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By D. H. Davidson

In situ leaching (ISL) of copper has the potential of reducing both capital and operating costs for copper production. The ISL process combines surface facility (SX/EW) and wellfield operations, each of which must process the same total flow rate and pregnant liquor copper concentration. Commercial cost data are only available for SX/EW facilities. This paper discusses: the interaction between the principal wellfield costs associated with well modules, and wellfield start?up with SX/EW costs; how to estimate what the level of wellfield costs must be to optimize DCF/ROR; and how to relate these wellfield costs to orebody geologic and mineralogic characteristics.

Jan 1, 1988

Evaluation of Comminution Circuit Design for Sustainability Using EcoNomicsTM

Sep 13, 2010

By C. H. Curtis

The valuable mineral content of the current feed to the Miami concentrator is as follows: copper, 0.7 pct total; molybdenum, 0.01. Flotation of this ore yields a sulphide concentrate containing: chalcocite, 44 pct; molybdenite, 0.5; pyrite, 50.0; insol, 5.5. A combination of potassium ethyl xanthate and pentasol amyl xanthate as collectors, and pine oil as frother, are used in this flotation. Rejection of pyrite is encouraged by holding the amount of collectors used to the minimum consistent with copper recovery and by operating at high alkalinity (equivalent to 0.35-0.40 lb CaO per ton solution of pH 11.0).

Jan 4, 1950

By R. D. Young, E. A. Harre

Nitrogen exists in two broad categories commonly designated as elemental nitrogen and fixed nitrogen. Elemental nitrogen is found in nature as a diatomic molecule and constitutes about 78%, by volume, of the earth's atmosphere. Fixed nitrogen is a common term used for nitrogen that is chemically bound to other elements. Although elemental nitrogen is very abundant, nonleguminous plants cannot utilize nitrogen unless it is in the chemically combined form. The content of this chapter is confined to fixed nitrogen since the uses and properties of elemental nitrogen and the fixed nitrogen compounds are different. Certain bacteria associated with legumes are able to fix atmospheric nitrogen, but not to the extent required by succeeding nonleguminous crops. The need to use fertilizers containing fixed nitrogen compounds to grow food crops has been recognized for hundreds of years, and from antiquity farmers have used organic wastes such as animal manures, vegetable wastes, sewage sludge, fish scraps, etc., containing these compounds for fertilizers. These organic materials have a low nitrogen content, however, and cannot support large-scale food production. Known commercial-size deposits of natural nitrates containing much higher nitrogen content exist only in Chile, and the possibility of the discovery of other significant deposits is remote. The Chilean deposits were the major source of nitrogenous fertilizers until the Haber-Bosch process for the production of synthetic ammonia was developed. In the Haber-Bosch process, nitrogen reacts with hydrogen at high temperatures and pressures and in the presence of a catalyst to form ammonia. Modern plants use air, water, and natural gas or other hydrogen sources to produce the ammonia that is now the key building block of the fixed nitrogen industry. Several major problems that developed in the 1970s continue with the nitrogen industry into the 1980s. These are (1) the continuing sharp escalation in the cost of feedstocks for ammonia production as well as all energy sources, and (2) the very steep increase in the investment cost of production facilities. More than 75% of the fixed nitrogen produced domestically is consumed as fertilizers. The types of materials used as fertilizers have changed significantly during the past years. There has been a trend from the use of low-analysis fertilizers to types which contain high percentages of plant nutrients. The average plant nutrient content (N + P2O5 + K2O) of fertilizers used in the United States has increased from 18% in 1930 to 32% in 1960 and today approaches an average of 44%. In the case of nitrogen fertilizers, the low analysis natural nitrates (16% N) gave way to ammonium sulfate (20% N) after about 1920. After World War II, ammonium nitrate (33.5% N) previously used in munitions, became established as the leading nitrogen fertilizer. Urea use as a fertilizer (46% N) began in the 1960s, and in the past 10 years has become the world's leading solid nitrogen fertilizer. Nitrogen Materials Anhydrous Ammonia-Anhydrous ammonia is a colorless gas at ambient temperatures and pressures and has a sharp pungent odor. Anhydrous ammonia is stored and transported as a liquid in high-pressure cylinders and tanks at ambient temperature, and in low-pressure tanks, barges, and ships at -28°F. Anhydrous ammonia is applied directly at 4 to 7-in. depths in the soil as a high-pressure liquid by special applicators, after which it expands to a gas that dissolves in the soil moisture or is absorbed on soil colloids. In other systems ammonia is metered into irrigation water and is thereby introduced into the soil.

