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By Robert B. Parsons

"The February 18, 1987, Federal Budget contains a proposed amendment which would simplify somewhat the ""successor corporation"" rules in the Income Tax Act. Despite this amendment, though, the important successor rules will continue to be relatively complex.IntroductionThe February 18, 1987, Federal Budget papers propose an income tax amendment whereby the so-called ""successor corporation"" rules would be revised by removing the present provision which limits the application of these rules to a maximum of two ""successions"". The successor corporation rules represent one of the most complicated sets of rules in the Income Tax Act. This month, Tax Notes seeks to explain these rules and the proposed amendment in simplified terms.Basically, the successor rules provide a mechanism for transferring unused exploration and development expenses from one taxpayer to another , in specified circumstances. The aforementioned limitation of two successions refers to the rule which allows a maximum of two such transfers with respect to any particular pool of deductions."

Jan 1, 1987

By P. J. van Staden

Several differences exist between the columns used for laboratory simulations of heap leaching and commercial heaps. Column walls support part of the weight of the ore and restrict the particle packing arrangements. Columns are typically of a diameter that is smaller than the dripper spacing to be used on the commercial heaps. The stacking practices that cause segregation and stratification on heaps are absent from columns. Intuitively, these physical differences would be expected to be the reasons behind the observed differences between column and heap leaching performance. But how can they be quantified, and what is the magnitude of the differences? Could some of these differences be built into column leaching experiments in order to better simulate commercial-scale heap leaching performance to ease the scale-up calculations from column leaching data? Alternatively, could heap construction practices be improved so that the ideal performance obtained in columns could be emulated on heaps? Data from a few heap leaching cases studies that permit direct comparisons between column and heap leaching performance is analysed, to reveal the extent of the differences in resistance to mass transfer. Discussion is provided on the implications for column and heap leaching practice, and for scale-up design procedures. INTRODUCTION Differences have been known to exist between leaching performance observed in laboratory columns and that of commercial-scale heaps. Both the heap leaching kinetics and finally achievable extent of extraction are generally found to be inferior in heaps compared to that achieved in columns. Heap leaching design engineers extrapolate the anticipated heap leaching performance by multiplying the time-axis of a column-leaching curve by a factor of about 2 and the extraction-axis by a factor of about 0.8, as explained by Jansen and Taylor (2002), Scheffel (2002), John (2011) and Scheffel, Guzmán, and Dreier (2016). The procedure is illustrated in Figure 1 by means of a hypothetical example. The solid line represents the leaching performance observed in a laboratory column, and the dashed line represents the anticipated leaching performance of a heap, extrapolated from the column leaching data using these empirical scale-up factors.

Jan 1, 2019

By George B. Saunders

The mines in western Canada producing steam coal will find a better opportunity this year to market their product in Winnipeg - for two reasons: First, the new wage schedules, signed with local unions at each mine, have enabled them to reduce the selling price materially. Second, the duty on slack coal coming in from the United States has been raised to 50 cents, which is equal to the duty on run-of-mine coal. This has had the effect of raising the cost of mine-run to .the importer. Formerly, it was the practice to bring in slack coal under a duty of 14 cents and lump coal under a 53-cent duty and, by judicious mixing of the two, manufacture a mine-run coal at an average duty cost of about 22 cents. Fortunately, through efforts of the Alberta Government, and other friends of the Canadian coal trade, the Federal Government was persuaded to adjust the duty on slack coal as indicated. While it will be found that the Manitoba market, this season, is slightly more easy of access we have still a long way to go before we reach the desired goal. Geographically and economically the Manitoba market should belong to western Canada. However, it has been found a very profitable market for United States mines because large tonnages of coal can be shipped, practically at the convenience of the mines, via the Great Lakes, during seasons of slack business. They will therefore not relinquish this market without a struggle.

