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By A G. Grice

WMC Resources Pty Ltd û Copper Uranium Division operates the large underground Olympic Dam Mine at Roxby Downs, South Australia. These operations mine and process the ore to produce refined copper, uranium oxide, gold and silver. In mid-1996, the company committed to the Olympic Dam Expansion Project (OEP) to expand production from 3.0 million tonnes per annum of ore (85 000 tonnes per annum of copper metal) to over 9.0 million tonnes per annum of ore (over 200 000 tonnes per annum of copper metal). Along with the increase in the ore production capacity of the underground mine and the surface ore handling and processing facilities, expansion of the backfill system was required. The target backfill placement rate was 2.0 million cubic metres of backfill per annum which was to be predominantly delivered as cemented aggregate fill (CAF). This paper discusses the engineering activities undertaken to assess and change the method of designing the required strength of fill exposures. In addition, the operational changes that were introduced to achieve the required fill quantities and the mix designs to meet the specified strengths, including the use of alternate binders, are discussed. This work resulted in a large increase in the fill placement rate and a reduction in the overall unit cost of fill.

Jan 1, 2000

By Konstantinos Komnitsas, Evangelos Petrakis, Emmanouil Varouchakis

During the modeling of grinding systems, population balance modeling (PBM) which considers a constant breakage rate has been widely used over the past years. However, in some cases, PBM exhibited some limitations, and time-dependent approaches have been developed. Recently, a non-linear framework which considers the traditional linear theory of the PBM as a partial case was introduced, thus allowing the estimation of product particle size distribution in relation to grinding time or the specific energy input to the mill. In the proposed model the simplified form of the fundamental batch grinding equation was transformed into the well-known Rosin–Rammler (RR) distribution. Besides, the adaptability and reliability of the prediction model are among others dependent upon the operating conditions of the mill and the adjustment of the RR distribution to the experimental data. In this study, a series of grinding tests were performed using marble as test material, and the adaptability of the non-linear model was investigated using three loads of single size media, i.e., 40, 25.4, and 12.7 mm. The results indicate that the proposed model enables a more accurate analysis of grinding, compared to PBM, for different operating conditions.

Jun 24, 2023

By D. J. Parker, J. B. Benson, J. H. Bird, F. E. Cash

"INTRODUCTION The organic act that became effective July 1, 1910, imposes two very definite primary obligations upon the Bureau of Mines: (1) The prevention of loss of life and limb and the protection of the health of workers in the mineral industries, and (2) the conservation and scientific utilization of the country's mineral resources.The subject of this publication falls within the scope of both of these responsibilities by reason of the fact that (1) certain safety precautions are involved in combating even surface fires and, (2) although peat is not now, so far as known, utilized commercially or otherwise in this country as a fuel, it is extremely valuable agriculturally in at least one of our States, The justification for the conservation of such low-grade fuel through fire prevention appears warranted because of its present value to agriculture and the possible advantages accruing to future generations as a source of heat and power.Although the Bureau of Mines has published information on the origin and uses of peat, this is the first attempt to give out data concerning the prevention and control of peat-bog fires. Although the information presented here is restricted to the Lake Superior District, California, and Florida, there may be similar conditions in other sections of the country that have not come to the attention of engineers of the Bureau of Nines."

Jul 1, 1947

By G. Merle, David L. McKay, Elmar Randveer

"THE ENGINEERING AND TECHNICAL SERVICES department is responsible for supplying the following services:1. Administration and co-ordination of the work required for capital projects.2. Engineering, design and drafting services for inplant changes or improvements as requested by the operating• and maintenance departments.3. Rock mechanics.4. Preparation of plans and layouts required for efficient extraction of the ore as mutually agreed with the mine operating departments.5. Mine planning and long-term schedules in co-operation with the mine operating departments.6. Grade control (long term and short term) and the preparation of ore and waste removal schedules to maintain a uniform grade of mill feed. This also includes the calculation of metal reserves and metal production forecasts.7. Surveying, underground and surface.8. Operations research at the mine site.9. Industrial engineering.10. Chemical analyses and assays.11. Instrumentation.12. Environmental control.A staff of approximately 35 supervisors, engineers and scientists, and 80 technicians, supply the foregoing services. Consulting engineering and drafting firms are used to supply specialized services and technical personnel in-house at Timmins to handle overloads on capital projects under the direction of Ecstall engineers.The operating and maintenance departments depend on the engineering department to supply engineering, design and drafting services for any new facilities or for any planned alteration to existing facilities. To do this efficiently requires a high level of communication and co-operation with these departments. This has been a major factor in developing the present organization of the department shown in Figure 63.The organization is predicated on a strong central technical and engineering resource from which personnel can be assigned responsibilities for different projects, and in different areas, as the work load demands. Job satisfaction is very high because of the variety and challenge in the tasks. Additionally, participation in projects with production and maintenance personnel broadens each technical employee's knowledge of operating and maintenance problems."

