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By James R. Yeager, Eric L. Hoffman, John R. Clark

"Abstract -This paper describes fire assaying and ‘high tech’ alternatives for gold analysis, including advantages and disadvantages of each method. These ‘high tech’ methods include INAA (instrumental neutron activation), aqua regia digestion/AA (atomic absorption), GFAA (graphite furnaceatomic absorption) or ICP/MS (inductively coupled plasma emission mass spectrometry) and a combination of cyanidation with AA, GFAA or ICP/MS methods.Fire assay remains the stalwart among analytical methods for gold but, even with its multiple analytical finishes, is not fool-proof for recovering 100% of the gold present. Consumers of assays should not blindly trust the assay results without consideration of quality control data. Laboratories can and do make mistakes. Some of these can be easily discovered if you do your own due diligence. All these measures should ensure that gold analysis values from successive campaigns and from different laboratories meet acceptable levels of accuracy and precision, and can be correlated together, particularly when they occur in neighboring holes. This is essential just as much for prospect evaluation as for project feasibility."

Jan 1, 1998

By Chan-ho Park

As the building has recently become bigger, higher, and freeform, a technology called BIM(Building Information Modeling), which is a key technology that integrates construction and IT(Information Technology), has been rapidly introduced and expanded. Because BIM technology offers various benefits, countries that introduced BIM early has been actively promoted. However, misperceptions of BIM are prevalent in countries such as South Korea that have adopted it relatively late, with lack of awareness of its fundamental purposes. Under these circumstances, transparent and quantitative performance assessment needs to be executed in order to eliminate the misperceptions, and to explain and revitalize the BIM introduction. These quantitative performance measure KPI (Key Performance Indicators) to be measured should be prioritized. As derive performance indicators in terms of the four types (financial, customer, internal processes, learning and growth), and performance management systems, Uses the BSC to seek a balance between short-term financial goals, values and the value of long-term goals. Uses the BSC(Balanced Scorecards) to derive performance indicators in terms of the four types (financial, customer, internal processes, learning and growth), and performance management systems, seeking a balance between the value of short-term financial objectives and the value of long-term objectives. Through this, the KPI (Key Performance Indicators) which is used for measuring the effect of the BIM will be generated and also the method that can determine whether the generated KPI figures are objectively inter-connected will be suggested as well.

Aug 1, 2013

By Jorge Loredo, Jesús Garía Iglesias

"Abstract - The Asturian fluorspar district consists of vein and stratiform deposits where mineralization is controlled by a combination of lithological and tectonic factors.It is postulated that these fluorspar deposits have been formed under disequilibrium conditions created during circulation of ascending hydrothermal solutions along faults and other high permeability conduits. Mixing of solutions is inferred from fluid inclusion studies. Cavity filing and replacement processes are very important in localizing the ore deposits and in determining their morphology.Permian volcanic rocks in the area yield a regional positive geochemical anomaly in fluorine implying that Permian vulcanism may be a possible primary source of fluorine.On a regional scale a relationship can be established between some of the ore deposits and important tectonic lineaments. The stratiform deposits preferentially occur within a calcareous-detrital facies located at the margins of basins. These basin margins are related to important synsedimentaryfaults.Fluorite is the only economic mineral in these deposits. Quartz, carbonates, barite and pyrite are comnmon minerals accompanying fluorite. Other minerals that may occasionally be present as minor components are: marcasite, chalcopyrite, fahlore, sphalerite, galena and related supergene minerals."

