on his , indicated ore containing 2% copper. The canyon's 19th Century mines were relatively small, and it wasn't until the end of the century that very large-scale exploitation of the canyon's ore bodies began to develop with open-pit mining. In 1896, Samuel Newhouse and Thomas Weir acquired the Highland Boy Mine, which was rich in copper, silver, and gold. Together they formed the Utah Consolidated Gold Mines, Ltd. with English investors. They then formed the Boston Consolidated Gold and Copper Co., Ltd., for the development of low-grade copper ore adjacent to the Utah Copper Company site. Another significant development took place in 1903, when Daniel C. Jackling and Enos A. Wall organized the Utah Copper Company. Utah Copper immediately began construction of a pilot mill at Copperton, just beyond the mouth of the canyon, and the company actually started mining in 1906. The success of Utah Copper in mining the huge but low-grade porphyry copper type ore body at Bingham Canyon was based on Jacklin's 1904 decision to use open-pit mining, steam shovels, and the railroad. The mine became a showplace for "railroad-pit operations," and the industrial complex defined by the mine and the ASARCO smelting operation made it the "largest industrial mining complex in the world" by 1912. Utah Copper and Boston Consolidated merged after their separate surface operations approached each other in 1906. The Kennecott Copper Corporation, established to operate mines in Kennecott, Alaska, purchased a 25 percent financial interest in Utah Copper in 1915, which increased to 75 percent in 1923. Bingham's Canyon mine expanded rapidly, and by the 1920s, the region was a beehive of activity. Some 15,000 people of widely varying ethnicity lived in the canyon in large residential communities constructed on the steep canyon walls. The population declined rapidly as mining techniques improved, and several of the mining camps were swallowed up by the ever-expanding mine. By 1980, when Lark was dismantled, only Copperton, at the mouth of Bingham Canyon and with a population of 800, remained. The 21 separate mining operations in existence by 1911 were consolidated into two in 1970: Kennecott and The Anaconda Minerals Company. In 1985 open-pit mining operations were halted by Kennecott's Utah Copper. In 1986, Kennecott discovered gold in nearby Barney's Canyon. KCC was purchased by Sohio in 1981, and the mine reopened in 1987 after BP Minerals purchased the assets. In 1989 the Rio Tinto Group