Jan 1, 1974

The Mt Todd Project is located 42 km northwest of Katherine in the Northern Territory. The identified mineral resource estimate for the Batman gold deposit is 66.7 million tonnes (Mt) grading 1.4 grams/tonne (g/t). Proved and Probable Ore Reserves total 42.3 Mt grading 1.5 g/t. Orebody definition and reserve estimation is based on extensive percussion and diamond drilling. Exhaustive bias analysis comparing grades produced from different drilling techniques has been undertaken. Similarly, detailed check assaying programs have been run to validate grade data produced by commercial laboratories used during the exploratory drilling phase. Significant biases were established from both studies and appropriate 'corrections' were made to drillhole databases prior to final resource and reserve estimation. 3D geostatistical modelling has been utilised for resource and reserve estimation, with specialist consultants contracted for this work. At all times, interpreted geological controls on mineralisation, provided by

Jan 1, 1994

By B. J. Scheiner, A. G. Smelley

The Bureau of Mines, US Department of the Interior, is conducting research on a dewatering technique for fine particles generated during the mineral beneficiation process that will recover a portion of the water now being lost using conventional waste disposal methods and significantly reduce the time required for land reclamation. The technique utilizes a flocculant, polyethylene oxide (PEO), that forms strong stable flocs that can be dewatered rapidly on static and/or rotary screens. Infield tests, phosphate clay waste has been dewatered from a nominal 2.5% solids to greater than 20% solids. In other field tests, coal-clay waste has been dewatered from a nominal 3% solids to greater than 55% solids. In addition, small-scale continuous tests have shown that bentonitic clays can be dewatered from 12% solids to 40% solids.

Jan 1, 1985

By T. T. Chen

Gold in the Twin Creeks ore is primarily associated with arsenian pyrite. During pressure oxidation, the sulphides are solubilized, but part of the dissolved iron reprecipitates as jarosite and as an iron sulphate-arsenate-phosphate phase. The pressure oxidation products are subjected to cyanide leaching. The cyanide leach residues consist of quartz, gypsum, bassanite, anhydrite, small amounts of jarosite, an iron-sulphate-arsenate-phosphate phase, as well as trace amounts of orthoclase, rutile, pyrite, hematite and monazite; all these particles are dispersed in a fine grained matrix of illite-muscovite. The autoclave leach residues contain a small amount of carbonaceous matter. Many gold grains are detected on the surfaces of the carbon particles, and these gold particles are not leached during cyanidation. The gold particles are typically 0.1-0.2/Lm in size and commonly are embedded in the carbon surface or are coated with a K-AI-Si-S-O phase on the surface of the carbon. The gold grains are consistently associated with elevated CI contents (50-300 ppm Cl). The poor gold cyanide leach recoveries, which initially occurred in the Twin Creek developmental circuit under certain operating conditions, are attributed to the presence of chloride in the feed. This results in the formation of soluble gold chlorocomplexes in the autolcave and the subsequent sequestering of the gold on the surfaces of the carbon particles.

Jan 1, 2000

By W. V. Kotlensky, H. E. Martens

In an earlier communication, Ref. 1, the authors presented the tensile properties and the changes in crystal structure and microstructure for pyrolytic graphite tested at 2750°C. It was suggested that changes in the structure may have an effect on the tensile properties of this material. Accordingly, tensile tests were run on a series of specimens, from one block of pyrolytic graphite, some of which were hot-worked by being strained at 2750°C, others of which were tested in the as-deposited condition. According to the manufacturer, General Electric Co., the polycrystalline material was deposited at 2100°C on a substrate of synthetic graphite by decomposition of a dilute natural gas mixture. The as-deposited material had a density of approximately 2.19 g per cc, and as shown in Fig. 1 had a structure of medium size growth cones which were regenera-tively nucleated. All specimens had a gage section 0.75 in. long by 0.06 in. wide by 0.1 in. thick with the thickness direction perpendicular to the basal planes. The testing method and equipment used have been previously described, Ref. 2 and 3. For both the hot-working and the testing the load was applied parallel to the basal planes; a cross-head speed of 1.5 x l04 in, per sec was used. All heating was done in an atmosphere of bottled helium.

