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By Corbett G, Iwai N

The Japanese gold mining industry has a long and productive history and is presently undergoing a period of revitalisation encouraged by the Hishikari discovery. Deposits exhibiting the characteristics of epithermal mineralisation are very widely distributed throughout the island chain and an encouraging number of these are large, seven containing gold in excess of one million ounces. All the important deposits are quartz vein type and contain extremely high grade, or "bonanza". Zones.

Jan 1, 1990

By George Cole

WHILE many parts of Canada's pre-Cambrian shield are well served by railway, it is frequently necessary for prospecting purposes to proceed farther into areas in-accessible by rail. To such areas in summer the canoe was at one time the accepted means of travel for the prospector while the dog team was much used in winter. Al-though summer travel was much improved by the development of the outboard motor, the lack of facilities for cheap transporta-tion has been a serious hindrance to the employment of capital in opening up the distant fields. The pre-Cambrian surface of Manitoba, like that of Ontario, is hummocky, with rounded hills and ridges of rock alternating with basinlike depressions and valleys oc-cupied by lakes and rivers or by many low-lying portions covered with muskeg. Routes to the mines have not usually been direct or easy and seasonal vagaries have presented problems in themselves. In summer, water transportation may be the cheapest method for the longer dis-tances but it is not every water route that will satisfy the conditions of loading freight onto a boat or scow and of conveying it without interruption to its destination. By its location, a mine may require a large program of boat transportation in summer over part of its route, to be followed by winter freighting for the remainder. In order to carry on development and produc-

Jan 1, 1940

By Vladyslav M. Sokolov

The cost effective and environmentally friendly recycling technology was developed and tested. It enables utilization of the fine nickel-base superalloy scrap in a form of heavily oxidized scarfing granulates. The process of granulates generation was discussed in details. Their properties were investigated. The results of literature search showed anticipated sufficient improvement of the properties of cast iron by its alloying with the elements from the scarfing granulates. The novel alloying approach is based on the two stage reduction operation. Firstly thegranulates were partially reduced in a solid state by their exposure with powdery carbon at the range of 1550 ? 1700°C. Then the gotten product was efficiently introduced into liquid iron since it has a form of fine natural agglomerates for arranging the optimal conditions for reduction of the granulates. The thermodynamic evaluation demonstrates higher reduction efficiency of carbon and silicon dissolved in iron than of the same elements in a form of the separate phases. The considered process partially provides itself by energy since the reaction of reduction of the chromium oxide by silicon dissolved in liquid iron has exothermal character. The mostly complete extraction of Ni was received. The sufficient reclamation of Cr was gotten at the same time.

Jan 1, 2006

By R. A. Cattell

The Bureau of Mines recently observed its fortieth anniversary, and with the close of the fiscal year 1950 it completed 36 years of close cooperation with and helpfulness to the petroleum and natural-gas industries, whose technical problems it studies. Petroleum people likewise observed the ninetieth anniversary of the start of this truly American industry when "Colonel" Drake drilled the first well at Titusville, Pa., in 1859 (see fig. 1). Throughout the period, during which there have been many changes in the fuel and related economy of the country, this work has been carried on systematically by an organized entity of the Bureau first known as the Petroleum Division and in recent years as the Petroleum and Natural Gas Branch. Changes in the industries have been brought about partly by economic forces, partly by advances in technology, and in some measure by the impact of two world wars. As the needs of industry and the Nation have changed, so have the studies of the Bureau changed to meet these needs. Consistently, Bureau technologists and scientists have tried to keep in step with progressive movements; frequently, in fact, have taken the lead. Wherever possible, they have looked far ahead in their program of research, at the same time recognizing the needs of the hour.

Jan 1, 1951

By J. C. Jaeger, G. A. Wiebols, N. G. W. Cook

It is usual practice in engineering to design a stable structure by ensuring that the stresses in the elements of the structure are always less than their strength, which may be defined as the yield stress, the ultimate stress, or the fatigue stress, according to the type of the load. Such restrictive design is not practical in the design of underground excavations since the rock surrounding such structures is usually failed, but only occasionally does this give rise to instability of the structure. Thus, while the usual criterion for the design of a stable structure is certainly sufficient, it is not necessary for underground excavations. A proper understanding of the conditions necessary for stability is vital to the useful application of rock mechanics knowledge to the design of underground structures. Most tests on the properties and strength of brittle rocks are disrupted at or near maximum load by the rapid release into the specimen of energy stored in the resilience of the testing machine. This is in contrast with a phenomenon, which may be observed frequently, where the rock immediately surrounding an excavation is both failed and subject to stress. By postulating a complete stress-strain curve for rock, it can be shown that failure is unstable or stable, depending upon whether the stress-strain curve of the rock lies inside or outside the stress-strain characteristics of the applied stress. Stability is, therefore, a function of the stiffness of the system applying the stress relative to that of the failing rock. Many workers have established that the strength of rock specimens under a lateral hydrostatic confining stress varies linearly with confining stress, in a way which may be expressed by the equation CT=Co+K[o]3

