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By George Langford

Introduction The manufacture of ductile beryllium is one of the most interesting problems confronting the metallurgist today, and one which becomes more acutely in need of resolution as the uses for beryllium increase. Beryllium belongs to the hexagonal group of metals along with zinc, magnesium, and cadmium. The melting point of the metal is about l,280°C. ± 5°C. Due to its brittleness, the metal's chief use is as an alloying agent in copper and iron. The very low absorption coefficient of beryllium for x-rays makes the metal ideal for x-ray windows, and, similarly, because of its low capture cross-section for neutrons, the metal holds a preferred position in the field of nuclear physics. Modern x-ray diffraction methods were responsible for explaining the mechanism whereby zinc metal, although brittle when cast, could be made ductile at room temperature. The diffraction patterns of zinc and magnesium indicated the importance of the parts played by recrystallization and preferred orientation in this mechanism. It was with this in mind that an Investigation into the recrystallization and preferred orientation of beryllium was undertaken. The investigation, after a series of experiments were conducted involving cold-working and annealing, yielded the recrystallization temperature curve for beryllium. Both the texture of preferred orientation and the effect of recrystallization on this texture when subjected to compressive stresses were also determined. W. A. Alexander, J. K. Swinton and L. M. Pidgeon, in their investigation on The Recrystallization Temperature of Beryllium (C.I.M., Trans., Vol. L, 1947, pp. 657-664), utilized the Brinell ball as a means of cold straining the metal. Sufficient strain was developed to estimate the recrystallization curve for the metal. However, in order to determine the lowest recrystallization curve, as well as to develop a preferred orientation structure, larger deformation than that possible with a Brinell ball was required. The plastic deformation of beryllium can be carried out at an elevated temperature above 700°C. Above 850°C., the metal is quite ductile and can be readily compressed or extruded.

Jan 1, 1948

By Jef M. van der Zel

The idea of veneering rich yellow gold alloys with a low-melting, high expansion porcelain, has been a driving force for metal-ceramic research in dentistry. Since 1990, with the advent of the Carrara System (1), a low firing temperature veneering ceramic allowed the use of gold alloys with a lower content of platinum and palladium than the traditional gold-platinum ceramic alloys and thus a richer yellow color. The earlier high gold-platinum ceramic alloys contained at least 12 percent platinum group metals to allow for dimensional stability when firing the relatively high melting traditional ceramics. This amount of platinum group metals gave the alloys a greyish tinge which made them unattractively steel colored and difficult to present as ?high gold alloys?. In the 90?s the new generation universal low-melting, high expansion gold alloys gained market share at a steady rate, starting in Germany, and have now for a great part replaced the traditional gold-platinum alloys (Fig. 1). The first alloys contained 75 wt-% gold and up to 9 wt-% platinum or palladium. They provided a metal-ceramic system in which a gold alloy having an aesthetic yellow colour is fired on with a dental porcelain tailored thereto. The tailoring is meant in respect of compatible coefficients of thermal expansion, and compatible melting or softening points of metal and porcelain. The major concerns in the beginning were with thermal stability during firing, the thermal expansion coefficient of the alloy against the porcelain (compatibility) and the yellow color. In a later stage, alloys with gold contents in the range of 50-60 wt-% gold were developed in analogy with the pale yellow gold-reduced alloys that were formerly used for crown & bridge work and the white gold-reduced alloys used for metal veneering where gold was substituted in part by palladium.

