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By D. Farrish, W. A. Grell

"IntroductionMost base metal mines sell their concentrate to a custom smelter. The two parties concerned therefore draw up a contract which would detail the conditions under which concentrate sales will take place. The contract will identify treatment and marketing charges (including escalations), deductions for metal losses in the smelter, pricing formula, timing of payments, penalties for deleterious elements, etc.An understanding of the smelter contract is important to the mineral processor, for it will determine how he operates the plant to maximize economic return.Description of Contract ClausesUsing copper concentrate as an example, the smelter contract generally contains the following three basic charges:I. Metal Deductions- as the smelting process does not recover all the metal contained;2. A Smelting Charge- expressed per ton of material to cover costs on the bulk material such as receiving, unloading, thawing in winter, sampling, roasting to drive off sulphur, smelting through the matte and blister stages to recover mostof the copper and precious metals;3. A Refining Charge- expressed per pound of copper.The following is a review in some detail of a number of clauses which could be considered typical of a treatment and marketing type of copper concentrate sales contract. Most normal considerations in an agreement could be covered by the following types of clauses.Terminology- covers definitions, units of measurement to be used (e.g. short tons, troy ounces, etc.), currency (Canadian dollars). The term ""unit"" may be defined - l OJo of a ton of concentrate, e.g. one unit of copper means 20 pounds of copper per short ton of concentrate."

Jan 1, 1989

Presentation Outline ERM ? corporate profile Background to sustainability reporting GRI G3 Guidelines (Oct 2006) Best practice examples Contact information ERM ? corporate profile Over 35 years of experience World?s largest all-environmental consultancy* 130+ offices in 40+ countries; 3,200+ professional staff Worked with >50% of the Global Fortune 500 (FY07) Annual turnover > US$500 M (FY07) 2008 Environmental Advisor of Year** Offices/Staff ? Canada (5/50) and US (65/1,350) *Source: Engineering News Record: July 2, 2007 ** Source: Acquisitions Monthly: December 2007

May 1, 2008

By G. Griffiths

"P. WitteWitteck DevelopmentThe implications of using a tower mill for fine grainding in the ore processing of tailings are significant. What can those of us who are in a research and development situation do when we recommend this equipment to a client? When this prototype is placed on stream next to a conventional grinding mill as you suggest how do we estimate the power requirements and the grind which will be achieved?ReplyLet me explain the Macassa circuit. The tower mill here was running in parallel with one of the ball mills. The feed entering the tertiary system is scalped in a primary cyclone. The finial cut is made in a secondary cyclone. The actual feed to the tower mill is the underflow from the two cyclones and was split to the ball mill and tower mill. During the testing we were unable to isolate the tower mill to determine its contribution to the overall system. We then started to look at the amount of material produced across the mill. We entered the mill at between 17% and 20% finished material and exiting at between 36% and 40% finished material. We were able to project, with a high efficiency classification system, and arrived at 6 Kwh/ton or better."

Jan 1, 1984

By J. Defreyne

CESL has developed a proprietary hydrometallurgical process for base metal concentrates, notably those of copper and nickel. The process is based on pressure oxidation (PO) of the sulphide minerals, which is done at elevated temperatures in mixed sulphate-chloride liquor at about pH 2 ? 3. The process achieves maximum oxidation of the metals whilst minimizing sulphur oxidation to sulphate. Almost all base metal sulphide minerals are efficiently treated under these conditions. In the case of copper minerals, pressure oxidation does not generally put the copper into solution, because of the relatively high pH prevailing in this process. Therefore, PO is followed by an acidic leaching stage, which specifically aims at maximum copper dissolution with minimal leaching of iron. The overall copper recovery is largely determined by the efficiency of this stage. The process has low capital and operating costs, partly because there is minimal use of acid or neutralizing agents for iron dissolution or precipitation, respectively; this is achieved by minimizing iron leaching during both the oxidation and leaching stages. Iron sulphides in the feed concentrate deport almost entirely to the solid leach residue as hematite, which has superior handling characteristics for filtering and washing. Iron minerals play a key role in the process, with pyrrhotite and pyrite having very different responses to the oxidation process. Acid management for the whole process is affected by the iron mineralogy, and the flowsheet is therefore tuned to the specific concentrate.

