Search Documents

By J. C. Ingles

"A survey of possible methods for controlling cyanide concentration indicated that the simplest method would involve the use of a potentiometric technique. Such a method was suggested by a paper from the laboratory of Mines Safety Appliances, which described a method for determining hydrogen cyanide in air. In this application, the cyanide was absorbed in caustic and a silver electrode immersed in the caustic solution provided a measure of the cyanide concentration. However, our attempts to use the silver electrode in this simple manner to measure the cyanide concentration of solutions were not very successful. A study of the mechanism by which a silver electrode responds to cyanide concentration made it evident why this simple procedure is not satisfactory.Basically, the silver electrode provides an indication of the free silver ion concentration of a solution, and generally speaking, ignores the other ions' present. It can be used to measure an anion if this anion complexes silver. This technique has been used in complexing studies to determine the activities of such anions as acetate, citrate, oxalate and chloride. To do this, the electrode has to be placed in a solution which initially contains a known concentration of free silver ions. Addition of the complexing anion causes a drop in the free silver ion concentration and hence a change in the potential of the silver electrode. The change in potential can be expressed in terms of the concentration of the complexing anion, and used to indicate its concentration in the solution being analysed. The determination of chloride-ion by a silver-silver chloride electrode is an example of an application of this technique. The solubility of the silver chloride with which the electrode is coated provides the initial free silver-ion concentration. Depression of this free silver-ion concentration by the presence of the excess chloride ion of the sample solution results in a change in the potential of the electrode which is proportional to the chloride-ion concentration."

Jan 1, 1965

By W. L. Strand, D. N. Madge

"Experimental and pilot operations in bituminous sand processing require due care and attention in the design and analysis of measurement programs. This paper deals with a case study in experimental design and data analysis for a series of experimental campaigns that have been conducted over the past five years by Kilborn Western Inc., acting on behalf of Bitmin Resources. Beginning with the design of the experiment and following into the use of linear and nonlinear regression models, the phenomenology of bitumen extraction is illustrated. The final testing program tested 13 oil sand types as well as a wide range of process variables for all the unit operations of the complete process.The program was successful in developing process fundamentals and scale-up criteria. Several phenomenological models were proposed and tested. Their range of applicability was explored. This paper illustrates the range of applicability of these models and discusses the development of alternative models.IntroductionOver the past five years Kilborn has conducted a series of bench scale and pilot scale experiments designed to explore the phenomenolgy of a new concept in medium temperature processing of bituminous ores. These experiments at feed rates ranging from .1 to 24 t/h were conducted on water wet sands from the .Athabasca region near Fort McMurray. They were based on experimental designs chosen to provide a systematic means of identifying the response surfaces of the process over a range of conceptual designs. The following diagram shows the experimental arrangement:"

Jan 1, 1998

By Bill Charbonneau

Lumen, lm The measurement unit of light emitted by a light source 60W incandescent840 lumens 32W T8 linear fluorescent3200 lumens 54W T5HO linear fluorescent5000 lumens 400W metal halide24,000 lumens

Oct 1, 2010

By Ayako Iwakoshi

Highly concentrated pastes of gold nanoparticles were successfully produced by use of a special kind of protective polymer and a mild reductant. Solid part of the pastes consists of up to 85wt% of gold nanoparticles, 10~30 nm in diameter, and residual protective polymer. This component can be diluted by any kinds of solvent at arbitrary rates. Electronics, optics, catalysts, colorants and surface metal coatings are possible application fields. 1. Introduction Noble metal nanoparticles are of interest in a variety of fields ? such as colorants, metal coatings, electronics(1), optics(2), and chemical catalysis(3). Especially, in the color field, the gold nanoparticle has been known as an aesthetic red colorant for stained glass and fine glassware, such as Venetian glass. The mechanism of coloring is attributed to surface plasmon absorption of gold nanoparticles(4,5). The gold nanoparticle in stained glass shows very clear red color, which is very durable for hundreds years. On the other hand, the red color of organic pigment in paint films often fades away within several years. We intended to reproduce the elegant and stable coloring of stained glass in paint films. In order to color a very thin, 20~50?m, paint film like stained glass, production of highly concentrated dispersion of gold nanoparticle is necessary. To achieve this, there were two issues to be overcome. One is how to prevent the coagulation of gold nanoparticles in highly concentrated solution. So far, several methods to prepare gold nanoparticles(6,7) were reported. But only a few methods succeeded to stabilize the gold nanoparticle dispersion at higher concentration than ppm order. The other is controlling of the particle size, this is because the color of gold nanoparticles is very sensitive to the particle size. Only when the particle size lies around 10 nm, the suspension exhibits red color like stained glass.

