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By A. J. A. Janse

The Argyle diamond mine is located in the Kimberley region in the northern part of Western Australia at approximately 16°43'S, 128°23'E in subtropical bush/shrub savannah. The 46 ha (113 acres) pipe is situated in the Halls Creek mobile zone, which was cratonized about 1800 Ma ago and adjoins the Kimberley Block, a plateau upheld by Early to Middle Proterozoic rocks underlain by presumably Archean basement. The crater and upper pipe zones of the diatreme have been preserved within tilted and faulted strata of Middle to Late Proterozoic age. Its age of intrusion is about 1178 Ma. The diatreme rock is not kimberlite but olivine lamproite which was not recognized as a primary diamond host rock until 1978. The Kalumburu Joint Venture, a syndicate of local and overseas mining companies, started in 1972 to prospect the Kimberley Block with a modest annual prospecting budget of $125,000. Annual expenditure doubled each year and reached $1 million in 1975 after which CRA took over management of the newly-formed Ashton Joint Venture with an annual expenditure of $2 million (all figures are in current US dollars). The Argyle diatreme was found near the end of the eighth field season and after a total expenditure of $12 million. Annual production is about 34 million carats which places Australia as the world's number one diamond-producing country, although, because of the low value per carat, it is number four in terms of total annual value. The global cost required for a major diamond mine is between $300 and $400 million, with a discovery every 10 to 12 years. Because Canada contains large areas of prospective platform rocks underlain by Archean basement it is likely that a major diamond deposit does exist there. It is probable that it will be found before the end of this decade and exploration expenditure may be in the order of $100 million.

Jan 1, 1992

By I. Yutronic

Compañía Minera Doña Inés de Collahuasi's (CMDIC) Concentrator Plant is located at 4300 meters above sea level, approximately 2000 kms north from Santiago, Chile. The concentrator has three grinding lines. Each one, Lines 1 and 2, have one SAG mill at the primary grinding stage followed by a secondary grinding and classification stage consisting of one ball mill, two hydrocyclone batteries and a sump with two pumps. Line 3 has one SAG mill (Gearless Mill Drive), followed by a secondary grinding and classification consisting two ball mills, four hydrocyclone batteries and a sump with four pumps. Average throughput for these three lines is 150 Ktons per day. Peak values of 180 ktons per day have been achieved. Since late 2008 and throughout 2009 and 2010, Operations and Automation areas developed an optimization program for the grinding process, considering the implementation of Model Predictive Controllers (MPC) for the three SAG mills, and later, extending MPC to the secondary grinding and classification stages. The implementation of a MPC solution was based on stability considerations (high variability of the SAG process, high interaction between sump level control and classification efficiency, etc), requirements for an automated and consistent operation, the need to maximize throughput under timevarying scenarios and, in the long term, optimization of grinding process considering Specific Energy Consumption, among other parameters. MPC solutions had proven control robustness and strong optimizing capabilities in terms of helping in discovering new operational points and so achieving all of the aforementioned goals. On the first stage of the program, MPC implementation considered identification of dynamical process control models based mainly on historical data, in order to know the impact of a group of Manipulated Variables over Controlled Variables. Also, the impact of measured Disturbance Variables was modeled in order to take into account the high impact and interaction of these variables over the processes. At the end of this stage, 4 controllers were successfully operating for the 3 SAG mills and the secondary grinding and classification process. In response to challenges made by the working group, the second stage of the development of control applications in the grinding process required to achieve a design and implementation of a solution capable of governing the milling process, in addition to stabilization and optimization of both processes (SAG milling and secondary grinding), to integrate from a point of view of process control and automation. Therefore, in the second stage, MPC performance was continuously monitored and optimized through advanced tuning, inclusion of more process models (with proper step tests), redefinition of specific optimization criteria and adjustment to new process needs. Finally, successful MPC implementation at Collahuasi has proved that fast development and deployment of process control solutions is possible and allows immediate process stability, higher throughput, specific energy consumption reduction, and successful product size control, among many others.

