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By D. H. Rubisov, V. G. Papangelakis

Sulphuric acid pressure leaching is the process of choice to recover nickel and cobalt from laterites with variable iron and magnesium contents. The latter influences the acidity levels required for effective leaching of nickel and cobalt, and during leaching, iron is rejected in-situ as hematite. Classical solid/liquid separation is performed via a CCD circuit, the performance of which depends upon the size and shape of precipitated particles. In this paper, precipitates obtained by acid-leaching of various lateritic feeds at 270°C are characterized using SEM/EDX and laser particle size analysis. It is shown that as acidity increases, the shape of the precipitates gradually changes from platelets to spheres, thus improving the S/L separation properties of the residue. The use of hydrogen ion concentration “at temperature,” calculated from a speciation analysis, allows the explanation of this change of morphology independently of the type of the ore feed. The possibility of precipitating magnesium sulphate “at temperature” is also discussed. In order to take advantage of this precipitation for scale reduction (as has been proposed in the past) without compromising the residue quality, [H+] “at temperature” must be controlled within an optimum range.

Jan 1, 2000

By H. Powell

"This paper discusses how elemental analysis of conveyed bulk flows in real time using PGNAA (Prompt Gamma Neutron Activation Analysis) technology has resulted in significant improvements in advancing plant control in mineral processing operations. PGNAA through belt, full stream, continuous, multi-elemental, real time analysis technology is explained. Capabilities and limitations in plant operating environments are discussed including comparison with other real time, on-line technologies through review of published information available for on-conveyor minerals applications. Case studies include an iron ore and copper-gold company, both of which consider the technology an essential component in advanced plant control necessary in new process flow sheet designs, rather than an optimisation tool.INTRODUCTION Process operators rely on supply of a reasonable ore quality and consistency from the mine. Unfortunately neither the mining nor process operators have much control over the ore quality once it has been put into the crusher. Grade control typically stops once the material is designated as ore and the process plant operator needs to process it irrespective of quality. Plant control is most effective when technologies measure process streams directly and preferably in real time. Measuring sampling streams that are not representative of the primary flow will result in incorrect plant control decisions. Sampling coarse conveyed flows is expensive and impractical at many operations, however, this does not mean those flows cannot be measured. Investigations to find techniques suitable for real time elemental analysis have focussed on the application of known laboratory techniques to process streams. For conveyed applications, development of neutron irradiation techniques were most promising and early studies indicated potential success for bauxite measurement (Beurton et al, 1995). Tran & Evans (2001) concluded there was no equivalent technology to PGNAA in terms of material penetration power and that the technology was eminently suitable for basic industries such as cement. Nelson and Riddle (2003) evaluated PGNAA for possible use in the phosphate industry by using a unit installed in a cement plant to test performance on phosphate samples and ultimately recommended its use for further characterisation of the mine’s various ore types to improve stockpile allocation and grade control"

Jan 1, 2014

By B. Qiu

The large surface ground movements induced by underground mining could threaten the safety of the pipelines laid across the subsidence-prone area. Existing analytical methods for the stress analysis of buried pipeline over mine subsidence area were based on the assumption of ?thin? pipeline, which limited their applicability. This paper presents the improved model with the capability to determine the stress distribution of the ?thick? pipeline. The pipe-soil interaction in this model was also updated to adapt various pipe soil contact conditions. In addition, the time-dependent effects of dynamic subsidence effects were also added to the model. A case of protecting a long section of a buried large-diameter pipeline over two longwall panels in a shallow mine is shown. The stress distribution along the pipeline is determined and the overstressed sections are identified. A partial uncovering plan was developed based on the predicted stress and complicated terrain at the site.

