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By Michael A. Werner

"A Yieldable Structure for Use in Areas of High Rock Stress & Deformation." Rock stress of up to 9000 psi have been recorded in the mines of the Coeur d'Alene Mining district. Associated with these large stresses are rock fractures and deformation. In order to maintain openings required for mining, large wood preparation structures are constructed to provide access to the work areas for men and materials. These wood raise preparation structures are costly to construct and maintain. Therefore a steel-foam concrete structure was designed and proposed for testing which would be less costly to construct, require no maintainence and maintain its structural integrity while allowing up to 53 inches of wall rock deformation.

Jan 1, 1984

By E. O. Fromm, R. I. Jaffee, R. M. Evans

IN connection with a research on gallium alloys, a method for the thermal analysis of very low melting alloys was developed, which appeared to be worthy of more than passing interest. As used, the method was suitable for work in the temperature range, — 72° to 250°C. However, with suitable adjustment, the method could be adapted for use over broader temperature ranges. The Rosenhain temperature gradient furnace,' adapted for low-temperature use, was the basis for the method. The gradient was set up in a stainless steel tube. The specimens were lowered through it at a constant rate while time-temperature or inverse rate data were taken. It was essential to maintain careful control of the top and bottom temperatures of the gradient. Also essential was good heat transfer from the walls to the specimen. This was accomplished by a liquid heat-transfer medium.

Jan 1, 1953

By Walter C. Labys

INTRODUCTION Interest in multicommodity stabilization schemes has increased recently for several reasons, a most important one being the experienced wide swings in primary commodity prices. These prices rose sharply between mid - 1972 and end - 1974 giving commodity exporting countries an opportunity to gain sizeable increases in export earnings. But since then, prices have tumbled and these countries are searching for a means to stabilize if not to increase their earnings. While this problem is particularly serious for developing countries, the developed countries are concerned about the impending upward price swing, which would increase inflation before recovery from the world recession is assured. As a direct consequence of the emergency meeting of the U.N. General Assembly devoted to commodity problems in April of 1974, interest has been renewed in the Keynesian (4) plan for an international multicommodity buffer stock program. In particular, UNCTAD (8) is designing an integrated commodity scheme to be discussed within that body. In terms of approaches that have appeared in designing such a program, none exist which relate to the interpretation of the independence and interdependence of prices of the commodities of interest. Typical criteria for selecting commodities for the scheme have included their importance in world trade, their particular origin from developing countries, and their feasibility for storage. But the financial management of a multicommodity buffer stock requires a consideration of commodity prices, yields, and risks as does as any portfolio of assets. The approach which we take in this study is that of application

Jan 1, 1977

By J. S. Long

A finite-difference model using a digital computer was constructed to assist in the water management of a proposed oil-shale mining operation in the Piceance Basin in Colorado. The presence of ground water is both a detriment and a benefit for development of the resource. On one hand, dewatering is required because permeable zones are present in and above the oil-shale sequence, and rich oil shale at the proposed mine is as much as 457 m (1500 ft) below the water table. On the other hand, ground water is the most feasible source of water for processing the oil shale. A ground- water model was constructed to simulate the development of an environmentally acceptable water-management system that will satisfy both the mine-dewatering requirements and the water-supply requirements for processing. The ground-water model discussed in this chapter was constructed for the Rio Blanco Oil Shale Co. (RBOSC) by International Engineering Co., Inc., a subsidiary of Morrison-Knudsen Co. The model was applied to evaluate dewatering and water control systems for several open-pit mining plans initially investigated to develop Federal Lease Tract C-a. A collateral application of the model analyses was to project effects of the proposed dewatering operation on the regional ground-water regime in connection with a permit acquisition program by RBOSC. Subsequently, RBOSC has completely changed its mine development plan and has adopted modeling and related techniques more suitable for study of that plan and dewatering operation. The authors of this chapter are solely responsible for the contents and conclusions.

