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By A Bird

Gravity gold circuits have an important part in reducing operating costs and maximising recovery in modern gold plants where coarse gold is present in the ore body. The design and selection of equipment has a vital part in the overall effectiveness of the gravity gold circuit. There are a number of associated factors that need to be taken into consideration when selecting the most suitable equipment for gravity gold circuits including occupational health and safety, security and labour requirements. This paper is a case study that outlines the validation behind the design, selection of equipment and subsequent benefits of the recent upgrade of the gravity circuit at the Marvel Loch gold mine with the main component to the upgrade being the installation of a Consep Acacia Reactor. Since the upgrade there has been a significant increase in gravity recovery, which has reduced the amount of gold reporting to the leaching circuit therefore reducing reagent consumption and overall operating costs. There has been an increase in overall gold recovery and therefore increased gold production. The benefits to occupational health and safety include the removal of toxic gases being released in the gold room during the previous practice of gold concentrate calcination and the removal of the arsenic and nickel from the gold doré, which poses a risk during refining. Manual handling and security has improved as there is no physical contact with gold concentrates during the automated process using the Acacia reactor. The total time for gold room personnel working in the gold room has also reduced from around six hours per day to less than one hour per day.With the continuing development of low grade gold deposits, there will be an increase in demand for low capital, high recovery gravity gold circuits that can significantly increase overall production while reducing operating costs.

Aug 8, 2011

Past issues of Minerals and Materials have discussed such aspects of the economy as consumption and investment expenditures, interest rates, productivity, and international trade barriers and their effect on the minerals industry here and abroad. In this issue, we will (l) look at recent indications of a possible economic recovery, (2) present 1983 expectations reflecting the results of industry surveys conducted by the U.S. Department of Commerce (DOC), and (3) briefly discuss the contribution of the U.S. mining industry to total gross national product (GNP). THE RECOVERY Throughout most of 1982, DOC's Composite Index of Leading Indicators provided evidence of impending improvement in the economy. The index increased moderately during eight of the months in 1982 and then jumped an estimated 3.6 percent in January 1983 (table 1). While the leading indicators continued to predict improvement, the general economy, as measured by the Index of Industrial Production, continued its slide through November 1982 (table 2). Finally total industrial production increased in December 1982 and continued on an upward path in January and February, as predicted by the leading indicators.

Jan 1, 1983

By D. W. Scott

Ontario has a diverse industrial mineral resource base including abundant resources of structural industrial minerals such as sand and gravel, crushed stone, building stone, clay, shale, limestone and dolostone. These resources are used in the production of aggregates, brick, metallurgical stone, fillers, lime, cement and other construction materials. The majority of the operations are in deposits of Paleozoic and Quaternary age in southern Ontario, close to the major markets. Province-wide, there were over 140 million metric tonnes of aggregates produced in 1985, approximately 115 million tonnes of which was produced in southern Ontario with the remainder being largely from Crown land in northern Ontario. The structural industrial minerals account for over 80% of the value of total industrial mineral production, with the remaining 20% of the value king accounted for by the non-structural minerals being led by salt which is produced in southwestern Ontario. A host of other non-structural industrial minerals are known but production is currently restricted to calcite, gypsum, quartz, talc, nepheline syenite and by-product metallurgical sulphur products (Fig. 1). Location and Market Area Major production is in the area closest to the large markets of urbanized southern Ontario and the northeastern and north-central United States. In general, with the abundant variety and widespread resources of industrial minerals and the large population within 400 miles of most deposits, the market offers great potential. Ontario's 9 million population accounts for about 35% of the entire gross domestic product of Canada of $476.361 billion dollars in 1985. This equates to about 113 of the nation's buying power being within a 200 km (125 miles) radius of Toronto. This major concentration of industrial and economic activity has resulted in a well developed industrial minerals industry fulfilling most of the structural industrial minerals demand in Ontario, as well as a subsidiary demand in neighbouring provinces and states.