Jan 1, 1962

By Hillary W. St. Clair

The purpose of this investigation was to determine the practicability of refining crude aluminum-silicon alloy or aluminum scrap containing silicon and iron by selective dissolution in zinc of the aluminum from the alloy followed by distillation of the zinc from the aluminum.

Jan 1, 1949

By Lewis Carroll

AS he contemplates the numerous good things the hard-working committees have evolved for the 140th Meeting of the Institute, the Editor knows just how the walrus felt when he uttered his memorable, if somewhat lugubrious lines. For there are the Annual Reception and Dinner at the Commodore, 'the Gold Supply Symposium, the luncheons, general and special, and the Annual Institute of Metals Lecture, a Round Table on Iron Ore and a wonderful Informal Dance at the Grand Central Art, Gallery, substantial general sessions, a Smoker-and many other things. -Old, friends and new, reminiscences and confidential chats, horizons pushed back by new information and adjusted perspectives, courage revived and ambitions stimulated-one with a flair for the modernistic might make something-or nothing-of the kaleidoscopic preview 'of the coming Annual Meeting.

Jan 1, 1931

Effective pre-splitting is a key feature of wall control blasting. Most mining operations use historical designs or rules-of-thumb for designing pre-split blasts. If productivity and safety benefits are to be gained, these methods need to be improved in order to accurately predict pre-split performance. This will become more pertinent as overburden depths increase, placing more demands on the pre-split operation. A classical qualitative quasi-static description of pre-splitting (Kutter and Fairhurst, 1968) is presented and it is shown to give some useful insights into the pre-splitting process. In particular, it is clear that the time interval between the initiation of adjacent pre-split holes is a very important factor. In terms of this analysis, it is shown that current techniques which employ detonating cord as the surface initiation system are not optimal. A static quantitative model for pre-split design which has been widely reported is then discussed and its simplifying assumptions and their implications are examined. It is shown that several of the assumptions may be reasonably justified in the light of real pre-split results. It is concluded that the model should yield conservative designs. For this model, the key calculation of the blasthole pressure that is needed to determine the required explosive charge is highlighted. Popular methods employed in the literature for describing the expansion of real detonation products are shown to be inappropriate and an alternative method using the non-ideal detonation code, CPeX, is proposed.

Jan 1, 1995

By J. Duncan Keppie

"Auriferous quartz veins occupy zones of dilation. Foldgenerated dilation zones are systematically distributed and are dependent upon the folding mechanism. Comparison of natural and theoretical folds indicates that different mechanisms operated in the Halifax and Goldenville formations.In the slates of the Halifax Formation, the folds are of similar type and internal strain is most intense in the limbs. This internal strain is probably accommodated with little or no dilation.In the meta-sandstone and slates of the Goldenville Formation, a combined flexural and tangential longitudinal strain mechanism, modified by pure strain, produced the folds. Tension fissures produced by this mechanism are: (a) saddle 1'eef veins in slate horizons, (b) veins normal to bedding in meta-sandstone layers in the fold hinges,(c) veins along faults in the cores of tight fold hinges and (d) zones of en- échelon veins in slate honzons in the limbs of folds. Because veins in fold hinges (a, b and c above) account for most of the gold production in the Meguma Group, other factors controlling the distribution and size of these veins are summarized below.1. The size of saddle reef veins is controlled by the curvature of the fold hinge. Thus, a Curvature Index greater than 600 degrees indicates a promising prospect, where"

Jan 1, 1976

By G. Cailletaud, I. Guillot, D. Larouche, R. Martinez, D. Massinon

The precipitation of Al2Cu particles in a 319 T7 aluminum alloy has been modeled. A theoretical approach enables the concomitant computation of nucleation, growth and coarsening, based on an implicit scheme using the finite differences. The equation of continuity is discretized in time and space in order to obtain a matricial form. The inversion of a tridiagonal matrix allows us to determine the evolution of the size distribution of Al2Cu particles at t + dt. The fluxes of solute in-between the boundaries, as well as the ones at the boundaries, are computed in order to respect the conservation of the mass of the system. The main results of the model are compared to TEM measurements. Simulations provide quantitative features on the impact of the cooling rate on the size distribution of Al2Cu particles in good agreement with the TEM measurements. This metallurgical model is integrated into FEA software in order to perform mechanical computations. This kind of multiscale approach allows new perspectives to be investigated in the process of designing cylinder heads. It enables a more precise prediction of the microstructure, its evolution as a function of continuous cooling rates and its impact on the integrity of the structure.