Jan 1, 1994

Heap leaching accounts for around 20% of the global production of copper. In heap leaching coarsely crushed ore particles are contacted with an aqueous lixiviant percolating through large packed beds (heaps) of the ore particles, with the loaded solution collected at the foot of the heap for metal recovery, solution make-up and recycle. While dominant for copper oxide acid leaching, it finds application also in copper sulphide (bio) leaching. Despite their apparent simplicity, heaps are in fact complex chemical reactors in which a number of competing sub-processes determine the overall rate of metal extraction. Therefore, meaningful prediction of copper production rates from heaps, as well as operational optimisation and control, all hinge on a comprehensive and quantitative understanding of these complexities. The paper gives a comprehensive overview of the various sub-processes in copper heap leaching and their interactions, including those relating to mineral-particle-solution-gas phase interactions at the micro-scale bulk transport and distribution of solution in unsaturated dense beds at the macro-scale. On the basis of a more fundamental understanding and modelling, the potential for optimized operation offers new opportunities for the extraction of value from both low-grade and complex polymetallic ores. INTRODUCTION Heap leaching is one of the percolation leaching technologies, which includes in situ leaching, dump leaching, heap leaching and vat leaching (Bartlett, 1998). The common phenomenon in all these technologies is the transport of leach solution through a fixed bed of ore particles, which interacts with the solid as it migrates along its path. The target minerals are released into solution and with its flow are carried out of the bed. The targeted dissolved metal species are recovered from solution through various hydrometallurgical techniques, especially solvent extraction (SX), before the barren solution is returned to the leach process. Heap leaching is practised in three main types of applications: sulphuric acid leaching of copper oxide ores, cyanide leaching of gold ores as well as the oxidative acid leaching of secondary copper sulphide ores, usually with the assistance of certain microorganisms and, more recently, in the presence of chlorides (CaCl2, sea water). While gold heap leaching dates back to the 1960s, large scale copper heap leaching commenced in Chile from the 1980s, and sulphide heap leaching emerged essentially as a consequence of acid leaching from mixed oxide/sulphide ores from the 1990s (Watling, 2006).

Jan 1, 2019

By N. Maleki

In recent years, research and development of magnesium alloys have been greatly promoted by the lightweight requirements in critical industries. The use of these alloys, however, has been restricted by their limited mechanical properties especially at high temperatures. The disadvantages can be overcome by producing Mg matrix composites. The Mg?Si alloys containing in situ Mg2Si particles have found a great potential as structural materials. Unfortunately, Mg2Si compounds are prone to form undesirable coarse Chinese script morphologies, which would deteriorate the properties of the materials. Refinement of microstructure is performed for improvement of wear and corrosion resistance. This paper investigates the microstructure and corrosion behavior of pure magnesium, unmodified and modified magnesium matrix composites reinforced with Mg2Si particles. The Mg2Si/Mg composite was prepared via a normal cast route, and then various amount of zinc was added to melt in order to modify the Mg2Si reinforcement particle morphologies. The microstrucrures were characterized by optical and scanning electron microscopy followed by EDX analysis. The corrosion behavior of Mg/Mg2Si composite was investigated by using potentiodynamic polarization measurements. The results showed that by addition of zinc, the average size of the primary Mg2Si became significantly decreased from about 100µm to about 20µm, as well as its morphology changed from dendritic to a polyhedral shape. However, by adding extra amount of zinc many primary Mg2Si particles become coarse again. It was also found proper amount Zn addition increased the corrosion resistance of Mg/Mg2Si composite.

Oct 1, 2011

By D. W. Davis, P. Landais, L. J. Robb

Nodules of carbonaceous matter have been observed in several Archaean peraluminous granites adjoining the gold- and uranium-bearing Witwatersrand Basin. These nodules, which resemble solid bitumen, usually replace uraninite or uranothorite and are paragenetically late. They show many similarities to kerogen seams and nodules associated with the conglomerate horizons in the Witwatersrand Basin, including composition, maturation, intimate association with uraninite, and a late paragenesis. U-Pb isotope ratios for granite-hosted and Witwatersrand kerogens define a single, albeit somewhat diffuse, Ph-loss discordia suggesting an upper intercept age of circa 2300 Ma. Carbon isotope analysis indicates lighter Ol3C values for the granite-hosted nodules than for the sediment-hosted kerogen seams. Raman spectroscopy indicates that granite-hosted kerogen is more highly ordered than Witwatersrand seam kerogen. A model is presented which links the granitoidand sediment-hosted organic matter to an event of oil generation in the Witwatersrand Basin circa 2300 Ma ago. Light hydrocarbons migrated through the sediments and into underlying/adjacent granitic rocks, undergoing polymerization and accumulation in response to radiation accompanying the presence of high-uranium phases.