Jan 1, 2006

Microseismic (MS) methods offer one of the few ways to monitor a 3D volume of rock and essentially see into the rockmass and the regions of real time rock fracture. This is a critical component when considering workplace safety as well as the economic viability of a mining operation. New Gold Inc. New Afton Mine, an intermediate copper-gold mining company located 350km northeast of Vancouver in the south-central interior of British Columbia, Canada, has recently installed a MS system to help understand the block caving process in space and time. For a block cave mining operation is it important to utilize the MS events to map out the seismogenic zone related to the regions of stress concentration and fracturing mechanisms which lead to caving. The geological setting within the local array is complex, consisting of several distinct lithologies with unique material properties that each affect the microseismic signal differently. The block cave consists of a muck filled void, also affecting the seismic waveform path. This paper compares the use of a single velocity model to a variable velocity model which accounts for the differing lithologies and cave. The variable velocity method determined 3D raypaths for all source to receiver possibilities through five irregular shaped geological domains and the estimated cave. For calibration blast data, the variable velocity model is found to successfully decrease the error for event location from an average of 38m to 20m (47% improvement), and its importance to location accuracy is expected to increase as the cave develops in size.

Aug 1, 2013

By J. F. Adams, V. G. Papangelakis

Chemical modelling is becoming increasingly useful in the development, analysis, design, and control of hydrometallurgical processes. The paper presents the development of reliable databases for chemical modelling of selected hydrometallurgical systems using state-of-the-art software, such as OLI. The modelling strategies are also demonstrated. The high pressure acid leaching (HP AL) of laterites, oxygen solubility in the oxidative leaching process of zinc sulfide, gypsum solubility and lead chemistry in mixed sulfate-chloride solutions are presented as case studies. This on-going work attempts to bridge the gap between theoretical research and industry needs. Computational Analysis in Hydrometallurgy 35th Annual Hydrometallurgy Meeting held in conjunction with the 44th Annual Conference of Metallurgists ofCIM Calgary, Alberta, Canada Edited by

Jan 1, 2005

By W. L. Single

"LET ME FIRST OF ALL thank you for sending this invitation to me to participate in this Annual Meeting of The Mining Society of Nova Scotia. As an engineer, although I don't get an opportunity to practice very much engineering these days, I am, of course, always pleased to be able to meet with my fellow engineers to exchange views, but I must admit that today I feel a little bit out of place in the midst of all the experts that are here today. Let me make one thing clear - I'm a generalist! Your program states that I am to make a keynote address. I have always thought that a keynote speech is one that says something that has not been said before - announces some new program or policy, or says something startling. I am sure you will understand when I tell you that keynote addresses are made by politicians and that civil servants speaking publicly are usually expected to give an account of what is, or what is likely, to happen as a result of policies that have been announced in keynote speeches by politicians. I am reminded of a statement by a distinguished parliamentarian who said, ""However exalted a civil servant may be, he is not above the elected officials."" So today I will confine myself to giving you an overview with particular emphasis on the development side of oil and gas. The theme of ""Oil and Gas"" is a topical one these days. I suppose it's because of all the copy that is being generated by the media on the U.S. energy crisis, the Mid-East situation, the fact that most of the world's proven oil reserves are in Arab hands and, of course, the accelerated exploration activity that is taking place in the North Sea, in the Arctic, and off the coast of Newfoundland and Nova Scotia."