Oct 1, 2003

By George P. Demopoulos

In this paper the author will provide an overview of over 20 years of research & developments in the area of hydrometallurgical arsenic immobilization that culminated recently in the industrial implementation of the atmospheric scorodite process. The paper will consider various aspects of arsenic fixation in the non-ferrous metal industry from the iron-arsenic co-precipitation process employed to arsenic-bearing effluent solutions; to autoclave processing of arsenical copper and gold feedstocks and the fate of the in-situ formed iron sulphato-arsenate precipitate phases; the precipitation and stability of scorodite; the possible stabilizing role of mineral phases like yukonite, and the development of "scoroditeplus" processes employing novel encapsulation strategies. Emphasis is placed on the characterization and long-term stability of the various forms of arsenic-immobilized phases under either oxic or anoxic conditions over a wide pH range and the establishment of critical links between process parameters and hazardous material stability, contributing thus to advancement of new generation safe and sustainable waste management technologies.

Jan 1, 2014

By Tyson C. Birkett

Initial indicator mineral sampling covering 425,000 square km of northern Quebec and subsequent follow-up of positive results convinced the Ashton ? SOQUEM joint venture to acquire mineral rights to 380,000 hectares prospective for diamond in late summer, 2000. Drilling in 2001 and 2002 identified eight kimberlitic bodies, all significantly diamondiferous. Commercial size stones (retained on a square mesh sieve with openings 0.85 mm) and encouraging grades have been returned by several bodies tested to date: The Renard bodies are formed by steep-sided breccia pipes with kimberlitic matrix surrounded by irregular outboard breccia zones within country rock. These bodies were emplaced in high-grade metamorphic rocks of the Superior Province of Archean age. Orthogneiss with lesser tonalite hosts the breccias, although regionally paragneiss is also present. Diatreme facies portions and nearby country rock are intruded by minor to major (Renard 1) amounts of hypabyssal-facies kimberlitic rock. Renard bodies are macrocrystic, with large olivine crystals set in a groundmass of olivine, phlogopite, monticellite, spinel, carbonate, apatite and serpentine. Proximity of various Renard bodies, with most in a core area of 0.5 square km will allow planning of an efficient mining operation. Geophysics, especially magnetic surveying, has contributed to identifying bodies of kimberlitic rock.

May 1, 2003

By E. M. Yates, H. M. Hamilton

"For the assent of any new mining project it is essential to determine a realistic value of revenue from the sale of concentrates.A description of the market factors influencing the concentrate terms will be presented along with a detailed review of historical terms of a smelter contract for zinc concentrates. OverviewFor the assessment of any new mining project it is essential todetermine a realistic value of revenue from the sale of concentrates.This applies at all stages of assessment through to the final feasibilitystudy. In forecasting revenue for a zinc mine the followingfactors must be considered:(a) mill recovery and zinc concentrate grade;(b) metal price forecast for all payable metals;(c) smelter terms; and(d) other selling costs.Normally, data from test work are used to determine mill recovery and concentrate grade.Market forecasting, and indeed all economic prediction is an inexact science and probably will always remain so. We have our econometric models our input/output models and a lot of other tools. But they are of no help in predicting the unpredictable. OPEC's huge increase in the price of oil was certainly the most dramatic example of this. It had a tremendous effect on the cost of producing most products world wide and on the price of these products. Any forecasts made prior to the OPEC action were obviously proven wrong."

