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By Chris McBean

Due diligence mistakes ? lost opportunity ? High profile write-downs and cost overruns ? Result ? tight market for financing ? Implications for due diligence ? need to get it right ? maybe only one chance ? Where should focus be?

May 1, 2013

This paper presents a case study where Cenozoic age detritals and an ancient buried landslide have been modelled in the final walls of an iron ore pit. Orebody 25 is located in Western Australia’s Pilbara region and is an operating pit where a redesign of the final wall cutback was required. The existing slope design utilised a simplistic geological model of mixed conglomeratic, calcretic and clay –dominated detritals overlying deformed bedrock sequences. This simplicity resulted in a conservative design that was not reflective of the slopes performance to that point. Further field investigation was carried out with the results assessed in conjunction with historic drilling, mapping and laboratory testing. A detailed geotechnical model was developed including three conglomerate and two clay dominated units and laterstage calcrete overprinting. The clay units were of significant importance to the stability assessment and resulting slope design due to the thickness and poor strength conditions indicated by the laboratory and field testing. However, the drilling investigation shed only limited understanding as to the origin of the clays and thereby how they should be treated as a component in the stability analysis. A comparison of the ratio of various geochemical elements measured by assay was made between the clays and 1) shale bedrock and 2) clays of known detrital origin from other nearby sites. This indicated the clays had a strong affinity with weathered bedrock. This and other textural features resulted in the interpretation that the clay units were relic debris preserved following ancient landslides in bedrock shale. Using laboratory testing data and calibration of results for a landslide origin, stability analyses were run, resulting in a steeper slope design being implemented. Excavation of the final cutback is now in progress with the model confirmed as appropriate.

Jan 1, 2015

By C. A. Sosa-Blanco

Minera Sabinas in central Mexico treats a complex sulfide ore containing galena, chalcopyrite, sphalerite and argentite as valuable minerals, and in some cases important amounts of non-magnetic pyrrhotite. For high pyrrhotite ores, results obtained by selective flotation showed good grades and recoveries in the lead-copper circuit, but a commercial zinc concentrate could not be produced due to the high floatability of pyrrhotite. When this is the case, an alternative method was proposed to produce a bulk concentrate by flotation which is then leached to recover copper and zinc from liquor in a SX-EW circuit. Leaching was conducted in an autoclave in order to study the effect of temperature and pressure, but bioleaching tests were also conducted. Leaching lead-silver residues were treated by cyanidation in order to recover silver values. The results obtained by selective flotation and by bulk flotation with leaching of the bulk concentrate showed that the latter alternative increased zinc recovery by 30 % with similar recoveries of the other metals.

Jan 1, 2007

By N. Erarslan, M. Ghamgosar

With the increased use of mechanized rock excavation, there have been developed internationally a number of methods to assess the abrasivity of rock materials. These methods range from determination of abrasive and hard mineral content using petrographic thin section analysis to weight loss or rate of wear flat development on specified test pieces. The Cerchar abrasivity index (CAI) test has been widely accepted for the assessment of rock abrasiveness and is determined as the abrasion of a steel pin after scratching over the freshly-broken or saw-cut surface of a rock. Two types of testing devices are in use today: (i) the original ‘Cerchar apparatus’, and (ii) the ‘West apparatus’, which was adopted herein. The CAI is calculated from the measured diameter of the resulting wear flat on the steel pin after 10mm scratching. This test has been considered to provide a reliable indication of rock abrasiveness for isotropic rocks. However, a great amount of rocks in natureis anisotropic. Phyllite is an anisotropic and foliated metamorphic rock and various types of phyllite specimens were tested in this research. Although phyllite is a type of rock primarily composed of quartz and the expected CAI value can be high, mechanical cutting of this rock should not be very problematic compared with igneous rocks have same CAI value. As phyllite is a foliated metamorphic rock, most of the specimens split into sheets through the quartz seam by the tip during scratching normal to the axis of quartz seams. Hence, viability assessment of Cerchar abrasivity test and F-Schimazek index values for the anisotropic rocks is investigated in this research.