Jan 1, 2012

By Andre du Preez

Emergency Fall Arrest System Rio Tinto?s Primary Objective: ?To achieve repeatable controlled safe deceleration rates during emergency fall arrest activation (Ontario OHSA Regulations) ?Must operate effectively on mine specified steel shaft guides.

May 1, 2013

By A. Bhowmik

Uranium Refining is the process in which undesirable neutron absorbing elements such as Boron (B), Gadolinium (Gd), Cadmium (Cd), Europium (Eu), Samarium (Sm) and other heavy metals (Fe, Ni, Co, Ca, Mg etc.) are removed to make it nuclear pure. At present, Uranium refining is carried out by solvent extraction process by using organic based solvent e, g. TBP diluted with Kerosene. The above process generates lot of nitrate bearing liquid waste and degraded organic. In order to eliminate use of hazardous organic and ammonia for Uranium refining altogether, a new process has been developed. In the new process, Yellow Cake is dissolved in nitric acid and uranium peroxide hydrate is precipitated selectively from the solution leaving all the impurities in the solution by using commercial grade hydrogen peroxide at a pre-defined pH, U conc., temperature and stoichiometric quantity of hydrogen peroxide under mild agitation. The precipitate is filtered and washed with DM water to obtain nuclear pure product meeting purity standard as per ASTM C ? 753-99.The product is spray dried and calcined to obtain uranium oxide. The process eliminates use of organic, flammable, toxic chemicals, consumes less quantity of nitric acid and uses environfriendly chemical hydrogen peroxide. The process is simple and can be integrated in the mill. A patent application is entering national phase in several countries including CANADA and abstract/full paper is available in WIPO publication no: WO/2009/013759.

Aug 1, 2010

By D. Houghton

"I am very pleased to be a member on this panel today because abrasion and wear in mills has been part of my life over the past forty years. My presentation will deal with the role Ni-Hard has played in combating wear and abrasion in mills. Before Ni-Hard came along, unalloyed white iron was used in ball mills and one of the most popular types of white iron liners was the pocket liner. Slide #1 illustrates the design of the pocket liner used at Dome Mines in their 5' x 22' pebble mills. The pockets filled with grinding media and it was on this that the wear took place. The concept is not unlike the new magnetic liner which utilizes the ore and grinding media to form the wearing surface. In this slide please note the tapered pocket type of cored bolt holes. If cored bolt holes do not fill with grinding media there could be excessive grooving or wear at that area. Therefore all cored bolt holes should be tapered in this manner.Before Inco patented the name Ni-Hard several foundries were making the alloy iron under different brand names such as Diamond Alloy, Mitchelloy and Specialloy. In the early days some of the Ni-Hard was poor quality. Inco provided foundries with technical knowhow and provided assistance to licence them to sell under the name of Ni-Hard. This was in the late 1920's. The material we are discussing is Ni-Hard type I with the following analysis (slide #2). It is a martensitic white iron with BHN of 550 - 600 and is a relatively easy alloy to produce in either a cupola or electric furnace. The annual average production of Ni-Hard in North America is 90,000 tons with mill liners making up 25,000 tons and grinding media 30,000 tons, according to Warren Spear of Inco."