Jan 1, 1972

By Horacio Reeves

Las maquinarias son elementos importantes en el proceso de minería de tajo abierto -en tanto optimizan el rendimiento del trabajo y de los operarios. Sin embargo, su contínuo uso conlleva riesgos ocupacionales en el trabajador como la exposición a vibraciones de cuerpo entero en el caso de equipos pesados. En ese sentido, el presente texto compara los niveles de vibración en los equipos pesados que operan en Antamina con el estándar europeo: Directiva 2002/44/CE, así como los efectos de este en los operarios.

Sep 12, 2005

By Ning Yang, Yuxiang Chen, Ming Chen

An ultraviolet laser Raman spectrometer was developed to detect and analyze material components of seawater, seafloor sediment and rock at a depth of 7000m maximally. Wave length of the excitation resource of the spectrometer is set to 355nm, which can enhance eigen scattered intensity and detecting sensitivity, and avoid fluorescence interference. Miniaturization design was adopted for deep-sea application. Design of the optical system and pressure cartridge, material selection and seal design of the observation window, and design of the Lithium batteries are the key technologies in the procedure of research and development. The spectrometer was carried by a Lander sank to sea bottom of the Pacific's Mariana Trench for verification. During the sea trials, data acquisition for Raman spectra was conducted for analyzing seawater in the detection area, and the spectrometer was verified synthetically. According to the data, the spectrometer is stable and practicable with high resolution and precision, and it is appropriate to detect and analyze composition of substance under the tremendous ocean.

Jan 1, 2017

By E. M. Córdoba

The effect of the Fe3+ lFe2+ redox couple on the chemical and biological dissolution of chalcopyrite was studied. All the tests were carried out in stirred flasks with 100 mL of a ferric/ferrous sulphate solution, in the absence or in the presence of bacteria (iron- or sulphur-oxidizing) and at low (35 DC) and high (68DC) temperature. The initial redox potential was controlled between 300 and 600 m V Ag/ AgCI and silver was used as chemical catalyst. The results showed that the oxidizing action of ferric ion on the chalcopyrite was controlled, in all cases, by nucleation and precipitation of jarosites on unreacted particles. The tendency of Fe3+lFe2+ solutions towards equilibrium favours the activities of both ions to be equal. Consequently, the dissolution rate was faster at relatively low redox potentials (between 400 and 500 mY) than at high values (600 mY). In this sense, the presence of ferrous ion in the system is a key factor to control hydrolysis and precipitation of ferric ion. Unlike jarosite, the elemental sulphur produced during dissolution of chalcopyrite was porous and did not act as a diffusion barrier.

Jan 1, 2007

By S. W. Kan, M. G. Kakarkis, J. Zelanco

Grouting has been used in underground mining for more than 20 years. Chemical grouting is often used as a remedial measure when the implemented ground-control program is unable to completely prevent structural failures or when there is a need for preventing a structural member from unraveling. The utilization of polyurethane grout is restricted by its limited range of physical and mechanical properties. To overcome some of the drawbacks of polyurethane, research is being conducted on a newly developed polyester based grout. The polyester resin, identified by Sandvik as Strata Grip, provides a number of features, including variable gel times and a much-reduced chemical hazard. Equally important are the mechanical properties of the product. The strength and deformability of any chemical grout must be compatible with the intended purpose of grouting and the expected deformation of the rock that is to be grouted The assessment of the mechanical properties of polyester grout is the focus of this work. Field experiences and laboratory research defined the properties of an effective grouting material. Experimental results indicate that the polyester grout meets or exceeds the recommended properties for many injection applications. Furthermore, the results suggest that the ability to adjust mechanical properties via resin formulation has the potential to expand the applicability of chemical grouting in ground control.