Oct 1, 2003

By W. T. Irvine

"The Britannia ore deposits are approximately 20 miles north of Vancouver; and occur in a prominent ridge facing Howe sound. A large ironstained bluff first attracted the serious attention of early prospectors. This; upon investigation; proved to be the outcrop of a large copper orebody. The highest outcrops were 4; 300 feet above sea-level.The original discovery was made in 1888, but no real development took place until 1902. The first mining was done in what came to be known as the Jane orebody, and some production was obtained from this in 1905. Underground exploration led to the discovery of several other orebodies. The first main adit, the 1,050-foot level, was driven to tap the ore at an elevation of 3,300 feet above sea-level. During succeeding years, however, long adits were driven from points lower down on the mountain side. These, with connecting shafts, followed the ore to horizons well below sea-level. The lowest working has now reached to 880 feet below sea-level. The property has been in almost continuous operation since its original exploitation in 1905. Until the end of 1944, 732,414,420 pounds of copper and 261,125 ounces of gold had been produced from the mine."

Jan 1, 1954

By M. H. Allan

"This paper presents the geographic and geological setting of Saskatchewan Power Corporation's Poplar River Mine in south-central Saskatchewan, about 8 miles from the U.S. border. Generally the mine, which is being expanded to four million tons per year, is in an extremely disturbed geological area with severe dewatering problems. The lignite coal, which is strip mined, is supplied directly to an electric power generating station by means of a 7-mile unit-train private railroad.A number of unique reclamation and socio-economic problems were encountered because of the proximity to the U.S. border and because of the lack of experience of the regulatory authorities in projects of this kind. These are described in some detail, as well as the performance of one of the largest draglines in Canada. IntroductionThe Saskatchewan Power Corporation is a publicly owned utility which has the franchise to supply electricity and natural gas to all customers within the boundaries of Saskatchewan.Saskatchewan is a province which can almost be divided in two: the populated southern portion, principally devoted to farming, and the northern portion which is mostly on the Precambrian Shield and consists of lakes, rocks and muskeg. This portion is largely uninhabited except for a number of small villages. However, in the last few years there has been considerable mineral exploration and development, notably for uranium. This has helped considerably in the diversification of the basic agricultural economy of the province.Saskatchewan consists of 251,700 square miles, 761 miles north to south and an average of 335 miles east to west. It has a population of approximately 960,000, giving a population density of four persons per square mile. The Saskatchewan Power Corporation supplies 357,249 electrical arid 221,378 natural gas customers."

Jan 1, 1982

By D. R. Rice

"The Smoky Valley Common Operation is managed and 50 percent owned by Echo Bay Mine' s Round Mountain Gold Corporation. The other partners with 25 percent each are Homestake Mining Company and Case Pomeroy. The operation in central Nevada includes an open pit, 3-stage open-circuit crushing train and heap leaching on asphalt pads. Presently, about 18,000 tons per day of 0.039 troy ounce gold per ton are transferred to the leach pads, and a similar tonnage of leach residue is transferred to a waste dump. One million tons of ore are being leached at any one time.Gold and silver cyanide are adsorbed from pregnant leach solution on activated coconut shell carbon granules. Pressure stripping desorbs values from loaded carbon to electrowinning solution.Three electrowinning cells are operated in parallel. Each contains six cathodes. Each cathode includes about 40 troy ounces (2.7 pounds) of Number 2 medium coarse steel wool. The wetted area of each cathode is about 24 by 30 inches. Solution flow is 2 to 3 gallons per minute per electrowinning cell. Average current flow is 25 amperes per cathode. The voltage is controlled in the range of 3 to 4 volts to maintain desired amperage.Twice a week two cathodes are pulled from each cell and drained. Each cathode is split into four portions. These are put in a steel pan coated with WD-40 and dried overnight.Each dried cathode portion is put into a paper sack. Each group of four sacks corresponding to a cathode is weighed together. The typical weight ratio of loaded cathode wool to new cathodes is 9 or 10 to 1. To each sack is added 35 troy ounces of silica, 45 troy ounces of anhydrous borax, 35 troy ounces of nitre, and 5 troy ounces of fluorspar. The sacks are taped shut."