Jan 1, 1994

By Ken G. Stowe, Stephen L. Chryssoulis, Christian Bendel, Joe Y. Kim, Ewald Niehuis

"TOF-SIMS (Time-of-flight secondary ion mass spectrometry) was used to detect collectors sorbed onto the surface of mineral particles in concentrate and tailings samples from the Brunswick, Matagami and Kidd Creek concentrators. This technique uses ion beams from either Cs or Ga sources to sputter the particle surface, a method which reduces fractionation of the collector molecule during sampling.In the Brunswick Zn circuit, sphalerite particles lost to the scavenger tails had less amyl xanthate and isobutyl xanthate compared to sphalerite recovered to the Zn final concentrate. Xanthates were detected on the surface of sphalerite particles floating to the CuPb final concentrate.At Matagami, significantly more isopropyl xanthate and isobutyl dithiophosphate were detected on sphalerite recovered to the Zn final concentrate, compared to sphalerite lost in the Zn rougher tails.In the Zn circuit of Kidd Creek, sphalerite lost to the tails had on average ten times less xanthate compared to sphalerite recovered into the Zn final concentrate. Xanthate was also detected on the floated pyrite particles. In addition to isobutyl xanthate, amyl xanthate was also detected on the floated sphalerite and pyrite particles.This preliminary investigation has (a) demonstrated the ability of TOF-SIMS to detect individual collectors on particle surfaces from plant samples and (b) shown that TOF- SIMS is an excellent tool, complimentary to TOF-LIMS, in establishing the surface chemistry of minerals as related to mineral processing."

Jan 1, 1995

By Tiago Webber

Mineral resources estimation comprises basically two stages: (i) data collection, analysis and validation, and (ii) the estimate of the grades and tones of the deposit. The most applied method for sampling survey in mineral exploration is rotary drilling with total core recovery. High drilling costs make borehole geophysical logging attractive to obtain the maximum possible information from each borehole helping to understand ore intersections, grades variability, limits of the deposits and continuity of the mineralization. In this paper, borehole geophysical logging was used to enhance the sampling survey and to derive grades indirectly (without lab analysis) with a certain amount of uncertainty. Indicator kriging (IK) was the estimation method used, as it is adequate to incorporate the uncertainty associated with the geophysical derived grade values. The results were compared to the conventional procedures using grades determined via core analysis and ordinary kriging. Borehole geophysical logging proved to be efficient to define the essential features of ore deposit and IK provided results with acceptable precision and accuracy if compared to the model provided by ordinary kriging.

Oct 1, 2009

By Magdy Ibrahim

Detailed as-built project schedules are necessary to close out construction projects, benchmarking, forecasting, dispute resolution, and improving cost estimates of future projects. Manual procedures for developments of as-built documentation is time consuming, involves numerous interfaces and human interventions. This paper presents computational framework that encompasses automated site data acquisition and generates schedule updates utilizing commercially available project scheduling software. The work is carried out collaboratively with a Hydro Quebec team. The site data is captured employing mobile computing using iPad® type computers and Wi-Fi. The information is directly compiled in a centralized database server. The synchronization tool is a bi-directional application and is used on servers to communicate with iPad® computers deployed onsite. The captured data is stored in Microsoft SQL® relation database that consists of 63 entities. Computer software application has been developed in Microsoft Visual Basic® (vb.net) environment for extracting the collected site data, linking the database to the as planned schedule, and generating the actual, also known as as-built schedule. The development can be utilized in automated progress reporting, evaluating future bids, generating master schedules and a wide range of efficient EVM applications.

Aug 1, 2013

By P. R. A. Andrews

"Garnet occurs in schists and gneisses in all provinces of Canada, all mainly in Quebec and Ontario. There is currently a renewed interest in exploration for economic sources of garnet for abrasive applications because of the inherent dangers from exposure to ground silica from sandblasting operations.High-quality garnet is used for lapping and grinding of glass and ceramics; for coated and bonded products such as sandpaper and cloth; and abrasive wheels for grinding and finishing various metals, woods, rubber and plastics. Low-quality garnet is used for cleaning and conditioning aluminum and other soft mewls, particularly by aircraft manufactures. Garnet may be added to grouting cements for oil-well drilling applications, and it has also been used for low- to medium-level radiation shielding. Garnet has been studied extensively by CANMET and its predecessor, Mines Branch, between 1917 and 1990. Twenty-nine studies relating 10 various aspects of beneficiation are presented and a review of the more important studies is presented. The information includes mineralogy, beneficiation methods, product sizes and analyses."