Jan 1, 2015

By Carol A. Pilon

"IntroductionRECENTLY, the Saskatchewan Research Council (Saskatoon ) marked the completion of one of its coal-related projects with the publication of the Bibliography and Index of Coal in Saskatchewan and Adjoining Provinces and States, hereafter referred to as the Bibliography and Index of Coal. Over a two-year time period, literature was surveyed and indexed and bibliographic data were compiled using a computer-assisted information retrieval system called FAMULUS. The final publication contains 1150 bibliographic references, which are cross-referenced by six indices.The project was initiated in September 1974, in support of Saskatchewan's Coal Resources Evaluation Program , an ongoing research program sponsored by the Department of Energy, Mines and Resources (Ottawa) and the Province of Saskatchewan. This program places emphasis on such areas of concern as the occurrence of deposits, chemical and physical properties, calculation of reserves and computer-assisted applications for the evaluation of lignite resources in the Province. Attention is also given to aspects of geophysical exploration, mining conditions and economics, by-products and the transporting of lignite. These are the subject areas .covered by the Bibliography and Index of Coal.The over -all objectives of the literature indexing project may be enumerated as follows: (1) to build a specialized resource library by surveying established public and specialized libraries, and commercial data bases; (2) to enter library data into the FAMULUS information retrieval system, to be used to generate bibliographies and indexes, and to retrieve information by the use of specified searching techniques; (3) to make this library data available to interested persons."

Jan 1, 1977

By Warwick Bullen

A hypothetical economic model has been developed for diamond projects in the Canadian Arctic using data from recent exploration and mining projects. The model reflects economic conditions as it applies to the diamond mining industry in the Canadian Arctic at the present time. The economic model captures pre-production expenditures, production data, and post-production costs. Before- and after-tax cash flows are derived from the data along with the relevant economic criteria. From the corporate perspective, the model provides guidance as to the minimum size and/or in-situ value per tonne requirements of targets being sought in order to ensure economic success and probable exploration and development expenditures. From the government perspective, the model provides an indication of income and mining tax revenues that can be expected from a particular diamond project. The model shows, on average, diamond projects in the Canadian Arctic are expensive to explore for and develop, but are economically robust. They generate great economic return for mining companies and significant amounts of tax revenue for governments. The fact that diamonds can be transported directly from the mine site by air makes them particularly attractive targets for mining companies that operate in the Canadian Arctic.

Apr 1, 2005

By L. J. Cabri

A gold sample assaying 11.4 g Ault was selected for this study. Approximately 99% of the gold in this sample occurs as discrete gold minerals; the balance occurring as invisible gold in pyrite (determined by SIMS analysis). The sample was coarsely ground and sieved, yielding -38, 17, 22 and 22 wt.% in the -400+160 um, -160+80 um, -80+40 µm and -40 µm size fractions. Assays of the size fractions gave a gold distribution of -32, 20, 21, and 27% respectively. Processing with the hydroseparator (model HS-02) gave two tailings products and one concentrate from each size fraction. Assays of the concentrate from each size fraction gave gold recoveries of -7, 7, 24, 19%, respectively. Polished sections were prepared from each hydroseparation product and studied by image analysis to automatically search for gold minerals. Calculations were done using the surface area of the grains of gold minerals found on the polished sections.

Jan 1, 2005

By K. Yamaguchi

To contribute highly efficient and environmentally conscious copper smelting process, several topics in chemistry of the continuous converting were discussed. Through the reviewing the authors' thermodynamic simulations, it is recognized that small amount and low copper content of the coexisting slag is preferable. Some discussions were added to the Takeda's diagram for Cu20-FeOx-CaO ferrite slag, and the activity curves of the constituents were derived. Thermodynamic calculations were carried out on the copper contents of the slag during the blister copper formation. The dissolution of copper in slag decrease somewhat with increasing temperature, but the effects of increasing S02 pressure and decreasing %S in copper are considerable to increase in copper content of the slag. The optimum oxygen enrichment in the supplied air, and regulation of the oxidation degree for the blister copper are important in practice. The gypsum phase separation in the calcium ferrite slag was also evaluated thermodynamically, and concluded that decreasing temperature, increasing CaO content or S02 pressure, and extensive oxidation of the blister copper tend to separate CaS04.

Jan 1, 2007

By Robert B. Parsons

"Effective January 1, 1990, mines in British Columbia are subject to a new provincial mining tax statute, the Mineral Tax Act. Under this Act, mines are subject to a two-tier tax system, with a minimum tax payable on ""net current proceeds"" and a higher tax paid on net income. For many mines, the present value of tax paid under the new rules should be comparable to the amount paid under the old rules. Earlier cash payments could pose difficulties, particularly for smaller mines, but existing producing mines could benefit in the short-term.IntroductionEffective January 1, 1990, British Columbia has replaced the provincial mining tax regime under the Mineral Resources Tax Act with a new system under the Mineral Tax Act. The new rules borrow some ideas from other provinces (New Brunswick's two-tier concept, and Saskatchewan's indexed costs) with a view to levying a tax that is fairer to both the producer and the province."