Jan 1, 1979

By I M. Platten, Y Xie

Sampling protocols that are designed to suit the mineralisation style will result in a reduction of the nugget effect and hence resource risk. The a priori need for all sampling programs is the effective characterisation of the mineralisation type(s) to support optimisation. This requires a program of sampling for sampling followed by holistic characterisation. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for coarse nuggety mineralisation. Many deposits contain a proportion of both particle size types. The proportion and size of coarse gold particles has a direct impact on the effectiveness of sampling, where coarser particles will require larger samples and more specialised protocols. The nature of mineralisation geology/mineralogy and associated gold particle sizing can only be determined by sampling to facilitate optimised protocols. Mineralogical studies, focusing on particle size, particle clustering and distribution in host minerals, are required as part of wider paragenetic and metallurgical investigations. This paper discusses the role of mineralogical studies in the characterisation of gold ores for sampling optimisation through a series of case studies.

Jan 1, 2008

This project was started 8 June 1971. As set forth in our Proposal of 28 April 1970, responding to the RFP of 30 March 1970, the plan was twofold: 1) choose fluids and develop techniques for measuring coat porosity, and 2) construct a porosimeter for making such measurements, By the time plans for the porosimeter had been drawn up, the picture had changed; and it was found more advisable to do further researches on porosity rather than build the equipment. This development arose from a meeting with Dr. Fred N. Kissell on 14, 15 October 1971, annotated in our letter of 19 October 1971, and was contracted for 6 December 1971. The technical effort of the project was completed 7 May 1972. From the beginning it was realized that the ratio of 'hole volume to the whole volume' might be too simplistic a definition for coat porosity and that its measurement might be confounded by complications which were not yet known, We were hopeful that an exploration of fluids and techniques would provide early feedback on both these points which could be used in subsequent developments. This turned out to be the case.

Jan 1, 1972

By P A. Williams, P Leverett

Many of the worldÆs stibnite deposits are found in orogenic zones and are mesothermal or epithermal in origin. They commonly occur near contacts between intrusives and metasediments. However, the spatial extent of anomalous Sb levels around such deposits is not well documented. This project has aimed to gain a better understanding of the mineralogy and geochemistry of Sb by deriving solubility and thermochemical data for some of the most common secondary Sb minerals. This has then been applied in field exploration for Sb ore deposits. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Satayev IS, Shepelev DV

Various ways for applying the X-ray fluorescent method to process lump-by lump separation of secondary aluminium raw materials (scrap, slags, waste) as well as ferrosilicon and ferrochromium are being considered and physically demonstrated. A commercial X-ray radiometric sorter has been developed for processing secondary raw materials. Marketable quantities of aluminium scrap with appropriate copper and zinc content have been produced for smelting with a minimal additional of pure aluminium. An industrial complex for scrap processing, incorporating two X-ray radiometric sorters from the Hammermils company is successfully operating at one of the works in Russia.

Jan 1, 1993

By A. D. Shuloyakov, V. A. Zukerman, G. A. Finkelstein, V. I. Kurets

Possibilities of electric pulse disintegration are discussed with emphasis on high selectivity of the process as compared to mechanical comminution methods especially when applied to polymineral ores. Physical explanation of this phenomenon is suggested. The authors present results of some experimental tests illustrating regularity of this phenomenon irrespective of origin of ores or dissemination pattern of valuable minerals including both dissipated and accessory minerals. Some operating plants applying this principle are described the plants used either for mineral research purposes or for obtaining pure monomineral fractions or for treatment of gems to be faceted. Obstacles for implementation of this technology are mentioned.

Jan 1, 1995

Reduce the time, complexity and expense of dissolving metal and mineral samples in solution in preparation for chemical analysis. Approach In earlier research, the Bureau of Mines developed a rapid and inexpensive method for the dissolution of mineral and metal samples in plastic pressure bottles heated in a boiling water bath. Using this technique, samples could be prepared for chemical analysis in less than one hour compared with several hours by traditional dissolution methods (see Technology News No. 85, December 1980 for further details). By heating in a microwave oven, sample dissolution time can be reduced to approximately 5 minutes.