Aug 1, 2013

By Karl J. C. Harries

"5.1. INTRODUCTIONThis chapter is intended as a general overview of the subject of royalties between private parties – royalties extracted by governments are not dealt with. This same subject is covered in detail in Volume II, which critiques many sample provisions taken from agreements, giving both pros and cons. If you find something that interests you in this chapter, check Volume II for extra information. Detailed cross-referencing to Volume II has not been attempted, however, most subjects mentioned in this Chapter will also appear in Volume II, usually in greater detail. Reference should be made to the Index.A Brief History of Royalties1In the early days of mining in Canada, the tendency was to sell a claim for cash and to move on, using the stake to look for and stake more prospects. As prospectors became more sophisticated and Canada’s North opened up, the market for properties and the number of mining properties available increased dramatically. Speculation and the practice of consolidating several small properties into one large holding entity became common. In “hot” areas, the speculators2 could far outnumber the prospectors, many of the former having little or no prospecting expertise but lots of market and promotional savvy. However, to consolidate a number of small parcels into one large project can be expensive, and many of the parcel owners became interested in keeping a share in the project, rather than giving up everything. Speculators who were trying to consolidate small parcels wanted to minimize cash payments to parcel holders (usually they did not have much cash and preferred it flowing in their direction rather than away from them). Accordingly, non-cash transactions were developed to meet the aspirations of both owners and speculators."

Jan 1, 2003

By Jochen Petersen, Diane Taggart

"At an average of 90.3% (for the period of 1 January 2009 to 30 September 2011), Zincor’s zinc recovery was well below the industry standard of 96%. The losses through the residues, in particular the iron residue, were the biggest contributors to the overall zinc loss. It was believed that this loss could be decreased with the implementation of seed recycling. A plant trial was run to test the implementation of a seed recycle. The rate of seed addition through recycle was increased over a 4-week period. The presence of seed decreased the insoluble zinc loss by providing additional surface area for iron to precipitate onto, and reducing coating of unleached neutralising agent. The soluble zinc loss was also decreased at low and moderate seed recycle volumes. The improvement was attributed to agglomeration growth of the recycled particles, which improves the dewatering characteristics of the precipitate. In contrast, the soluble zinc loss increased at high seed recycle rates. This result was attributed to particle crowding and a low wash ratio.INTRODUCTION The Zincor refinery, which closed in December 2011, was situated just outside of Springs in the Gauteng Province of South Africa and employed the conventional Roast-Leach-Electrowin process, which accounts for 75 to 80% of the annual primary zinc production in the world. The refinery fed up to 220 000 t/a of zinc sulphide concentrate. The major portion of the raw material was sourced in Southern Africa from the Rosh Pinah and Black Mountain mines. Between 20 000 and 40 000 t/a of material was imported to make up the deficit and to improve the grade of the feed material. The iron contained in the zinc concentrates, at an average of 6.03% (for the period of 1 January 2009 to 30 September 2011), resulted in the formation of zinc ferrite during roasting, which is insoluble under atmospheric leach conditions. At Zincor, most of the zinc ferrite was dissolved in the residue treatment plant at elevated temperature and high acid strength. The leach liquor from this aggressive leach contained between 15 to 30 g/L of iron, mostly in the ferric form, and was known as the hot iron solution (HIS). The presence of iron in the liquor had an adverse effect on the zinc operation, particularly on the current efficiency in the electrowinning circuit. Therefore the iron needed complete removal."

Jan 1, 2016

By M. Reda

Erosion corrosion is acceleration in the rate of corrosion attack in metal due to the relative motion of a corrosive fluid and a metal surface [1]. The increased turbulence caused by pitting on the internal surfaces of a tube can result in rapidly increasing erosion rates and eventually a leak [2]. Engineers and scientists in different disciplines have worked for many years on methods of complete protection from flow induced corrosion or partially reducing corrosion of this type, and they have proposed or applied different countermeasures [2]. The accident at the Surry-2 nuclear power plant (USA) and other similar incidents have once again disturbed the scientific-technical community. This has forced the plant operating personnel and the management to undertake wide-ranging measures in order to discover on time, assess, and monitor such cases. In these extreme cases, protective coating and even metallic bulk material coating (the substrate itself) may suffer considerably from mechanically induced damage [2]. At high velocities, the "leaching out" dissolution reaction of particular, for example, steel elements at the solid-liquid interface become the rate determining step. One practical example for the difference between erosion corrosion and flow induced corrosion is the famous steam eruption from a Japanese [3, 4] nuclear power plant cooling system at the pressurized water reactor (PWR), turbine and in the condenser-steam generator connecting pipe. The rupture occurred in the carbon steel pipe connecting the condenser and steam generator. The damage occurred in the easily eroded/corroded carbon steel at a vulnerable location downstream of an orifice plate, In general, when there is significant reduction in pipe thickness through erosion/corrosion, distinctive patterns are visible, but those patterns were not observed in this case, Thus one can speculate that another phenomenon is possibly controlling, Fluid flow within pipes reduces the pipe thickness leading to an eventual rupture, The thickness reduction mechanism is erosion/corrosion, One example is "cavitations corrosion", Erosion and corrosion occur at the same time, and it is difficult to determine which one is dominant, Therefore, the term, "erosion/corrosion," is used [5]. In the atomic energy field, the terms "Flow Accelerated Corrosion" and "Flow Induced Corrosion" are also used. It is the purpose here to show that during flow induced corrosion a different mechanism may possibly be operating and in some cases it can be different from the well known erosion corrosion. Another example is fretting failures in early Canadian nuclear steam generators which was thought to be due to excessive vibration caused by high.