Jan 1, 1990

By C. H. Knight

"THE OBSERVATIONS that follow are confined to simple wet cyclones such as the cylindro-conical unit developed by the Dutch States Mines and marketed in America under the trademark 'Dorr-Clone'. Energy to do the work comes from the inlet velocity of the feed slurry, which is usually pumped' to the unit by a centrifugal pump.Such cyclones are simply classifiers of enormous capacity and depend for their separating effect on differences in rates of particle settlement. These particle settling rates, of course, vary with particle size, particle density, particle shape, pulp viscosity, and pulp density.The dilution of the overflow product affects both pulp viscosity and pulp density. In most operations, the temperature and the composition of the liquid -hence its viscosity --are fixed, but both pulp viscosity and pulp density can be changed by changing pulp dilution.Since the separating effect depends on differences in rates of particle setting, a perfect split with 100 per cent of the particles coarser than a given size in the underflow and 100 per cent of the finer sizes in the overflow is not possible. Just how far the separation departs from this perfection can be calculated rather exactly from the following principles, which also apply to mechanical classifiers. In removing or settling out of the overflow product all particles up to a specified size, some of the finer particles must settle out simultaneously."

Jan 1, 1955

By L. B. Tsymbulov, L. Sh. Tsemekhman, A. N. Golov

Gipronickel Institute, JS is developing a process of continuous converting of Nicontaining copper matte and concentrates resulting in the production of blister copper and fluid NiO-containing slag in a two-zone Vaniukov furnace. The process under development is an alternative for the existing technology of blister copper production in converters, the latter being characterized with insufficient sulphur utilization, low direct copper recovery and the production of inconvenient for further processing solid slag on the basis of NiO and NiFe20 4- The results of pilot testing on processing of copper concentrate obtained from high-grade matte (HGM) separation in the two-zone Vaniukov furnace with the hearth area of 11.4 m2 are presented.

Jan 1, 2007

By Dennis E. Bell

"This paper describes exploration and development to 1982 in the southern half of the northeastern British Columbia (Peace River or Northeast Block) inner foothills metallurgical coal belt. Gates Formation, Fort St. John Group, is the primary target; Gething Formation, Bullhead Group, is secondary. This part of the belt remains wilderness when compared to its other parts. Practical formational and structural mapping is described. A local problem known as the Secus Mountain or Mount Belcourt conglomerates is discussed. The three major explorers have been Denison Mines, PetroCanada, and Crows Nest Resources, all with partners. Initial mine construction and rail spur construction are continuing. The new town of Tumbler Ridge is being built. Introduction This paper describes exploration and development to 1982 in the southern half of the northeast British Columbia metallurgical coal belt. The area (Fig. 1) trends 120 km northwest from the Alberta border to the Wolverine River and Bullmoose Creek. The belt averages 15 km in width, and is 20 km at its widest. Physiographically, the area is dominated by rugged inner foothills, with relief to 1,500 m. The trend of the structures is transected by a dozen rivers flowing southwest to northeast away from the Continental Divide. The Rockies, lying immediately to the west, control the climate. One fact continues to colour all coal work in the area. When compared to the other parts of the western Canadian foothills and Rockies coking belt, it remains the least accessible and least mapped portion. Lack of access also makes all work expensive. Current activity centres about two mines in construction at the northwestern end of the area. Denison Mines and partners are developing their Quintette project, and Teck Corporation and partners are developing their Bullmoose project. PetroCanada and partners have intensively explored their Monkman-Duke Mounta,in project, but mine construction awaits better economic times. The rest of the area remains lightly explored, with the exception of some intensive work on particular structures by Denison and Petro-Canada. The focus of coal work has been metallurgical bituminous coal seams contained primarily in the Gates Formation (Fig. 2) and secondarily in the Gething Formation. These formations are found in generally en-echelon structures ranging to several kilometres in width."