Jan 1, 1983

By Paul Dewison

For nine years, from mid-1987 to mid-1996, the copper market enjoyed what appeared to be an endless boom in which prices were much higher relative to production costs than for most other base metals. After the boom ended abruptly mid-1997 with the Sumitomo affair, copper was burdened by an overhang of new projects that promised to swamp demand in what, with the Asian financial and economic crisis of 1997, had become a considerably worse consumption environment. Now, demand prospects do not look so bad. If, as we suspect, we will be dealing with a more rational market in the future, it becomes all the more important to forecast accurately the prospects for consumption. In this paper, we present a new methodology for copper demand forecasting. The methodology forms the backbone of the demand-side analysis for the multi-client study entitled "Long Tenn Outlook for Copper", co-authored by Metalica Ltd. and Bloomsbury Minerals Economics (BME). Key components of the methodology are as follows. (1) Relate demand to economic structure. (2) Focus on products rather than refined consumption. (3) Apply a consistent products/applications analysis to all countries and time series. (4) Incorporate scrap market dynamics within the analytical framework.

Jan 1, 1999

By K. Terhaar, K. Prisbrey

The objective was to determine operating protocols for a lead and silver column flotation cleaner, being considered for installation at Sunshine Mining & Refining Co.’s Kellogg mill in Northern Idaho. In this column, tetrahedrite and galena were floated, and pyrite and other gangue minerals, including siderite and silica, were depressed. The procedure was to develop a dynamic simulation using a linear transfer function approach. The transfer function related cause and effect variables such as the influence of collector and depressant dosages on recovery and grades. Bench-scale flotation tests followed by pilot column testing provided the data used to develop a linear transfer function. The transfer function was derived using a spreadsheet. This model was applied to simulate how the flotation column could be made to respond to disturbances in feedgrade. The results were that xanthate, zinc sulfate, and sodium cyanide were found to be suitable controls for grade and recovery. Simulations showed the best sequence of manipulations of these reagents, and these sequences were useful for future operator training. The conclusion was that linear transfer functions were able to simulate lead and silver recovery, develop scenarios for operator training, and provide a foundation for future on-line control.

Jan 1, 1999

By C. Kruger

Anglo American Platinum has adopted a strategy of best practice principles (BPP) for sampling, mass measurement, analysis, and metal accounting for more than a decade now. When new plants are designed, the most suitable sampling equipment and sampling protocols are implemented and material flows and plant layouts are designed around sampling strategies. A few years ago, a crushing plant for a high-grade matte stream was commissioned. The design called for the high-grade material to be crushed to 95% passing 2 mm, and the design allowed for a single-cutter primary Vezin sampler taking increments from a gravity flowing stream at regular intervals while filling a tanker for pneumatic offload at the base metal refinery. This was a single point of sampling and analysis that would measure the wanted output from the smelting complex and the input to the refineries. In addition, the design incorporated the functionality to collect increments in an ?interleaved? fashion from the Vezin sampler for internal precision checks. The metal accounting strategy for Anglo Platinum involves the ongoing measurement of all inputs, outputs, and stock levels for all operations for platinum group metal (PGM) and base metal (BM) content. Included are yearly stocktakes, usually done on 1 February, across the smelters and refineries (at least the base metal refinery). In the accounting period immediately following the introduction of the new crushing and sampling facility, a trend was developing whereby the absolute difference between the physical stock and theoretical stock (PGMs predominantly) increased for the two respective sites on an ongoing basis. The smelter showed an increase in physical stock compared to the theoretical stock (sender) and the base metal refinery showed an increase in theoretical stock against physical stock. Because of this anomaly, an additional stocktake was held in September for the period in question, and it was confirmed through the physical stock measurement results that the PGM accounting problem was indeed pointing towards the evaluation of the high-grade matte stream. This paper showcases parts of the process that took place to explain the poor accountabilities for the two sites. Previous results from the sampler ratification process (of the interleaved sampling design) were reanalysed, a physical inspection was carried out on the sampling system again, and the sampler performance was monitored (quality control parameters) for the period. From these investigations, it was found that airflows inside the Vezin introduced the sampling bias. A change in sampling protocol was introduced, as well as certain physical changes to the sampling equipment, to eliminate the airflow and thus the bias conditions significantly. The accounting period that followed the phased upgrading process showed that the accounting between the smelter and base metal refinery had been restored to within statistical limits (difference between physical and theoretical stock below 5% relative to theoretical stock). Keywords sampling, metal accounting, Vezin sampler, sampler bias.

