Development and Operation of the Mine

ACCORDING to the records, Phelps Dodge made its original entry into the production of copper in the oldest copper mines of Arizona at Morenci in 1881. The ore body now being mined as the Morenci open-pit, as outlined by churn-drill holes, diamond-drill holes, and underground workings, is estimated to yield 230,000,000 tons of ore averaging 1.06 per cent copper. This development will add 2,500,000 tons of copper to the 900,000 tons already produced in the district. Some five years ago preliminary development of the ore body began, with big-scale production planned including the erection of a new treatment plant to be built near the mine. Inasmuch as the Morenci open-pit was an entirely new project this required the grading of roads, establishment of mining benches, construction of railroad grades, building of railroad tracks, erection of shops, as well as the purchase of the necessary equipment to satisfactorily and economically maintain the schedules of production forecast. Along with the preparation of the main ore body it was also desirable to mine and deliver to an experimental mill a relatively small daily tonnage of typical ore.