Jan 1, 1983

By R. V. Typliski, G. J. Labarre

"Hudson Bay Mining and Smelting Co., Limited, Flin Flon, Manitoba, has developed a metallurgical wastewater treatment system employing two-stage lime neutralization, sludge recirculation and conventional mechanical thickening.Laboratory investigations, initiated in 1970, led to the construction of a pilot-scale minewater treatment plant, at Schist Lake Mine, in early 1971. This plant, treating 600 cubic metres /day of wastewater containing 30-60 mg/1 zinc. demonstrated metal extraction efficiencies of 99% under normal operating conditions.On the basis of this pilot work, a second pilot-scale treatment system was established in 1975 at the Flin Flon metallurgical plant to treat zinc refinery process waste water. Through numerous improvements, including automatic con¬trol equipment, the system has evolved to a full-scale operation capable of treating 800 cubic metres/day of wastewater containing 4-11 gm/1 zinc. Treated effluent contains 0.2-20 mg/1 zinc. The hydroxide sludge produced returns to the metallurgical process for the recovery of metals while clarified effluent discharges to waste.With the system, Hudson Bay Mining has achieved its original goal: the reduction of environmental contamination, while realizing a return from metal recovery.IntroductionWith the goal of reducing environmental contamination, Hudson Bay Mining and Smelting began laboratory testwork, during the late 1960's, into the methods and technology for neutralizing and removing heavy metals from acid mine drainage. Based on lime treatment, early tests showed much promise and culminated in the construction of a pilot-scale test plant at Schist Lake Mine in early 1971.This pilot system utilized technology developed in laboratory studies, and related to work then underway by state authorities in Pennsylvania coal mines. The basic operation consisted of a lime slurry tank, baffle reactor and a free-settling basin. Through three summers of operation, the Schist plant, capable of treating 600 cubic metres/day of minewater, produced a heavy-metal extraction of 99% under normal conditions. Although successful in proving the treatment chemistry, the plant displayed deficiencies in sludge densification and handling."

Jan 1, 1980

By Bob Butler

Brunswick Mine has been involved in a comprehensive research program investigating site specific aspects of thiosalt management to eliminate its adverse environmental effects. Minimum annual reagent cost estimates for thiosalt treatment using hydrogen peroxide and sodium hypochlorite are $400K and $1.5 million respectively. Also, minimum costs for the use of bicarbonate to buffer the pH depression associated with thiosalt oxidation in the receiving environment is in the order of $400K annually. A design of experiment (DOE) research program identified that natural UV radiation, temperature, DO and water chemistry are key factors influencing the natural oxidation rate of thiosalts within Brunswick?s water management system. A DOE surface response model was used to describe the thiosalt oxidation kinetics, which were then used to develop a predictive oxidation model for thiosalt and pH control of the mill?s reclaim water system.

Nov 1, 2002

By Robert B. Parsons

"1984 was an eventful year in the courthouse f or observers 0/ the mining tax scene in Canada. For the first time in a number of years, the Federal Court heard several important tax cases which pertain directly to the resource industries. Tax Notes discusses/our cases that could affect the taxation 0/ operations and investment in the mining sector.Capital Gain or Income?Ever since tax reform, risk-takers in the exploration business have maintained that the taxation of capital gain s is a significant impediment to raising risk capital. It must be akin to rubbing salt in the wound, then, when an entrepreneur sells shares and the Court upholds Revenue Ca nada taxing the gain as ordinary income instead of capital gain. But, this is precisely what happened in the case of The Estate of Murray Watts, et al. v. The Queen.The issue that had to be decided by the Federal Court, Tri al Division, in this case was whether or not the profit from the sale of shares in Hearne Coppermine Exploration s Limited in 1968 was a capital gain, or income subject to tax.Hearne was incorporated in July, 1967. At that time, the three plaintiff s, together with seven other individuals, subscribed for 400,000 shares at 10 a share. The plaintiff subsequently subscribed for an additional 500,000 shares at $1.A pooling agreement was entered into by all ten shareholders regulating the disposition of any o f their shares; any sale required approval of seven of the ten initial sub scribers. It also provided for the sale of their shares 30 days after any public offering."

Jan 1, 1985

By Jim Robertson

Summary of Presentation ??What is the GARD Guide ??The Need for a GARD Guide ??Mining Industry?s Commitment to Solving ARD Problems ??The Ultimate Solution ?You ??The GARD Guide ?Scope ??The GARD Guide ?Structure ??Wiki Demonstration

