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By R. J. Sandberg

The Copper Creek area, part of the Bunker Hill District, Pinal County, Arizona, lies within the southwest porphyry copper province of North America at the intersection of a northwest trend and an east-northeast trend of Laramide porphyry copper deposits. The Copper Creek area has been mined and explored for copper and molybdenum since the early 1900?s. The majority of this work focused on the more than 400 surface exposed breccia bodies. In the 1960 to 1970?s deeper drilling discovered a deep porphyry copper-like setting. Redhawk Copper currently has NI 43-101 compliant resources of about 0.652 billion pounds of measured and indicated and 2.745 billion pounds of inferred copper equivalent in breccia hosted and porphyry style deposits. See Figure 1.

Jan 1, 2010

By Pat McCarran

WHEN this Government was founded, the framers of the Constitution wrote into that instrument a provision that Congress should "coin money and fix the value thereof;" and the Constitution prohibits making anything but "gold and silver" lawful money. So silver is written into our basic law. Shortly after President Washington took office in 1789 the Congress passed the first Mint Act, setting up the U. S. Mint. In that Act, signed by President Washington on April 2, 1792, the weight of the American dollar was fixed, and it was provided how much silver should be contained in a silver dollar and how much gold should be contained in a gold dollar. It was decided that 371 1/4 grains of pure silver was to be the standard dollar of America. That standard with respect to the pure silver content of the dollar has never changed.

Jan 1, 1947

By C. E. Semler

A 5 year test program, involving on-line, in-vessel exposures at Barrick Goldstrike Mines. Inc. has provided valuable information and experience about the materials and designs for brickwork linings in pressure oxidation autoclaves. A variety of brick and mortar products have been evaluated. Properties before and after exposure are used to document the performance. Benefits have included the development of a new silicate mortar improved understanding of brick requirements and increased autoclave operating time between maintenance shut-downs. More improvements are expected in the future based on further information from the test program.

Jan 1, 1997

By Staff

The Tetreault mine, operated by the British Metal Corporation (Canada), Limited, holds a unique position in Canadian mining, being the only steady producer of zinc in Canada east of the Rocky mountains. Its importance in Canadian zinc production may be gauged with some accuracy, since, in 1927, it was responsible for over 13 per cent of the zinc output of the Dominion. In addition, it also made valuable contributions to the production of lead, silver, and gold. Location: Situated in the foothills of the Laurentian mountains, 600 feet above sea level, 20 miles from the St. Lawrence river, and 52 miles due west from the city of Quebec, the property is in the township of Montauban, county Portneuf, Province of Quebec, as shown in Figure I. The municipality of Montauban, immediately adjoining the mine, has a permanent population of 700 people and is six miles by road from Notre Dame station on the main line of the C.N. Rys. between Montreal and Chicoutimi-Notre Dame being n6 miles by rail from Montreal. Connection by 19 miles of dirt-and-gravel road with the Provincial highways' system of Quebec Province, the city of Quebec, which is distant 78 miles, can be reached by automobile in less than three hours, while the distance to Montreal by road is 16o miles .

Jan 1, 1928

In todayÆs evolving and globalised world, mining companies are being pressured to move beyond compliance towards long-term sustainability and sustainable development. Companies are expected to æengageÆ communities and measure the success of these engagements without a clear understanding of æhowÆ to do this. This move, away from compliance, develops more of a focus on sustainability and æcommunityÆ social responsibility rather than corporate social responsibility. This shift leads to the development of world-class projects that provide sustainable development for people, reduce the incidence of costly delays, and promote good global citizenship for companies. The process of æengagingÆ communities in mining project design and development leads to sustainable development, a stronger license to operate, and a reduction in social and political risk. To create this mutually beneficial relationship between communities and companies, communities must be æengagedÆ in the project development and risk assessment processes as early as possible, preferably during the exploration or the concept phases. How to create this æengagementÆ and manage this risk will be discussed.

Jan 1, 2007

By Theodore J. Hoover

WHAT are the chief branches of the mining engineering profession today? In an effort to analyze the structure of the profession, for practical purposes, a quantitative study has been made of the membership of the A.I.M.E., and is herein reported for the first time. In spite of the effect that a long history and a relatively small group of professional workers have had in limiting specialization in mining engineering, there has nevertheless grown up a wide variety of specialties in this field. More than a hundred different kinds of engineers were discovered among the titles given by Institute members in the Directory, ranging from "advisory engineer" and "American engineer" down to "wire-rope engineer" and "works engineer." How should all these titles be defined and interpreted? How many of them should be relegated as meaningless or confusing? What are the relationships among the remaining useful designations? Should some of them be grouped as "metallurgical" or "chemical," or under some other head?

