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By B. R. Boardman

Project Environmental Approval is a multi-faceted issue. From a mining perspective, it is a costly item because of avoidable time delay. The government perspective is that the approvals are a necessary part of meeting departmental requirements to ensure that the wellbeing of other uses of the environment is maintained. This paper outlines some of the problems inherent in the environmental approvals process and makes recommendations to both the proponent and government about improving the efficiency of the process.

Jan 1, 1978

By C. A. Godden, T. N. Atkinson

Metallographic techniques developed from studies of corrosion films and electroplated coatings on aluminum alloys, are discussed. These methods, the result of work at the Naval Research Establishment, give extremely flat fields at the interface despite the large difference in hardness, in cases where electrolytic polishing could not be used. Techniques to overcome the similarity in refractive index of immersion oil, aluminum ox1d~, and mounting plastic are also considered, as are methods for improving visual and photographic contrast in areas of interest. A device for marking specimens is also de-scribed. ELE•CTROLYTIC polishing is inapplicable in the study of surface films on aluminum, whether corrosion films or electrodeposits. Mechanical procedures must there-fore be followed. Sample flatness and edge retention are of paramount importance. Special measures are required in the study of oxide films, because of the close proximity of the refractive indices of aluminum oxide, mounting plastic, and immersion oil.

Jan 1, 1962

By S. Fahland, P. Vogel

"The Gorleben salt dome has been investigated since 1979 for its suitability as a repository for the disposal of high-level radioactive wastes. The geoscientific surface exploration was followed by underground exploration of the site beginning in 1983: underground excavation work included the sinking of two shafts from 1986 to 1994, the excavation of the infrastructure area and of drifts located in the first exploration area EB1 within the following years. The exploration was interrupted for ten years from 2000 to 2010 as part of a moratorium. After the expiry of the moratorium in March 2010, the geoscientific underground exploration at the Gorleben site was resumed. The investigations were interrupted again in autumn 2012 due to a political decision. The exploration programme included extensive geoscientific investigations: geological exploration, geophysical investigations, mining exploration and mining observation, laboratory tests, in-situ geotechnical measurements, geological modelling and numerical model calculations. To analyse and interpret the results of the in-situ measurements and mining observation geomechanical, thermal and thermo-mechanical model calculations were carried out. One of the main elements of the in-situ geotechnical investigations were high-resolution geothermal measurements performed in boreholes used for geological exploration and geotechnical tests.The geothermal measurements are used to evaluate several geotechnical findings, e. g. drift closure, rock deformation, stress change, and are completed by thermal model calculations to analyse and interpret the results of in-situ measurements and mining observation. The model calculations have been carried out using the special purpose JIFE code. To consider the whole exploration mine with the adjoining host rock as well as the successive excavation of drifts and boreholes in detail a three-dimensional finite-element model was developed. The model calculations are used to analyse the cooling-off of the surrounding rock of the drifts caused by ventilation. The cooling-off of the surrounding rock is an ongoing process affecting the results of further geotechnical measurements in the near field of the drifts. To predict a realistic time and space dependent distribution of the temperature field of the host rock within the exploration area which is influenced by ventilation thermal model calculations are necessary. Comparing the calculated temperature field with the in-situ determined rock mass temperature field within the exploration area EB 1 the results show a sufficient agreement. Furthermore there is very good correspondence, both qualitatively and quantitatively, between the experimental and the calculated findings regarding the temperature profiles including the effects of excavation and ventilation of the drifts."

Jan 1, 2015

By F. R. Erick Mulder

"AbstractTwo bottom-hole samples have been taken from two new completions in the Turner Valley field, Royalite Lowery No. 8 on the west flank and Royalite No. 73, which was deepened into a lower fault block, on the northeast flank. From the bottom-hole oil of Royalite Lowary No. 8 a synthetic sample was prepared to simulate the original fluid in the reservoir, saturated at the gas-oil contact conditions. The sample from Royalite Lewery No. 8 has been shown to be the original fluid present at this well and represents the oil phase near the oil-water contact in• the reservoir. Complete chemical analysis, P.V.T., and viscosity data have been obtained on these reservoir fluids, which represent the range of saturation from the gas-oil to the oil-water contact in the Turner Valley oil structures. Sampling techniques and the application of the analytical data to reservoir conditions and field operations are discussed. Super-compressibility curves for an average separator tail gas have also been prepared. These data have not been available before. They will be of fundamental value in futu.re reservoir engineering studies of this field and will also serve as a guide in determining operating practices."