Jan 1, 2015

This report, 27th in a continuing series1, describes Bureau of Mines research and technologic work on coal and related investigations during 1962. While the brief discussion in each section of the report presents only the highlights of Bureau work during the year, details of many investigations can be found in publications cited in this text. Other work, reported here for the first time, will be covered in greater detail in later publications. Recent trends in coal research and technology both at home and abroad were reviewed in several publications2. Bureau research, as in the past3, continued to stress improved methods of mining, preparing, processing, and using coal. The program included a wide variety of applied and basic studies for developing information useful to the coal mining industry and the coal consumer while promoting wise conservation and utilization of our coal resources.

Jan 1, 1963

By Takahiko Okura

Most non-ferrous raw materials are associated with sulphur. To extract the metals, the sulphur is recovered typically as sulphuric acid or liquid SOz, On the other hand, natural gas may contain over 20% of hydrogen sulphide (HzS) and a huge quantity of elemental sulphur is produced through oil and gas refining processes in the world. A large fraction of the sulphur mined from natural sources is eventually returned to the earth as fertilizers, by-products of desulphurisation and neutralisation processes, or as fugitives to the atmosphere. However, the supply and demand for sulphur are in imbalance. Such situation urges to develop a new smelting process without sulphuric acid production. This paper briefly reviews the global sulphur balance and the technologies for recovering elemental sulphur. The core of this paper is a proposal to convert SO2 gas to elemental sulphur by using organic materials. Some results of thermodynamic calculations and experiments are presented.

Jan 1, 2003

By Brinkmann J. R

In the narrow stopes of South African gold mines, rockbreaking is carried out by drilling and blasting with safety fuse and igniter cord being used as the initiation system. The fuse/gniter cord system is used primarily because of its low cost, however several limitations of this method include: inaccurate delay time, unreliable firing, inflexible application to varied configurations, and the absence of dynamic interaction between holes. Alternative initiation systems that incorporate millisecond timing are being developed to overcome the limitations of fuse(tgniter cord systems. Current investigations by the Stoping Technology Division of the Chamber of Mines Research Organization (COMRO) into the effects of millisecond initiation are being conducted at a deep test site. Experimental blasts using various millisecond delays and the independent firing of holes with fuse/igniter cord are being studied in order to quantify the influence of delay time on the blasting process and to identify the best methods of applying millisecond initiation systems. The effect of design variables such as delay time, hole firing pattern, stemming, and panel layout are discussed. Blast results including throw distance and direction, muckpile profile and rock cleaning times are used in the discussion of different combinations of blasting variables.

Jan 1, 1990

By R. E. Mitchell

Los proyectos mineros son revisados por medio de dos estudios: el primero es el Estudio de Impacto Ambiental (EIA) que evalúa proyectos mineros e industriales propuestos para obtener una programación reglamentaria y así ayudar al plan de desarrollo responsable de las compañías. El segundo sistema de evaluación es el Estudio de Impacto Social, Ambiental y sobre la salud (ESHIA) , cuyo enfoque es más inclusivo y comprensivo para evaluar potenciales impactos. En este sentido, el presente texto describe las normas de EIA para la provincia Alberta (Canadá) al tiempo que realiza un análisis comparativo entre el EIA y ESHIA.

Oct 1, 2012

By Wright S

The feed to the Cockle Creek Imperial Smelting Furnace consists of mixed Pb/Zn con- centrates and lead sulphate-containing elec- trolytic zinc plant residues. Roasting was investigated as a means of desulphurizing the feed to less than 1%. Laboratory studies showed that two process streams were required in which concentrates containing 20% Pb were roasted separately from the leach residues. The residues along with fume from the roast- ing and a portion of concentrate were desul- phurized by means of the roast reduction reaction. Conditions were defined to give

Jan 1, 1986

By Bob Burnham

Agenda 1 Overview of forecasting process 2 Review of Pre and Post Recession Forecasts 3 US Demand/Supply Summary 4 Coal Demand by Region 5 Coal Distribution by Census Region 6 Coal Price Outlook 7 Carbon Cases 8 Takeaways

Jan 1, 2009

By L. C. IlsLey

[In 1922 a conference of representative coal-mine operators, cable manufacturers, mining-machine manufacturers, and representatives of the United States Bur eau of Mines vas held at the Pittsburgh Experiment Station, regarding suitable cables for use with permissible raining machines. This conference recommended that the Bureau investigate rubber-sheathed trailing cables in order to obtain specifications for tests leading to approval for rise with mining machines. Effective until such time as an investigation could be made, the bureau asked the several manufacturers of approved mining machines to recommend cables for wise with their machines. In general the Cables recommended tentatively approved. Arrangements for the tests were completed in 1927. Concentric-type cables were investigated first, and Reports of Investigations, Serial No. 2909, covering the tests, was issued in January, 1929.]

Jan 1, 1929