Jan 1, 1935

By Lloyd Williams

1. The investigation shows that the Wilder (locally known as the Bon Air No. 2) is the only known bed of commercial importance in Putnam County, although at least 5 coal horizons are known. All of the coal production now reported comes from this bed, which is found In a basin with no known coal outcrops. Further drilling in the east end of the basin should disclose the location of the eastern end of the axial trough and the lateral extent of the basin in Putnam County and adjoining areas in Cumberland County. Continuity of this deposit with that in the area in Putnam County north of Monterey is not conclusively established but may exist. 2 Known (measured plus indicated) reserves of coal, based on a minimum bed thickness of 14 inches and on 1,800 tons per acre-foot in place, are estimated at 29 million tons, as of January 1, 1953. Of this total, 28 million tons are in beds 28 inches and more thick. All born coal reserves in Putnam County me under less than 400 feet of overburden.

Jan 1, 1954

By A. J. Kraemer

This paper is the second and concluding report of the results of the Bureau of Mines' twenty-second semiannual survey of motor fuel marketed in the United States. The first paper Was published as Report of Investigations 30634 and reported data relating to gravity, vapor pressure, and distillation range of the samples. The present paper deals particularly with results of the determination of copper strip corrosion (method 530.22),5 color (method 10.11),6 sulphur content by the lamp method, 7 copper dish evaporation residue (method 530.1),8 and "gum" content as given by the steam-oven method as developed by the Bureau of Mines. 9 The price at the time the sample was taken and the tax are also stated for each sample. The sample numbers used throughout this report are identical with those used in Report of Investigations 306310; ?for example, No. 225 of this report is the same sample as No. 225 of Report of Investigations 3063.

Jan 1, 1931

By Thomas A. Davidson

The Bureau of Mines Helium Field Operations has developed a method for determining the helium-3 CHe) content of natural gas and mixtures eontaining 0.5% to 100% helium. The helium is preconcentrated by passing samples through anhydrone, a liquid-nitrogen-cooled chareoal trap, and a titanium absorption trap. The mass spectrometer used to analyze the samples is tuned to 3He at mle ::=; 3.016. Hydrogen deuteride (HD+) interference is minimized by the titanium absorption trap and high instrument resolution. Sample measurements are compared with identically made measurements of a gravimetrically prepared primary standard. The method has a limit of detection of 0.15 ppb with a relative deviation of 13% below the 1~ppb level. The relative deviation is less than 7% for gases eontaining over 100 ppb 3He. The helium isotope ratios of natural gases from the Bureau's Tuck-Trigg Dome Red Cave, the Bush Dome Red Cave, and the Bush Dome Brown Dolomite Formations are distinguishable from one another and from the isotope ratio of crude helium produced from the Panhandle-Hugoton Gasfield.

Jan 1, 1990

By Horace C. Porter

Much has been written of the changes undergone by coal in storage and the deterioration of coal through exposure to the weather. In order to obtain definite information for the benefit of the Government departments and of all who store coal in large quantities, a series of tests was begun in the fall of 1909 under the supervision of J. A. Holmes, then chief technologist of the United States Geological Survey, and was continued by the Bureau of Mines after its establishment in 1910. The tests were confined to determinations of the loss in heating value of the coals and did not include a study of other deterioration; for example, in coking quality or the yield of by-products in coking. The Bureau of Yards and Docks of the Navy Department cooperated in tests of New River (W. Va.) coal, a variety largely used by the Navy. A preliminary report presenting a brief account of the early results of these tests has been published by the Bureau of Mines as Technical Paper 16.a The detailed report is presented in this bulletin, which gives a full account of the tests and the analytical data covering a period of five years' storage. Data of somewhat similar experiments for shorter periods with gas coal from the Pittsburgh bed, with Pocahontas coal on the Isthmus of Panama, and with Sheridan, Wyo., subbituminous coal, which is used for railroad and other purposes in the West, are included.