Jan 1, 1994

By H. C. Cooke

"The Eustis mine, which was discovered in 1865, lies about 6 miles southwest of the city of Sherbrooke, Quebec, in lots 2, 3, and 4, range 9, Ascot tp. The mine was operated almost continuously from 1865 to 1937, under vanous owners.The ore was pyrite with varying amounts of chalcopyrite, a small amount of zinc blende and galena, and a low content in gold and silver. Parts of it ran quite high in copper, but the mine average would probably have been between 3 and 4 per cent. The high percentage of pyrite made it profitable to separate the ore into a copper concentrate and a pyrite concentrate. The latter was shipped away for manufacturing sulphuric acid, or was treated in a plant erected in 1887 at Capelton by the Nichols Chemical Company.The ore is a replacement of mica schist, which in turn was formed by the shearing of rhyolite flows. Ore also replaces the 'green rock', a term locally applied to carbonatized mica schists. The ore contained numerous 'horses' and smaller fragments of country rock, in all stages of replacement, ranging from those whose character was quite distinct to those whose ancestry could only be detected by an indefinite banding preserved in the sulphides."

Jan 1, 1954

By Ajit K. Sinha

"Electromagnetic surveys were conducted over the Yava sandstone-hosted lead deposit in Nova Scotia to evaluate the usefulness of such surveys for detecting and mapping sedimentaryhosted metallic ore deposits. Both transient and multifrequency systems were used for that purpose. The deposit consists of three zones of disseminated galena which also contain minor amounts of pyrite and sphalerite filling the interstices of the sandstone grains. Each zone overlies a basement depression and is separated from the adjacent zone by an intervening basement high. A conductive shale layer underlies the galena-rich sandstone formation at all three zones.Because the concentration of galena (3070 to 4% ) and other sulfides is too low to affect the resistivity of the sandstone formations for detection by ground electromagnetic (EM) methods, the strategy for our survey was to look for areas of basement depressions and the presence of conductive shale in those depressions by EM depth soundings. The presence of the galena-rich sandstone formations could be inferred because of the close association of these two features with the deposits in the Yava area. Both transient and multifrequency EM systems were successful in mapping the basement depressions and detecting conductive shale at the three known mineralized zones. The technique, therefore, seems to offer good prospects for mapping similar stratabound sedimentary-hosted sulfide deposits."

Jan 1, 1993

By Y. M. Shneerson, I. V. Fomenko, M. A. Pleshkov, E. A. Ospanov, A. A. Shakhalov, S. S. Naboychenko

Low-grade copper concentrates (with copper content less than 20%) often contain impurities such as arsenic, zinc, lead, mercury, antimony and bismuth. The pyrometallurgical treatment of such concentrates is associated with several problems, which will ultimately affect the cost and the quality of copper cathodes as well as by-products. SRC Hydrometallurgy proposed a complex hydrometallurgical technology which allows the removal of impurities and the enrichment of low-grade copper concentrates to a quality which will be more suitable for pyrometallurgical processing. Laboratory batch tests and pilot plant results for the pressure leaching steps are shown in this paper. The key parameters of the leaching steps were determined and optimized. The quality of possible by-products were also determined. The developed flowsheet includes two pressure leaching steps: pressure oxidation (POX) and hydrothermal alteration (HTA). Both operations are carried out at 170°C with subsequent flotation of POX and HTA residues and recovery of copper, zinc and lead into separate concentrates for further processing. The development of the flowsheet was based on the Balkhash Zinc Plant (Balkhash, Kazakhstan), which had been non-operational since 2009. The developed flowsheet for processing of low-grade concentrates will utilize 80% of the existing equipment of the Balkhash Zinc Plant, thus leading to a significant reduction in required capital expenditure. INTRODUCTION As the age of copper mining operations advance, copper grades continue to diminish and impurity levels increase. Therefore, copper producers are forced to look for new innovative hydrometallurgical technologies which are able to handle low-grade raw materials and solve problems associated with impurities in an economically justifiable way. New technologies allow to extract valuable components selectively and to process low-grade concentrates which had previously been marked as non-technological and economically unviable. Hydrometallurgical technologies for processing of copper-containing materials can be divided into two main categories: chloride and sulfate (atmospheric, autoclave and bacterial) based technologies. Since the 1970s, many autoclave techniques for the processing of copper-containing materials have been developed and implemented (Naboichenko, 2002; Dreisinger, 2005; Habashi, 2009; Shneerson, 2011). The mineralogical composition of the ore (or concentrates), geographical location of the deposit, distance from industrial areas, availability of existing treatment facilities, availability of skilled labor, cost of electricity and cost of neutralization are some of the factors which are usually considered when the appropriate technology is selected (Halbe, 2002).