Jan 1, 1983

By Robert P. Roberts

In order to obtain data on the thermal effect of the blast-furnace jacket and on the water consumption in these jackets a series of tests were run on the 56 by 180 in. blast furnaces at the Great Falls Reduction Department of the Anaconda Copper Mining Co., at Great Falls, Mont. The arrangement of the jacket is shown in the transverse section of one of the furnaces (Fig. 1) on which the tests were made. The nose, spout, and breast jackets have independent water supplies and discharges. The end and side jackets are connected in pairs, as regards water supply, the feed water entering at the bottom of the lower jacket and overflowing into the bottom of the jacket immediately above it, and discharging into an independent overflow pipe for each pair of jackets. Tests were run on the main side and end jackets, the breast jacket, the spout, and the nose. Measurements were taken of the quantity of water discharged per minute and the rise in temperature of the water in its passage through the jacket. The product of these two results, expressed in the proper units, evidently gives the number of units of heat removed per minute by the water. Sufficient work was done on each type of jacket to determine its behavior under different conditions, and the results from each set of conditions were checked by repeating the work from three to six times. The method used was as follows: The overflow from the jacket to be tested was arranged to discharge at will into a barrel, mounted upon platform scales. The discharge temperature was read just before turning the water into the barrel, and just before turning it back to the sluice; if the test lasted more than a minute, additional temperature readings were taken at 1-min. intervals from start to finish. The elapsed time of running the water into the barrel was determined with a stop-watch, and this figure, combined with the in-

Jan 1, 1914

By P Breuer, D J. Robinson, A McFarlane, L L. Kuhar

Increasing global demand for commodity metals and capital and the greater operating costs of mining and metal production present significant challenges for the metals mining industry. Current conventional technologies may not be feasible for processing deposits of declining grade, challenging mineralogy or those that occur at increasingly greater depths. To overcome these issues, the development of a step-change technology such as in situ recovery (ISR), which reduces mining and avoids milling costs, may be vital in ensuring future economic metal production. ISR has been used extensively to treat porous soft rock deposits such as the water-soluble salts, sylvite and halite. Although ISR has typically been used for mining conventionally uneconomic uranium ores, it has also been used less frequently for the treatment of other restricted permeability hard rock deposits, such as those containing copper and gold. The reason for the limited uptake of the technology for hard rock mineralisations is primarily due to low natural rock porosity and permeability and hence poor response to available lixiviant. However, additional challenges include solution containment, management of groundwater and regulatory, ecological and societal requirements and expectations. CSIRO has focused on understanding the challenges of hard rock ISR and identifying global capabilities that can contribute to developing the essential enabling technical areas required to realise ISR. Specific focus areas include geochemistry and advanced resource characterisation; drilling and controlled rock-breaking technologies; solution chemistry and environmentally benign lixiviant systems; lixiviant delivery systems and ‘subsurface mixing’; subsurface hydrology and reactive transport mechanisms and models; downstream processing options; legal, social and environmental aspects; and techno-economic modelling. This paper will discuss ISR challenges including industry feedback focused on addressing this issue, gaps preventing ISR from being applied in practice, capabilities to overcome these gaps and the development of a collaborative approach to making hard rock ISR a reality.CITATION:Kuhar, L L, Breuer, P, Robinson, D J and McFarlane, A, 2015. Making hard rock in situ recovery a reality, in Proceedings Third International Future Mining Conference, pp 189–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Anthony (Sam) J. S. Spearing