Jan 1, 1917

By Xiaodi Huang, Matthew Andriese, Zheng Zhang, Jiann-Yang Hwang, Zhiwei Peng

"The thermal decomposition and regeneration behaviors of wüstite were investigated by in situ high temperature X-ray diffraction (HT-XRD) under non-isothermal condition at heating rate of 4 K min-1 in vacuum ranging from 294 K to 973 K. Wüstite on heating decomposes to magnetite and iron up to 823 K, above which it exhibits marked tendency to regenerate. Investigation of thermal stability of the reaction system shows that the decomposition proceeds under kinetic reaction control while the regeneration is under thermodynamic control. Kinetics study based on the Coats-Redfern integral approximation method indicates that the decomposition reaction follows a Komatsu-Uemura model-based diffusion-controlled kinetics with activation energy of 32.860 kJ mol-1. The thermodynamics analysis of regeneration reaction demonstrates that wüstite regenerates at lower temperature than stoichiometric ferrous oxide.IntroductionOwing to its importance in preparing various magnetic ceramic/metal nanocompostites or nanocrystals with high values of coercivity for the application as recording media, wüstite (non-stoichiometric ferrous oxide) has been attracting the attention of scientists over a long period [1-6]. The thermal behavior of wüstite was investigated by several researchers and phase transformations due to thermal decomposition and regeneration of wüstite during the heating in a specific temperature range was observed [7-9]. In spite of wüstite being found to dissociate to magnetite and iron at temperatures lower than 848 K and then regenerates at higher temperature, a clear understanding of the reaction mechanisms is clearly lacking [9]."

Jan 1, 2012

By Loui Geoffroy, Philippe Gaultier, Martin Piotte, Claude Coache, André Drouin

"Automatic driving at high speed of an underground truck was tested at Brunswick mine in September 1995. Modifications to the truck included: a remote interface to control actuators, front and back video cameras to follow a roof mounted optical guide and proportional hydraulic controls on the steering.The mathematical model of the hydraulic system was adjusted using least square regression. The steering data, used in calculating the regression parameters, were acquired from the moving truck. The automatic steering control used three measured variables: lateral deviation, angular deviation and steering angle. Lateral deviations are obtained using the cameras, which are in continuous view of the guide, while steering angles are acquired from an extensiometer placed at the articulation point of the vehicle. Gain scheduling was used to compensate for vehicle speed and available hydraulic flow. Non-linear characteristics of the modeled hydraulic system were offset using open loop compensation.Speeds up to 23 km/h in forward direction and 13 km/h in reverse were achieved deviaduring continuous testing along one of the mine’s production drifts. Proportional steering was essential in achieving high speeds, as it enabled more precise positioning of the vehicle’s steering direction while reducing the abuses on cylinder and cylinder pins via diminished oscillations about the optical guide at high speeds."

Jan 1, 1997

By Karl W. Mote

CALIFORNIA'S iron and steel industry had its beginning in San Francisco in 1849 when the first iron casting was poured at the old Union Iron Works. Soon after, in 1856 at Grass Valley, enough iron ore was smelted to supply pig iron for the castings of a quartz mill there. From 1880 to 1886, iron ore was produced from the Hotaling mine in Placer County and converted to pig iron in a local blast furnace using charcoal. From 1907 to 1914, the Noble Electric Steel Co. produced pig iron from iron ore mined at the Shasta Iron Co. mine, and followed this for three years in the production of ferro-alloys. Between 1917 and 1941, the State's industry in- creased its capacity for open hearth and electric furnace scrap treatment, but the real impetus was supplied by the need for more steel at the beginning of World War II. The result was the State's first integrated steel plant-the Kaiser Steel Corp. facilities at Fontana.

Jan 7, 1958

By S W. Robertson, A Vercuil, P Craven

Mintek is currently developing a design approach for the heap leaching of low-grade primary copper sulphide material. Since the leaching of chalcopyrite requires elevated temperatures, the generation and management of heat within the heap is crucial. Furthermore, the precipitation of iron needs to be managed to prevent premature blinding of the heap, and acid consumption needs to be limited to contain cost and limit the dissolution of gangue impurities. Standard column tests using jacketed 1-m and/or 6-m columns do not allow accurate prediction of temperature changes and heat generation in an actual heap. Mintek therefore utilizes a computer model to calculate the energy balance and heat generation with time, based on the measured sulphide oxidation rates in the column. The temperature in the column is then adjusted to reflect the computer-predicted temperature in an actual heap. Using this approach, an overall copper extraction of 70% was achieved in 120 days, using 1-metre columns, when treating an ore blend containing 1.36% chalcopyrite, 0.23% chalcocite, 0.07% covellite, 3.8% pyrite and silicate gangue (92%). The chalcopyrite contribution to the total copper content in the feed was 75%. This was followed by 6-m columns using a similar approach, and the column results will be validated on a 23,000 tonne test heap. Key Words: heap; bioleach; chalcopyrite

Jan 1, 2005

By Augustus Locke

THE technical sessions at the Regional Meeting of the A.I.M.E. in San Francisco are to be de- voted LO changes, current or predictable, which may be expected to alter today's practices in mining and metallurgical engineering. Our present condition may be summarized as follows: Capacity to produce is excessive for domestic needs in molybdenum, copper, iron, and oil; sufficient in lead, zinc, and potash; deficient in aluminum, manganese, tungsten, chromium, and tin. Gold and silver are complicated by their use as money. Or, to look at it in another way, the "growth curles" of production, as C. K. Leith emphasizes, characteristically rise slowly at the beginning, show a second stage of rapid growth, and a third stage of leveling off. The third stage is already reached here in coal. copper, iron, lead, and zinc. But still in the second slage are oil, molybdenum, potash, and others.