Jan 1, 2010

By Zoë Mullard

Just as a mine has a lifecycle, employees working within the mining sector also make several transitions throughout their career, from initial recruitment to retirement from the industry. Throughout the employment lifecycle, employees bring skills and knowledge that significantly contribute to the global economy. These skills are developed through education, professional training, coaching and through hands-on experience. Despite the current economic conditions and the demand for minerals, the mining industry is facing a substantial skills shortage due to the disparity between the number of new workers entering the mining industry and a largely ?graying workforce?. Although educational programs continue to evolve to attract people with a wide range of skills, the diversity of jobs and the strains of working in remote mining operations continue to present challenges for recruitment and retention of employees. This gap also presents challenges around knowledge transfer at a corporate and mine-site level; employers will require cultural and techno-sociological approaches to ease through these transitions. At the same time, there has been an explosion of social media tools that facilitate information sharing, cross-organizational collaboration, distance learning and knowledge capture. These tools have become increasingly popular in the last few years and their applications vary widely. The mining sector has started to adopt these tools for a number of purposes, including opportunities to harness social media to enhance human resources interactions, outreach and oversight. This paper will outline several case studies that explore leading practices for how the application of new media can assist organizations and individuals as they progress through their careers. This paper will illustrate how new social media communication technologies can be used to increase employee engagement and build organizational capacity in the mining industry. The paper will also include strategies for how to implement social media to enhance human resources applications and will cover ideas for monitoring and evaluation.

Aug 1, 2013

By Jerry Ran

Stope back caving in a mine using open stope mining interrupts the planned mining sequence and causes oversize muck and dilution with adverse economic implications. As many underground mines are mining or have plans to mine at depth, stope back caving could have significant impact on the mine sustainability. Therefore understanding the caving mechanism is important in preventing future occurrence and improving the mine economic performance. Falconbridge Ltd Kidd Mine is an underground mine using open stope method producing more than 2 million tonnes per year. Its current lowest mining level is approximately 2070m below surface and the lower portion of the orebody is being developed. In years of 2002 and 2003 the back of three stopes of approximately 1900m and 2040m below surface caved and caused substantial mining difficulties at the mine. As these caved stopes are subject to stress concentration, seismic activities and near major geological structures, the caving mechanism is much more complex than that of stopes near surface. In addition to the recorded caving history by site observations, the mine carried out cavity surveys and test drilling to define the caved profiles. The mine seismic monitoring database provided information at these stopes. Stress modeling work conducted by an external consultant provided the stress patterns at the caved stopes. Based on the field collected data and stress and seismic information, this paper presents details of the stope caving process and cavity surveyed profiles, reviews the predictability of the stability graph approach for these cases, discusses the caving mechanism and proposes preventive measures to stabilize the stope back.