Jan 1, 1950

By L. Frost

Physical Conditions Great Britain The physical conditions in the mines investigated in Great Britain are similar to those found in the mines of the Dominion Steel and Coal Corporation, with the important difference that many of the coal seams visited were interspersed by a large number of heavy faults, making the development of a continuous face operation difficult, and in many cases the life of a unit development was exceptionally short, adding to unit cost; but in spite of these difficulties, a great deal has been accomplished in the application of mechanical loading units in a number of the mines in the areas visited. The coal-bearing measures, as in Nova Scotia, consist of shales and sandstones, and in some sections mussel bands overlie the coal seams making roof conditions difficult'. In several mines, the main roof consisted of weak shale bind, being held by a coal roof of varying thickness. This shale bind had a tendency to flow when the coal roof was broken. The floor, in some cases where cutter loaders were operated successfully, consisted of weak, flaky shales with very little resistance and a tendency to disintegrate into powder when broken. The depth of cover under which these mines were operating varied from 250 feet to 2,340 feet, with an average of 1,700 feet. The coal seams varied in height from 3 feet to 8 feet 6 inches, and the gradients from level to 33 per cent. The seams vary in hardness, but all-with the exception of one seam, the 'Morrison Busty'- presented a cutting problem similar to that found in Nova Scotia. The structure and cleavage of the coal was well defined and uniform. Some of the seams visited were gassy, ?but the temperature of the workings generally was not in excess of 70°F.

Jan 1, 1948

By P. Scinto, P. Hudson

"Modern day ore bodies are becoming increasingly harder, more abrasive and lower grade. The Mako deposit is located in Senegal and consists predominantly of primary mafic and felsic lithology that are both very competent and very abrasive ores (Axb < 30, BWi >20 and Ai >1.0). The deposit was initially discovery in 2010 and the Toro Gold management team fast tracked the Mako Project through development and into production to achieve its first gold pour in January 2018. The comminution circuit comprises primary crushing single stage SAG milling with recycle crusher (1oCR SS-SAC). The mill reached design throughput and grind size seven weeks after first ore. The Mako project marks another successful international application of single stage milling, which represents a simple and easy to operate comminution circuit for small-to-mid size projects with a low capital cost. This paper describes the ore interpretation, comminution modelling, grinding circuit selection and design, as well as an overview of the commissioning and ramp-up of the mill.INTRODUCTION The Mako Gold Project is operated by Toro Gold Ltd., which holds a 90% interest in the project. The project is located in south-eastern Senegal in the Kedougou region, close to the Gambia river and township of Mako. The Mako deposit lies in the “Kenieba Window” of eastern Senegal and western Mali, which hosts a number of gold mining operations and development projects. The Mako Gold Project has an estimated life of 8 years with overall recoverable gold estimated at 924 koz. The process plant is designed to treat 1.8Mt/a of ore and produce 128 – 143 koz of gold per annum. Lycopodium Minerals Pty Ltd (Lycopodium) was appointed to provide feasibility studies and EPCM services for the greenfield project. Forming part of consultancy services provided by Lycopodium, Orway Mineral Consultants (OMC), a subsidiary of Lycopodium, was involved in the design, commissioning, ramp up and ongoing post commissioning support of the comminution circuit."

Jan 1, 2019

By Frédéric Flament, Mary Goldman, Gille Barbery

"Pilot plant testwork on autogenous and semi-autogenous grinding was conducted at the Centre des Recherches Minérales du Québec (CRM) to investigate the effect of ball addition, solids concentration in the feed, specific energy consumption and feed size distribution.A mathematical model that incorporates breakage and surface mechanisms of loss of mass was developed to predict load size distribution of autogenous and semi-autogeneous mills. An empirical model was used to predict product size distribution of autogenous and semi-autogeneous mills.IntroductionAutogenous (AG) and semi-autogenous (SAG) grinding circuits offer potential capital and operating cost savings when compared with conventional grinding. Empirical relationships have been developed to calculate specific power consumption for SAG mills using pilot plant test results (Mular et al., 1989; Barrett and Allan, 1986). Empirical models can be obtained from plant practice data but are applicable only to the particular ore and set of operating conditions used in the model. Grinding mechanisms have to be taken into account in order to develop a model that can be applied to different ores and mills.In AG and SAG, the ore itself acts as grinding media, with the finer sizes being crushed by the coarser ones. Surface mechanisms of loss of mass, in which the inner core of the particle remains intact, also take place. In SAG milling, the effect of balls also has to be taken into account. The role of each one of these mechanisms changes with particle size and the model has to account for such changes."