Jan 1, 1995

By R. Pérez, James A. Finch, F. Tavera, Cesar O. Gomez

"Gas holdup is a variable which affects the operation of flotation columns. On one hand, gas holdup is a function of bubble size (a function of sparger type, frother characteristics and concentration, and air flowrate), tailings flowrate, solids content, and mixing patterns in the collection zone. On the other, gas holdup defines flotation kinetics and carrying capacity. Therefore, gas holdup is a useful variable to control and diagnose the operation of a flotation column, but the lack of a reliable sensor for on-line gas holdup monitoring has prevented its use in industry.This work describes the principle and the practical difficulties associated with the development of a gas holdup sensor based on the measurement of the electrical conductivity of dispersions. Two different approaches have been devised. These approaches will be described and test results presented of prototypes in laboratory and industrial columns.Background.Several years ago, a research program was initiated at McGill to use electrical conductivity as the basis for developing sensors for process measurements in mineral processing. Electrical conductivity is an intensive property which is a function of the concentration of the different phases present in a dispersion. The initial focus was on the detection of the interface between two dispersions with different characteristics (i.e., that between the collection and froth zones in flotation columns or that between clear water and sedimented solids in thickeners). The technique works in this case by searching for the location at which a sudden change in specific conductivity occurs, as a consequence of different gas holdup or solids content, and absolute values of the specific conductivity of the dispersions involved are not necessary1,2."

Jan 1, 1995

By A. E. Reschke

Optimized mine planning of the Leeville Gold Mine, Nevada, necessitated the requirement for an average of 2540 tpd of high quality cemented rockfill (CRF) in primary stoping blocks and underhand cut and fill workings. To meet this requirement, a number of innovative design features were incorporated into the overall batching plant design. Foremost is the use of a dedicated skip to transfer crushed aggregate from surface down through the ventilation shaft to twin underground storage silos. Also, the use of a high shear colloidal mixer on surface to pre-slurry a cement/flyash binder with pipeline delivery to one of two separate underground CRF mixing stations was incorporated. Finally, the binder and aggregate are combined in a 9 m3 twin shaft compulsory type mixer before loading into teleram trucks for placement.

May 1, 2007

By K. V. Konigsmann

"The mill at Mattagami Lake Mines treats 3,850 tons per day. The mill feed is a heavy sulphide ore. It is composed ofPyrite & Pyrrhotite - 40%Marmatite - 17%Chalcopyrite - 2%Magnetite - 10%Talc and other Silicates - 31%The sulphides are intimately associated with each other and often finely disseminated throughout the siliceous gangue. An abundance of middling particles exist in the circuit and a delicate balance has to be maintained between concentrate grades and metal recoveries.The metal content of the mill feed fluctuates between 0.4 to 0.7% for copper and 6 to 13% for zinc.The flow sheet of the concentrator is shown in Figure 1.Eight sample streams have been selected for on-stream analysis, namely1. Copper Concentrate 2. Copper Cln Tailings 3. Copper Tailings 4. Zinc Concentrate5. Zinc Rgh Concentrate6. Zinc Cln Tailings7. Zinc Rgh Tailings8. Flotation TailingsThe mill feed is not being analysed. Only a very coarse sample could be obtained which would be difficult to pump, and the fluctuations in the copper content are too small in absolute terms to have much of a bearing on circuit operations."

Jan 1, 1969

By Michel Ruel, Ali Soltanzadeh

This paper describes how to make advanced control choices when difficult processes need improvement. The decision-making process involves choosing between a rules-based approach and a model-based approach as well as weighing benefits and drawbacks, complexity and simplicity, investment and results. This paper will present briefly each solution: basic control, advanced regulatory control, model predictive control and expert systems such as fuzzy logic controllers and neural networks. Three examples are presented: ARC (Advanced Regulatory Control) on pH in a comminution circuit, MPC (Model Predictive Control) for combustible management and FLC (Fuzzy Logic Control) on a Semi Autogenous Mill. The article then proposes a decision tree for selecting the most appropriate approach. A table will compare usage, development, commissioning, maintenance and lifecycle costs for each approach. Finally, conclusions and suggestions will summarize the methodology.

Jan 1, 2014

By Mark Stephenson, Paul Henharen

"The objective in the mineral processing of primary ores is to liberate and effectively recover each individual economically viable diamond with minimal reduction in its potential value.There are three distinctive phases in diamond processing:Feed PreparationWhere the diamonds are liberated and waste material finer than the economically selected cut-off size is rejected. In this section we will discuss the various techniques utilised worldwide to effect feed preparation.Primary ProcessingWhere the diamonds are recovered into a high grade concentrate suitable for the more expensive and selective final recovery process. In this section we will discuss the development of primary processing from jigs and pans to the more current techniques utilised worldwide.Final RecoveryWhere there is selective rejection of waste particles until only diamonds remain. The diamonds may then be acidised prior to packing and marketing.Within these distinct phases a variety of unit processes have been utilised and this paper will discuss their relative merits, limitations and suitability in respect to the various stages of diamond project development from prospecting through to production.Basic capital and operating costs are compared for the autogenous milling route developed in the CIS and the crushing and scrubbing route utilised in the west."