Jan 1, 1999

By G. M. Ritcey, V. M. McNamara

"In the processing of gold ores by the cyanidation route, effluents which are discharged to the tailings areas can contain up to several hundred parts per million of cyanide in complex combination with similar quantities of heavy metals. Complicating this obvious problem of waste control are concentrations of thiosalts and thiocyanates which are roughly equivalent to the amounts of cyanide species. Although most gold mills are located in thinly populated areas, such contaminants can represent a potential environmental problem due to the various limitations exhibited by on-property ponding.The former Extraction Metallurgy Division of CANMET recognized the problem and, in early 1974, invited representatives of the gold mills to Ottawa to discuss the situation. At that meeting members of the Division presented a ""state of the art"" literature survey of cyanide abatement technology for waste solutions, together with preliminary cost estimate data(1). Shortly thereafter, Environment Canada, together with Environment Ontario, decided upon a guideline of 0.1 ppm (0.1 mg/l) total cyanide content as tolerable for an effluent stream which is discharged, in any manner, to the watershed."

Jan 1, 1978

By Bennett McLaughlin, Gille Brousseau, John F. Cook

"La Mine Bousquet commenced operations in October 1979. Mining has been by underground methods from two main zones which dip steeply to the south , Sub-level stoping methods with following fill are used.The orebody and immediate country rocks are sericitic and highly schistose. The intensity of schistosity varies significantly and poor ground conditions prevail, especially within the orebody,Initially few mining problems were encountered but in May 1981, significant damage occurred. A system of stabilizing pillars was introduced with improved support systems. Predevelopment in ore and pre-drilling of blastholes were reduced with extra footwall development.Damage has continued to occur on a regular basis particularly during the spring thaw. Generally, the adverse conditions have been successfully overcome.IntroductionMost of the mining problems that have been experienced at Bousquet have been caused by poor ground conditions . This pa per describes these conditions, considers the cause and describes the ways in which the conditions have been dealt with . Despite the problems, Bousquet is a successful operation which in 1983 produced 95,000 ozs of gold from 514,000 tons of ore."

Jan 1, 1985

By Robert U. King, John W. Vanderwilt

THE Climax molybdenite deposit in Lake County 100 miles southwest of Denver is located in the central part of the mineral belt extending north-easterly across the state. Principal geographic features and geology are shown on Fig. 1. The first period of molybdenite mining, which began in 1918, ended in April 1919 because of limited demand and a price drop to about 724 per lb. During this time the ore came from the Leal level and surface outcrops at a higher elevation. Rate of mining was 250 tpd and several million tons of ore averaging 0.7 pct molybdenite were developed. Since April 1924, when the second period* began, Climax Molybdenum Co. has been the only operating company. Production in 1924 was 400 tpd and finding ore was a continual problem. When the White tunnel was extended, however, further ore was encountered. The orebody was thought to be tabular until 1926, when B. S. Butler recognized the relation of the developed ore on the Leal and White levels to a central area of fine-grained hydrothermal quartz, and by 1929 diamond drilling had blocked out indicated ore reserves in excess of 100 million tons.

Jan 1, 1955

By J. W. Whitney

Itronics Inc., through its wholly owned subsidiary Itronics Metallurgical, Inc. (IMI), has successfully developed technology that allows it to be fully integrated as a photochemical recycler. IMI is now using this technology to expand its regional operation, which collects used photographic chemicals, chemically removes 99.997% of the silver and uses the residual to make a line of high quality liquid multinutrient liquid fertilizer products. Elevated silver discharges from the Reno-Sparks sewage treatment facility, that were traced back to incoming waste photographic chemicals and which were seriously impacting the sensitive fishery, provided the impetus for this project. This paper is updated from a paper presented at the Twenty-Second International Precious Metals Conference Toronto, Ontario, Canada in June 1998. It presents an overview of the scope of the problem solved by the technology, some of the permitting and development issues, and some of the specific fertilization formulations that are now being marketed.

Jan 1, 2000

By Betty L. Gibbs

Mine planning and scheduling done with computer programs is possible only after extensive work has been completed to define the geologic extent of an ore body and an overall mine design. Mine planning methodology on computer can vary from computerized engineering tasks through systems which completely optimize a plan with little input from an engineer during the actual scheduling process. However, a strong emphasis is placed on producing practical mining sequences which may be "best" rather than "optimum". This section offers several viewpoints on the planning process using computers. Interactive planning and scheduling systems are attractive for many companies because they are easy for engineers to understand, and the results are acceptable. The engineer develops an open pit mine sequence by trial and error using interactive graphics. The results of this approach can usually be improved. A computer program can help an engineer make many trials in a short time period and provide a higher level of confidence that a "best" plan has been generated.