May 1, 2004

By D G. Boxall

As an alternative to heavy water cooling, reactors cooled by organic liquids are being actively developed in Canada under the sponsorship of Atomic Energy of Canada Limited. One of the areas in which development has been required is that of core materials. The factors affecting the selection of fuel canning and coolant tube materials are discussed. It is shown that S.A.P. is a potentially attractive material for these applications. The fabrication of fuel sheathing is discussed. Difficulties met due to large inclusions and blistering due to high hydrogen contents have been overcome by magnetic separation and vacuum sintering of the powders. High-quality tubes can now be produced by extrusion to finished size. A study has been made of the mechanical properties of fuel-sheathing tubes and bar stock. The stress rupture properties of the tubes subjected to uniaxial and biaxial stress have been determined. The biaxial stress tests were performed by internal pressurization. For times in excess of about 200 hours, the curve of stress against time to rupture is extremely flat. The secondary creep rates of

Jan 1, 1965

By B. R. MacKay

Introduction During the past six seasons the writer has been engaged in semi-detailed investigations on the coal areas lying along the front of the Rocky mountains between the Brazeau river and the Smoky River Coal Reserve (see Map, Figure 1). The purpose of this paper is to present some observations pertaining to the stratigraphy and structure of the district, touching especially upon the lithological units into which the Lower Cretaceous sediments have been divided, the thicknesses of the formations at different localities, the number, thicknesses and horizons of the principal coal seams, and the structural conditions which exist in the various fields.

Jan 1, 1930

By Mario Gerards, Axel Wellendorf, Arulnesan Rajesh

"In times of increasing energy cost and global demand for improved machine technology, the optimization of industrial mineral processes in terms of efficiency and production cost is an important factor when choosing industrial equipment suppliers. Of course this applies for screening machines, feeders and distributers as well!Besides of the ability of a screening machine for being adjustable to changing requirements during the production process itself, it becomes more and more important to choose the correct screening machine type, peripheral equipment for arising screening tasks and to optimize the overall design of the screening machine starting at a very early stage.The different types of screening machines bring many advantages and disadvantages with them. The selection of the correct type of screening machine can improve the flow rate, energy, efficiency, yield, quality, output, availability and decrease the maintenance costs and structural steel work.The machine optimization has to be a consecutive process in which at any time results of simulation and “real-life measurement” are compared and the findings are implemented in machine development and design. As an example, it is possible to reduce machine weight and reinforce the steel structure of a screening machine at the same time, which enables the manufacturer to use smaller drives for the screen.This paper will present the methods ANSYS and 3D Solid Works used at RHEWUM GmbH for this way of optimizing machine design and construction and examples for results gained from this continuous improvement process."

Jan 1, 2016

By R. T. Jones

The largest known platinum group metal (PGM) deposit in the world is the Bushveld Complex in South Africa, with the Great Dyke in Zimbabwe also being one of the biggest. It is therefore not surprising that the majority (just over 5 million troy ounces or 156 metric tons per annum) of the world's platinum is produced in Southern Africa. Primary smelting of ore concentrates is carried out in that region by five companies, namely Anglo Platinum, Impala Platinum, Lonmin Platinum, Northam Platinum, all of South Africa, and Makwiro Platinum in Zimbabwe. The only other primary smelter of platinum group metals is Stillwater Mining of Montana, USA, although very significant quantities of PGMs are produced as co-products by Norilsk Nickel of Russia. Smaller (but still significant) quantities of PGMs are produced by Falconbridge and Inco of Canada, also as co-products from nickel sulphide smelting. There are many similarities between PGM smelting and nickel sulphide smelting, and the range of technologies in use includes six-in-line rectangular electric furnaces, three-electrode circular AC furnaces, Peirce-Smith converters, and Anglo's ACP (based on Ausmelt technology). PGMs are also recovered from residue materials using DC arc furnace technology.

Jan 1, 2005

By K. Baris

Methane (CH4) present in coal seams, generally known as Coalbed Methane (CBM), Coal Mine Methane (CMM) or Coal Seam Gas (CSG), is a major energy source, as it is the primary constituent of natural gas. At the same time, released methane is a potent greenhouse gas (GHG) and a major safety hazard in underground mining operations. Therefore, a considerable effort has been undertaken to develop coal bed methane extraction and utilization technologies that can achieve both environmental and safety benefits. Countries with significant coal reserves and gassy seams, i.e., USA, Australia, Canada, China, India, Poland and Germany have developed mature methodologies and practices to extract, before and during mining, and utilize significant amounts of methane from coal seams. Nevertheless, on a global scale, methane recovery remains untested and many technical and economic challenges require urgent attention. The research presented in this paper, sponsored by the United States Environmental Protection Agency (EPA), is focused on the Zonguldak Basin, the only hard coal region in Turkey. The basin is known to contain very gassy coal seams and consists of three major regions: Armutcuk, Zonguldak and Amasra. Among the three, the Amasra coalfield is considered as the most favorable for CBM recovery, as it comprises of deeper coal seams and where a private company, Hema Enerji A.S. (Hema) is already developing coalbed methane production facilities. This study aims at developing a reservoir model to predict the potential CBM recovery from the CBM-2 well, the only producing CBM well drilled by HEMA Enerji A.S in the Amasra coalfield. History matching was utilized to model the 15-day production data and uncertainty analysis was performed to estimate the optimum values for the reservoir parameters. The produced model yielded an average production rate of 143 m3/day for 10 years. The total amount of CH4 to be produced during this period was 0.53 million m3. Furthermore, the total amount of GHG to be avoided was estimated at 6585 tCO2e.