Jan 1, 1994

By Frank Wright

"The Icon Sullivan Joint Venture ore deposit was discovered in June, 1965 by Messrs. Paul Benard, Bob Galipeau and Mac Watson working under the direction of Mr. Andrew J. Troop, as employees of the Icon syndicate. The deposit is located on the Waconichici River as the south end of Baie du Poste of Lake Mistassini, approximately 45 miles north of Chibougamau. Property acquisition and Winkie drilling was followed by a diamond drilling program to evaluate the deposit. Stripping of the open pit area connnenced in the late fall of 1966 and the first test sample of ore was shipped to Chibougamau in December of that year.Regular ore shipments to the mill of Merrill Island Mining Corporation Limited for concentration commenced May 25, 1967. Production to December 31, 1970 amounts to 42,960,000 pounds of pay copper.The ore is chalcopyrite in white quartz dolomite, and it contains a very small amount of precious metals. The quartz dolomite assumes a flat to gently dipping attitude and is associated with a graphitic argillite contact zone on both hanging and footwall sides, in dolomitic limestone rocks. There is practically no other sulphide present in the ore.During the summer of 1969 a series of pre-concentration tests were completed and a Wemco heavy media sink float plant was installed in late 1969 and early 1970. This pre-concentrator eliminates at least one third of the ore mined in the form of barren quartz dolomite prior to ore shipment by truck to the concentrator in Chibougamau."

Jan 1, 1971

By Chris M. Healey

"Perhaps the single most significant variable in the evaluation of a mining project is the reserve estimate. Many parameters are considered when estimating reserves, among them geology. This paper examines the link between the quality of a reserve estimate and a good understanding of the geological controls for the deposit. A clear understanding of the geometry is essential to the accurate definition of the shape and size of the deposit. This includes the definition of any structural controls as well as the proper interpretation of the stratigraphy. Further when the distribution of grades is erratic and there is consequently a high nugget effect, there are significant problems in estimating the true grade of the deposit.Two Saskatchewan examples are presented, one with good knowledge of the controls and therefore good estimates of reserves, and the other with a poor understanding of the geology and resultant problems in deriving good estimates. In both cases the reserve estimates at various stages in the project development are compared to actual results from underground work. The first example is the Star Lake Mine where just about all the estimates were within 10070 of the actual on both tonnage and grade. The Laurel Lake deposit is discussed to show how problems in interpreting the geological data make reserve estimation very difficult. Laurel Lake has the additional problem of erratic grade distribution."

Jan 1, 1992

By Patrick Andrieux

Cet article décrit une nouvelle méthodologie qui quantifie les chances de succès d’un sautage confiné à grande échelle de relaxation des contraintes dans un pilier de mine souterraine, pour un massif rocheux et un régime de contraintes donnés. La méthode est basée sur un nouveau paramètre nommé « Indice de relâchement », qui considère huit paramètres géomécaniques et de forage-sautage qui contrôlent ultimement le procédé. La rétro-analyse d’études de cas bien documentées a démontré que l’approche peut indiquer de manière fiable si une situation donnée de hautes contraintes de terrain est susceptible d’être améliorée par un tir de relâchement confiné à grande échelle et si le design proposé est adéquat pour atteindre ce but.

Jan 1, 2009

By F. Mercier-Langevin

ABSTRACT; Agnico-Eagle’s LaRonde mine is one of the deepest mines in Canada. Ground conditions in the deeper levels can be very challenging, ranging from hard and brittle to soft and squeezing. As a result, rock mechanics and ground control practices have had to evolve considerably to accommodate progressively deeper mining activities. This paper focuses on the deeper levels of mines and how the difficult ground conditions encountered there have influenced the mining strategy. The first section examines ground control practices and support systems in highly stressed, poor quality rock. The evolution of level layout is also presented. Finally, improvements in stope sequencing are reviewed.

Jan 1, 2010