Jan 1, 1989

In the past two decades the global metalliferous mineral industry has trended away from pyrometallurgical (pyromet) and towards hydrometallurgical (hydromet) technologies including biometallurgical (biomet) processes. Pyromet, biomet and hydromet technologies have all developed considerably over this period. New projects have been biased or directed by legislation towards supposedly cleaner and greener hydromet and biomet technologies. The environmental cost and energy cost of pyromet production processes for copper and cobalt are compared with comparable hydromet processes using Life Cycle Assessment (LCA). The æreal costÆ of the global warming obsession and negative public perception of pyrometallurgy include greater carbon dioxide emissions and energy consumption per unit, associated with current hydromet technologies. Specific examples for copper and cobalt produced via the different routes are provided. The poor science involved with the global warming hypothesis is discussed. The use of LCA with sensitivity analysis as a decision making tool for mineral processing projects and technology developers is discussed.

Jan 1, 2004

By J. S. Levine, M. Prats

Several methods are available for calculating the performance of solution-gas-drive reservoirs from the PVT properties of the oil and from the relative permeability and other properties of the formation. These methods require a number of simplifying assumptions. The present method of computation has made use of a high-speed computer to solve simultaneously the nonlinear partial differential equations that describe two-phase flow by solution-gas drive in order to calculate the performance of a reservoir. Some of the results obtained by the nonlinear partial differential equation solution are compared with those obtained with an approximate method, which has been called the semisteady-state solution. The pressure and saturation profiles from the wellbore to outer boundary calculated by the two methods are compared for one constant-terminal-rate case and two constant-teminal-pressure cases. The agreement in these profiles, as well as in the values of average reservoir pressure and cumulative recovery, leads to the conclusion that, for most engineering calculations, the semisteady-state method will give a reasonable approximation to the numerical solution of the differential equations describing solution-gas drive. An unfavorable (as regards ultimate oil production) set of relative permeability curves was used in the calculations in the belief that the effect of the parameters which were studied would be emphasized to a greater degree. Furthermore, the reservoir was assumed to be completely homogeneous, and these results should not be considered applicable to any other type of reservoir. Gravity effects are not considered. The absolute permeability was varied from 25 to 0.5 md. At an economic limit of 2 B/D, the recovery for a 25-md reservoir is about 1.8 times as great as that for a 0.5-md reservoir. The effect of permeability on the producing gas-oil ratio is minor. Once PVT properties of the oil and the relative penneability properties of the reservoir are fixed, the pro- during gas-oil ratio is found to be a function of the fraction of oil recovered. Well spacings of 10, 40 and 80 acres were considered. For the assumed homogeneous-reservoir properties, the effect of spacing on recovery at an economic limit of 2 B/D was very slight. Certain dimensionless groups can be used to extend the results to other fields having different penneabilities, spacings, reservoir thicknesses, well radii and porosities, so long as the PVT and relative permeability properties are similar to those used in this paper. INTRODUCTION An important aspect of reservoir engineering is the prediction of the performance of the reservoir based on the limited information normally available early in the life of a field. Usually, soon after a field has been discovered, it is necessary to decide upon the spacing to be employed and the production program to be used for most efficient utilization of reservoir energy. Where these decisions have not been dictated by legal or political considerations, they have frequently been based on experience factors which indicate that two fields with similar characteristics will probably have similar performances. To the extent that the industry has been successful in economically exploiting oil reservoirs, this rule-of-thumb method has been found to have merit. A large amount of theory has been developed with which it is possible to predict the performance of a reservoir by using certain known properties of the oil and the formation. Because of the difficulties of the mathematics involved for a drainage area having square or rectangular boundaries, the problem usually has been simplified and idealized by assuming each drainage area to have radial symmetry and the field to be represented by a number of these drainage areas. Muskatl was one of the first to formulate the theory for two-phase flow and to solve the equations for a few cases by numerical integration, using the relatively slow means of computing available at that time. His equations describing

By F. J. Chernosky

In the past, a number of papers have been written on the use of various reagents as coal flotation frothers. For the most part, these papers have attempted to correlate the intrinsic chemical and physical properties of the reagents or reagent groups to the floatability of various fine coals. Because of the type or nature of evaluations made, chemically pure reagents were normally used. Generally, these reagents are unavailable in commercial quantities. Therefore, the results obtained with these reagents were usually limited in usefulness to the plant operator or metallurgist. This paper presents the results of a study in which commercially available forms of various reagents were used as flotation frothers. Flotation procedures which would conform in general to those employed in a large number of commercial coal flotation plants were utilized. The objective of the test was to compare these reagents on yield-selectivity-cost basis, that is, (1) the yields obtained, (2) the ash levels obtained, and (3) the reagent cost relating to these results.