May 1, 2009

"The standards set out requirements of the Toronto Stock Exchange for company’s providing information to investors, regulators and/or the media regarding their mineral properties. In addition, information contained in new releases, continuous disclosure documents [annual report], or other forms of communication [printed investor relations materials and electronic publications] are also subject to these standards.1.0 INTRODUCTIONThe disclosure of the results of exploration and development activity on mineral properties mustcomply with the requirements of the Toronto Stock Exchange Policy Statement on Timely Disclosure, theOntario Securities Act and all applicable policies and rules of the Ontario Securities Commission and anyother securities regulatory body having jurisdiction over an issuer listed on the Exchange. In particular,the requirements of National Instrument 43-101 must be followed.The purpose of the standards is to set out the requirements of the Toronto Stock Exchange when acompany provides information to investors, regulators and/or the media regarding its properties, whethersuch information is contained in a news release, a continuous disclosure document such as an annualreport, or other form of communication, including, but not limited to, printed investor relations material andelectronic publications such as Internet Web sites. These standards do not apply to prospectuses orlisting applications, the standards for which are contained in the policies and rules of the securitiescommissions and the Exchange. These standards are also not intended to establish requirements for thecontent of technical reports.Any information published by or on behalf of a company must comply with these standards. If acompany becomes aware of information published by others regarding its mineral properties which ismaterially misleading to investors, it should take appropriate action to correct such information orotherwise make it known that it is not responsible for publishing such information and does notnecessarily agree with such statements.Disclosure concerning mineral properties should identify the ""qualified person"" as defined in NI 43-101 who is responsible for the work conducted on the property and such person shall have read andapproved of the technical disclosure."

Jan 1, 2003

By V. I. Ryaboy, V. P. Kretov, I. V. Ryaboy, E. D. Shepeta

This paper studies the features of known and newly synthesized dialkyldithiophosphates and reagents with thioamide groups when separating copper-containing and arsenic-containing minerals in the flotation of skarn-scheelite-sulphide ore at the Primorskaya concentration plant. The optimization of dialkyldithiophosphate collectors was based on the study of their surface activity at the liquid-gas interface and estimated hydrophobic abilities. The flotation experiments show that the selectivity of action of the reagent increases with an increase of its surface activity and a reduction of hydrophobic ability when separating chalcopyrite and arsenopyrite. IMA-225-5 was proposed as a more efficient dialkyldithiophosphate collector, which increases the recovery of copper by 2.8% compared to the industrially used collector IMA-I413. Selection of the optimal structure for reagents with thioamide groups (derivatives of thionocarbamate and thiourea) was carried out according to their acidity and the presence of hydrophilic particles in their structure. Calculations were performed depending on the pH of the solution of chalcopyrite to determine the optimum reagent sorption and to further optimize the structures of these reagents. The tests with reagents with thioamide groups show an increase in copper recovery by 3-4% together with a significant increase of arsenic content compared to IMA-225-5. As a stronger collector with thioamide groups, it was recommended to use sample 234, which belongs to the thiourea derivatives. IMA-225-5 was recommended for industrial tests at the Primorskaya concentration plant. Thus, this study has shown that using dialkyldithiophosphate is more appropriate if it is necessary to increase the selectivity of separation of copper-containing and arsenic-containing minerals, and using reagents with thioamide groups, or their combinations with dialkyldithiophosphates, is more appropriate if it is necessary to increase the recovery of copper or the quality of copper concentrate with less selectivity of the process.

Jan 1, 2016

By Deni Pageau, Deni Caron

"This paper describes the operations of the open pit and emphasizes particular aspects of Les Mines Selbaie. The open pit as well as its related services were incorporated into a complex which includes an underground mine and a concentrator. The equipment was chosen with the objective of auto-sufficiency during each phase of mining. The paper outlines the organization and the methods used in each step of mining, notably: drilling, blasting, loading, transporting and crushing. The responsibilities of the Engineering Department are also outlined from the conception of the open pit to the latest follow-up methods. A short resume of the results which have been obtained as well as suggestions for improvement are provided.Layout in Consideration of Main SiteThe A-I zone deposit is located I km from 8 zone. Open pit mining of A-I zone required the regrouping of different services to those already existing.I. The crusher was placed in an area close to the concentrator in order to minimize the length of the conveyors and to provide space for the crushed ore reserves (50000 tonnes).2. The location of the service building (warehouses, mine offices, maintenance, engineering and geology) raised a few problems. Because of the multiple services provided therein , it was impossible to fulfill all the requirements, and the garage in itself is located a fair distance from the pit. Added to this inconvenience is the fact that heavy equipment regularly travels throughout the main yard.3. The storage of explosive magazines has been changed to obtain more surface space and meet government regulations.4. A space has been provided for minor repairs in the garage used during exploration. A trailer was installed next to the garage to provide a lunch room for the employees working at the open pit."