Jan 1, 1986

By G. A. Gamble

"The inlet air velocity profile of any surface mine ventilation fan is an important factor when designing the connecting ductwork from the mine shaft collar to the fan. Deficient fan performance can be the result of ductwork that adds unnecessary pressure loss and/or adversely influences the fan inlet air conditions (velocity profile). The need for optimized inlet air conditions begins with discussing the process of performance testing during the development of the fan performance curve. Additional discussions include design of the shaft collar connection and the connecting ductwork. A preferred design of ductwork for parallel fan installations will be illustrated.INTRODUCTIONThe inlet air velocity profile of any surface installed mine ventilation fan is one of the most important factors to consider when designing the connecting ductwork from the mine shaft collar to the fan. Oftentimes deficient fan performance can be traced to poorly designed ductwork that adds unnecessary pressure loss and/or adversely influences the fan inlet air conditions (velocity profile). Such designs may lead to added power requirement, excessive vibration and noise, and reduced fan performance.Understanding the need for optimized inlet air conditions begins with discussing the process utilized when factory testing takes place during the development of the fan performance curve.Additional discussions include design considerations for the shaft collar connection, the connecting ductwork, and fan inlet. Illustrations of cost savings and pressure losses will be included for audience consideration. The design of ductwork for parallel fan installations on the surface is another issue that requires consideration. A preferred method will be illustrated.The selection of accessory components, such as self-closing doors, can also add to the potential for reduced fan performance. Several components will be discussed.An elementary presentation of the Air Movement and Control Association (AMCA) Standard 201 “Fans and Systems” will be included to provide background for those audience members that want additional technical explanations of the need for a uniform inlet air velocity profile at the fan inlet."

Jan 1, 2019

By T. H. Peters

The historical development of this program, dating from the construction of Nickel Park at Copper Cliff in 1917 to the various current projects carried out in the Ontario Division's program, is reviewed. Practices used to grow vegetation on stressed areas, the beneficial aspect of the improved aesthetic appearance of company properties from the point of view of public relations and the improved approach to the workplace by the employee are discussed. The revegetation of the tailings area and its gradual transformation into a Wildlife Management Area is reviewed.

Jan 1, 1978

By Tyler Roberts

New Afton mine is an 11,000 tonne per day block caving operation, located 8 km west of the city of Kamloops, British Columbia. Due to the nature of block caving and the weak rock mass at New Afton, the mine has faced and overcome many blasting challenges during its ramp-up to commercial production. As New Afton Mine continues to grow the demand for drill and blast precision has continued to grow as well; any misstep incurs delays in achieving full production capacity. The block cave mining method used at New Afton employs single-shot draw-bells, fired with very little void and blind undercutting, allowing little margin for error. New Afton has made continuous improvements to its blasting strategy by reacting quickly to real-time problems and employing sustainable, repeatable solutions to overcome its unique blasting requirements. Examples of these solutions include: increasing blast hole diameter, casing production drill holes, developing pre-loading procedures and developing strategies for remotely blasting under-broken remnants in both draw-bells and undercutting. Increasing the blast hole diameter has alleviated initial problems with hole plugging in the highly jointed rock mass at New Afton. This has reduced drill-cleaning time significantly and enabled New Afton to meet blasting targets. PVC hole casing was trialed when blasting in extremely fractured ground, where drill holes continually plugged. The casing allowed the drill holes to remain open long enough to load and blast. Calculations were carried out in order to achieve the same explosive energy in the cased holes as a typical blast. Results were generally positive, but more testing is required. Production flexibility and scheduling reliability have been maintained at New Afton by developing a pre-loading procedure for the production undercutting. In doing so, New Afton has been able to keep productivity high by having a flexible production schedule that is not reliant on a specific piece of equipment or production drive to remain productive; this flexibility is because the mucking of undercut material can occur at any stage of the drill/blast/muck cycle. New Afton has developed a strategy for blasting remnant under-break in its draw-bells and undercutting by remotely drilling holes near to the under-broken section and then loading the toes of these holes with emulsion, the remainder of the hole is then filled with grout. The holes are grouted in order to prevent damage to permanent pillars between draw-bells (where the majority of the recovery holes need to be located). Several critical areas were recovered using this technique with little to no damage to the remaining permanent pillars. Innovative blasting solutions have allowed New Afton to overcome obstacles in order to become a producing operation. Moving forward, New Afton looks to continue its trend of innovative drilling and blasting techniques when faced with out of the ordinary situations.