Jan 1, 2014

By Ellis WK, Greenwood-Smith R

A nuclear technique for the analysis of copper in bulk materials has been developed and successfully field tested at Mount Isa Mines Limited. The technique utilises the gamma-ray resonance scattering process. A bulk analyser based on this technique gives a rapid and accurate measurement of the percentage by weight of copper or nickel aver- aged over a large mass of sample, typically 20 kg. The only sample preparation required for accurate analysis is crushing to -2.5 cm. At Mount Isa over 100 mineral samples covering a wide range of rock types and copper contents were analysed. Bulk analyser assays and chemical laboratory assays agreed closely for underground pillar-extraction and geolog- ical chip samples, conveyor belt samples, and finely ground samples from the ore concentrator. For the concentrator samples, the root mean square deviation between bulk analyser and chem- ical laboratory assays was 0.06 wt.% copper. The chemical assay errors for these samples were about 0.06 wt.%

Jan 1, 1975

By Viacheslav Lyakhov, Cornelis H. Iestra, Victor I. Beloborodov, Vitaliy Bogdanovich

The results of a study and effective use of flotation for processing of ores with complex mineral composition containing fine-disseminated minerals with high specific density are presented in the paper. The object of research was complex baddeleyite-containing ore from Kovdor deposit (The Kola peninsula, Russia). Baddeleyite is a valuable, rare mineral, natural Zirconium dioxide with 5.8 - 6.0g / cm density, grade content 0.15 - 0.17 and dissemination less than 0.2 mm. The authors carried out a thorough investigation of baddeleyite- containing products selected in different sites of gravity flowsheet. It was determined that due to similar specific weight some sulphide minerals (pyrite, pyrrhotite) come into concentrate together with baddeleyite and, also, minerals of pyrochlores group (hatchettolite). The results obtained revealed the possibility of use the flotation for retreating rough baddeleyite concentrate. he given gravity concentrate has a number of specific features, e. g. high density of its minerals which, in its turn, provides for high speed of sedimentation of solid phase in pulp, and for the presence of large amount of sulphide minerals (up to 10%) having good flotability. With these features being taken into account a technology for flotation of baddeleyite-containing products after their preliminary gravity concentration has been developed (up to 5 - 10% Zirconium dioxide). The technology has three flotation stages. At the first one the reverse flotation of baddeleyite is carried out during which "light" minerals (forsterite. apatite and carbonites) come into froth product and at the second one flotation of sulphide minerals and at the third one direct flotation of baddeleyite is performed from the underflow product. The following reagents were used for flotation: of phosphate type (sodium tripolyphosphate, mono and diethers of alkylphosphpric acid) and sodium xanthate as collector for sulphides. The given set reagents provides for high effectiveness of flotation due to selective of collectors and presence of froth layer with high carrying ability. New flotation technology of recovering of baddeleyite from complex ore was developed and applied at the Kovdor Mining Plant, using AKER flotation machines.