Jan 1, 1987

By R. E. Hucko

The goal of the U.S. Department of Energy (DOE) coal preparation R&D program is to develop technology to reduce the ash and sulfur contents of United States coals to levels such that the resultant product can be formulated into a high- quality solid or slurry fuel that could replace oil or natural gas in both new and retrofit applications. The Coal Preparation program is implemented by the Pittsburgh Energy Technology Center (PETC) and is conducted both in-house and by a cross section of industrial organizations, universities, and national laboratories.

Jan 1, 1986

By W. R. Hopkins

Over 95 percent of the world's refined copper is now produced by electrolytic processes. The bulk of this electrolytic copper comes via the conventional route for sulfide ores of concentration, smelting and electro-refining. A rapidly increasing percentage of world production is now achieved using hydrometallurgical routes involving dissolution of the copper values from minerals, purification of the resultant leach solution by solvent extraction and finally deposition as cathodes by electrowinning. The technology can now be considered mature and this paper endeavors to summarize recent developments which, from the authors' perspectives, are important.

Jan 1, 1989

In this paper, a number of novel hypotheses that provide a fresh perspective on the characterization of strata movements associated with longwall mining are developed by analyzing subsidence measurements with an influence- function-based computer program. With this influence-function technique, easily obtained surface displacements can be used to determine some of the complicated, expensive, and difficult to measure movements of the immediate roof strata in a longwall panel. The primary hypothesis developed by this analysis proposes the existence of an area of partial roof caving near the edge of a panel called the "edge effect." A second hypothesis, interrelated with the first, promotes the importance of the effect of gate-entry closure on the observed strata movements. Both the primary edge effect hypothesis and the secondary hypothesis concerning gate-entry closure are justified and quantified in an extensive analysis of surface subsidence that uses supporting information from related theories, design criteria and insitu measurements. Next, the edge effect and the gate closure hypotheses are extended further and used to provide an explanation of the complex subsidence interaction of adjacent longwall panels in what is termed a "redisturbed" effect. Finally, in the conclusions of this paper, the importance of accurately understanding these longwall strata movements for proper subsidence prediction or gate design is stressed.

Jan 1, 1986

By Jonas Addai-Mensah

Despite the fact that nickel (Ni) laterites accounts for about 60 % of the world?s nickel mineralization, commercial processing of complex, low grade Ni laterite ores by conventional beneficiation (e.g. magnetic, electrostatic and flotation separation) still presents intractable challenges, particularly in heap leaching. Invariably, low grade laterite ores require aggressive hydrometallurgical techniques (e.g., highly acidic lixiviant leaching at ambient or elevated temperatures) for Ni and cobalt (Co) extraction. As a precursor to heap leaching, agglomeration of the multi-mineral phase feed particles into robust and porous granules of 4-10 m permeable bed, is essential. In the present work, several basic and applied studies of the agglomeration behavior of real Ni laterite ores and selected oxides and clay minerals (hematite, quartz smectite and kaolinite) which constitute the predominant host gangue phases of typical laterite ores are performed. Isothermal, batch agglomeration tests involving sulphuric acid solution as a binder were carried out to produce coarse, narrow-sized (5 ? 40 mm) granules which were well characterized. The influential role of feed ore characteristics (e.g., mineralogy/chemistry and primary particle size distribution) and binder composition (30 vs. 44% w/w H2SO4) and dosage (15-25 wt.%) in agglomeration behavior and granule properties were examined through several characterization techniques including granule size, compressive strength, bed percolation and re-wetting stability and 3-dimensional micro-structure analyses. Links between feed mineralogy/chemistry and size, binder formulation, agglomeration behavior, curing conditions and final granule properties and structural characteristics are established. The implications of the findings to Ni laterite plant agglomeration for enhanced heap leaching are discussed. Keywords: nickel laterite, complex low-grade ores, agglomeration, heap leaching, micro-structure