Aug 1, 2013

By L. Don Leet

Abstract Earthborne vibrations from blasting and other sources, including rock bursts, can now be recorded effectively. The nature and magnitude of vibrations from various sources have been investigated and certain applications of the knowledge thus gained have been made. Vibrations from blasting have been measured on special equipment over a range from an electric blasting cap at a few feet, through the largest quarry shot in history to date ( 1,-362,985 lb.), to the first atomic bomb, in uew Mexico on July 16th, 1945. Laws relating amount of explosive to amount of vibration at different distances have been developed and tested. Special studies have been made of the effects of vibrations on buildings, particularly from the standpoint of possible structural damage. Recorded vibrations are used to study the effects of modern short-period delay shooting. It ?has been found that short-period delay firing is extremely effective in reducing vibrations under the right conditions, but with certain limitations. In quarry shooting, there appears to be a minimum number of holes below which vibrations are not appreciably reduced by short-period delay firing. In several instances this minimum has been near 7. Vibrations in the ground from rock bursts and the effects of mining in stresesd ground have been studied both underground and on the surface in a search for a rock burst warning system. Introduction Earthborne vibrations from blasting and other sources, including rock bursts, can now be recorded effectively. Analyses of blasting records have been yielding increasing funds of information of practical as well as theoretical interest. The nature and magnitude of the vibrations have been investigated with special reference to their effects on structures.

Jan 1, 1951

By K. H. J. Clarke

SINCE the beginning of this century the non-ferrous mineral industry has contributed $17,809,-000,000 to the economic growth of Canada. To contemplate the vast amount of investment capital required and the resultant beneficial distribution of these billions of dollars for labour, transportation, supplies, taxes and dividends, challenges the imagination. It is the purpose of this paper, (a) to trace the development of the industry since its formative period to the present; (b) to discuss the current situation and problems; and ( c) to attempt to peer into the hazy future. Although there are 21 metals currently being produced in Canada which are classified as non-ferrous, or as alloying metals, copper, lead, zinc, nickel-the metals which will be discussed in this paper-constitute almost 60 per cent of their total value. ;The story

Jan 1, 1961

By T. Binnert Haites

INTRODUCTION NUMEROUS examples of troubled zones, interfering with the normal development of coal seams, have been cited in the literature. From a geological point of view they can be subdivided into structural and sedimentary troubles. Of the latter type, wash-outs are usually the most bothersome. Some years ago, A. A. Thiadens and the author arrived at the conclusion that they represent fossil river-beds. A method of predicting the course of these rivers was developed, which has been successfully applied in the Netherlands coal measures, and more recently by P. Stassen in some of the Belgian coalfields and by the author in the Sydney coalfield. The Sydney coalfield has long .drawn the attention of geologists, and three main periods of systematic geological research may be distinguished. The first period, 1872-1900, is covered by the studies of Ch. Robb and H. Fletcher (32, 10-13) (1). Their detailed sections of the cliffs have lost nothing in value, and are frequently consulted today.

Jan 1, 1951

By F. Siciliano, D. Bai, S. Yue, A. M. Elwazri

The influence of niobium addition and very low temperature (`cool') deformation on the microstructure and properties of low carbon microalloyed steels was investigated. In this work, the specimens were heated at 1200°C and held at this temperature for 20 minutes. Some specimens were aged at 400°C for times ranging from 10 minutes to 10 hours followed by air-cooling. Others were subjected to deformation at 400°C (`cool deformation') prior to aging. It was observed that the proportion of acicular ferrite was increased as the amount of Nb was increased. It was found that cool deformation increased both yield and tensile strengths significantly compared to that of the aged only specimens.

