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By M. Jennings

In 1987, Echo Bay discovered a major silver/gold ore body at their McCoy property in Nevada, and quickly made a decision to build a 5000 tpd mill which was expanded during the design to 7500 tpd. Since the ore reserves consisted of cyanide leachable oxide as well as sulfide, the plant flow sheet involved an oxide leach, a gravity circuit, and lead sulfide and a pyrite sulfide recovery by flotation. The paper describes the process development, equipment selection, plant design and the startup of the oxide treatment.

Jan 1, 1990

By Yves Pépin, Sylvain Lefebvre, Dimitrios Filippou, Guillaume Hudon

"Titanium dioxide pigment plants using the so-called “chloride process” produce considerable amounts of chloride waste, which contains predominantly iron chloride. In most cases, this waste is dissolved in a weak hydrochloric acid solution and then neutralised. The metal content of the waste is dumped as hydroxide sludge, while its chloride content is lost in an effluent.Rio Tinto Iron & Titanium has developed a new proprietary process whereby pure metallic iron and chlorine gas are recovered from chloride waste by electrolysis. This process uses a two compartment cell separated by an anion exchange membrane to prevent iron cycling between its trivalent and divalent valence. The cathode is made of titanium Grade 7, while the anode is a dimensionally stable one of the type “metal–mixed metal oxide” (MMO) for the evolution of chlorine gas. The catholyte is concentrated and pH-adjusted iron-rich chloride solution originating from chloride waste. The anolyte is recirculating solution containing alkali or alkali earth chlorides such as MgCl2, NaCl, etc. Current efficiencies above 90% can be achieved at temperatures about 80°C using catholyte solutions almost saturated in iron chloride and other chlorides.In this paper, we discuss the details of this process, and how this could be integrated within a chloride pigment plant for the treatment of chloride wastes."

Jan 1, 2016

By Izabela Silva Bicalho

A utilização de fluidos de corte no processo de retificação tem como principais objetivos lubrificar e refrigerar a zona de corte, limpar a superfície do rebolo e minimizar a corrosão. Observa-se que a maioria dos óleos de corte aplicados na zona de retificação apresentam vantagens quanto às propriedades lubrificantes e corrosivas, porém perdem seu poder de refrigeração, quando comparados aos fluidos emulsionáveis. O presente estudo tem como objetivo avaliar o ganho da propriedade refrigerante dos óleos vegetais com e sem aditivos, e compará-la com a dos fluidos de corte integral. Para isso foi realizada análise da curva de resfriamento, termogravimetria (TG), ponto de fulgor e teste de corrosão em amostras com e sem aditivos de óleo vegetais (soja e milho) e de um fluido de corte mineral parafínico. As curvas de resfriamento foram obtidas conforme a ASTM D6200 e as curvas TG foram determinadas em uma termobalança. O ponto de fulgor foi determinado conforme a ASTM D92-25. O teste de corrosão foi realizado conforme a NBR 10505. O ponto de fulgor e a termogravimetria indicaram uma maior estabilidade ao aumento da temperatura dos óleos vegetais em relação ao mineral. Os óleos vegetais analisados apresentaram melhor capacidade de resfriamento quando comparados com o fluido de corte mineral sendo sua ordem apresentada da seguinte maneira: milho > soja > mineral. A amostra aditivada de óleo de soja também promoveu aumento da capacidade de resfriamento e diminuição da estabilidade térmica.

Aug 7, 2018

By Robert R. Perron

The U. S. Bureau of Mines is engaged in many diverse programs for improving mine safety. Of particular interest to the Bureau are new and improved means for minimizing the hazard of fire which can be initiated by prolonged low energy electrical faults on trolley line systems. When a high energy fault occurs on a trolley line, wherein the current exceeds the magnitude normally drawn by legitimate loads, such as locomotives, then the circuit breakers at close-by power rectifier sets trip. Tripping of the breakers not only protects the equipment at the rectifier sets, but also disconnects the energy source from the fault and thereby minimizes the fire risk. However, the fault current is frequently of a level substantially below that required to trip the overload breakers. When the fault is a substantial percentage of the set level of the breakers, the energy dissipated by the fault is frequently sufficient to clear the system by rapidly burning itself clear. Such a fault is often short-lived and does not present as serious a fire risk hazard as a prolonged, much lower energy fault, wherein the energy level is too low to clear the system. The breakdown of a trolley line insulator, in which there was a 15 to 30 ampere fault to ground, would represent such a fault or illegitimate load and a substantial fire risk.