Sep 1, 2012

By I Zulkarnain, H Permana, R A. Binns

Through an ambitious but relatively low-cost program of marine fieldwork, laboratory investigations and technology-transfer and training activities, three Indonesia-Australia-led marine expeditions were undertaken aboard KR Baruna Jaya VIII between 2001 and 2003. These IASSHA (Indonesia-Australia Survey for Submarine Hydrothermal Activity) cruises have sought to discover and investigate a variety of potential ore forming hydrothermal systems in a range of tectonic settings. All cruises have been successful, both scientifically and from the point of view of training, creation of capabilities and capacity building for such research in Indonesia. Over 60 scientists and technicians from Indonesian and Australian institutions and agencies have been involved. Three new sites and a possible fourth site of hydrothermal activity were discovered in the Sangihe arc in northern Sulawesi. Surveys in the Tomini basin tested a hypothesis based on previous data which suggested this might be an isolated anoxic, brine-filled basin over 2000 m deep where igneous heat sources existed to generate hydrothermal mineralisation. The bay, however, was found to be open to adjacent deep ocean circulation, and there was no evidence of massive base metal sulfides. Subdued evidence of hydrothermal activity was found in the Sunda Strait associated with the famous Krakatau volcano and the extension of the seismically active Semangko Fault. The BANDAMIN program (Indonesia-Germany) covered a portion of the Banda arc in eastern Indonesia, and also found evidence of recent hydrothermal activity and epithermal sulfide mineralisation.

Jan 1, 2004

By R. E. Gilmore

Introduction The Sydney coal-field extends for a distance of thirty miles along the northeastern coast of Cape Breton island. At a central focal point at the tip of the south arm of Sydney harbour, seven miles or so in from the Atlantic ocean, is the city of Sydney, with Port Morien to the southeast and Sydney Mines to the north . Mining centres along the ocean coast between these points include Birchgrove, Reserve, Glace Bay, and Waterford. The field is divided into three districts or 'basins', namely, Morien basin to the south, Glace Bay in the centre, and the Lingan-Sydney Mines basin to the northeast. The eastern and western portions of the latter are known as the Lingan and the Sydney Mines basins, respectively. Six distinct coal seams are described as existing in the Morien basin, nine in the Glace Bay basin, and six in both the Lingan and the Sydney Mines basin. Although known by different names in the several basins, a definite continuity of the seams has been established.

Jan 1, 1933

By N Takamatsu

The environments surrounding the iron and steel industry have changed greatly in recent years. Reported in this paper are the technologies adopted by the Japanese iron and steel industry to fititself to change in global steel demands, degradation of iron ore and coal, prolonging service life of the facilities and requirements of energy saving. In addition, innovative technologies for CO2 emission control in iron making processes are also discussed.

Jul 11, 2011

The Court rejected the suggestion that CRAE had actively misled DMR concerning the worth of its tenements. The Court agreed that CRAE remained silent about certain significant information concerning CRAE's own tenement area. It was a significant question as to what duties CRAE'was under, given that it was in joint venture with DMR in respect of one of the tenement areas. Did that joint venture create an obligation on CRAE to disclose everything it knew? The Court said no. The Court said that the fiduciary duties were defined by the terms of the farm-in agreement between DMR and CRAE. When the Court examined the disclosure obligations within the confines of the contract, it held that CRAE had not breached those terms.

Jan 1, 1990

By J. Urosek

Since the promulgation of the Mine Safety and Heath Administration?s (MSHA?s) Final Rule on mine seals (30 CFR § 75.335(b)), which became effective on October 20, 2008, many seal designs have been approved by MSHA and constructed by the mining industry. Since the effective date of the Final Rule, several issues on the design, construction, and/or inspection of seals have been brought to the attention of MSHA. Several such issues discussed in this paper include; the directional, design-load criteria required by MSHA for 50-psi seals, 120-psi seals, and greater-than-120-psi seals; the presence of fireclay in the surrounding strata where a mine seal is to be built; the measurement of convergence of the mine opening in which a seal has been constructed; where gob-isolation seals can be used; and the importance of periodic inspection of seals.