Backfilling using coal waste is not a novel means for waste disposal throughout the world; yet, backfilling using a high density (paste) backfill is relatively new, except in Germany and Poland. One of the main benefits of a high density backfill, as opposed to a low density (slurry) backfill, is that, if placed at a low permeability and low moisture content, the risk of water table contamination can be relatively low. In addition, if paste backfill can be placed cost effectively, environmental benefits are huge because the surface impoundment footprint can be greatly reduced or even eliminated. This is especially true in room-and-pillar applications. In its current state, backfilling is considerably more costly than surface disposal. This is mainly because paste, as opposed to slurry, significantly increases backfill placement costs; however, this could be offset by increasing the achievable extraction rate. Overall, such a system could potentially improve the public?s image of coal mining in the US for a myriad of reasons. This paper discusses a proposed backfill system for a typical room-and-pillar coal mine in the Illinois Basin of the US and clearly shows the technical advantages, although costs are still higher with fill. The cost differential will likely reduce over time, in favor of the backfill option, as costs of traditional surface disposal increase, due mainly to ever-restrictive disposal regulations.

Jan 1, 2013

By R. E. MacDougall

Very few mineral properties spend their entire lifespans from discovery to depletion in the hands of one owner. More likely, properties will have several owners, and partial interests may change quite often. Similarly, mineral companies are bought and sold with frequency, in recent years at what appears to be an accelerating rate. The reasons for selling a property can be manifold -need for additional capital in other parts of the business, need for development capital, realization of a large gain at a perceived high point in the market, pessimistic commodity outlook, retirement of principals, or resolution of estate problems. Regardless of the reasons for a sale, there are specific steps that logically follow. Spruce up the business, package the information, market the property, negotiate the terms, close the sale, and make sure it stays sold. Adherence to certain very basic ground rules in property sales can maximize the profits and minimize the effort.

Jan 1, 1990

By Yuexin Han

The wet preconcentration of haematite, comminuted by high-pressure grinding roller was studied, using the cylindrical ferromagnetic medium. The effects of various factors including rod diameter, rod gap and background magnetic field intensity (BMFI) on the performances of preconcentration for different size fractions and the force analysis of single mineral particles with different diameter in the separation zone were emphatically investigated. The results showed that as the rod diameter increased, the rod gap decreased, and the BMFI increased the tailings grade and the tailings yield reduced while the concentrates recovery raised that was regardless of variations in feed size distribution. For the -3.2+0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 7 mm at BMFI of 454kA/m is used to get a higher performance. For -0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 4 mm at BMFI of 263kA/m is used to get a higher performance. After the classifying preconcentration, at the optimum condition, the overall concentrate grade increases by 9.56 percentage points and the concentrate recovery is up to the 82.67% with a tailing grade of 10.68% and a tailing yield of 40.31%. The magnetic force, exerted on weekly magnetic minerals was proportional, to the specific susceptibility and square of BMFI. For the same BMFI, the magnetic capturing force on coarse particles increased, and that on fine particles decreased with the increasing of rod diameter. For the lean locked-particles, considering the gravity and viscous resistance of particles, rods with a big diameter were beneficial to the capture of coarse particles and had no influence on the capture of fine particles, while rods with a small diameter were good for the capture of fine particles and not suitable for the capture of coarse particles of lean locked-particles. Keywords: low grade haematite, high-pressure grinding roller, high intensity magnetic separation, pre-concentration

Sep 1, 2012

Freeport's Floating Mine Begins Sulphur Operation Eight years of research were culminated when Freeport Sulphur Co.'s floating mine plant went into operation on Bay Ste. Elaine in the remote Louisiana bayou country 60 miles southwest of New Orleans.

