Abstract The trip begins at the Doubletree Hotel in downtown Salt Lake City, heads south to historic Midvale, west to Lark, and then begins a field tour of the Bingham mining district and Kennecott Utah Copper's Bingham Canyon porphyry copper mine (Fig. 1). The trip returns through Lark and then north past the Copperton concentrator, Barneys Canyon gold mine, Utah Copper's tailings impoundment, North Concentrator, and the smelter and refinery complex. The first 10.2 miles of this road log may be used for Day One: Central Wasatch Mountain field trip (John, 1997) and the first 20.6 miles will also be used for the Day Three: Barneys Canyon and Melco gold mine tours (Austin and Gunter, 1997). This road log is modified from logs prepared by Hunt (1933), Smith and James (1961), Bray and Wilson (1975), Shadrick et al. (1991), and Krahulec (1995). Assistance in the preparation of this log was provided by Steve Richardson, Mary Jo Sweeney, Geoff Ballantyne, Bill Stockdale, Richard Rubright, Richard Warnick, and Jaren Swenson. 0.0 Exit Doubletree Hotel parking lot at 215 South Temple, head north on West Temple, stay in the right hand lane. 0.1 Turn right, east, on 200 South, stay in the right hand lane. 0.2 Turn right, south, on Main Street, stay in the right hand lane. The Walker Building on this intersection, is named after a preeminent Utah pioneer family of mine promoters and bankers. The Walker brothers made the first shipment of base metal ores from the Bingham mining district -

ABSTRACT The Bingham District is a large polymetallic mining district centered on an Eocene porphyry copper deposit 20 miles southwest of Salt Lake City, Utah. Since its discovery in 1863 the district has at various times been a silver-lead, gold, lead-zinc-silver, and copper-gold-molybdenum district. The Bingham District is located in a zone of overlap between the Basin and Range extensional terrain and the Cordilleran fold and thrust belt. Permian quartzites and limestones were folded and thrust-faulted during several Mesozoic orogenies and then intruded by 39.8 to 37.5 Ma calcalkaline monzonite, quartz monzonite, and quartz latite. Volcanic breccias and flows petrochemically similar to the intrusions were erupted from centers close to the deposit from 39 to 33 Ma. The Bingham Porphyry Copper Deposit exhibits the concentric alteration and mineralization zoning characteristic of many porphyry deposits. However, the deposit is notable for the magnitude and intensity of the various kinds of mineralization present: It is one of the largest copper deposits in the world with pre-mining reserves of almost 3 billion tons of 0.67 percent copper ore. Nested within the copper orebody are overlapping zones of molybdenum, gold, and silver mineralization that mimic the shape of the copper deposit and contain greater than 0.1 percent MoS 2 , 0.01 ounces per ton gold, and 0.5 ounces per ton silver respectively. Major copper-gold skarn deposits flank the copper orebody on two sides. They include the Carr Fork Deposit (61 million tons of 1.90 percent copper, 0.01 ounces per ton gold, and 0.31 ounces per ton silver) and the North Ore Shoot Deposit (82 million tons of 2.81 percent copper, 0.05 ounces per ton gold, and 1.57 ounces per ton silver). Vein and replacement lead-zinc-silver deposits located in a halo around the porphyry and skarn deposits have produced 28 million tons at an average grade of 8.6 percent lead, 6.6 percent zinc, 5.0 ounces per ton silver, and 0.039 ounces per ton gold. The Barneys Canyon and Melco Deposits located five miles north of the porphyry copper deposit have combined pre-mining reserves of 19 million tons at a grade of 0.05 ounces per ton gold. They are sediment-hosted gold deposits characterized by sub-micron sized disseminated gold mineralization, an arsenic-antimony-barium-mercury-thallium geochemical signature, low silver and base metal contents, and an almost complete absence of quartz veining. The deposits lie at the outer edge of an extensive arsenic-gold geochemical halo about the Bingham Porphyry Copper Deposit, but chronological and genetic relationships to the porphyry deposit have not been clearly established.