Jan 1, 2005

By Karl J. C. Harries

"12.1. NO DEPRECIATION/GAAPAll calculations and computations relating to the Royalty shall be carried out in accordance with generally accepted accounting principles consistently applied to the extent that such principles are not inconsistent with the provisions of this Schedule and the agreement attached hereto, it being specifically agreed that nothing herein contained shall permit, or be construed to permit, the Operator to deduct any amount for depletion, depreciation, amortization or any deduction that represents a non-cash outlay.Comment: In cases like net profit royalties where recoupment of prior expenditures is permitted, care should be taken to avoid any implication that depreciation may also be taken. It is only logical and equitable that Property Owners should not be permitted an apparent ability to “double dip” with respect to deductions. A provision like this example should accomplish the task. It will be noted that the example specifically contemplates that the negotiated arrangements will prevail over any requirements of GAAP. Accordingly, if the parties agree to an unusual formula for recoupment, it will not be set aside to accommodate GAAP requirements. Under GAAP, revenues and expenditures are accounted for on an accrual basis. In addition, it specifically prohibits the taking of non-cash deductions, which is in keeping with the concept of recoupment.Although in some ways the example states the obvious and could be considered redundant, its presence, especially in provisions contemplating recoupment, makes it clear to the financial people that there may well be some variations from normal practices dictated by GAAP, while at the same time confirming the availability of GAAP to fill any voids.The accounting profession often makes the caveat that application of GAAP is an “art”, not a “science”. GAAP do not provide a cure-all and can create problems that will have to be addressed. For example, GAAP contemplate that asset costs are to be reduced by investment tax credits, which can cause a problem for a payor with more than one mine."

Jan 1, 2003

By Harry V. Warren

THE Dolly Varden Mine is situated in the Kitsault River valley, eighteen miles from the head of Alice arm, in the Nass River mining division of British Columbia. During the years 1919-21 it was operated by the Taylor Engineering Company, Limited, and produced 1,300,000 oz. silver from about 36,000 tons of ore. The ore was transported by narrow-gauge railway to Alice arm, and shipped to the smelter at Anyox for treatment. During recent years, a small quantity of high-grade ore has been extracted by leasers and shipped to the smelter at Tacoma, Wash. Unfortunately, the bonanza ores which occurred near the surface did nor persist to depth, and two hundred feet below the exposures only rare and unimportant patches of ridi ore have been found. Two opinions exist as to the origin of this rich silver ore. One, advanced by V. Delmage (1, 2), is that the ores are hypogene, and the other, by G. Hanson(3, 4, S), is that the ores are the result of supergene enrichment. It is true that Dolmage first advanced his view that the ores are primary because they appeared to be analagous to Premier ore, which he had studied in detail and which he considered to be primary. The present authors have had access to excellent suites of material from both mines and consider the comparison well taken, the only essential mineralogical difference being the presence at the Premier mine, in addition to the silver minerals, of gold and electrum. Although the arguments put forward by Delmage have, in the opinion of the authors, never been refuted, nevertheless R. P. D. Graham(6), in a reference to the mine published in 1924, describes the ore as of supergene origin, and since then nobody appears to have challenged this statement. Indeed, in 1935, Hanson re-affirmed his earlier conclusion(5).

Jan 1, 1942

By P. Fossi

This report describes a pilot-scale study of a hydrometallurgical process to treat high-grade nickel matte or a nickel-cobalt sulphide precipitate to produce high-purity electrolytic nickel. The first step of the process is the oxidative leaching of the nickel-bearing material by nitric acid; the nitrous gases generated during leaching are reconverted to nitric acid. The crude nickel sulphate nitrate solution is purified and is then subjected to a denitrification step. Nitrate separation is effected either by the crystallization of nickel sulphate or by precipitation of basic nickel carbonate. The electrolyte is prepared from the nitrate-free material and nickel is then recovered by electrolysis of the sulphate solution using insoluble anodes. Some technical and economic problems encountered with this processing route are discussed and the method is compared to the "all-chloride" process developed by Société Le Nickel.

Jan 1, 1977