Jan 1, 1975

By F. Enrique Toledo

El presente texto señala la aplicación del método Casapalca como técnica empleada en la explotación minera. Este método pertenece al grupo de métodos de "Almacenamiento Transitorio de Mineral con Subnivel de Troceo", donde la caída y extracción del mineral no se efectuará por buzones, sino a través del largo de un subnivel de extracción, desarrollando el espacio suficiente para contener el mineral y dejando el acceso libre para el tránsito. En este sentido, el método simplifica algunos ciclos de operación en el proceso de explotación clásico puesto que elimina los trabajos manuales y es adaptable al uso de la maquinaria moderna en la explotación de yacimientos de baja potencia.

Oct 14, 1980

By Charles Will Wright

DESPITE the war, the First Pan American Mining Congress, held in Santiago, Chile, Jan. 15-23, was attended by about 300 persons including the official delegates from sixteen of the American republics. The United States delegation consisted of Elmer Pehrson, of the U. S. Bureau of Mines; D. F. Hewett, of the U. S. Geological Survey; William H. Hobbs, of the Carnegie Foundation; and C. W. Wright, delegate of the Board of Economic Warfare and of the A.I.M.E. Mr. Wright was elected to head the delegation. Among the other members were Edward Steidle, of Pennsylvania State College and also an official A.I.M.E. delegate; John Huttl, of Engineering and Mining Journal; W. 0. Vanderburg, foreign mineral specialist from Lima, Peru; O. B. Hundley, of the American Cyanamid Co.; Horace Graham, of the Anglo-Chilean Nitrate Co.; and several officials and engineers from the Anaconda, Kennecott, and Bethlehem Steel companies' mines in Chile.

Jan 1, 1942

By Howard Lum, Sergio Valles, John Bednarski, Gordon Enas, Jay Arabshahi

"Water drawn from the Sacramento-San Joaquin Delta provides water supply to 66 percent of California’s population and supports the state’s agriculture industry. The existing through-Delta water system is outdated and unreliable with environmental risk to some fish and wildlife species. The Bay-Delta Conservation Plan (BDCP) has been established to environmentally retrofit and modernize California’s water delivery system through the Delta by restoring habitats, constructing new diversion points in the north Delta and providing a means to transport water supplies under the Delta, rather than through sensitive natural channels.Under BDCP, the Delta Habitat Conservation and Conveyance Program (DHCCP) has developed several alternatives to convey water from the Sacramento River in the north to the existing pumping facilities in the south Delta through an isolated conveyance system. The new conveyance system would become an integral part of the State Water Project (SWP) and the federal Central Valley Project (CVP) by transporting water to the export pumping plants for each of these projects. The DHCCP is managed by the California Department of Water Resources (DWR), while state and federal water contractors provide technical support to the program.The initial conceptual study efforts on the overall program commenced in 2007 and examined various options for the proposed conveyance system. Several conveyance alternatives were analyzed at that time. The Conceptual Engineering Report published on Oct. 1, 2013 identified the modified pipeline/tunnel option (MPTO) as the preferred alternative to be included in the BDCP environmental documents. MPTO includes three river intakes and pump stations along the Sacramento River, various sizes of pipelines and tunnels, junction structures and two forebays that are capable of delivering up to 4 million gpm (9,000 cfs) from the Sacramento River to the SWP and CVP. The river intakes are located near Hood in Sacramento County approximately 64 km (40 miles) from Clifton Court Forebay (CCF) in Contra Costa County. This route would cross portions of Sacramento, San Joaquin and Contra Costa counties. Figure 1 depicts the configuration of the MPTO alternative."

Apr 1, 2016

By T. E. Ackman

Scale inhibitors and slow-release polymers were tested by the Bureau of Mines at mine drainage treatment facilities. The scale inhibitors were investigated to determine their effectiveness in controlling gypsum (CaSO4) scale; the polymers were investigated to determine their effectiveness for increasing settling rates of suspended iron hydroxide. Two types of scale inhibitors were tested at a site having a severe CaSO4 scaling problem. Both proved to be effective in controlling scale formation; in addition, one caused the dissolution of CaSO4 deposits. Slow-release polymers were tested at three mine drainage treatment facilities. These gelatinous polymeric flocculants were found to be convenient and easy to use, but only effective when pH could be controlled.