Jan 1, 1990

By P. R. Brito-Parada, G. Bhutani

"The physical processes occurring in flotation columns are very complex as they take place at different scales over a range of sizes and multiple phases. Column design and optimum operating parameters are usually obtained from empirical studies and although progress has been made on its numerical modelling, most column models rely on simplifications that do not fully capture the hydrodynamics. In particular, Computational Fluid Dynamics (CFD) models of the pulp phase in flotation usually assume the bubble population to be monodispersed. While this assumption may be reasonable in some situations, the polydispersed nature of the gas phase can have a significant impact on the predicted flotation rates.Techniques to model size distribution do exist in the literature and have been rigorously analysed in the past two decades for bubble columns, which are very similar to flotation columns from a hydrodynamics point of view. In fact, available CFD models of flotation columns are an extension of bubble column models, sometimes including additional equations for solids treated as passive scalars. This work focuses on the development of an efficient CFD model for flotation columns. The bubble size distribution in the column has been modelled using the Population Balance Equation (PBE), which is solved using the Direct Quadrature Method of Moments (DQMOM). Coupled with the PBE, the multiphase flow equations in the column have been modelled using the standard Eulerian–Eulerian approach. The solution of this coupled system has been made tractable in this work with the implementation of a highly parallelised adaptive-mesh finite element method. This powerful framework has been implemented in the open source CFD code Fluidity and it allows the carrying out of detailed simulations of flotation columns in 2D and 3D, with important implications for industrial column evaluation and design."

Jan 1, 2016

By Roger M. Nendick

"IntroductionThe stages of development for bringing a mill into production demand that a flowsheet for the process be developed at an early stage. Detailed engineering of the mill may then proceed without duplication of engineering effort on alternative processes. In the case of gold and silver mills, several process alternatives exist which must be evaluated before the flowsheet is finally fixed. The recently developed Carbon-in-Pulp process has added to this choice.Clearly, the major factor in determining the most suitable process is the amenability of the particular ore to a given treatment. Other factors that will also influence the choice are location, climate, power and water supplies, and available capital.Gold and silver milling processes can be divided into three main types:Gravity Concentration;Flotation;Cyanidation.Combinations of the three are frequently used; i.e. flotation followed by cyanidation of the concentrate, or gravity concentration in the grinding circuit with cyanidation of the classifier overflow. The following are the salient advantages and disadvantages of the three main alternatives.Gravity ConcentrationGravity concentration is suitable for free-milling gold ores, i.e. ores in which the gold is relatively coarse and free from sulphides. It should be noted that just because an ore is high grade, it is not necessarily free milling.Gravity concentration methods include jigs, shaking tables, spirals and more recently Reichert cone concentrators. All methods exploit the density difference between gold, which has a specific gravity greater than 15, depending on how it is alloyed, and the gangue, which usually has a specific gravity range of 2.7 to 3.5.A concentrate grade of several hundred ounces per ton might be produced, but recoveries by gravity alone are generally low in comparison to other methods. For this reason, gravity circuits are usually used in combination with flotation or cyanidation circuits."