Abstract The Bingham Canyon porphyry Cu-Mo-Au deposit is located in the central part of the Oquirrh Mountains, 30 km southwest of Salt Lake City, Utah. The Cu-Au-Mo deposit lies at the center of a large polymetallic district, which includes proximal Pb-Zn-Ag replacement and distal sediment-hosted gold mineralization. Open-pit copper mining commenced in 1906 and through 2011 has produced 2.666 billion tonnes of ore averaging 0.74% Cu, 0.035% Mo, 0.448 g/t Au, and 3.29 g/t Ag. Bingham lies near the west end of an 80-km-long belt of petrochemically similar Eocene to Oligocene intrusions and coeval volcanic rocks, which host base and precious mining districts. The Bingham district is centered on the Bingham stock, a multiphase mid-Eocene intrusion emplaced into a thick succession of folded mid- to upper Paleozoic siliciclastic and carbonate rocks. The 2 × 2 km Bingham stock consists mainly of premineral equigranular monzonite that was intruded successively by a 2-km-long dike-like body of quartz monzonite porphyry (QMP), long narrow dikes and sills of intramineral latite porphyry (LP), and narrower dikes of late-mineral quartz latite porphyry (QLP). The intrusions and associated porphyry-style mineralization dip steeply to the northwest and persist from the pre-mine surface at 2,390 m to below sea level. U-Pb zircon dating indicates a 38.6 Ma age for the equigranular monzonite and suggests that the subsequent porphyry intrusions were emplaced at ∼ 38 Ma. Porphyry intrusion and mineralization were approximately synchronous. Early actinolite-stable alteration in igneous and sedimentary rocks is flanked by distal chlorite-epidote alteration. Magnetite-destructive secondary biotite alteration is pervasive in intrusive rocks that contain > 0.7% copper but typically is fracture-controlled and overprints earlier actinolite alteration in lower grade intrusive rocks and quartzites. K-feldspar alteration accompanies the highest grade copper and gold mineralization. Sericitic alteration is locally pervasive but, more typically, it is restricted to the margins of late quartz-pyrite veins. Late, low-temperature montmorillonite ± kaolinite alteration is ubiquitous in the intramineral porphyries and adjacent equigranular monzonite. An outer zone of 0.35 to > 0.70% Cu mineralization surrounds and overlaps an inner zone of 0.05 to > 0.15% Mo mineralization, which in turn forms a cupola around a barren core. Intense bornite-chalcopyrite-chalcocite-gold mineralization (> 0.7% Cu and > 1 g/t Au) occurred directly above the barren core but has largely been removed by mining. The copper mineralization in the flanks of the deposit is dominated by chalcopyrite. Copper and gold grades decrease downward but quartz-molybdenite stockwork mineralization grading > 0.05% Mo extends to the lower limit of drilling. Equigranular monzonite is the predominant ore host, containing 53% of the ore mined to date. Vein types proceed in a sequence from early biotite through quartz-sulfide to late anhydrite and zeolite. Early copper-bearing quartz veins are truncated by the LP and QLP dikes, but later copper-bearing veins cut the dikes. Cathode luminescence studies indicate that copper-bearing sulfides were deposited within micro-fractures and vugs created by dissolution of earlier quartz. Quartz-molybdenite veins postdate the copper-bearing veins and cut all of the porphyries. Vein densities reach > 10 vol % in the barren core and decrease to ∼ 1 vol % at the outer boundary of the > 0.35% Cu zone. Published fluid inclusion and vein density studies, together with modeled grade distributions, show that mineralization was precipitated by a plume of metal-bearing fluid approximately 2 km in diameter, centered near the southeastern edge of the QMP. The barren core apparently represents an upflow zone near the top of which supercritical fluids separated into vapor and brine. Copper-bearing sulfides and gold precipitated as vapor-dominant fluids cooled from 430° to 350°C. Inclusions in quartz from the deep flanks of the copper deposit indicate similar fluid compositions, but less separation into vapor and brine.

