the family home in Wisconsin, and financial support from the two Storey brothers, operations began in 1872 under the name, Smith and Storey Brothers Borax Co. When the Storey brothers' interests were subsequently acquired in 1873, the name was shortened to Smith Brothers Borax Co. A few years later (circa 1884) it was changed again to Teel's Marsh Borax Co. In 1880, the separate and previously existing Pacific Borax Company (with no "Coast" in the name) was acquired by Smith. Frank Smith also developed holdings with his business associate William Tell Coleman at the Harmony Borax Works as well as the Meridian Borax Company, which were subsequently combined to form the Pacific Borax, Salt & Soda Company in 1888. The Pacific Coast Borax Co. name was not adopted until Smith acquired all of Coleman's borax interests in central Nevada and California, after Coleman's bankruptcy, and incorporated them all under the new company name in 1890.