Jan 1, 1991

By J. Stiksma, R. Kalanchey, M. J. Collins, G. Owusu, R. Raudsepp, K. R. Buban, L. A. Barta, L. Masters

This paper describes the results of testwork for the treatment of Ambatovy laterite by an acid pressure leach process, with recovery of the soluble nickel and cobalt values as mixed sulphide intermediate by precipitation with hydrogen sulphide, and subsequent refining of the mixed sulphide to nickel and cobalt metals. These process development studies were carried out primarily in 2004, as part of a bankable feasibility study for the Ambatovy Nickel Project.

Jan 1, 2004

By Limao Zhang

This paper presents a novel model to assess the risk of adjacent buildings in tunnelling environments based on Extended Cloud Model (ECM). ECM is an organic integration of Extension Theory (ET) and Cloud Model (CM), where ET is appropriately employed to flexibly expand the variable range from [0, 1] to (-8, +8), and CM is used to overcome the randomness and fuzziness during the gradation of evaluation factors. The risk level of a specific adjacent building is assessed by the correlation with the cloud models. A confidence indicator ? is proposed to illustrate the rationality and reliability of evaluating results. Ten buildings adjacent to Wuhan Metro Line Two (WMLT) are randomly chosen among hundreds of adjacent buildings for a case study. Results have proved to be consistent with the actual situation. Compared with other traditional evaluation methods, ECM has been verified to be a more competitive solution with high calculation accuracy, wide adaptability, as well as simplified computer programming. There are no stringent requirements on the quantity of training data during the modelling process, and the original data can be directly entered into ECM without a normalization procedure, avoiding the potential information loss. ECM can be offered as a decision support tool for the risk assessment in urban tunnelling construction and worth popularizing in other similar complicated projects.

Aug 1, 2013

By A. Brown

"The first printed report on Canada's coal resources was published in Paris in 1672(1. Written by Nicholas Denys, then Governor for France of Isle Royale (Cape Breton Island), the report dealt exclusively with the coal of the Atlantic region because little or nothing was known about the interior of North America. Clearly, also, he wrote about a resource of which much was known among the military and early settlers of that day. This early knowledge is not surprising because the presence of coal is clearly displayed in the coastal cliffs of Cape Breton as it was also, at a later date, to the first arrivals on Vancouver Island.An example of early use was that of the French garrison at Fort Louisburg in the first half of the 1700s. Still earlier, in 1643, Governor Winthrop of New England reported the receipt of a small ship load of coal from New Brunswick (2). Despite this early knowledge there was no significant development of coal mines until the 1800s. This had to await the ending of wars between the French and British factions and the growth of population. Basically, also, its development awaited the beginning of the Industrial Age. Organized coal mining began in Canada in 1825 with the formation of the General Mining Association. This British firm was the creation of a group of London jewellers which had been granted royal rights, by the British crown, to all minerals in Acadia (substantially the present Maritime Provinces). The Association took over a number of existing small mines and opened up larger operations in the Sydney coal field. Subsequently, it expanded to the mainland Nova Scotia fields at Stellarton and Springhill. The Association continued in existence as the major coal producer in Canada until 1899 when it sold its properties to the Nova Scotia Steel and Coal Company, Limited (3). This Montreal-based firm managed the coal mines as a major Canadian producer of coal until 1968 when financial problems led to the expropriation of the mines by the Government of Canada. The federal government established the Cape Breton Development Corporation to operate the larger mines on Cape Breton Island. This Crown corporation continues to be a .major producer of coal in Canada."