Jan 1, 1925

By M. Leroux, C. J. Martin, S. R. Rao, J. A. Finch

"The effect of nitrogen on the flotation separation of sulphides from complex ores from Brunswick Mining and Smelting (New Brunswick) and Mattabi Mines (Ontario) was investigated. The most significant finding was enhanced pyrite floatability after as little as 3 minutes nitrogen conditioning. This was used in a novel sphalerite/pyrite separation process developed on the Brunswick ore. After aeration and Cu/Pb bulk flotation in air using xanthate the slurry was nitrogen conditioned, xanthate added and the pyrite floated in nitrogen. As an example up to 70% pyrite recovery with about 20% sphalerite recovery was achieved. Sphalerite was recovered from the pyrite tailings and the pyrite concentrate by copper-activation, raising the pH to 10 and floating in air. About 65-70% recovery at 35-40% Zn grade was achieved compared to 25% Zn grade by the conventional route. The process offers a promising alternative to current practice which seeks to depress pyrite at all stages. A possible mechanism of the effect of nitrogen is presented. INTRODUCTIONUse of gases other than air in froth flotation has been reported from time to time. [Podobnik and Shirley, 1982; Lin and Metzer, 1975]. Of all the gases, nitrogen would appear to hold the greatest practical promise because of its easy availability and chemical inertness. It is used in froth flotation in chalcopyrite-molybdenite separation [Redfearn, 1983]. The use of nitrogen in polysulphide chalcopyrite. this case is mainly to reduce the oxidation of a compound (Nokes reagent) used as a depressant for There is no reported use of nitrogen in the flotation of other sulphide minerals."

Jan 1, 1988

NANA Accepts Mining ­ 1974 - Leadership presented mining option to people ­ Community meetings; recognized need for cash economy ­ 1979 - Poll shows consensus in favor of mine development ­ 1980 - Shareholders approve mining; Congress approved land selections

May 1, 2002

By J. H. . MORGAN

Talc-soapstone deposits exist in Patton Township of Quebec and have been mined by Bakertalc Inc. or its predecessors since 1938. The company produces products ranging from purified and micronized talc through to soapstone lumps. The deposits are found within serpentinite dykes and are zoned. Zoning grades from a serpentine core through zones of talcmagnesite, schistose talc and talc-chlorite schist be/ ore reaching the wall rock of quartz-sericite-chlorite schist. Talcmagnesite zones generally comprise 80 to 90% of the mined rock. The serpentinite dykes containing the talc probably were originally post-Ordovician peridotite of the same series that hosts the Eastern Townships asbestos deposits. Alteration of serpentine to talc-soapstone and magnesite apparently resulted through addition of silica and carbon dioxide along shears and fractures. Talc concentrations occur also at the intrusive contact between dykes and wall rock. The present Bakertalc Inc. operation at the Van Reel Mine is being worked from an inclined shaft 200 m below surface. The talc rock undergoes a variety of milling processes, depending on its particular market, be/ ore being bagged and shipped.

Jan 1, 1984

By F. R. Deluca

"ClassificationClassification is a combination of mechanical and hydraulic operation which separates a pulp into two portions according to their respective settling rate. The finished product, the overflow, is removed from the other product, sand, which requires further grinding.Pulp is the uniform suspension of solids in a liquid. Overflow is the fines and therefore the more slowly settling portion of the pulp which is carried over the top of the classifier by the flow of water; sand is the coarser and more rapidly settling portion of the original pulp which is discharged from the classifier by the mechanical action of the rakes or conveyed out by a ""screw"" .Selective classification is classification that has for its object the concentration of the heavy constituents of the original pulp in the sand product so that it may be ground finer than the lighter constituent.Classification is used as follows:I. To make a size separation, for example, a sand-fines separation so that each product may be given a different treatment.2. For closed circuit grinding so that the maximum size of particles entering the circuit is limited, and so that the useful work is increased by enabling the mill to operate mainly on the particles that require the reduction.3. For differential grinding of the heavy mineral constituent and the gangue. In this case, the heavy mineral is concentrated in the sand product and is reduced further, while the lighter gangue material overflows the classifier.The selection of the proper size and type of classifier is determined by the function required, the character of the ore, and the tonnage to be handled, the initial cost and the operating cost."

Jan 1, 1989

Stope performance and geotechnical information at Xstrata Zinc George Fisher Lead-Zinc-Silver mining operations have been analysed in detail since the beginning in October 2003. This work has been included in a joint dilution study between Xstrata Zinc and the University of Saskatchewan. This paper presents an analysis of site geotechnical data and stope reconciliation that led to major changes in stope design, a reduction in dilution, and a significant increase in mining efficiencies. Detailed geotechnical data collection for a mine site or particular stoping area represents a large amount of information which is time consuming to review. However, it is this data that can make a significant difference in rock mass behaviour understanding. Simplification and averaging of conditions into zones of similarity, called structural domains, are common approaches for managing large amounts of data. There is a tendency to average rock mass properties to obtain inputs for numerical modelling and empirical design tools. This approach may be misleading if the inhomogeneity of the rock mass is contributing to the failure mode. This paper summarizes a novel approach for rock mass characterisation and stope design in a bedded sedimentary rock mass.