Jan 1, 1983

By A. J. Sinclair

Abstract-Exploratory data evaluation is an essential part of every high quality, mineral inventory estimate. Efficient analysis involves a thorough organization of available quantitative data that are the basis of the estimate and perhaps the formation of composite grades. Data organization and evaluation can involve more than 50% of the time necessary to conduct a mineral inventory estimation. The principal purpose of exploratory data evaluation in mineral inventory work is to improve the quality of estimation by providing insight into characteristics of the variables under investigation. Specific aims include: (1) to recognize and eliminate errors; (2) to provide a comprehensive knowledge of the statistical characteristics of all variables of interest for resource/reserve estimation; (3) to document and understand the interrelationships among the variables of interest; (4) to recognize systematic spatial variation of variables such as grade and thickness of mineralized zones; (5) to recognize and define distinctive geological domains that require independent estimation of mineral inventory; (6) to identify and characterize outliers; and (7) to evaluate similarity/dissimilarity of various types of raw data, especially samples of different supports. These aims are not mutually exclusive but they can all have their own impact on resource/reserve estimation. Error must be minimized. Individual variables can have characteristics that lead to different decisions in the course of estimation. Similarly, interrelations of variables might contribute to the ease (or difficulty) with which estimates of several variables can be obtained. Trends can impose the need for two or more domains, each of which might be estimated independent of the others. Outliers, a perennial problem, require detailed evaluations because they impact on reserves much out of proportion to their abundance. Data, of widely different supports, generally must be standardized if all are to be used for purposes of estimation.

Jan 1, 1998

By D. E. Ayres, J. Farstad

"The Midwest uranium deposit is located within the Athabasca Basin near its eastern margin and displays many of the features seen in a number of other similar deposits in this area. The mineralization occurs in the vicinity of a tectonically disrupted portion of the unconformity separating the clastic sedimentary rocks of the Helikian Athabasca Group from Aphebian pelitic meta-sediments which are equivalent to the basal pelitic meta-sediments of the Wollaston Group. The orebody consists of pods of massive pitchblende and sulphur-arsenides within an elongate and tablular envelope of disseminated and fracture controlled mineralization. The massive pods are intimately associated with overbank mudstones of the lowermost Athabasca Group. Both structure and lithology have played major roles in localizing the deposit as follows:1. The basement lithology influenced the mineralogy of the regolith produced on the pre-Athabasca unconformity.2. The style of clastic deposition and the character of the regolith on this unconformity favoured local preservation of mudstones.3. The basement lithology influenced the location of zones of post-Athabasca faulting.4. The proximity of these fault zones to mudstones provided for the coincidence of circulatory channels for fluids bearing uranium, with a good precipitant for the metal.IntroductionA brief summary of the geology of the Midwest uranium deposit was presented by J. Farstad (1979) to the attendees of the Saskatchewan Potash and Athabasca Basin uranium deposits field trip organized by the Canadian Institute of Mining and Metallurgy (May 28 to June 1, 1979). Since that time a substantial amount of data has been collected and studied. This paper is a precis of a report by J. Farstad (1981) which summarizes the geology of the deposit as inferred by visual examination of diamond drill core, augmented by information obtained from detailed examination of selected cores by D.E. Ayres."

Jan 1, 1986

By R. G. McDonald

"High iron solution concentrations often result in the formation of basic ferric sulfate during the high temperature oxidation of sulfidic materials such as base metal and refractory gold concentrates. Consequently, the “Hot Cure Process” followed by limestone neutralization is required to facilitate subsequent processing and/or disposal of the leach residue. The present paper discusses strategies that can be employed to influence the composition and nature of the high-iron content leach residues produced during pressure leaching.INTRODUCTION Control of iron deportment in hydrometallurgical processing remains a key challenge for a range of reasons. Strategies generally relate to the control of conditions under which iron is optimally rejected (Demopoulos, 2009). Supersaturation provides the driving force for crystallization and this can be controlled by a number of factors that include (1) pH and/or Eh control, (2) the presence of matrix anions and impurities, (3) dilution, (4) complexation and dissociation and (5) manipulation of the rate at which the metal to be precipitated is released to solution. Each of these factors is impacted by temperature. Good control of crystallization is essential to the control of precipitate properties such as the degree of crystallinity, stability, particle size and quality which covers both the extent of impurity uptake and suitability of the precipitate for waste disposal. The quality and properties of iron precipitates in turn can impact downstream processing. It is the aim of this paper to discuss the generation of iron-containing residues produced during the pressure oxidation of sulfidic ores and concentrates and how the nature of these can be controlled to potentially facilitate further processing. A brief overview of several related topics will now be given and include, where relevant, discussion of work undertaken in our laboratories. In addition, brief discussions of selected process options that enable good control of iron rejection will be provided."