Jan 1, 1984

By Regina Krachler, Herbert Ipser

"The principles of the derivation of statistical-thermodynamic models to interpret the compositional variation of thermodynamic properties in non-stoichiometric intermetallic compounds are discussed. Two types of models are distinguished: the Bragg-Williams type, where the total energy of the crystal is taken as the sum of the interaction energies of all nearest-neighbor pairs of atoms, and the Wagner-Schottky type, where the internal energy, the volume, and the vibrational entropy of the crystal are assumed to be linear functions of the numbers of atoms or vacancies on the different sublattices.A Wagner-Schottky type model is used for the description of two examples with different crystal structures:For B'-FeAl (with B2-structure) defect concentrations and their variation with composition are derived from the results of measurements of the aluminum vapor pressure; the resulting values are compared with results of other independent experimental methods.For Rh3~ (with an NiAs-derivative structure) the defect mechanism responsible for nonstoichiometry is worked out by application of a theoretical model to the results of tellurium vapor pressure measurements. In addition it is shown that the shape of the activity curve indicates a certain sequence of superstructures.In principle, there are no limitations to the application of statistical thermodynamics to experimental thermodynamic data as long as these are available with sufficient accuracy, and as long as it is ensured that the distribution of the point defects is truly random, i.e. that there are no aggregates of defects."

Jan 1, 1996

By R. V. Higgins

In a recent report3/ the authors presented a rapid method of calculating, by means of a desk calculator, the future performance of oil reservoirs in which the motivating agent was gas. The accuracy of the method was tested by data obtained from an electronic computer. Because of the accuracy obtained for the limited number of calculations performed, considerable interest has been expressed in the electronic computer program used to obtain the comparative data by an analytical solution. Accordingly, the computer procedures for the analytical solution are presented in this report. In an earlier report, 4/ a reservoir appraisal procedure was published in which an iterative method was used. Many requests were received for the computer program used to obtain the values given in that paper. That program, with some modifications, also is presented in this report. The modifications are given because of the progress that his been made in computers, and because much of the program for the analytical solution is usable for the iterative procedure.

Jan 1, 1960

By D. S. Davies

Further development of the Nitric-Sulfuric Leach (NSL) process has led to an improved design of the leach and nitric acid recovery steps. NO produced in the leach step is reacted with oxygen, regenerating N02, which is sparged directly into the leach reactor. Leaching is simplified to two steps and the nitric acid plant is replaced with an oxidation recycle gas sys-tem. Laboratory work substantiated the concept and led to selection of operating conditions. The lab work also pointed to improved process control compared to use of nitric acid as the sole oxidant. Recovery of copper from purified pregnant liquor is modified to use air agitation electrowinning improving cathode quality and lowering tankhouse costs. Economic evaluation shows reduction of capital requirements from $2400/AT to $2000/AT in 1978 dollars for 50,000 TPY of copper production.