Jan 1, 1985

By M. Kane, B. Bissonnette, D. Hodouin

"A laboratory cell has been designed for a careful investigation of gold ore cyanidation using mathematical modelling of the process kinetics. The cell is a stirred vessel with continuous monitoring and control of pH, oxygen and free cyanide contents. Samples are automatically extracted for gold analysis. The instruments are connected to a microcomputer which records all the measured variables and calculates the reagent consumption (air or oxygen, cyanide, lime). For cyanide control a sample is automatically extracted and filtered and the solution analyzed, using a specific electrode, by a flow injection technique. The rate of gold dissolution is modelled using a kinetic model the parameters of which are calculated by a non linear least-squares technique. The parameters of an empirical model of reagent consumption are also estimated. The resulting model is used in a simulator for gold cyanidation plant design, tuning and control.INTRODUCTIONThe leaching of gold ores in a cyanide solution is the usual method for gold extraction from raw ores. This process requires long reaction times and leads to very significant consumption of cyanide. The optimization of the cyanidation plant operation is a very important aspect of gold ore processing for increasing gold recovery and decreasing operating costs. The key parameters to the improvement of gold extraction are the selection of an efficient solution chemistry, the design of the size and the arrangement of the equipment and the correct tuning of the operating variables. Automatic control strategies can then be applied to maintain industrial operations at their optimum setpoints.Two approaches can be used for optimizing design and control of cyanidation circuits, either empirical trials for improving process performances or mathematical modelling of the process kinetics for subsequent analysis, simulation and optimization. The advantages of the second approach, which is used in this study, is that it gives a systematic pattern to interpret data and reliable tools, in as much as the models are good, to improve operation performances. In order to determine the structure and the coefficients of cyanidation models, well controlled measurement and calibration procedures must be used. The purpose of the paper is to present an equipment and a test procedure for modelling the kinetics of gold ore cyanidation."

Jan 1, 1990

By Carlos Avalos Casillas, Saul Ortiz Landeros

The current work shows metallurgical results obtained at the Centro de Investigación y Desarrollo Tecnológico (Peñoles CIDT), as a continuation of the work first published in February 2012. With the aim of optimizing the economic values of the products, ores from San Julian (Fresnillo) were selectively floated to produce a lead concentrate and a zinc concentrate containing high silver values. In the laboratory, this included regrinding of the rougher and scavenger lead concentrate to increase the liberation of mineralogical species and thus lower zinc recovery. Cyanide leaching bottle tests were conducted to improve the value of the silver. It is proposed to leach the silver contained in the zinc concentrate and then recover the silver using the Merrill Crowe process. The results show a reduction of zinc recovery in the lead concentrate from 11.3% to 2.0% after regrinding to a P80 of 10 microns, improving the metallurgical quality and economic value of the lead and zinc concentrates. Also laboratory and pilot scale cyanidation tests showed that about 65 to 80% of silver will be leached from the zinc concentrate, after regrinding to a P80 of 10 microns. The proposed processing increases the economic recovery of silver from 72.7% to 78.8%.

Jan 1, 2014

By James J. Scott

"In the two years since their introduction, Friction Rock Stabilizershave replaced40 per cent of the previously used fixtures in the metal and non-metal mines in the United States. The Friction Rock Stabilizer, or ""Split Set "" , is a mechanical rock stabilizing system which uses friction to prevent rock movement . The Split Set is a tapered, rolled, steel tube that is slotted along its length. As it is driven into a drilled hole smaller than its diameter, it compresses, pre-loading the surrounding rock. This paper discusses the uses and acceptance of the friction rock stabilizer in mines in the United States. IntroductionFriction Rock Stabilizers, commonly called Split Set™· Stabilizers, have been under development by the author and Ingersoll-Rand Company since early 1973. Five years of intensive laboratory and field testing led to their introduction to the metal mines in the United States in the fall of 1976. Actual sales started in February of 1977and, to date, over five million units have been marketed to metal mines. The present rate of usage is near 3 V2 million units per year, which is approximately 50070 of all roof fixtures used in the United States metal mining industry,Richard Hoppe, senior editor of Engineering & Mining Journal. , in an article in the February 1979 issue entitled ""Winning the Battle Against Bad Ground"", said: ""In hardrock mining operations in the western U.S., particularly underground uranium mines where exceedingly difficult ground is common, no roof support system has been accepted more quickly than the Split Set friction bolt invented by Dr. James J . Scott and developed by Ingersoll-Rand Co."" This paper describes how Friction Rock Stabilizers function and presents technical data to show the uniqueness of such systems."