Aug 1, 2013

"These standards were developed by the CIM for use with the value or worth of a Mineral Property as opposed to “evaluation” where the key objective is an economic assessment or determination of the economic merit of a propertyP1 .0 BACKGROUNDPl.1 There are at present no comprehensive standards for valuation of Mineral Properties in the Canadian mining industry. The Mining Standards Task Force (MSTF) of the Toronto Stock Exchange and the Ontario Securities Commission in its Final Report (January 1999) specifically recommended that the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) form a committee of valuation practitioners to review and advise on approaches to valuation of Mineral Properties.Pl.2 On May 5, 1999 at the Calgary Annual General Meeting, CIM Council approved the formation of a Special Committee on Valuation of Mineral Properties (CIMV al) to be co-chaired by Keith Spence (Chairman of the CIM Mineral Economics Society) and Dr. William Roscoe (Roscoe Postle Associates Inc.).Pl.3 The mandate of CIMVal is to recommend Standards and Guidelines for Valuation of Mineral Properties to be used by the mining industry in general and to be adopted by Canadian securities regulators and Canadian stock exchanges.Pl.4 The members of CIMVal represent of a mix of professional disciplines and experience in the field of Mineral Property valuation:Keith N. Spence (Co-chair), Alliance Pacific Resources Inc., TorontoWilliam E. Roscoe (Co-chair), Roscoe Postle Associates Inc., TorontoMichael J. Bourassa (Secretary), Aird & Berlis LLP, TorontoChristopher R. Lattanzi, Micon International Limited, TorontoRoss D. Lawrence, Watts, Griffis and McOuat Limited, TorontoPaul E. Lunney, Noranda Inc., TorontoCraig A. Roberts, Pacific International Securities, VancouverDavid A. Scott, CIBC World Markets, TorontoIan S. Thompson, Derry, Michener, Booth & Wahl Consultants Ltd., VancouverWilloughby A. Trythall, retired Placer Dome executive and consultant, Vancouver"

Jan 1, 2003

By J. S. DeLury

Introduction The problems of metallogenesis are largely related to those concerning the origin of igneous rocks, which, in turn, are involved with the question of crustal mechanics. Many ore-bodies are genetically related to associated intrusive and there is an equally close association apparent between igneous intrusion and crustal deformation. The problem of ore-deposition is concerned, therefore, with the fundamental problems of geology. For a long time speculations regarding crustal movements rested largely on the contraction theory and its associated conceptions. Vertical movements were considered to be all important and horizontal movements secondary to them. Magmas were pictured as rising more or less vertically in the crust and were believed to form in vertically disposed magma-chambers or reservoirs. The principle of magmatic differentiation seemed to offer the best explanation of the origin and association of diverse rock types and it seemed also to require the existence of quiescent magma-chambers for the admittedly slow process of differentiation. Accumulating evidence of the importance of horizontal movement in the crust, has, along with other considerations, discredited the contraction hypothesis and many of the inferences that go with it. The same evidence may require some change in the prevailing conception of the origin of the various types of igneous rock and of the mechanics of intrusion. Geologists are now at sea concerning some of the vital and fundamental problems of the crust, and the field is open for speculation. The writer is developing a hypothesis which seems to permit an explanation and? a correlation of earth structures and phenomena. If it rests on a firm foundation, the hypothesis, because it is fundamental, is certain to have a profound bearing on the problems of economic geology. It is for this reason that an outline of the hypothesis is offered at this time. Only a few of its economic bearings are foreseen at this time and these will be indicated.