Jan 1, 2019

By Mary Jean Buchanan

The last twenty years have seen the advent of environmental concerns and sustainable development, and the industry has witnessed the rise of Environmental Management Systems and their registration through several international standardization systems such as EMAS and ISO 14001. Beyond EMS and ISO 14001, which new goal the mining industry should aim at. Life-cycle assessment (LCA), another tool from the Environmental Management System series, is also on the rise and currently the object of an international standard (ISO 14040:1997). Through LCA, it is possible to assess the environmental aspects and potential impacts associated with products and services, taking into account all the activities required for its fabrication, its use, its transportation and its disposal. How could LCA be applied to the mining industry ? Is the international market pressurizing on mining companies to supply an ?environmental ore?? What about the automobile industry and its use of LCA ? Will it influence the ferrous and non-ferrous metal industry, suppliers of raw materials ? This paper presents a review of possible applications of LCA for the mining industry as well as world trends.

May 1, 2001

By Bruce C. Smart

"Very little attention was given to the regulation of uranium mills by the Atomic Energy Control Board prior to 1974. The ore grade treated by Canadian mills in the past was in the order of 0.08 - 0.3% U and it was not difficult to keep the exposure of workers well below regulatory limits. Furthermore, uranium milling has also been substantially free of occupational illness because environmental control has been generally satisfactory (l).The discovery of higher grade ore bodies in Canada has resulted in higher radiation levels in one mill and this has partly contributed to a need for increased radiation monitoring in the mill. In addition, as greater insight is gained on the effects of radiation, the implementation of the ALARA principle is being stressed at all mills.The concept of ALARA was emphasized by the ICRP (International Committee for Radiological Protection) in 1977 and stands for '""as low as reasonably achievable'"". It is based on the premise that no proven threshold for potential effects of radiation exists and that the actual individual exposure should therefore be kept as far below the regulatory limit as possible, economic and social factors being taken into account."

Jan 1, 1982

The original JKMRC AG/SAG mill model was developed over 30 years ago and has been upgraded a number of times since then, with the current published version being the Variable Rates model that is now over 15 years old. Since this model was developed further enhancements have been derived, some of which are applied in-house and some which have yet to be incorporated. The published and the commercially available model in JKSimMet is currently undergoing a comprehensive overhaul with a vastly extended data base for model evolution and validation. Improvements developed within the AMIRA P9 project, in-house development and a number of collaborative projects, are being incorporated into the upgraded model structure. Enhanced capabilities will include: power-based breakage rates scaling; a far wider mill filling range (from 10% to 40%) that exhibits peak in throughput as mill filling increases; higher ball loads; improved pebble discharge function; improved slurry discharge function incorporating important mill design and operational influences; and the new size dependent breakage function. The model will also be able to accommodate some influence of liner design and multi-component ores (blends of hard and soft components). This upgrade is still a work in progress but substantial changes have been made to date. This paper presents some of the new improvements and their influence on the predictive capability of the model.