Apr 1, 2005

By Miguel A. Cuba

Resource models are generally constructed using data of different types and/or from different sources. A common issue is the consistency of scale in the information that often leads to a requirement to composite the data prior to model construction. For the purposes of mine planning, development and/or resource assessment, this model may then be upscaled to a relevant selective mining unit. It is well established that the geostatistical parameters for resource model construction is scale dependent. In particular, the volume variance of integrating these various scales has a direct impact on the variogram that should be used in model construction and/or the assessment of volume variance relations as it affects resource estimation. The scaling laws are a set of guidelines that detail how the variogram should change as a result of a change in the volume; these laws are empirically derived and involve some simplifying assumptions, not the least of which is an assumption of shape invariance in the variogram structure. An alternative approach was proposed to directly upscale the variogram via numerical integration, which demonstrates that the assumption of shape invariance is not required and we can directly access the new variogram shape given any volume of interest. This paper compares these two different approaches to variogram upscaling by considering two applications: the first corresponds to a 2D synthetic case and the second looks at a 3D case with data from a porphyry copper deposit. The simulation studies in these cases show that the direct upscaling approach performs better than the scaling laws in fitting the average experimental variogram values at any block size. This is based on a mean absolute error criterion. Moreover, it is also shown that with an increase in the block size, direct variogram upscaling significantly outperforms the scaling laws approach.

Oct 1, 2009

By N. H. Grace

"IntroductionA STRIKING FEATURE of the past twenty years has been the application of organized scientific and industrial research to problems of national defence and security and to the development of our natural resources. It has been shown that effective research improves public health, increases the productivity of land, makes mineral wealth available, and increases the efficiency and productive capacity of industry. Alberta is a region bounteously provided with a variety of natural resources, and the Province has entered into a period of unprecedented industrial development. There is, surely, a great opportunity to bring scientific research to bear •on problems associated with the development of these natural resources.I propose to spend a little time discussing the term 'research', indicating something of the various types of research and those fields which appear to •be the particular responsibility of government bodies. It seems logical, also, to outline the course of development .of industrial and scientific research in the English-speaking world during the past twenty-odd years.Research is investigation, examination, or enquiry, and involves the application of human thought, and actions, to the unfolding of new knowledge. That knowledge may assume a variety of forms. Fundamental knowledge may be new facts related to some form of matter, to motion, space, thought, and so on. Those engaged in applying the natural sciences have no monopoly on research as this term is equally valid for those engaged in obtaining, sorting, relating, and interpreting the facts of history, literature."

Jan 1, 1952

By LeRoy A. Thorssen

The use of lightweight aggregate as a constituent of concrete is not a recent development. Pumice was used by the early Romans, in pozzolana cement concretes, in the construction of many of their works. However, the recent development of manufactured lightweight aggregates, such as the expanded shales, vermiculite and perlite, has created a possible use for a whole new group of Portland cement concretes. Concrete can now be produced with unit weights ranging from 30 to 150 pounds per cubic foot and with various insulating, fireproofing, acoustical and structural properties. The tonnage of such materials being used has increased considerably in each of the past ten years, and can be expected to increase for the next several years as availability of the aggregates becomes more widespread and the properties of such concretes become more thoroughly investigated and more generally known. LIGHTWEIGHT aggregates of many types have become avail-able to the construction industry in most localities on this continent

Jan 1, 1963

By Lawrence B. Cochrane, Olivier Tavchandjian, J. Michael Anderson, Christopher R. Davis

"Abstract - Resource modelling is a complex process involving different specialists with relevant experience using a multi-disciplinary approach and the best available technology and reviews by independent auditors. The reliability of the final resource estimate is highly dependent on the quality control exercised at each stage of the process. At each step in the resource modelling process it is necessary to define the specific objectives, the methodology proposed to achieve those objectives and to establish a set of checks and validation tools to assess the effectiveness of the proposed methodology. Designation of responsibility and authority for meeting these objectives must also be clearly identified. External audits must also be incorporated to review and validate the implementation of new procedures.Resource modelling is the basis for any economic appraisal of a mining project and includes a number of steps from data acquisition and validation to resource reporting, classification, and risk analysis."