Jan 1, 1980

By P. Bramwell, R. Tremblay

"The Port Radium leaching plant of Eldorado Mining and Refining, Limited, produces 450 t./d. of sulphuric acid leach liquor containing l. 73 g. /I. U 308. After solvent extraction, the waste solution is discarded at 0.002 g./l. U30s for a recovery of 99.8 to 99.9 per cent. The solvent is acidified with weak sulphuric acid, loaded to 4.5 g./l. U80:1 in three-stage extraction, scrubbed with water, and stripped with soda-ash solution in single-stage stripping. Caustic removes the UaOs from the pregnant strip solution as a precipitate. The slurry is filtered, re-pulped with water, and re-filtered. The pressed precipitate at 81 to 82 per cent equivalent U30s is dried and packaged. The carbon-ate filtrate is cooled to remove sodium sulphate build-up and carbonated to convert excess caustic. Reagent consumptions are 4.1, 0.22, and 0.39 pounds per 1,000 gallons of pregnant solution for Diesel oil, amine, and alcohol, respectively. Caustic consumption averages 1.3 to 1.4 pounds per pound U3O8.Extraction and stripping is accomplished in sheet-iron mixer-settlers lined with Phenoline. Piping on both circuits is Schedule 80 polyvinyl chloride. Valves are straightway Buna N lined with American Hycar diaphagms. Extensive instrumentation ensures good metallurgy with a minimum of variations and labour. Mixing in a continuous organic medium and careful acidity control are required to minimize third-phase formations. Heating the precipitate slurry is conducive to good filtering in Perrin presses with neoprene-coated, rolled-steel sectors. Sodium sulphate is crystallized from carbonate filtrate solution by batchwise cooling to 54°F. with lake water."

Jan 1, 1959

By S. M. Bradshaw, E. Charikinya

"Microwave induced cracks have the potential to enhance metal recovery from coarse sphalerite particles in heap leaching operations by creating new crack surface areas for lixiviant and enhancing value mineral exposure. The mode of fracture and the extent of mineral exposure due to microwave induced cracks have not yet been investigated. The objective of this study was to determine the extent of particle damage and mineral exposure in microwave treated particles. This was done using X-ray computed tomography (XCT) and image analysis techniques. XCT analysis was conducted on small (–5+4.75 mm), medium (–16+9.5 mm), and large (–25+19 mm) sphalerite ore particles before and after microwave treatment (MT). Geometrical properties, such as volume and surface area of each mineral phase in each particle was determined from the XCT reconstructed images using VGStudioMax image analysis software. These geometrical properties were used to calculate the interfacial areas of sulphide mineral grains in microwave treated particles before and after MT. The ratio of specific interfacial area after MT to specific interfacial area before treatment was used as an indicator of the degree of preferential grain boundary fracture. The results showed significant grain boundary fracture after MT at all sizes. For small sized particles, about 31% of the interfacial area was lost compared to 23 and 16% for medium and large particles, respectively. The results also showed an increase in the degree of mineral grain exposure of 28, 26, and 15% for small, medium, and large particles, respectively, after MT. These results provide experimental evidence supporting improved mineral exposure due to MT. INTRODUCTIONFor some years it has been suggested that microwave treatment (MT) of ores might result in preferential grain boundary fracture that would have benefits such as improved grain exposure and particle weakening. (Kingman, 2006). Most of the experimental work investigating the application of microwaves to mineral processing flow sheets has focused on assessing the benefits of applying microwave technology to flow sheets consisting of size reduction and mechanical flotation cells (Kingman et al., 2004). Experimental studies have shown that coarse crushing during tertiary grinding of microwave treated ore resulted in a better liberated coarser flotation feed (Scott, Bradshaw, & Eksteen, 2008). It has been suggested that improved liberation in milled flotation feed, was due to the presence of grain boundary fracture in microwave treated particles. However, this improvement in coarse particle liberation does not necessarily translate to a significant improvement in downstream flotation recovery (Kobusheshe, 2010). This is as a result of the size limit to the flotation of coarse material, due to detachment forces acting on particle-bubble aggregates, which increase as the particle size increases (Jameson, 2012). Current conventional, mechanically agitated flotation cells are not designed to float coarse material (Jameson, 2012). Hence it has been difficult to show the downstream processing benefits of applying microwaves to ores processed by comminution followed by flotation (Kobusheshe, 2010). It is clear from investigations carried out so far that inappropriate downstream exploitation of microwave treated ore would fail to realise a meaningful process benefit (Kobusheshe, 2010; Ali & Bradshaw, 2011)."

Jan 1, 2016

By Robert B. Parsons

"It is generally felt that flow-through shares face a bleak future under the set of tax rules proposed in the federal government&apos;s tax reform white paper. Industry and government circles are beginning to give thought to alternatives to flow through as a mechanism for facilitating equity financing in the exploration industry. Despite suggestions that grants and tax credits may someday be on the table, industry is sticking to its position that there is no substitute for flow-through. Alternatives toFlow-throughProposals in the federal government&apos;s tax reform white paper have cast significant doubt on the ability of the mining industry to raise risk capital after 1989by way of flow-through shares. There is serious concern that introduction of the ""cumulative net investment loss"" (CNIL) rules, the phase-out of the mining explorati0! 1 depletion allowance (MEDA), and the Increased capital gains inclusion (750/0 versus 50%, at present) will make the economics of flow-through so unattractive after 1989 that these shares will hold little appeal to most investors. The question might be raised, then, as to what alternatives exist by way of tax or other government assistance that could help the exploration sector.The purpose of this paper is to survey the types of government incentives that could be of some value to explorationists and to the mining industry in general. For the past several years, flow-through has been in the spotlight insofar as incentives to the exploration industry are concerned. Other potentially useful and attractive incentives have been partially hidden in the shadow of flow-through. These incentives, in certain circumstances, can be of considerable benefit, and should not be ignored."