Jan 1, 2012

By Pierre Boulanger

This paper describes a generic technology for modeling in real time the various operations of surface mines. Based on various sensor fusion techniques and high-speed network, a virtual reality model of a mine capable of representing not only static infrastructures but also mobile equipment such as trucks and excavators is created. The modeling technique deal with a wide range of sensors such as survey data, satellite pictures, ore concentration, machine condition indicators, video, sound, real-time GPS locator, range sensor, etc. The model created allows for every piece of information to be displayed in context allowing for a better temporal and spatial correlation of events by mine operators, planners, and supervisors. Syncrude, a Canadian mining company located in northern Alberta, is planning to use this technology, not only to understand oil sands mining processes better, but also to give decision-makers better access to the timely, accurate information from the field that they need to make informed decisions.

May 1, 2001

By Simon C. Dominy, Alwyn E. Annels, Mark A. Noppé

Abstract - Mineral Resources and their subsequent conversion to Ore Reserves are of key importance to mining companies. Their reliable estimation is critical to both the confidence in a feasibility study, and also to the day-to-day operation of a mine. Together with sampling, assaying, geological and other errors introduced during interpretation and estimation, additional errors are likely to be introduced during the application of technical and economic parameters used for conversion of resources to reserves. There is thus a requirement for high-quality interpretation and estimation to be supported by high-quality data. Any company expecting to make sound investment or operational decisions must base this on both relevant and reliable information. An Ore Reserve statement generally contains a single set of grade and tonnage figures without a discussion of the potential inherent errors in these estimates. Some sensitivity studies may be run, but confidence limits are rarely quoted and, if they are, often do not take into account many of the factors that cause uncertainty in the grade and tonnage estimates. Mineral Resource and Ore Reserve estimates thus carry certain errors leading to uncertainty and risk; some of these are unquantifiable for various reasons, for which the operator should be aware. This paper presents a review of the potential sources of error that might occur during a resource estimation program, which are carried through into the reserve estimate. A number of methods are discussed that allow the estimator to be more transparent about the inherent risks in his/her estimate. Emphasis is placed on data quality, and the requirement for strong quality management to be linked to continuous improvement.

Jan 1, 2002

By George Dogbe

Open pit optimization forms the basis of mine design, production planning and construction of mine facilities. The negative effects of this phase may include substantial reductions in ore recoveries, relocation of waste dumps and surface infrastructure, extraction of unwanted waste, with a cumulative effect on mine value reductions. As a result, this area has received significant research focus using linear and dynamic programming, heuristic, genetic and stimulation algorithms and the graph theory. These algorithms are derived from rigorous mathematical models, but they are built on the assumption that all the periodic production capacities are extracted at the time of analysis. This assumption weakens the models because mining occurs over significant time period. In order to develop a comprehensive model that accounts for the timing of material extraction, the current models, which are built on the economic block value (EBV) concept, must be modified to account for time. In this paper, the authors develop a model of the optimization problem using the 2-D Lerchs-Grossmann?s optimization algorithm. This model is used to investigate the effect of periodic discounting on the optimal pit layout design by designing an integrated pit optimiser (IPO) that incorporates ?production scheduling?. IPO uses the ensuing discounted economic block value (DEBV) as a basis for the pit optimisation process. The time-dependent model is compared with a time-independent model. The results show that discounting has no effect on the optimal pit contour although the reported pit value is overstated if the EBVs are used instead of the DEBV. The authors, however, believe that this conclusion may not be general and could have been influenced by the nature of ore body geometry and the proposed mining strategy.

May 1, 2004

By W. S. (Steve) Vaughan

The Origins of Joint Ventures in Canada?s Mining Industry ? Among the most important financing structures used in our mineral industry today ? Virtually unheard of in the Canadian industry prior to the 1970s ? Borrowed from the U.S. oil and gas sector where it came into prominence in the late 1930s ? The Securities Acts of 1933 and 1934 in effect killed the sale of (equity) shares for financing oil and gas wells and start up mining companies