Jan 1, 1985

By Magella Pelletier

"IntroductionDepuis une vingtaine d'année, les nombreux travaux de géochimie effectués par l'industrie privée et les milieux gouvemementaux ont permis:• de découvrir de nombreuses zones minéralisées a valeur économique;• d'identifier et de vérifier certains patrons de dispersion géochimique au-dessu s de secteurs minéralises déjà connus;• de favoriser le développernent des techniques analytiques;• de forcer le développement d'une mise en carte des résultats d'analyse, qui soit plus adéquat afin de permettre une meilleure interprétation géochimique.L'une de ces cartes géochimiques qui permet le mieux de mettre en valeur les données analytiques et qui fut instaurée au debut des années 80, est la carte d'interprétation géochimique par pondération.Cette carte numérique semi-quantitative, qui est construite à partir des données de base et de l'importance des éléments indicateurs pour une substance donnée, permet d'identifier et de définir des zones possédants de fortes probabilités pour la recherché de sources minéralisées."

Jan 1, 1987

By W. H. Hodgson, A. R. Preston

"Improved rail production techniques provide new options for the rail user. Steelmaking improvements offer tighter composition control, lower oxide and sulphide counts, greater control of segregates and freedom from hydrogen problem s. New ultrasonic, laser and eddy current equipment gives printout information on surf ace flatness, straightness and internal condition. These have come along at a time when dramatic changes have occurred on the rail heat treatment scene. Rails can now be deep hardened on or offline in ways which should eventually result in a complete rewrite of the world's specifications. Rails of simple composition can be produced in the hardness range 2801400 BHN as required. The rail user can choose the hardness within this range according to requirement without the necessity for any step changes in the process routes.It is suggested that this is the pattern f or the next decade.IntroductionRails have been the subject of very slow improvement over many years but developments gathered momentum in the early seventies. Recent improvements in quality and properties have provided dramatic increases in rail life under the more severe service situations. Rail profile grinding, lubrication and other track improvements have greatly added to expectations of even longer life. All of this, coupled to even newer mill heat treatment developments, tilt both technical and economic advantages away from tradition to the point where specifications will need to be rewritten so that railroads can take full advantage of these new products."

Jan 1, 1988

By P. Archer

The Blondeau Formation has been examined in a stratigraphic drill section at Barlow Lake. The formation contains pyroclastic flows and volcanogenic sediments throughout, but epiclastic sedimentary rocks dominate the upper parts of the section. Five distinct types of pyroclas tic flows are known in the section, as well as minor mafic lava flows. Volcanogenic sediments are commonly intercalated with the true volcanic rocks. Sedimentary rocks include fine-grained intraclastic sandstones, heterolithic sandstones and green and black shales. Interpretation of the origin and relative disposition of the volcanic and sedimentary rocks favours a model of near-emergent vulcanism in an upward shoaling environment.

Jan 1, 1984

By Thomas Mütze, Frank van der Meer, Gunnar Kretschmar

"The air classification of moist bulk materials is addressed in the literature insufficiently. Therefore a feasibility study investigated the influence of feed moisture on the separation efficiency expecting a reduction with higher moisture content in the feed. Two iron ore samples were characterized in terms of the nature of bonding of moisture as well as its effect on the agglomerate strength. The classification tests themselves were conducted with two dynamic laboratory air classifiers at cut sizes from 45 to 110 µm and a moisture of the feed material between 0 to 10 wt.-%. The quality of classification was assessed by split factor, cut size, separation efficiency, moisture of both products, as well as the yield of the fines as product fraction in a corresponding processing plant. An initial approach was found for a technological implementation: A sufficient drying of a moist feed can be realized simultaneously to the pneumatic transport inside the classifiers. In the present case the drying effect and dispersion intensity was sufficient to provide good separation results up to 3 wt.-% feed moisture. An additional drying step was necessary beyond 3 wt.-%.INTRODUCTIONSpecific information about the influence of moisture in air classifiers is very rare. Mostly only dry products are processed and/or drying prior to classification is recommended. Apart from the specific influence of the feed moisture a lot of literature can be found regarding air classification itself. Altogether air classification can be divided into several sub-process (Leschonski, 1977):- dosage of the feed material,- dispersing the solid feed material into a gas stream,- feeding the dispersed material into the classification zone by pneumatic conveying,- separation of coarse and fine particles, and- separation of fine particles from gas.For wet feed particles also drying plays an important role. Interesting for the present investigation are the humidity of the feed and its influence on the single sub-processes."