Jan 1, 1953

By Richard J. Kline

The underground mining industry is presently using the fluid network analyzer and digital computer to analyze ventilation systems. The availability of the digital computer and ventilation programs to mining companies has escalated its use, permitting the design and modification of new or existing mine ventilation systems to be projected completely and thoroughly with consistent precision. Because the analog computer has been analyzing ventilation systems accurately for many years, a comparison of the analog and digital methods was warranted. This report summarizes a detailed comparison for one mine, based on parallel analyses by the two computer systems.

Jan 1, 1972

By D. Sohn

Work accidents have an essential impact on the economy of a country and in final consequence on each company. The main purpose of industrial OHS is to maintain and promote the health of all employees. Healthy working conditions increase efficiency and motivation and safeguard the success of the business against the background of the extremely dynamic processes of change. Maintaining and promoting the health of all employees, weather in operation, administration or on the mining site, has become therefore not only an ethical requirement but also an economic must. Creating a suitable working environment for people today entails much more than just preventing accidents and work-related illnesses. It is important to be proactive in establishing an even better culture of prevention and to convince everyone, workers and managers alike, of its importance. Especially in the age of rapid changes and above all in view of global competition we are more dependent than ever on healthy, enthusiastic, competent and creative employees. OHS provides you with the necessary competitive edge.

Jan 1, 2007

This paper reviews factors involved in the feasibility stage of underground mine project development. Emphasis is placed on the need to first select the best method of extraction and make the most accurate assessment of the expected output even with the uncertainties which may exist in structural interpretation, ground stress, geotechnical factors, and industrial conditions. The subsequent engineering planning should be undertaken from the point of view of the face requirements and is subject to constraints imposed by the method of work and nature of the deposit and, in the case of access, to surface constraints and services.

Jan 1, 1983

By João M. S. Rodrigues

The use of sandblasting as a treatment method for conditioning anodes for zinc electro-winning was investigated and compared with conventional fluoride preconditioning. The anodes were made from two different lead-based alloys (Pb-Ag-Ca and Pb-Ag). Laboratory results showed that sandblasting and preconditioning both minimize lead contamination in the zinc and sludge generation. Sandblasting was found to have no aggravating effect on the anode corrosion. The sandblasting treatment was tested on Pb- Ag-Ca anodes on an industrial scale in the celJhouse of a local zinc producer. An unexpected finding of the large-scale tests was that the sandblasting appeared to strengthen the anodes, resulting in reduced warping during handling and operation.

Jan 1, 1996

By A. Aly Selim

This report describes the feasibility of predicting percussive drilling rates by equations derived from statistical regression analysis. The least squares statistical method was used and the analysis was performed both by direct and by stepwise linear regression analysis. The predicted penetration rate is a function of the drill power and the physical properties of the rocks penetrated. The results show promise that the technique may be of value in providing a mathematical model by which percussive drill manufacturers and users can predict the performance of a given drill. Experimental work involved two mining type percussive drills. Penetration data for these drills were determined from nine rocks drilled in the laboratory. Drill work rates (power) were determined in a separate series of experiments. Rock physical properties were measured from diamond-drill core samples taken from the same blocks used for percussive drilling.

Jan 1, 1970

(There are 67 Student Chapters in the United States, 2 in Canada ) University of Alabama-University, Alabama, Mining & Metallurgical Society, James W Stewart University of Alaska-College, Alaska, Mining Society of the University of Alaska, Guinn Metzger University of Arizona-Tucson, Arizona, Miners' Society, A E Gorum Birmingham-Southern College-Birmingham, Alabama, Pick & Hammer Club, Daniel D Arden University of British Columbia-Vancouver, British Columbia, G M Dawson Club, A Gunning University of California-Berkeley, California, Mineral Technology Association, Bernard York Carnegie Institute of Technology-Pittsburgh, Pennsylvania, The Metals Club, Gerhard Derge Case Institute of Technology-Cleveland, Ohio, Pick and Shovel Club, Gerald M Cover City College of New York-New York, New York, CCNY Student Chapter AIME, Daniel T O'Connell