Jan 1, 1939

By K. H. McDaniel

An interactive mine ventilation simulation software program (WIPPVENT) was developed at the Waste Isolation Pilot Plant (WIPP). The WIPP is a U.S. Department of Energy (DOE) research and development project located near Carlsbad, New Mexico. The facility is designed to provide a permanent, safe underground disposal of U.S. defense generated transuranic waste in bedded salt. In addition to its regular functions, the underground ventilation system is engineered to prevent the uncontrolled spread of radioactive materials in the unlikely event of a release. To enhance the operability system, Westinghouse Electric Corporation has developed an interactive mine ventilation simulation software program (WIPPVENT). While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC (copyright © 1991 Mine Ventilation Services, Inc.), the user interface has been completely rewritten as a Windows ® application and screen graphics have been added. WIPPVENT is designed to interact with the WIPP ventilation monitoring systems through the site wide Central Monitoring System.

Jan 1, 1996

By D. B. Eccleston

Natural gas and mixtures of natural gas and hydrogen were used as fuels in a laboratory engine to determine the relationship of emissions to air-fuel ratio and to establish practical lean limits for air-fuel ratio. Synthetic gas manufactured from coal (Synthane) and natural gas were used as fuels in a vehicle to obtain comparative data on emissions and performance. Results showed that lean limits for air-fuel ratio when using hydrogen-enriched natural gas were extended significantly beyond Chat of natural gas. Synthane pro¬duced exhaust that was significantly less reactive than exhaust from natural gas. With lean air-fuel ratios, the acceleration performance of a vehicle fueled with Synthane was improved over its performance when fueled with natural gas.

Jan 1, 1972

By José Luiz Rodrigues Bravo

The production of electrolytic copper with assured quality corresponding to international standards, in a conventional electrorefkery of a custom smelter, is a hard and cautious task, if no advanced technologies for selective control of electrolyte impurities are available. The improper control of the amount of As , Sb and Bi in the anode that enter the tankhouse , attributable either to a bad schedule of concentrate input or to the unavailability of clean concentrates in the international market , as well as the lack of means to maintain the suitable level of these elements in the electrolyte together with other operational circumstances, can result in off-grade copper, as well as affect the starting sheet chemically and physically. This paper presents in a practical way the relationship between the operational conditions and the cathode and starting sheet quality produced at CMSA, covering the period of the last five years of operation, discusses the technologies available in the market for antimony and bismuth removal and compare the results of testwork, achieved in the laboratories of CMSA, using two resins not associated with patented technologies.

Jan 1, 1997

By S. Glen

Cyanide management practices on modern gold plants are becoming more onerous, due to environmental pressures, particularly for signatories to the International Cyanide Management Code. Operations are therefore seeking to reduce levels of weak-acid dissociable (WAD) cyanide reporting to spigot discharge as well as to any eventual discharges from the tailings storage facility (TSF). Current gold industry standard processes primarily include the oxidation of cyanide by means of sodium meta-bisulfite (SMBS, or SO2) with air, Caro&apos;s acid (H2SO5) or hydrogen peroxide (H2O2). These processes require the transport and usage of expensive oxidizing reagents, along with the safety and environmental issues associated with these corrosive and toxic chemicals. Maelgwyn Mineral Services (MMS) has developed the MMS CN-DTM process, which utilizes the Aachen ReactorTM, a high-energy mass-transfer superoxygenation system, in conjunction with an activated carbon-based catalyst and no additional reagents, to increase the rate of cyanide oxidation to cyanate, the thermodynamically more stable form. Testwork conducted at the Maelgwyn Australia testwork facility in Perth Australia is described, at both pilot scale and continuous bench-scale, on a sample of tailings effluent obtained from an Australian gold plant. WAD cyanide is demonstrated to be lowered using the MMS CN-DTM process from an influent of 130 mg/L to the required levels for discharge to TSF (<50 mg/L). The continuous test results showed stable operation over three residence time turnovers. The pilot-scale results demonstrated the efficiency of the process at the reasonably large scales required for engineering cost estimation.

Jan 1, 2011

By S. A. Allen

The Eufaula bauxite district of Barbour and Henry Counties in southeast Alabama covers an area approximately 14 miles long, 6 miles wide at the eastern extremity near the Chattahoochee River, and 10 miles wide at the western end near the east fork of the Choctawhatchee River (see figs. 1 and 2). The long axis of this polygon bears a little south of east.

Jan 1, 1949