Jan 1, 2016

By W. Kunda, J P. Warner

SHERRITT GORDON Mines Limited annually produce 300,-000 pounds of pure cobalt by processing a nickel-cobalt-copper-iron sulphide ore which is mined at Lynn Lake, Manitoba. The ore (containing 0.04 per cent Co) is •concentrated to give a concentrate containing l 1-12 per cent nickel, about 2.0 per cent .copper, and 0.25-0.35 per cent cobalt, which is treated at the Refinery in Fort Saskatchewan, Alberta. The concentrate is leached in an ammoniacal solution of ammonium sulphate using compressed air as the oxidant. After filtration the leach solution contains, besides nickel and cobalt, copper ammines, sulpharnates and salts of various thionic acids. The copper is removed by precipitation as sulphide and the sulphur compounds converted to ammonium sulphate by a combined oxidation and hydrolysis treatment. The purified solution •Containing about 45 gpl of nickel and 1 gpl of cobalt is treated with gaseous hydrogen under pressure at 350°F to precipitate metallic nickel powder, the precipitation 'being terminated when the nickel content of the solution is about 0.8-1 gpl. Only about

Jan 1, 1962

By D. Runnels, Daniel Roy, Ricardo Esteban, J. Torrealba-Vargas

"An intuitive way to reduce power consumption in grinding operations is to feed the grinding circuit with finer feed by enhancing blasting and fragmentation control. The optimization of blasting with the objective of minimizing power consumption in grinding is not new.The study was based on a Canadian mine that processes a very hard ore. BBA conducted blasting/fragmentation and grinding circuit surveys in 2014. The results of the exercise were used to develop a base case model to simulate the effect of blasting in the operation on the grinding circuit. Tools for fragmentation simulations, particle size measurement and crushing/grinding simulations were used with the objective of reducing the OPEX costs including power consumption.The paper describes the steps involved in the model optimization as well as an economical evaluation of the OPEX savings.INTRODUCTIONIn 2014 BBA was retained by one of its clients to conduct a crushing and grinding survey. The objective of the survey was to update the grinding circuit model with production data and also to develop a tool to investigate opportunities for process improvement.A second phase of the study involved the development of drilling and blasting and crushing models. The models were used to diagnose the operations and to investigate opportunities for process improvement.The objective of the present study is to describe the approach and to identify potential improvements to overall mine site operating costs by better integrating mining and milling operating costs with blasting and grinding models."

Jan 1, 2016

By R. Q. Honaker

A significant problem in ultrafine particle classification is the significant amount of submicron particle by-pass to the coarse particle stream. In classifying cyclones, submicron particle by-pass to the underflow stream can be reduced by decreasing water recovery. Past studies have shown that a reduction can be realized when the feed solids concentration is increased or the apex diameter is reduced. However, both adjustments tend to increase the particle size cut point and negatively affect classification efficiency due to the impact on slurry rheology. The addition of a viscosity modifier to the feed stream of a classifying cyclone improved the classification performance and decreased the particle size cut point over a range of feed solids concentrations. The detailed test program investigated the use of the modifier in conjunction with varying apex diameters to identify conditions that minimize ultrafine by-pass. With small apex sizes, roping conditions were readily eliminated by the addition of viscosity modifiers. The addition of the modifier had no deleterious effect on froth flotation performance, which commonly serves as a downstream separation process. The fundamental and practical benefits of viscosity modifiers in classification processes are discussed in this publication.

Jan 1, 2006

By J. O. G. Sanderson

Introduction In this paper it is proposed to review the history of petroleum geology in western Canada, to discuss some of the main events which have affected its progress, to mention its relationship to the petroleum industry, and, finally, to appraise its present status and possible future importance. It will be useful first to consider the meanings of the terms petroleum geology, petroleum geologist, and the petroleum geology of a terrain. Petroleum Geology. - In simplest terms, geology is the science of the earth. Hence petroleum geology is the science of that portion of the earth that encloses pools of petroleum. The systematic delineation and study of stratigraphic geology began about 1820. The systematic development and study of petroleum geology started about 1910. It is a relatively immature branch of geology. Petroleum Geologist. - This term may be applied to a fully qualified geologist who is engaged for a time, be it a job, a contract, or a lifetime, in the work of finding and developing deposits of petroleum and related substances. No man may properly be called a petroleum geologist who is not first a fully qualified geologist.

Jan 1, 1946