Jan 1, 2001

By G. E. Agar, W. B. Kipkie

"This paper deals with the prediction of locked cycle flotation results from data developed from individual batch tests. A postulate is made that the distribution of material in a separation stage is determined by the chemical conditions and the flotation time and that this distribution can be characterized by split factors which are constants for a fixed set of conditions. With this premise, it is demonstrated that a steady state balance can be calculated for a circuit.Although the necessary equations can be solved algebraically, a computer program was written that uses an iterative tec1nique to arrive at the steady state balance. The program is written so that a variety of circuits can readily be simulated.A number of examples are examined to demonstrate the validity of this simulation procedure. The sensitivity of the material balance to changes in the split factors was examined. Data developed from different flowsheets is presented on sulfide ores, on copper-nickel separation and on silver flotation,"

Jan 1, 1978

By John C. Loretto

"Answers to some of the problems ofRecovery and Metallurgical AccountingIn Gold and Silver Hydrometallurgical PlantsThe start-up over the last few years of new hydrometallurgical plants for the recovery of gold and silver has brought to the surface again a number of problems. Most of the problems have existed for some time and they manifest themselves mainly in two ways. Firstly, the plant results do not agree with the Metallurgical Test work figures and secondly, the Metallurgical Accounting figures do not balance.The plant results not agreeing with testwork figures are mainly due to:a) The testwork samples were not representative of the eventual plantfeed;b) Misinterpretation or misunderstanding of testwork;c) Plant losses;d) Plant design not allowing testwork results to be achieved;e) Operating deficiencies.a} The testwork samples being dissimilar to the plant feed occurs on a very high proportion of projects. The effects of this can beccr.ie exaggerated because the upper levels of the mining company often regard the original testwork figures as sacred and therefore base their judgement of current plant performance on these figures.Frequently the test work samples represent only a minor part of the orebody or alternatively a single composite of the whole ore body is used for the testwork long before it has been determined that all of the potentially different ore zones behave in the same manner. These errors can be compensated for by repeating the ""testwork tests 11 on current plant feed on a routine basis and using these tests to determine whether or not the plant is operating satisfactorily."

Jan 1, 1982

By Roger V. Pierce

"WITHOUT mineral wealth, modern man would not exist. True, man could survive on a stone-age basis with an average life expectancy of, say, 25 to 30 years -once he got past infancy.However, no metal would tip his arrow in a hunt for protein; no steel plough would break the soil for the organized planting of seed; and no coal, nor oil, nor natural gas nor uranium fuels would pro-vide him with light or beat or safety from either beasts, or other men, or an unkind nature that threatened him and his family.Modern agriculture, fishing and forestry represent the other three wealth-producing industries. With-out metals, non-metallics and energy minerals, however, it would be impossible to fit any of these to man's modern needs."

Jan 1, 1967

By Eric D. Marks

Fatalities resulting from ground workers colliding with objects and construction equipment accounted for approximately 18% of the total construction fatalities experienced in 2010. Current injury and fatality measuring methods have proven to be inadequate due to their use of passive measures of safety rather than a more active approach, such as the use of leading indicator data (also called near misses) of hazardous proximity situations between ground workers and heavy equipment on construction sites. The objectives are to create and evaluate the effectiveness of a reliable algorithm for collecting and analyzing the resulting leading indicator data from hazardous proximity situations. Numerous experiments emulating typical interactions between workers-on-foot and heavy equipment are used to evaluate the proximity sensing and detection technology. Safety leading indicator data (also called near misses) generated by the proximity sensing and detection technology during the experimental trials are used to create and assess the resulting algorithm. Results from the experiments indicate that leading indicator data generated from these systems can be processed and analyzed to identify hazardous proximity situations and incidents on construction sites.

Aug 1, 2013

By Paul J. Beck

The impact of mining development on the environment can be minimized through comp careful construction and accurate monitoring. Key to meeting these objectives is t information at all stages of design, development, operation and decommissioning. This paper will describe cost-effective means of gathering and managing reliable fiel groundwater flow and surface water regime within and surrounding the mine site, as localized contaminant plumes associated with mine operations, and monitoring ground quality. Recent research has led to the development of inexpensive, easy to install syst sampling/monitoring from different zones within a single borehole. Advances in elect developed small diameter probes and pumps for measuring water levels and taking wat continuous monitoring stations in remote areas can be colldeacttaeldo gaguetrosm aatnidc adlolwyn luosaidnegd from a central facility using telemetry systems powered by direct, battery or solar radio frequency, landline or cellular telephones, and satellite. Two case studies will illustrate the use of datalolgagregres sacnadl et eblaesmient rwyi dien mao nitoring sc and the use of multilevel samplers for managing a contaminant plume.