Jan 1, 1995

By M. A. Scheil, S. L. Hoyt

About three years ago eight standard steels were prepared for the cooperative investigation of methods for oxygen analysis, sponsored by the Iron and Steel Division of the American Institute of Mining and Metallurgical Engineers and by the National Bureau of Standards. A preliminary report of the results was made at the annual meeting of the A.I.M.E. in February, 1936. † This report showed the reliability of vacuum-fusion methods and further brought out certain advantages of the fractional vacuum-fusion method. The results obtained by the authors with the latter method will be discussed here, with some comments on the procedure for those who are interested in determinations of gases in steel. Some additional comments are offered on the use of the polarizing microscope for identifying the inclusions in the steel to check and amplify the findings of the fractional vacuum-fusion analysis. For details of the fractional method, see the paper by L. Reeve1. Degassing the Crucible One of the sources of error in vacuum-fusion methods has been the blank gases evolved from the graphite crucible after preliminary out-gassing. We have used 1750" C. as the outgassing temperature. This gives a base pressure at that temperature of less than 0.030 mm. after one hour and of 0.004 mm. on dropping the temperature to 1575" C. At lower extraction temperatures the base pressure is 0.001 mm. at 1050" C., 0.002 mm. at 1170" and 0.003 mm. at 1320' C. Because of the size of our induction coil we are limited to this temperature, although it 'would be advantageous to use 1950" to 2000" C. Hamilton2, after outgassing at 1850" C. for 100 min., was able to reach a base pressure of 0.001 mm. for a temperature of 1700' to 1725" C. This would give a blank corresponding to less than 0.00015 per cent 02 and 0.00005 per cent H2. Chipman and Marshall outgas at 2000" C. for one hour by using a special construction

Jan 1, 1937

By Battino S

ABSTRACT' The high gas emissions associated with coal extraction at some-Australian collieries have provided a need to investigate the methods used to predict these gas levels and the vent- ilation requirements for gas dilution. It is generally accepted that the introduction of longwall extraction in particular is associated with complex ventilation planning problems. These problems are made much more severe when the colliery introducing longwalls is already facing high gas emissions even during the development stages. A forecast of likely gas emissions during the longwall mining process indicated possible ventilation problems in maintaining the necessary ventilation levels to satisfy the statutory gas limitations for various production rates. Although there are sound principles used in world recognised methods of gas emission prediction a new approach developed from the findings of the Barbara Experimental Mine in Poland appears most suitable for Australian conditions. This has been applied to an Australian colliery preparing for longwall mining using statistical methods for air

Jan 1, 1983

By V. L. Gravitis

Radioisotope X -ray techniques of analysis for nickel have been tested in laboratory and plant trials. In the laboratory tests. a comparison was made of radioisotope and conventional analyses for nickel in solid s samples taken from streams of a nickel concentrator. Coefficients of variation of 1.7% for feed and concentrate samples , and equal to 10% for final tailing samples, were obtained. Continuous determination of nickel in final tailing slurries was demonstrated in a trial lasting 20 days at a nickel concentrator (Western Mining Corporation), nickel being determined with a standard error of 0.036% Ni in the slurry solids within the range of 0.24 to 0.68% Ni. This error, obtained by comparison of on-stream probe analyses with assays of samples taken from the stream, includes errors in sampling and assay by conventional techniques.