Jan 1, 1932

By Rashid Bashir

Shaft sinking through solid rock, which contains little or no water, poses little difficulty. However, when loose, water-bearing strata have to be contended with, water control measures, and pumping facilities are needed. Shaft sinking in Athabasca Basin requires sinking through water bearing sandstone which can be highly fractured. Intersection of local zones of extensive fracturing results in the potential for high water inflows with pressures up to 5 Mpa. Grouting is carried out ahead of each shaft sinking interval as water control strategy. In the grouting method, liquid cement is forced into the water-bearing earth under very high pressure. Shaft sinking performance which can be quantified in terms of rate of advance is highly dependent on the days spent at each interval grouting before sinking can advance to the next interval. This paper presents the shaft sinking experience in Athabasca basin and how some of this is translated into Geoscientific Investigations for Future Shafts. A comparison of Geoscientific data collected from future shafts at McArthur River and Millennium Mines is compared to historical data collected from pilot holes, where shafts have already been sunk. The paper concludes with the strategies for better integration of hydrogeological, geotechnical and geophysical data.

Aug 1, 2010

By Rashid Bashir

The presence of groundwater in the form of large aquifers can have an important influence on investment decisions for underground mines. The design for such mines requires development of special mining methods, and mine dewatering infrastructure to avoid hazards during shaft sinking and underground development. The costs associated with mine drainage control and Mine Dewatering Systems (MDS) are relatively small compared to the huge consequential losses that can occur in case of an uncontrolled inflow and subsequent flooding of the mine. The design of MDS needs consideration of accurate prediction of the maximum uncontrolled inflow rate, availability of the system during an uncontrolled inflow while the inflow is mitigated, and decision on pumping system technology to have capability to operate under water. The research presented in this paper provides a theoretical framework for a reliability based design procedure which takes into account the uncertainty in the estimate of the maximum uncontrolled inflow, performance of the system during the period of an uncontrolled inflow and a methodology to decide on appropriate pumping technology considering the reliability of the system and available underground storage. The reliability based mine design procedure integrates the ideas of Effective Reserve and Hydraulic Reliability Index to come up with a unified methodology for design of Mine Dewatering Systems.

Aug 1, 2010

By Franc R. Joubin, Donald H. James

"The Property of Rix Athabasca Uranium Mines Limited is in the Beaverlodge area of northwestern Saskatchewan. The mine is 7 miles by road north from the Lake Athabasca port of Bushell which is 250 miles north by aircraft or boat from railhead at Waterways, Alberta.The Rix property is a portion of the former DD 1 concession, obtained in 1949 from the government of Saskatchewan when private prospecting for uranium became permissible. The concession was prospected in detail during the 1950 and 1951 field seasons and a great many radioactive show-ings were discovered. Development and drilling were concentrated in two and later three of these areas, and by late 1952 enough ore had been indicated in the Leonard series and ""Smitty"" zone to justify underground development by adit-drift and shaft respectively.Four hundred feet of drift development on the Leonard No. 1 vein and the sinking of a two-level vertical shaft with related lateral development on the Smitty zone were completed in 1953. In April 1954 the Smitty section was placed in production at a rate averaging 100 tons per day, thereupon becoming the first privately owned post-war uranium producer in Canada. The ore is shipped for processing 12 miles by truck to the mill of Eldorado Mining and Refining Limited.Until recently all of the Company's production was drawn from the Smitty orebody. In April, 1955, ore production commenced from the faulted west extension of the Smitty structure, known as the Rix 62 zone, and from the Leonard No. 1 vein.The Smitty orebody (see Figure 2) is an intensely brecciated lenticular zone bordering both sides of the Smitty fault. The breccia areas are irregularly mineralized with pitchblende, very sparse galena, and pyrite in a gangue of feldspar, chlorite, calcite, and silica, all thoroughly soaked with fine-grained hematite to produce the locally-called ""red alteration"".Tenor of the ore currently being mined is classified information. The average grade estimated, prior to production, was 0.20 per cent (4.0 lbs.) U308 per ton."