May 1, 2004

By R. Sharma, I. Miskovic, S. Miskovic

Solvent extraction (SX) is a widely used method for the extraction of copper from pregnant leach solutions or other ionic solutions in hydrometallurgical applications. About 17% of total refined copper production worldwide is produced using SX followed by electrowinning (EW). Conventional SX units, such as mixer-settlers, consume a large amount of extractant, offer poor process control and yield low extraction efficiency. Extraction efficiency is poor due to low specific interface area, crud formation, emulsification, and slow phase separation stage. Micro solvent extraction (micro-SX) is a rapidly developing technology that provides an opportunity for improved process control, higher extraction efficiency, lower residence time and, as such, has a potential to reduce the environmental footprint of SX operation. In this research, extraction of copper ions in an acetate buffer media is investigated using D2EHPA with kerosene as a diluent. Chemical factors such as extractant concentration and ionic concentration of aqueous phase are varied to determine the optimum conditions. Subsequently, the extraction efficiency and reaction time of new micro-SX reactors are compared against previous bulk SX studies. Extraction in the microfluidic reactor was observed to be faster with a residence time more than an order of magnitude lesser than bulk SX. This study forms a prelude for developing new modular micro-SX units which will enable continuous, effective, and safe operation on a large scale. In future studies, numerical and analytical models validated through this work will help eliminate rigorous experimentation and enable faster design and fabrication of micro-SX units. INTRODUCTION Conventional industrial solvent extraction (SX) units such as mixer-settlers, extraction columns present various disadvantages. Low specific interfacial area, crud formation, and emulsification in industrial reactors lead to long extraction times and severely hamper extraction efficiency (Priest et al., 2011; Chen et al., 2017). Microfluidic extraction considerably improves upon the current extraction practices by (1) creating a large surface to volume ratio that enables rapid mass transfer across the interface, (2) better process control, and (3) easier separation of phases (Kashid, Renken, & Kiwi-Minsker, 2011; Ciceri, Perera, & Stevens, 2014). These factors establish micro-SX as a crucial mode for process intensification. Although, a micro SX unit has significantly low processing volume than conventional extraction methods, their throughput can be increased via massive parallelisation (‘numbering up’), which is an area of active research (Darekar, Singh, Mukhopadhyay, & Shenoy, 2016a; Kriel, Woollam, Gordon, Grant, & Priest, 2016).

Jan 1, 2019

By W. Yang, R. Rajasingam, B. Tadesse, K. Mohanarangam

Copper electrowinning is a complex electrochemical process that involves the production of LME grade copper from copper rich electrolyte. The process involves the deposition of the copper ions onto the cathode from copper rich electrolyte with the production of oxygen bubbles at the anode. Acid mist is produced by these oxygen bubbles bursting at the electrolyte free surface. It is an undesired by-product of the Electrowinning process which unchecked could result in mist generation higher than the recommended time-weight-average exposure limit. Various approaches to alleviate the problem have been adopted by companies, all with varying degrees of success. All of these have been attempts to treat the symptom acid mist rather than the inherent problem, often proving expensive and, in some cases, ineffectual. In this paper, a new method was developed for acid mist quantification based on ‘total acid mist’ capture above the EW cell under well controlled conditions. With the use of sophisticated diagnostic analytical tools and measurement techniques it was possible to study all the operating variables including current density, flow rate, temperature, etc. independently and their effect on bubble size, bubble velocity, gas hold-up as well as acid mist generation and its droplet size. Results show that total acid mist capture increases with an increase in current density but remains more or less constant between 300–500 A m-2. Total acid mist also shows an increase with increasing electrolyte temperature. These findings are substantiated with the aid of bubble size and gas hold-up measurements with the transparent EW cell.

Jan 1, 2019

By Marcel Vallée

Abstract -Traditionally, samples collected for mineral deposit evaluation have been viewed without explicit reference to reliability, with the illusion that a true value is attainable from a few samples and verifications. For exploration, mineral deposit estimation and production quality control the following definition is proposed: "a sample is a small quantity of material relative to the geological mass it represents, collected according to a systematic procedure, of measurable reliability, from which the grade/quality of the mass which it represents may be estimated, based upon appropriate protocols. This paper will concentrate on the actual rock sampling process. Too often, sample size has been, and is still viewed as a matter of convenience, leaving out representivity considerations, despite the importance of samples on project estimation. Linear samples (chips, channels, drill), panel samples, broken rock or mining samples and very large samples are considered. Collection procedures and quality control protocols to improve the representivity of non-mechanical samples are proposed.

Jan 1, 1998