Jan 1, 2010

By A. O. Dufresne

The mineral wealth of pre-Cambrian rocks in Canada has been the subject of much study by geologists and engineers (members of this Institute), particularly so in the past few years, following discoveries of mineral deposits in areas far a part. This interest is well worth sustaining knowing the numerous rich producing mines within the pre-Cambrian formations, and the vast area covered by its rocks throughout this country. The pre-Cambrian has yielded minerals, both metallic and non-metallic; of these a much diversified list could be made. In more than one district we can point to mining as being responsible for the opening up of new sections, attracting a population into regions which otherwise would have remained virgin land of little commercial value. In these pre-Cambrian formations are found the rich copper deposits of Michigan, producing without interruption since 1845, and from which seven billion pounds of copper has been won; while in Minnesota and the adjoining district, at the head of Lake Superior, are mined iron ores which have rendered possible the great steel manufacturing industry of United States, the base of the economic structure of that wealthy country. The pre-Cambrian has given Canada the nickel-copper mines of the Sudbury district, the silver deposits of Cobalt and the gold camps of Porcupine and Kirkland Lake. With all of these our members are familiar; and it suffices to mention them to bring to mind pictures of the wealth and 'the growing population, in a word the importance of mining in?those sections of the country.

Jan 1, 1926

By Thomas T., Read

IT will be recalled that the first professor of metallurgy in the United States, appointed in 1855, never really gave any instruction in metallurgy and gradually turned into a professor of mineralogy. Metallurgy was included with. mining in the early curricula, two students who took the B.S. in mining engineering from the Polytechnic College of Pennsylvania in 1862 wrote their graduation theses on the metallurgy of copper and zinc, respectively. Even after Columbia School of Mines established, in 1868, a separate curriculum leading to the Ph.B. degree in metallurgy, very few students elected it,* preferring to take the mining degree, since they received in its curriculum nearly all the metallurgical instruction they would have in the metallurgical curriculum. For many years a large proportion of the men who attained prominence in metallurgical enterprises had taken mining rather than metallurgical degrees. METALLURGY Clifton Sorby's study of thin sections of rocks under the micro¬scope, beginning in 1850, and its subsequent development by Zirkel and others, had made microscopic petrography a recog¬nized department of geological research as early as 1873. . It was inevitable that the idea of studying polished metal surfaces-¬under the microscope by reflected instead of transmitted light would occur to investigators. Sorby himself did it in 1864, and Adolph Martens and Floris Osmond may -be especially named among the many European workers who, by the late eighties, had so developed the, necessary techniques that they were able to photograph polished metal surfaces at magnifications as high

Jan 1, 1941

By H. A. Wentworth

The Central Manitoba mining district, as spoken of in Manitoba, refers to that portion of the country lying between lake Winnipeg on the west and the Ontario boundary on the east, and from a few miles north of the Wanipigow (or Hole) river on the north, to a few miles south of the Bird river. It embraces two known mineralized belts; the gold area in the north, extending from the shores of lake Winnipeg almost to the Ontario boundary (in a slightly southeasterly direction) a zone some eight or ten miles wide and perhaps forty miles long, lying (for the most part) north, and parallel to, the Manigotagan river; and the Bird river copper and coppernickel deposits, an area not yet clearly defined, but in general lying immediately north of, and roughly parallel to, the Bird river. To the south of the Bird river is a somewhat differently mineralized area, numerous pegmatite dykes being found, with minerals typically associated with such rocks. More specifically, the known gold deposits are largely segregated in the above belt; (1) around English brook; (2) along the north shore of Wanipigow lake; the Rice lake area (about midway of the belt); and the Long Lake-Bulldog lake area, at the eastern end of the belt. Not all the known gold occurences are found in these segregations, but the density of claim staking in these areas is perhaps an indication of the greater number of prospects found in them to date.