Jan 1, 1977

By E. I. Organick, B. H. Golding

A simple correlation is presented for the prediction of saturation pressures in condensate-gas and volatile-oil mixtures. Saturation pressure is related directly to the composition of the mixture with the aid of two generalized composition characteristics, B, the molal average boiling point, and W, the modified weight average equivalent molecular weight. The need for hydrocarbon equilibrium constants is entirely eliminated. Only the values of the two conlposition parameters need be obtained, and these are calculated in a simple and reproducible manner from the stream analysis of the mixture and the ASTM distillation for the heavy ends. The correlation is given .in the form of a set of 14 working charts in which saturation pressures, either retrograde dew points or bubble points, are plotted cs temperature, forming partial phase envelopes for mixtures having discrete values of the composition parameters, B and Wul. A locus of critical states on each chart intersects the partial phase envelopes, distinguishing retrograde dew point pressures from bubble pressures. A comparison Between experimental and predicted saturation pressures reveals that: the probable error of the predicted values, when considering the data as a whole (214 experimental points), is five per cent; for high gasjoil ratio condensate fluids (approximately 40.000 or more cu ft/bbl) the probable error is about 8 per cent. In either case, however, the probable error is comparable with the overall uncertainty of the data from which the correlation is derived. INTRODUCTION There is a present need for a simplified, yet reasonably accurate method for predicting upper phase boundaries of reservoir fluids. In the case of high gas/oil ratio fluids, namely the so-called highly volatile oils and the condensate gases, no simple method, accurate within 5 to 10 per cent, is now available by which bubble point and retrograde dew point pressures may be predicted. In order to calculate the upper phase boundary of a volatile reservoir fluid, using correlations now available, it is necessary to find and employ the proper K-values (equilibrium volatility ratios of the hydrocarbons in that fluid). This process of finding the Proper K-values usually involves a double trial and error computation. Since the K-values are in themselves dependent upon the composition of the fluid, their use in the calculation of a saturation pressure actually represents an unnecessary complication. The correlation described in this paper relates saturation pressure directly to the stream composition, entirely eliminating the need for K-values. The only data required to calculate the Stream composition are obtained from the customary low temperature fractional analyses of separator gas and liquidt and from the ASTM distillation of the c,+ fraction of the separator liquid. A considerable simplification in the procedure for predicting saturation pressures is thereby effected without significant loss in accuracy. BASIS FOR A CORRELATION Empirical relationships between the saturation pressure and the composition of the fluid in question have already been partially explored by one of the authors.V n particular, a relationship between the critical pressure for a hydrocarbon mixture and its composition was developed. The critical pressure is in reality a saturation pressure, as it repregents a limiting case either of a dew point or of a buhhle point pressure for any given mixture. It was found that the critical pressure may be correlated as a function of two generalized composition characteristics or variables. One characteristic expressed a molal average prop-erty, the other a weight average property of the mixture. Specifically, the molal average boiling point (MABP, or B as it

Jan 1, 1952

By Kristin Hemlein

Mining project development, permitting, environmental regulatory and compliance issues in Uzbekistan and the CIS are every bit as complex as those in the western world. The vast array of environmental permitting, monitoring and reporting regulations for mine project development and operation in the CIS are based on existing Soviet environmental regulations and policies which have remained in place after these countries gained independence from the former Soviet Union. The approach to mine project permitting in the CIS differs from the western world. Similar pre- feasibility, baseline data collection, and environmental monitoring requirements allow the project proponent to coordinate preparation and submission of documentation to support project permitting for Uzbek regulatory requirements with environmental requirements imposed by financial institutions and western environmental compliance structures. Implementation of generally accepted western environmental best management controls and monitoring into mine design, construction, and operation will not, however, ensure automatic compliance with Uzbek environmental regulations. Uzbek environmental compliance requirements that differ from western requirements include: 1) development and maintenance of an environmental database constructed specifically to address annual, biannual and quarterly statistical reporting requirements for emissions of "environmental pollutants" from the facility into air, surface water, ground water and soil; 2) preparation and submittal of specific permits for water utilization, hazardous waste storage and disposal, landfill construction and operation, and stack emissions inventories; and 3) procurement of approvals from the Uzbekistan State Committee for Nature Protection (generally analogous to the US Environmental Protection Agency). This paper outlines and summarizes the regulatory requirements for mine site permitting and the procedures for environmental monitoring and reporting during mining operation in Uzbekistan and the CIS.

Jan 1, 1997