_Group 6. W. A. Clark_: United Verde, Elm Orlu (Mont.) and Ophir Hill (Utah); 1917 output 88,390,038 _Group 7. Adolph Lewisohn_: Miami and, by sale of output, Shattuck-Arizona; 1917 output 57,058,666 _Group 8. U. S. Smelting, Refining & Mining Co._ Custom ore and Mammoth mine, Cal., Utah Apex, and Tintic (Utah) mines; 1917 output 22,600,000 _Group 9. Lake mines_ (other than Calumet & Hecla): Copper Range Co., Mohawk, Quincy, etc.[112]; 1917 output 99,700,000 [112] Ten different interests. There is also a group, discussed later, of uncertain or unclassifiable affiliations, owned by Americans, but in many instances worked under smelting and refining contracts that merit special mention: 1917 output, pounds Old Dominion (Ariz.), (perhaps group 4) 25,758,381 East Butte (and custom ore), (perhaps group 9) 18,000,000 Shannon Copper Co., (Ariz.), (independent) 6,138,219 Penn. Mining Co. (Cal.) (independent) 3,400,000 Cons. Arizona Smelting Co. (independent) 5,000,000 Ducktown Sulphur, Copper & Iron Co., Ltd. (Tenn.), (English) 5,523,573 -------------- Total unclassifiable and uncertain 63,820,173 Total of groups 1 to 5 1,407,518,679 Total of groups 6 to 9 267,748,704 -------------- Total of all interests 1,739,087,556 Total 1917 United States copper production (from domestic mines only) 1,873,546,171 Balance (custom ore from small shippers)[113] 134,458,614 [113] This balance includes copper produced as by-product in mining of other metals in Colorado and the East, estimated at 50,000,000 pounds, and custom shipments from 1,000 small operations, chiefly to smelters controlled by groups 1, 2, 3, 4 and 6, estimated at 84,458,614 pounds. Certain mines in the above groups are owned in England, but are classed with that interest which refines and sells the production. In group 2, for example, is listed the Tennessee Copper Co., whose copper is refined and sold at the American Smelting & Refining plant in Baltimore. In ownership, however, this property should be placed in group 7, (output 10,547,704 pounds).