Jan 1, 1978

By E. Yan, M. Mankosa, E. B. Wasmund

Mechanical cells are the dominant unit operation in base metal rougher flotation applications worldwide. As economic demand for metals increase, and as the feasible ore grades decrease, the installed capacity of mechanical flotation units worldwide has greatly increased, adding significant capital and operating cost. One opportunity to improve this situation is to use fundamental knowledge to make the industrial flotation process more efficient. A key insight is that the flotation process can be optimized by dividing the processing of the pulp into two distinct fluidic environments; a collection cell where air and pulp mix in a highly energetic compartment, and a low energy gravity separation cell. This is the basis of the “2-stage flotation device” that has been patented by Eriez and marketed under the tradename StackCell™. Two industrial case studies will be presented to highlight the potential metallurgical and commercial advantages of the StackCell. In the first, a train consisting of three pilot scale StackCells (each 0.6 metre diameter) was run in parallel with a train of conventional mechanical cells in a major copper concentrator and benchmarked against a batch Denver test. In the second, the performance of a 3 metre diameter StackCell in a nickel sulfide cleaning application was benchmarked against a batch Denver test. The flotation kinetics observed in the StackCells were 2.4 to 2.9 times faster when compared with the lab Denver test. In the first case study, the kinetics of the StackCell was about six times faster than conventional mechanical cells. It is hypothesized that the efficiency improvement in kinetics is because of reduced “drop-back” during the froth recovery phase, which is reduced because of the reduction in the shear that is present in a conventional mechanical tank cell. This result suggests that a 2-stage flotation system can be used to reduce the working volume of flotation units by five to six times. This would allow operators to significantly reduce the size of their flotation lines for a comparable flotation objective. Some discussion will follow about the scale-up criteria, maintenance and operability issues, comparisons of layout, and possible cost savings. INTRODUCTION The solution that most equipment suppliers have offered to reduce the cost of mechanical flotation equipment over the last 30 years has been to increase the size of the flotation unit cell (Mankosa, 2017). For example, three 100 m3 machines with three smaller motors, mechanisms and control valves could be replaced with a geometrically similar 300 m3 with a larger version of each ancillary component. While there are some efficiencies and cost improvements to be gained by this approach, it does not take advantage of fundamental insights into the flotation process, and it does not represent a step-change in terms of process design or economic benefit for the customer. The advantage of the “bigger is better” approach is that there is past experience of incremental improvements by making cells larger and there is a well-established scale-up method, which allows practitioners to estimate equipment capital costs based on very simple laboratory test- work. A different paradigm, which is gaining interest rapidly is to use a unit operation in which it is easier to optimize the flotation process, which will be described in this paper. This approach is often referred to “2- stage flotation”. Because this approach is new, it is important to benchmark it against existing conventional technology and to demonstrate a robust methodology for sizing equipment and flowsheets. This paper aims to address these issues with two case studies.

Jan 1, 2019

By J. L. Bowlby

The heats of combustion of fuels are determined in the laboratory by means of a calorimeter, usually of the oxygen bomb type. A known weight of the fuel is burned in an atmosphere of oxygen under approximately 400 pounds pressure in a heavy metal container-the bomb- and the heat evolved is imparted to a definite quantity of water. From the rise in temperature, measured by means of a Beckmann thermometer, and other data incidental to the determination, the heat value of the sample can be calculated. On paper, the method appears simple indeed, but in practice the determination of the heat of combustion is one of the most difficult of the various coal analyses. This h as led to considerable investigational work in order to obtain formula: whereby calorific values of solid fuels could be calculated from proximate analysis data al one. The proximate analysis of a fuel consists of the determination of moisture, ash, and volatile matter, with fixed carbon by difference. Sulphur determinations properly belong to the ultimate analysis, but in this section of the country, where the sulphur content of the coal is comparatively high, a request for the proximate analysis of a fuel implies the determination of the sulphur as well.

Jan 1, 1929

The John Fritz Medal is awarded from time to time for notable scientific or industrial achievement by a board composed of representatives from the four engineering Societies. The members of the Board of Award for 1917 are: A. S. C. E. A. S. M. E. George F. Swain Ambrose Swasey, Charles Warren hunt, John, A. Brashear, Charles D. Marx, Frederick R. Hutton, Clemens Herschel. John R. Freeman. A. I. M. E. A. I. E. E. Gybbon Spilsbury, C. 0. Mailloux, Charles F. Rand , Paul M. Lincoln, Christopher R. Corning, John J. Carty, Benjamin B. Thayer. Harold W. Buck. The John Fritz Medal was awarded in January, 1917, to Dr. Henry Marion Howe, for his "investigations in metallurgy, especially in the metallography of Iron and Steel." The presentation ceremonies were held in the Auditorium of the United Engineering Societies' Building, New York, on Thursday evening, May 10. Mr. Ambrose Swasey, Chairman of the John Fritz Medal Board of Award, presided, and addresses were delivered by Dr. Rossiter W. Raymond, Secretary Emeritus of the American Institute of Mining Engineers, and Dr. Ira N. Hollis, President of the American Society of Mechanical Engineers. Professor Albert Sauveur, Chairman of the Board at the time the award was made, presented the medal, and the ceremonies concluded with the response of Dr. Howe.