Jan 1, 1988

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 X. L. Song, G. W. Zhang, F. Y. He, X. Xiao, L. L. Huang

This paper presents the design of a model and process simulation of a vertical mill based on a population balance model. The simulator, Simulink, which is a systematic modeling tool within MATLAB, was used for the simulation. The model will simulate the real time variation trend of each size fraction in the feed material to the vertical mill, as well as, the size distribution of the batch grinding products. Breakage distribution and selection functions are calculated based on batch grinding laboratory experiments using Back-calculation method. The simulated size distributions correspond with those in the actual mill operation having a relative error of less than 0.50%. This work lays the foundation for future research on modelling and simulation of a closed circuit grinding operation consisting of a vertical mill with hydrocyclone classifier.

Jan 1, 2016

By A. Y. Senchenko, Y. V. Kulikov

"In recent decades HPGR technology has proven itself in comminution circuits of mining plants. High technical and economic performance, lower specific energy consumption and reliability of HPGR equipment makes it an efficient alternative to conventional circuits using stage crushing and rod/ball milling, as well as to AG/SAG circuits. However, despite all the advantages of this technology the correct selection of key and auxiliary equipment is very important since errors at testing and design stages may lead to discrediting of the whole concept of HPGR application. There is a great variety of possible circuit configurations using HPGR, e.g. with circulation of edge product, with crushing of the whole discharge and circulation of screen oversize, successive two-stage crushing, etc. Each type of minerals will require its own optimal crushing circuit. In this context the testing methodology for selection of an optimal configuration becomes of prime importance. It is common knowledge that the best simulation of material crushing and softening within a HPGR can be obtained only in the course of a large-scale pilot test. The main approaches applied to this kind of testworks are described in this article. Special aspects of HPGR technology design and industrial operation are revealed as well. Some operational issues of HPGR equipment and of circuit as a whole were detected. They are related to regions specifics, plants location, and other factors. Process solutions proposed to deal with these issues are also indicated in the article. INTRODUCTIONDesign and construction of the processing plants involving High Pressure Grinding Rolls (HPGR) technology becomes more and more common in mining as this technology has specific technical and economic advantages against the circuits with autogenous/semiautogenous mills (AG/SAG) and other circuits. The main advantage of the technology is low energy consumption and low operation costs respectively. The presence of microcracks and increased content of fine size fractions in the crushed product contribute to reduction of energy required for further ball grinding. Besides, HPGR technology applies a special wear resistant liner that enables significant reduction of operation costs of grinding media and liner comparing with AG/SAG circuits."

Jan 1, 2016

By J. M. Wolverton

CONSIDERABLE interest has always been taken in Safety-First and First Aid at the Sullivan mine. Even during the early days of development, Safety-First committees periodically held meetings, while lectures in first aid were given to any employees interested in the work. In 1929, a Safety Department was organized, and all accident-prevention and first-aid work was put in charge of a full-time Safety Engineer. An extensive programme has gradually been developed, the value of which can best be indicated by the reduction of the accident rate from 18.4 shifts lost per 1,000 shifts worked for non-fatal accidents and two fatalities for 1927, to 3.24 shifts lost per 1,000 shifts worked and no fatalities for 1936. SUPERVISION All work connected with accident prevention or first aid is under the jurisdiction of a central committee, known as the Accident Prevention Committee, which meets regularly once a month. It consists of all superintendents, department heads, foremen, and shift bosses, and is presided over by the Safety Engineer. At these meetings, the accident records of the previous month are reviewed and all accidents carefully analyzed and discussed. All proposed changes in the safety rules or in the accident tprevention programme are taken up and passed upon. Complaints or suggestions from the Safety-First Committee and the Employees Co-operative Committee, dealing with safety, are discussed and passed upon or a subcommittee is appointed to investigate and take any action found advisable. The question of underground ventilation and dust control, which recently has become a very important problem, always receives considerable attention.

Jan 1, 1937