May 1, 2013

By T. Patching

"MINING operations at the Star Key Mine provided an example of a small-scale prairie-type coal mine that employed several interesting procedures and achieved good productivity with low capital expenditures. The mine was located about 11 miles north of the city of Edmonton, on the north side of the Sturgeon River valley. It opened in 1945 and operated until 1979. Output in the winters reached about 500 tons a day in the late 1940s, but in the spring and summer periods activity was usually limited to only servicing and development work. In the later years of the mine's life sales fell to less than 100 tons per day. Most of its output was bought for domestic use in furnaces and stoves so production of large sizes was desired. A modest market for stoker coal did exist for a time. Screenings (-5 / 8 in.) were sold to the city's power plant until it converted to natural gas and were also used for thawing frozen ground for work on pipelines. These markets were comparatively small and the small sizes did not command as high a price as did the larger sizes. However the extension of natural gas services to rural markets cut into the domestic heating market and finally led to closure of the mine. The coal was strong when freshly mined, but because of its high inherent moisture content, about 25%, it did not store well on surface but tended to disintegrate. It was of subbituminous Crank with a heating value of about 8000 Btu per pound and burned with a clean flame. The seam mined was in the Edmonton Formation, of Upper Cretaceous age, at a depth of 60 to 80 ft below the surface. The seam in the mine area was about 11 feet in thickness but thinned gradually to the north and south and split to the west (1). It was approximately horizontal but gentle rolls in the floor of several feet in height necessitated brushing in places to produce suitable haulage grades. The floor material was of bone and clay, overlying a thin layer of coal. Above the seam there were only a few feet of mudstones and weak sandy shales while the remainder of the overburden was clay and unconsolidated glacial till and surface soil. Because of the soft floor and weak roof material the miners usually left about a foot of coal in the floor to provide a firm working surface and about a foot of coal above the rooms and two feet of coal above the entries to provide a competent roof."

Jan 1, 1985

By G. Viramontes-Gamboa

Approximately 70% of world copper reserves consist of the mineral chalcopyrite, and much international effort has focused on its study. Ultimate objectives include the development of environmentally friendly alternatives to smelting, and technologies to treat low-grade ores, for which concentration and smelting are economically unviable. Unfortunately, chalcopyrite leaching is inefficient in H2S04-Fe2(S04)3-FeS04 solutions, which is considered to be the most desirable oxidizing medium for leaching of copper sulfides, since the chemistry is well known, corrosion of industrial equipment is negligible, subsequent copper recovery by SXlEW is well established, and environmental impact is minimal. The main reason for this inefficiency is the self-passivation of chalcopyrite. We have devoted considerable effort in the understanding of this phenomenon, and have developed a predictive electrochemical methodology capable of establishing a priori the precise range of potentials within which chalcopyrite leaches and where it is passivated. Since potential control is a critical parameter in chalcopyrite leaching, this experimental methodology can be very useful for establishing the best conditions to leach chalcopyrite. In this paper, the scientific foundations of this predictive experimental technique are presented, and its practical application is demonstrated by comparing its predictions with leaching experiments from the literature.

Jan 1, 2007

By D. W. Morgan, K. W. Downes

"OVER half a million tons of chromite ore is used annually on the North American continent, all of which is imported from overseas. Chromite is essential in the manufacture of stainless steel, armour plate, and tool steel, to mention only three important uses. It is, therefore, a strategic mineral, and every effort should be made to discover a means of utilizing our domestic supplies.Both Canada and the United States possess deposits of chromite, but they are low grade with respect both to their chromium content and to the ratio of chromium to iron. Mechanical concentration can improve the chromium content •by rejecting gangue, but chromium concentrate produced is still lower in chromium than imported chromite and, more important, the ratio of chromium to iron is only about half that in the imported material. At present, a chromium to iron ratio •of 3:1 is desired by industry. To obtain this .ratio in the case of domestic ores, a chemical attack on the chromi'e is necessary."

Jan 1, 1952

By Gustavo Brunello

Motor Failure Rates and Cost ? Motor failure rate is estimated: 3-5% per year. ? In Mining, Pulp and Paper industry failure rate is up to 12%. ? Sometimes process downtime costs are higher than motor ?? Motor failures are due: Electrical 32% Mechanical 31% Environmental 36%

Feb 1, 2008