Abstract Of 1903 with its momentous changes in his life, Penrose with his accustomed modesty wrote (in a sketch of his life, dated December 27,1928) that he “resigned as President of the Commonwealth Mining and Milling Company, and proceeded to Utah, where he| became one of the founders, together with his brother Spencer Penrose, D. C. Jackling and Charles M. Mac-Neill, of the Utah Copper Company, which has since become a very important organization.” Today, one of the great sights of the world is Bingham Canyon, Utah, where the great open-pit mines of the Utah Copper Company represent the largest individual movement of material of any kind made by man in world history. It is famous in mining history as the first great mine to prove that the theory, advanced by a young metallurgist named Daniel C. Jackling, for the utilization of low-grade copper ore was workable and eminently profitable. In 1903, however, Bingham was just another mining community near Salt Lake City, its fabulous future undreamed of, even by its promoters. To be sure, it was one of the oldest of the Utah mining districts, having been worked since 1864, but its early history centered upon its production of silicious gold ore and silver-bearing lead ores. Today, it is famous as the largest single producer of copper in the world, the first shipment of copper ore having been made from the Highland Boy mine in December, 1896.

Abstract The Bingham mining district is located in the northeastern Basin and Range province of west-central Utah, immediately southwest of Salt Lake City. Mineralization in the district was first recognized in 1850, placer gold production began in 1864, and successful lead-silver production followed a few years later with the arrival of the railroad. The production of high-grade copper-gold ore started in 1897. Utah Copper became the first flourishing low-grade porphyry copper operation in 1904, using block caving, but switched to large-scale open pit methods a couple years later. Bingham is one of the most productive mining districts the world. The district is zoned outward from porphyry Cu-Mo-Au through Cu-Au skarn, pyrite halo, Pb-Zn-Ag vein and replacement deposits to distal sedimentary rock-hosted Au ores. District metal production includes over 2.8 billion tons of porphyry ore, averaging approximately 0.7% Cu, 0.05% Mo, 0.4 ppm Au, and 3 ppm Ag; 32.8 million tons of lead-zinc-silver ores with recovered grades of 7% Pb, 3% Zn, 125 ppm Ag, and 1 ppm Au; and an additional 30.6 million tons of 2.1 ppm Au in sedimentary rock-hosted gold ores. The remaining porphyry resources total an additional 1.4 billion tons of 0.5% Cu, 0.07% Mo, 0.2 ppm Au, and 2 ppm Ag.

Abstract Huron-Montezuma prospect south of Iron King mine. Turn south on Arizona Highway 69 toward Mayer. 0.5 Highway makes gentle turn to the left. Large, dark hill on the right contains bouldery outcrops of Laramide stock that intrudes metabasaltic rocks. Dumps of the Henrietta mine, a copper-rich Laramide vein, on the skyline at 3:00. 0.8 Mount Elliott, elev. 6,980 ft, on the skyline at the right. Bold cliffs of Mount Elliott are composed of the undated (probably ~1740 Ma) Crooks Canyon Granodiorite, an Early Proterozoic pre-tectonic leucocratic pluton (Anderson and Blacet, 1972a; DeWitt, in press) that forms extensive outcrops in the southwestern part of the Prescott area. In the foreground are bouldery weathering outcrops of the Laramide stock at Poland Junction (fig. 43). 0.9 Roadcut exposes meta-andesite and metabasalt flows of the Iron King Volcanics. 1.1 Poland Junction. Road to Walker leads to the right and follows the route of a 1900's narrow gauge railroad bed. The Poland-Walker Tunnel cut through the crest of Eugene Ridge and connected the Walker district with the smelter at Humboldt (Lindgren, 1926). This drainage divide is capped by Quaternary to Tertiary gravel that locally conceals the metavolcanic strata. Ridges of ferruginous metachert and iron-formation protrude above the gravel, especially near the Boggs (Hurlbut, 1986) and Iron Queen mines to the left at about 10:00. Behind and to the right at 5:00 are the dumps of the Henrietta mine. View straight ahead in the far distance is of the New River Mountains. The jagged peaks are