Jan 1, 2016

By Timothy W. Ellis

Gold-based materials have been a mainstay of the electronics and semiconductor industry since the physics was just a laboratory curiosity. Gold is the workhorse material in wire bond, flip chip and off wafer interconnections due to its corrosion resistance, ability to form metallurgical bonds by soldering or cold welding, and ease of fabrication. As the electronics and semiconductor industries grew, so did the use, of Gold in spite of the feature size reduction so elegantly demonstrated in Moore?s law. However, several revolutions in the Silicon miracle are threatening Gold?s place as the material of choice. Although cost is always an issue, the limitations are associated with the chemistry of Gold based alloys. Will Gold remain? Emerging requirements of bioelectronics, photonics and power requirements in conventional device represent new opportunities for Gold to shine. Additionally, as the world market demand for electronic, semiconducting, bio-electronic and photonic technology increases, given the right technology, Gold still can provide value proposition.

Oct 1, 2003

By A. J. Sinclair

"Abstract-Geology contributes essential information toward obtaining high-quality resource/reserve estimates. In this context, geology can be considered under the following overlapping topics: regional geology, detailed (deposit) geology, mineralogy, ore deposit models and continuity, with geological mapping being fundamental to all. Each of these topics is considered here in terms of potential contributions to "improved" mineral inventory estimation. Some of the principal conclusions are:1. Regional geological relations must be consistent with deposit geology. It is common that important geological relations are more clearly evident in various regional locales than in highly altered and/or highly deformed mineralized areas containing mineral deposit.2. Detailed geology provides information for a geometric model of a deposit, a model that serves as a basis for mine planning. It is important to distinguish fact from interpretation in such models. Substantial effort is required to characterize the geometric margins of a deposit and the relation of these margins to the simplistic geometric form that normally emerges as an interpretation.3. Mineralogical studies relate to many aspects of deposit evaluation including abundance of ore and deleterious minerals, spatial distribution of ore and deleterious minerals, grain size characteristics of important minerals, mill design, etc.4. Ore deposit models contribute substantially to confidence in developing a three-dimensional geometric model of a deposit for mine planning. Specifically, they are a basis on which to develop rules for interpolation and extrapolation of ore, and they contribute to recognition of domains, each with its own characteristic continuity and margin character.5. Continuity is dependent on mineralization style and may be controlled structurally and/or chemically. It is important to distinguish geological continuity and value continuity. A wide range of classical geological methods are useful in examining geological continuity; value continuity is best viewed as a statistical characteristic that is quantified by any of several measures of autocorrelation."

Jan 1, 1998

By Maurice Morton

THE use of organic and inorganic stains has found wide application as a means of detection and estimation of organic fibres. Such stains have enabled the analyst to distinguish between organic fibres of different type and even between wood fibres produced by different processes. Among these stains, aqueous iodine solutions have figured prominently, as in the case of the well-known Sutermeister and Herzberg stains. At the Johns-Manville laboratories, the idea of applying a stain to asbestos fibres was first considered solely as a visual aid in the microscopic examination of such fibres. The staining medium used in this work consisted of a 1 per cent solution of iodine in C.P. glycerine, the latter being used extensively here as a dispersing and mounting liquid for asbestos fibre. This iodine solution was found to have distinct staining properties when used on the local chrysotile fibres, and to improve greatly their visibility under the microscope. It was soon revealed, however, that this staining is apparently limited to the chrysotile variety of asbestos, as against other varieties. It can be readily seen that, if such were the case, the staining test would become a very useful tool in differentiating between chrysotile fibre and the other mineral fibres, without recourse to a lengthy chemical analysis. Hence this investigation was launched, with the purpose of obtaining more information as to the selectivity of this stain as well as its mechanism. The only previous work of this nature that could be found in the literature was that of Van Winsen and Graham (1, 2, 3) on the adsorption of erioviolet dye by serpentine and related magnesia minerals. However, these authors did not refer to any specific behaviour of chrysotile as against other types of asbestos fibre.

Jan 1, 1941