Jan 1, 1925

By N. Dahmen

The Robbins Mobile miner has been in development for more than ten years. Two machines have been trialed in mining environments. While day to day performance to date has fallen short of the levels anticipated, instantaneous performance has been impressive for given rock conditions and continues to encourage further development. The Pasminco mobile miner has been committed for a 1.8km main decline extension at Broken Hill. M.I.M. Holdings, parent company of Mount Isa Mines, owner of the first mobile miner, are considering a new machine for McArthur River. Robbins, Pasminco, and The Centre for Mining Technology and Construction have, joined forces to accelerate development of .mechanical rock cutting techniques in general, and of the Mobile Miner in particular.

Jan 1, 1995

By T. Ueno

Naoshima Smelter & Refinery of Mitsubishi Materials Crop. commissioned a new Mitsubishi continuous copper smelter in May 1991. Process offgas volume of the conventional reverberatory furnace line, one of the previous smelters having been shut down, was very large and thus two acid plants had been operated. It was expected that the offgas volume would be reduced at the new smelter to about a half of the sum of those from previous two 1 smelters and the sulfur dioxide strength would be increased. So various alternatives were studied to minimize the operation cost. And it was decided to utilize both of the plants with minor modifications by diluting the gas either with air or with dilute gases. The acid plants now receive offgases from the new copper smelter, a sintering machine of a lead smelter and a decomposer of waste acid. The paper discusses plant design, operation, improvements and modifications realized in relation with the retrofitting of the copper smelter.

Jan 1, 1992

By T. Ueno

Naoshima Smelter & Refinery of Mitsubishi Materials Crop. commissioned a new Mitsubishi continuous copper smelter in May 1991. Process offgas volume of the conventional reverberatory furnace line, one of the previous smelters having been shut down, was very large and thus two acid plants had been operated. It was expected that the offgas volume would, be reduced at the new smelter to about a half of the sum of those from previous two smelters and the sulfur dioxide strength would be increased. So various alternatives were studied to minimize the operation cost. And it was decided to utilize both of the plants with minor modifications by diluting the gas either with air or with dilute gases. The acid plants now receive off gases from the new copper smelter, a sintering machine of a lead smelter and a decomposer of waste acid. The paper discusses plant design, operation, improvements and modifications realized in relation with the retrofitting of the copper smelter.

Jan 1, 1992

By L. F. Pett

ALTHOUGH Kennecott's orebody has long been outlined, it is still necessary to define further its limits. This mine, long an advocate of churn drill methods, recently supplemented its practice by using a diamond drill. So far, the diamond drill holes have been along the main canyon floor which traverses the mine area. This zone, highly fractured, is cut by numerous friable quartz veinlets encountered within the porphyry. These veinlets, formed by filling contracted porphyry fractures with hot, siliceous, mineral-bearing solutions, are often more highly mineralized than adjacent porphyry. They pulverize on contact, yielding only slight amounts of core.

Jan 7, 1951

By Kosei Morita, Osamu Nakano, Katsuhiko Nagai, Kazuhiro Mori

"The Sumitomo Toyo Smelter and Refinery commenced its operation in 1971 with three Peirce- Smith (PS) converters. “2 hot – 1 blowing” operation was practiced, that is one of two available converters was blowing and the other was standby in a hot state while the third converter was under repair. After several improvements, the stack time ratio reached around 90%; and processing 5 batches a day became possible.As a result of the expansion program of the Toyo smelter and refinery that started in 2001, the converter operation pattern was shifted from “2 hot – 1 blowing” to “2 hot – 2 blowing” with the installation of second converter blowers and an additional ladle crane.In 2005 a, the fourth converter was installed and “3 hot – 2 blowing” operation began. Also, with improvements experienced in the anode furnaces and the anode-casting wheel operation, today, the number of cycles has been increased up to more than 8.5 a day.The treatment techniques of fugitive gas containing sulfur dioxide from converter furnaces have been gradually reinforced, and the fixation rate of treated sulfur is currently being maintained at more than 99.9%. This paper introduces the operations described above, and the improvements in environmental management techniques for the Toyo PS converter operation."

Jan 1, 2009