Jan 1, 1973

By L. H. Michaud

"Albian Sands Energy (ASE), an oil sands surface mining and extraction operation, is currently undergoing start-up and is scheduled to ramp-up to full production by mid-2003. Startup includes the selection and implementation of over 75 IT systems or computer applications which include: engineering applications; systems required to control mining activities, maintenance, the processing plant and utilities; and also systems required to run the company, such as human resources, finances and inventory/ warehousing.This paper outlines the processes used for the selection, implementation and integration of these systems in order to optimize the use of information and to meet the technical, business and IT requirements of the company. The first step in ASE’s approach to identifying system requirements is the development of a business activity model, outlining all tasks involved in running the operations. The computer applications required to accomplish each task are then identified by having the IT team work closely with each technical and business unit. Historically, at some companies, the selection of systems has been led by the IT team or by consultants, with little input from the technical or business units. Typically, this results in products that do not meet the company’s expectations. To ensure a more positive outcome, ASE believes that it is imperative that the company’s technical and business people be closely involved in the selection process.Integration of the IT systems is also key, including linking all applications through a data warehouse and EDMS. Over 120 required integrations have been identified. This ensures the storage of all data in only one location, data security, and easy data and document retrieval for all requirements throughout the company"

Jan 1, 2003

Today?s Topics ? Data to decision value chain ? Practical Considerations ? Example ? Before / After DSS ? Quick Decision Support Demo Practical Considerations ? More data is not necessarily better ? Organization and process silos ? Good vs. ?optimal?, but impractical Solutions

May 1, 2008

By V. G. Papangelakis, G. A. Moldoveanu

"Rare earths adsorbed on clay minerals are easily recovered via ion exchange during leaching with inorganic monovalent salt solutions. The leaching efficiency of various salts at 0.5M and 25°C was investigated as a function of cation type and salt system (sulphates vs. chlorides). (NH4)2SO4 was identified as the lixiviant of choice and a procedure was established to investigate the influence of lixiviant concentration, temperature, pH and agitation on desorption kinetics and REE extraction levels. It was determined that the kinetics were fast and the optimum leaching conditions (for >80% total REE extraction) required pH below 5 and moderate temperatures (<50°C). INTRODUCTIONRare earth elements (REE) are at the core of numerous advanced applications due to their various uses in high strength permanent magnets, lasers, automotive catalytic converters, fiber optics/superconductors, and electronic devices (as phosphors in TVs and display screens for computers and cell phones). Because of the ongoing development of new technologies, there is an increased demand for REE in the international market, with emphasis on identifying new resources to insure an adequate supply for present and future use. World production of rare earths is dominated by China, the United States and Australia; however, in terms of resources, China dominates the world potential with reserves estimated to be over 90% of the total (Chen, 2011).The main commercially significant REE sources, as reviewed by O’Driscoll (1991) are bastnasite (carbonate) and monazite (phosphate) minerals, containing up to 70% wt. rare earth oxides (REO). In spite of being high grade, these ores are associated with elevated recovery costs due to difficulty in mining, separation and beneficiation. Moreover, aggressive conditions are required to solubilize the REE from the mineral, such as leaching with hot, concentrated acids or baking in 70% NaOH (Gupta & Krishnamurti, 2005)."

