Arizona Copper Co. v. Gillespie

William Gillespie (plaintiff) owned farmland on the Gila River. Gillespie and prior owners had used water from the river to irrigate and cultivate the land since 1872. Many other farmers in the same valley relied on the river, and a large agricultural community grew up dependent on irrigation. Meanwhile, Arizona Copper Company and Shannon Copper Company (defendants) mined copper in the mountains above the farmland using water from Gila River tributaries to reduce and concentrate copper ore. Before 1885, the mining operations did not appear to seriously pollute the water, but when the mines expanded and adopted concentrators, they deposited slimes, slickens, and tailings into the water that were carried through irrigation canals and deposited on the farmers’ fields. Gillespie sued to enjoin the mines from polluting the water. The trial court found that the amount of pollutants the mines discharged continuously increased even after institution of the suit and enjoined the pollution. Shannon Copper settled by agreeing to spare no reasonable effort or expense to minimize the contamination and immediately designed and built large settling basins that kept most of the contaminants from its mine out of the river. The Arizona territorial supreme court modified the injunction to allow installation of the settling basins but otherwise affirmed the judgment. Arizona Copper appealed to the United States Supreme Court.