Jan 1, 1954

By Malcolm Ross

Of the six forms of asbestos, only three have been used to any significant extent in commerce. These are chrysotile, crocidolite, and amosite. Between 1870 and 1980, approximately 100 million tonnes of asbestos was mined worldwide, of which more than 90 million tonnes was the chrysotile variety, about 2.7 million tonnes the crocidolite variety, and about 2.2 million tonnes the amosite variety. The three principal diseases related to asbestos exposure are (1) lung cancer, (2) cancer of the pleural and peritoneal membranes (mesothelioma), and (3) asbestosis, a condition in which the lung tissue becomes fibrous and thus loses its ability to function. These diseases, however, are not equally prevalent in the various groups of asbestos workers that have been studied: the amount and type of disease depend on the duration of exposure, the intensity of exposure, and particularly, the type or types of asbestos to which the individual has been exposed. Lung cancer is caused by exposure to chrysotile, amosite, and crocidolite asbestos; however, increased risk of this disease is usually found only in those who also smoke. Asbestosis is caused by prolonged exposure to all forms of asbestos, whereas mesothelioma is principally caused by exposure to crocidolite asbestos. There is good evidence that chrysotile asbestos does not cause any significant amount of mesothelioma mortality, even after very heavy exposure. The common nonasbestiform amphibole minerals, cummingtonite, grunerite, tremolite, anthophyllite, and actinolite, which are often defined as "asbestos" for regulatory purposes, have not been shown to cause disease in miners. Chrysotile asbestos, which accounts for about 95 percent of the asbestos used in the United States, has been shown by extensive Canadian studies to be safe when exposures do not exceed 1 fiber per cm3 for the working lifetime. Chrysotile dust levels found in buildings rarely exceed 0.001 fibers per cm3. Such dust concentrations will have no measurable health effect on the building occupants. Present and future controls of minerals defined as "asbestos" and removal of asbestos from buildings and homes may cost many billions of dollars. Much of this expense is unnecessary and even counterproductive. Asbestos abatement could in fact produce a health risk to those exposed to dusts during and after removal operations overly restrictive controls could force the use of poor or dangerous substitutes, and could greatly affect the hard-rock mining industry.

Jan 1, 1987

Engineering Experiment Station, University of Arkansas, Fayetteville, Ark. W N Gladson, Dean and Director The Engineering Experiment Station has published a number of bulletins, only a few of which are of particular interest in this directory: Bulletin 3, Arkansas coal or oil for domestic heating; 4, Road materials of Arkansas, 5, A study of Arkansas coals, 6, Portland cement materials in Arkansas; 11, Natural gas versus Arkansas coal for house heating. Circular 3, Short cuts to combustion efficiency with natural gas Address the Engineering Experiment Station for any of these publications.

Jan 1, 1933

By S. C. Schaefer

The Bureau of Mines investigated tIle standard Gibbs energies of formation, 8Gfo, for MllF2 (manganese difluoride) and CoF2 (cobalt difluo-ride). High-temperature galvanic cells employing CaF2 (calcium diflu-oride) as the solid electrolyte were used to measure the open-circuit potentials for the cell reactions ?

Jan 1, 1985

By E. Peters

Roasting processes are divided into several elementary mechanisms, any of which could be significant or pre-dominant in a particular roast. The elementary processes considered in-elude beat transfer, gas-solid inter-actions with accompanying mass transfer between the bed and furnace atmosphere, vapor phase transport processes in solid-solid interactions, and solid phase diffusion processes. Examples are chosen of processes in which one of these mechanisms pre-dominates and some recently obtained data is presented to support the existence and significance of these mechanisms. Proposals are also made for future research in these areas, and for utilizing the information in the improvement of roaster capacities’ OASTING of ores as a preparative treatment for smelting or leaching has been practiced for so long that its origin has been lost in antiquity, but little has been under-stood of its basic nature until fair-ly recent times. The nominal chemistry of roasting processes is now understood; that is, the initial chemical com-pounds present in the ores or con-

Jan 1, 1961