Jan 1, 2012

By N. I. Basuki, E. T. C. Spooner

"Abstract - More than 2800 published fluid inclusion data (primary inclusions) from eighteen typical Mississippi Valley-type (MVT) Zn-Pb deposits and districts were examined to study possible relationships between MVT fluid properties and metal tonnages and ore grades. The mean Th and salinity values for fifteen MVT deposits and districts are 122°C ± 21°C and 20.7 ± 2.6 wt% CaCl2 equivalent, respectively. In general, temperatures increase from pre-ore to ore stages, and salinities decrease from ore to post-ore stages. From post-ore to late calcite stages, salinity and temperature decrease with various trends within specific districts.Several conclusions are drawn: first, results show that Hanor’s (1996) salinity threshold for metalrich basinal fluids applies to typical MVT ore fluids (~16 wt% CaCl2 equivalent). Second, the lower limit of mean Th values of measured MVT deposits and districts (n = 15) of ~75°C is similar to Hanor’s (1996) observed temperature threshold for metal-rich basinal brines of ~60°C (n = 224). Third, there is no statistically significant relationship between fluid inclusion homogenization temperatures (Th) and metal tonnages or ore grades. Fourth, there seems to be a tendency for large tonnage districts/deposits to be associated with mean fluid salinities that are relatively low (~16 to 21 wt% CaCl2 equivalent) within the overall range of salinity means (~16 to 26 wt% CaCl2 equivalent). There is also a correlation between higher ore grades and higher salinities. Finally, comparison with other sedimentary rock-hosted Zn-Pb deposit types shows a trend of salinity decrease and temperature increase from MVT, sandstone-hosted and diapir-related Pb-Zn deposits, to vein-type and Irishtype Pb-Zn deposits, and then to sedex deposits. However, more data are needed for sedex deposits. The salinity threshold for significant Zn-Pb transport decreases to =~10 wt% CaCl2 equivalent at ~250°C. This study suggests that fluid inclusion analysis during exploration may be useful in assessing ore-forming potential (threshold salinity) and possible ore grades (salinity)."

Jan 1, 2002

By Ausenco Engineering Canada

"This paper demonstrates the selection of grinding circuit technology for a number of recent projects including discussion of the key drivers and the role of energy efficiency. Decreasing head grades combined with a strong and sustained increase in operating costs has forced miners to examine increased project size, increased equipment capacity and efficiency improvements in order to reduce their unit operating costs and improve overall project economics. Comminution energy consumption, safety and capital cost considerations play a critical role in the success of projects. This paper presents some key guidelines for a successful and cost effective comminution circuit design and includes a case study on three projects, outlining the issues and the drivers which led to the ultimate circuit selection and the critical role that energy efficiency played.INTRODUCTIONComminution circuits for minerals processing are selected based on their suitability and efficiency in reducing run-of-mine ore to the desired feed size for the downstream process. The input material (ore) properties and downstream process requirements are the key determinants and there are standard approaches for each circumstance.The minerals processing industry has been a fast adaptor of efficiency improvements based on increasing capacity of equipment (e.g. trucks, crushers, mills, pumps) but less successful in adapting radically new technologies that disrupt incumbent flowsheets or processes.The installed power of grinding mills has increased linearly over the past 25 years (Meka & Lane, 2010) and pumps and classification equipment have kept pace. The autogenous grinding (AG) and semiautogenous grinding (SAG) mills displaced stage crushing as a dominant method of coarse rock breakage in many applications causing crusher manufactures to increase the capacity of cone crushers to meet the competitive demand.Examples of new comminution technology in the 20th and 21st centuries are the development and adoption of cyclone classification in the 1940s (Newtech, 2016), AG milling in the late 1950s, vertical grinding mills in the 1980s, high pressure grinding rolls (HPGRs) also in the 1980s and ultrafine milling technology in the 1990s (Meka & Lane, 2010)."

Jan 1, 2016

By A. Ignatieff

"A practical picture of the effects of stress and of the structural environment in an extraction area in a bedded deposit is described, and the main factors of ground control where principles of rock mechanics can be applied are discussed. Reference is made to early work in Europe, where systematic rock mechanics studies started in coal mines, as well as to the early work in the Canadian coal mines.During the past two decades, considerable theoretical and experimental knowledge, pursued both in the laboratory and in the field, has accumulated throughout the world, but the state of the science still does not permit application of substantiated theory such as is found in the design of above-ground structures, largely because of the complexity of the rocks. The mining engineer, as oppm1ed to the civil engineer, is constantly faced by exposures of new ground that is often subject to unpredictable discontinuities. However, the rationale already developed by rock mechanics principles and experimentation provides concepts and information that may be useful in selecting mining layouts. These concepts and existing measuring techniques can also assist ground control as mining progresses.Many of the bedded deposits, much as coals and evaporites, have pronounced deformation properties, and there are limitations in making stress measurements within short distances of mine openings or extraction areas. On the other hand, the measurement of movement of the hanging wall (roof) and footwall (floor) of roadways and extraction faces, as well as the sides of pillars, provides a most useful tool in assessing ground stability.This paper is to be regarded as a brief progress report with particular reference to Canadian applications of rock mechanics to bedded deposits."