Jan 7, 1917

By Burt Ensley, Viatcheslav Dushenkov, Ilya Raskin, David E. Salt

Roots of many hydroponically grown terrestrial plants, including sunflower (Helianthus annuus L.) effectively remove toxic metals such as Cu+2, Cd+2, Cr+6, Ni+2, Pb+2 and Zn+2 2 from aqueous solutions. It should be possible to scale up this process such that plant roots can be used to treat large volume aqueous waste streams. It can be extrapolated from laboratory results that to reduce the Cd concentration in a waste stream, from 1 ppm to below 4 ppb, with a flow rate of 4000 L/min, would require 3500 sq. m of plant roots with a density 5 kg fresh weight per sq. m. These results suggest that the roots of hydroponically grown terrestrial plants may provide an attractive alternative to the accepted water treatment technologies.

Jan 1, 1995

By D. J. Parker

Before the various States began to enact workman's compensation laws accidents were considered inherent in many industries, and little or no effort was made to prevent or reduce them. The hazard was accepted by the employee with the job, and the avoidance of accidents by mental alertness or physical agility was largely his responsibility. After the employee had given evidence of enough skill inn performing his allotted task efficiently the responsibility of the employer apparently ceased with respect to the personal safety of the employee. However, following the enactment of workmen's compensation laws, at least two facts that had not before been fully appreciated soon became apparent: (1) The majority of accidents can be prevented if the management firmly determines to prevent them; (2) frog a monetary point of view alone accidents are decidedly expensive, both to employer and to employee. It is now evident that savings effected by conscientious safety effort add substantially to net profits of operation.

Jan 1, 1934

Infacon 74 The National Institute for Metallurgy, the South African Institute of Mining and Metallurgy, and the Ferro-Alloy Producers' Association of South Africa extend a cordial invitation to participate in the International Ferro-alloys Congress to be held in Johannesburg, South Africa, in April 1974. Obituary RICHARD AUSTIN COOPER On the 31st March 1972, a once very active member of the Institute, R. A. Cooper, died at the age of 82. He had served on the Council for many years and was Vice-President in 1933/34. ALEXANDER JEREMIAH ORENSTEIN CB., CM.G., C.B.E., LLD., D.Se., M.D., M.R.C.S., F.R.CP., F.R.S.H. Dr Orenstein, who died on the 7th July 1972 at the age of 92, was so well known and so widely acclaimed during his lifetime that it is difficult to add to the tributes which have already been paid to him.

By Foster Fraas

This report describes the application of pulsed magnetic fields derived from alternating and intermittent magnetizing currents. Application of such pulsed magnetic fields to the matrix-type separator permits (1) the complete discharge of the magnetic fraction with wet feeds and (2) the dry separation at particle sizes down to 325 mesh. At smaller particle s indications are that frequencies above 60 hertz will be required. Applications of intermittent magnetizing current to the cross-belt separator give the cross-belt-separator an advantage over the conventional constant-field cross-belt and induced roll separators; the intermittent current enables the cross-belt separator to separate matted fibrous and magnetically coagulating feeds, a type of feed that occasionally occurs with mineral, industrial, and secondary materials.

Jan 1, 1973

By Wolfang Schoeps

El presente texto describe los factores para determinar la cantidad correcta de compras en los artículos de diversas empresas a través de los costos de un pedido de compras; los costos de almacenaje y los descuentos progresivos de cantidad.

Jul 1, 1960

By R. J. Craig

Introduction All mining operations produce rock dust. Inhalation of rock dust, particularly if it has a high silica content, causes silicosis. Silicosis is, therefore, recognized as a hazard of the mining industry and has been made compensable throughout most of Canada. Most of the dust in any mining operation is caused by rock drilling and blasting operations and the movement and transportation of broken rock. Dust from blasting cannot be eliminated, but it can be controlled by means of increased ventilation, the use of water sprays, and the control of blasting hours. Dust from ore movement can be reduced by keeping the broken rock in a moist condition at all times. The dust from the rock drilling operation has been found to be the most difficult to control. Concentrations of dust caused by rock drills in stopes can usually be reduced to the safe minimum of 300 particles per cubic centimeter (p.p.c.c.) by diluting the air with increased ventilation. In development headings, where the machines are more confined, this is not always practicable. Therefore, the dust must be eliminated at its source. This paper deals with the reduction of dust from Leyner machines by adopting improved designs.

Jan 1, 1947