Jan 1, 1962

By T. B. Counselman

AFTER several years study, the Universal Atlas Cement Co. decided to rebuild its plant at Leeds, Alabama. The entire old plant, which was to operate during the new construction, was then to be scrapped with the exception of two kilns. The quarry was to be mechanized, new and larger kilns installed, with the most modern type of equipment all through the plant. Raw grinding operations at all of the Universal Atlas plants were dry. However, the dust hazard of this operation and the growing emphasis on occupational diseases made wet grinding attractive. Coal at Leeds is cheap, so that a slightly higher coal practice was unimportant. Power was cheap, so that waste-heat boilers were not desirable. Since new kilns were to be installed, these could be made long enough to make filters unnecessary. Wet raw grinding could be either the old practice of open-circuit compartment mills or closed-circuit grinding in accordance with metal-lurgical practice. The latter saved power and steel wear and saved initial investment. This had been demonstrated in cement plants. Also, the elimination of tramp oversize was a most important advantage. Ease of chemical control was another factor. Blending in the thickener, with elimination of slurry mixers had been found practicable. Therefore, if wet raw grinding were used at all, the advantages were clearly in favor of closed-circuit grinding. Detailed layouts of the most modern possible closed-circuit dry-grinding plant and of a closed-circuit wet-grinding plant were prepared, and careful estimates were made of initial invest-ment and operating costs. Full consideration of all the factors involved resulted in a decision to install wet closed-circuit grinding.

Jan 1, 1939

By Benedict Shubart

The subject of this paper may seem threadbare to, many of you, but even if I repeat what you already know, just smile to yourself and think how much wiser you are than your neighbor, for it is startling what a number of tipples are erected that violate the elementary fundamentals not only of good design but of practical operation. Possibly a coal screening plant is a simple plant. If so, we treat it like we do a great many other simple things. We treat it entirely too lightly and fail to take into consideration, not only the changes that may occur later, the conditions we may be compelled to meet as competition changes, but even the elementary physical conditions that exist right at the tipple site. If I get too positive over some particular point, don't blame me, but remember some of the heart-breaking experiences we have had correcting these omissions, trying to make a tipple do merely what it was designed to do, when the builder tied everything up in such a constricted space, that no room was left to get the results he must have. Perhaps some of the things will look too expensive. Don't say that you can't afford them. Many of them you can't afford to do without, and when you figure that a tipple is put up for possibly twenty years of operation, you can't afford to omit any reasonable precaution not only in taking care of the present, but in foreseeing the future. We will consider a tripple screening plant, suitable for Western conditions, capable of handling approximately 2,500 tons per eight hours. The largest screen sizes must be loaded into either open cars or box cars, and arrangement provided for screening and loading not less than five sizes of coal: lump, egg, nut, slack, dust, or any reasonable combination of these. As we are considering only the preparation of the coal, we will omit all consideration of the method of haulage, pit cars, methods of dumping, and will take the coal after it is in the dump hopper. The track arrangement will frequently be determined by the ground layout. Our sizes and tonnage can be loaded on three tracks, but four tracks are better. The two outer tracks should be left for loading lump coal, No. 3 track should be left for egg coal, and No. 4 track for loading nut, slack and dust. Where a fifth track can be provided, No. 5 track should be held open only for run-of-mine coal, to act as a storage where emergency coal can, be run, should there be any delay in the screening equipment or in changing cars. Track No. I should be used for loading lump coal into box cars only. Track No. 2 should be used for loading lump coal into open cars only, and may or may not be provided with picking table, loading boom, or both. Where picking is necessary, a picking table can frequently be put between the two "lump tracks, heading down track, pivoted at one end, so it may be raised or lowered to feed either open or box cars; with

Jan 1, 1921

By B. M. Das, V. J. Hucka, J. H. Tu

Subsidence can cause serious damage to surface installations such as railroads, highways, pipelines, buildings and other facilities over a period of many years. Although total elimination of the effects of subsidence is difficult, the damage can be minimized through a systematic analysis. An example of such a study for reducing the effects of subsidence on pipelines is presented in this paper. Subsidence-induced stresses on a pipeline over some coal mining properties in Utah have been analyzed using a computer with graphics capabilities. The results are useful in predicting the extent of damages due to mining subsidence. In view of the gradual replacement of room-and-pillar mining by longwall with caving, this sort of analysis will become more and more important. In the next phase of this study the predicted results will be compared with the permissible stress levels on pipelines over actual subsided areas in an actual case.

Jan 1, 1989