Jan 1, 1968

By M. R. Hegge

The Jabiluka One and Two uranium deposits occur in Lower Proterozoic metasediments of the Cahill Formation, which is part of the Pine Creek Geosyncline in the East Alligator River area, Nothern Territory. The Jabiluka One deposit coincides with a "window" through unconformably overlying Middle Proterozoic sandstone of the Kombolgie Formation; Jabiluka Two is completely covered by that sandstone. The observed part of the Cahill Formation exhibits four horizons which are favourable hosts for uranium mineralization. These have been folded into an east-southeast-striking, gently plunging, open asymmetric syncline-anticline structure. The host rocks are mainly chlorite and/or graphite schists and their brecciated equivalents which have undergone initial regional prograde metamorphism to the amphibolite facies, then retrograde metamorphism to the greenschist facies. Mineralization consists of pitchblende, mainly filling open spaces and to a lesser extent in disseminated form. Chlorite, pyrite and quartz are commonly associated with the uranium mineralization. A portion of the Jabiluka Two deposit contains economic concentrations of gold. Structural preparation with low-pressure conditions at these sites appears to be the most significant ore control. Genetic hypotheses favour initial deposition in Lower Proterozoic sediments, followed by remobilization during later orogenic events. The deposits bear a marked similarity to some pitchblende deposits in central Canada.

Jan 1, 1977

By J. T. Fyles, C. G. Hewlett

"THE REEVES MACDONALD mine is in the Sa Imo-Pend d'Oreille mining area of southeastern British Columbia. It is on the Nelway-Waneta road 4 miles west of the border-crossing point of Nelway. The Reeves orebody from which all production has come is one of several mineralized zones in easterly-striking limestones occurring between the Pend d'Oreille and the lower part of Salmo River.The property was originally located as two groups of claims by R. M, Reeves and J. H. McDonald. The two groups were consolidated in 1925. and extensive development work was done from then until 1930 and again in 1937, but no ore was shipped. The mine was reopened in 1947 and, between 1949 and 1953, 1,057,804 tons of ore was mined. Concentrates recovered contained 85,626 ounces of silver, 19,394,092 pounds of lead, 72,076,495 pounds of zinc, and 455,051 pounds of cadmium. Low metal prices forced the mine to close in 1953, but operations were resumed in November, 1955.The orebodies at the Reeves MacDonald mine are steeply plunging lead and zinc sulphide replacement deposits in a banded limestone named the Reeves limestone. The orebodies contain pyrite, honey-coloured sphalerite, and galena, and are surrounded by a dolomitized zone. In the Reeves orebody, where the relationships are known, the dolomite has the same general shape as the orebody. Four zones of sulphides are known on the property (see Figure 1). Three of these, the Reeves, B. L., and O'Donnell, are believed to be faulted segments of one mineralized zone. The fourth, the Point ore zone, exposed on the north bank of the Pend d'Oreille River, is not developed and its structural position is not known, but it appears to be a separate deposit."

Jan 1, 1949

By H. C. Gunning

In spite of the fact that mining has been more or less active in the northern part of Vancouver island since the late &apos;nineties&apos;, there seems to be a remarkable lack of information regarding the nature and development of the region. Recently the operations at the Old Sport mine of the Coast Copper Company, Limited, and spectacular copper discoveries in the vicinity of Nimpkish lake, have directed the attention of the mining fraternity to the district. The writer spent the summer of 1929 making a reconnaissance examination of the general geology and mining properties of the area between Quatsino sound and Nimpkish lake, and he feels that a short paper describing the nature and mining possibilities of the region should be of interest at this time. A more detailed account of the ?geology and of the mining properties will be published in the forth- coming Summary Report of the Geological Survey. A short paper dealing with the Nimpkish Lake district was presented at the Annual Meeting of the British Columbia Division, held recently in Vancouver.

Jan 1, 1930

By Richard Poulin

Rehabilitation of mined out areas is often enforced by environmental bonding. It is usually assumed that this process provides financial assurance that rehabilitation will be carried out as agreed at the permitting stage. Shortcomings of the current practice in environmental bonding for mining are reviewed. Of particular importance for the public, for governments and for the environment is the absence of protection against cost overruns and companies defaulting before the bond amount is entirely paid. Elements of solution are identified through the emergence of environmental insurance as a complement to bonding for cost overruns and defaults. A cover of environmental catastrophes could also be added, hence reducing the risk for the public and the environment. We examine the merit of creating a captive insurance company under the responsibility of the mining industry. The use of insurance techniques would incorporate a genuine risk management dimension to the financing of rehabilitation.

May 1, 2004

By Shugang Li

Coal and coal-bed methane are valuable energy resources. If they can be extracted simultaneously and safely, the triple purposes of mine safety production, new energy resource supply and environmental protection can be fulfilled. After mining, the mining induced fissure distribution feature and methane delivery behavior in overlying strata were closely related to the relieved methane degasification. Using physical simulation and numerical simulation, it was explained that the distribution feature of mining induced fissure was the Elliptic Paraboloid Zone (EPZ) in three-dimensional space. Based on the key stratum theory, the types, parameters, characteristics and dynamic evolution behavior of the mining induced fissure EPZ were analyzed. Applying environmental fluid mechanics and the mass transfer theory, the relieved methane floating-diffusion equation of the EPZ was established, and the corresponding transport process was analyzed. Using the field practice of relieved methane degasification in Tianchi Coal Mine, it explained that the mining induced fissure EPZ was the storage and delivery area of relieved methane. The degasification effect will thus be useful if the drainage system is laid in the EPZ. Such studies can provide the theoretical basis and technical support for the safe simultaneous extraction of coal and methane.

Aug 1, 2013

By Michael G. Nelson

Control of the feed provided to mineral processing facilities is a continuing challenge. Much effort is currently being devoted to overcoming these problems. These projects are usually described under the general headings of Mine-to-Mill Integration or Mine-Mill Optimization. It should be possible to combine the knowledge of ore type, mineralogy, and other characteristics (located in the mine modelling system), with the advanced capabilities of state-of-the-art mill control systems, to achieve an improved level of control in mineral processing, allowing optimization of the mill processes on an almost realtime basis. This is not happening because mill feed it is often treated as a uniform material, when in reality it varies in composition and characteristics. The University of Utah is investigating the use of odor sensors for maintaining traceability in ore production and processing. Odor sensors now used in food processing, environmental monitoring, and other applications can detect the presence of very small amounts (0.1 - 500 ppm) of some molecules. An assortment of such molecules could be used to ?tag? blocks of ore as they are mined, according to their respective characteristics. Then, as the ore came into the mill, an array of ?electronic noses? could be used to assess its characteristics in real time.

May 1, 2004

By A. J. Stapleton

"This paper gives a brief description of the occurrence and development of the Needle Mountain mine at Gaspe Copper Mines, Limited and describes the trackless mining equipment used in this highly mechanized underground operation.Maintenance of the trackless equipment is considered in detail, with particular emphasis on scheduling and control, examination and inspection. All maintenance is carried out in an underground garage, and the facilities for maintenance and field repairs are also described. Maintenance costs are given for various units and the figures for different types of loading and haulage units are compared to support the trend toward larger units and the increasing use of rubber-tired loaders."

Jan 1, 1969