Jan 1, 1949

By A. W. White

Introduction To discuss all the technical details of incorporation laws, security laws, underwriting procedures, codes, and ethics-as laid down by varous associations -would be impossible in the time which has been allotted to me. My remarks, therefore, will be made in a very general way and will naturally be coloured with experiences which my firm and I have had. There is a common expression that "money makes the mare go". I hardly have to mention here that the best prospect in the country is of very little value unless its prospects can be developed-and this requires large capital expenditures. The art and problems surrounding the raising of this money is a long and interesting story. Since by its very nature mining is risky, the appraising of its risks in the many phases of its development programme is continuous. Very few men-if any-and very few corporations -if any -can afford to take all the risk of mining. Because of taxation policies-and the very scheme of present-day living -the truth of this statement can be seen throughout the whole industry by a close examination of the records. Since this is so, it is essential that the mechanics of distributing risk on a sound, and equitable basis be known to those engaged in the business and to the investor or spectator who proposes to risk his funds in the industry. Perhaps the greatest stimulant to modern business activities has been the creation of corporate bodies. It is evident, from the number of charters being granted by various jurisdictions, that this method of doing business is becoming more and more important. A limited company -or corporation-can be defined as a fictitious person existing solely in contemplation of the law.

Jan 1, 1951

By A. Pearson, F. A. Auld, S. O. Colbeck

"""The theory of buckling of shafts and Steel tunnel-linings"" was published by E. Amstutz in 1970 and commented on by S. Jacobsen in 1974. The authors have revised and enhanced Amstutz’s work to address Jacobsen's comments on its limitations and to extend its validity over a wider range of pipe/shaft geometries, including those commonly found in deep mine access shafts. The author has looked at Amstutz’s assessment of strengthening with flexible shear anchorages and adapted the theory of non-linear shear deformation response of bolts to develop a method of assessing increased buckling capacity utilising the full plastic shear capacity of studs. INTRODUCTION “Amstutz Buckling” refers to the buckling of pipe embedded in concrete under external uniform pressure. In terms of a mining environment, this relates directly to the design of a watertight shaft. This load case will commonly occur where a main shaft is cast against a geostatically stable primary liner and the only load applied to the final shaft is that of a uniform ground water load. Ernst Amstutz wrote his first paper on buckling of pressure-shaft steel linings in 1950 and subsequently improved his theory (Amstutz, 1970), which was then widely adopted for use within the industry. Years later, an alternative approach (Jacobsen, 1974) was proposed. Within his paper Jacobsen critiques Amstutz work, identifying some mathematical inconsistencies and highlighting limitations of the theory imposed by approximations adopted by Amstutz. Despite these limitations Amstutz work has still been used as the favoured design theory for use in the mining industry. In reviewing this body of work the author realised that with the advent of readily available computing software it was possible to adopt an iterative approach using Amstutz approximate formulae to find a solution to the original precise formulae, thus eliminating the limitations highlighted by Jacobsen The shear deformation to load characteristics of bolts has long been established (Crawford & Kulak 1968) and used for the plastic design of bolted connections in shear. This relationship is directly transferable to the design of shear studs, typical properties are well known, and actual values easily established in simple lab tests. The author has taken this relationship and modified Amstutz theory (Amstutz, 1970) for shear anchored strengthened liner buckling, to give a more efficient solution, using readily available material properties."

Jan 1, 2019

By V. L. Mitsopoulos

This paper provides a summary of tailings disposal techniques and the improvements that have been made through the introduction of thickened tailings disposal. The general properties and characteristics of thickened tailings are described, as is a design process for selecting appropriate technologies for thickening, pumping, transporting and storing tailings. The factors affecting the selection of an appropriate disposal site and operational considerations for the effective utilisation of tailings storage areas are also documented.

Jan 1, 2006

By J. Kang

There is increasing demand to utilize aluminium alloy sheets and their spot welds by the automotive industry. While traditional uniaxial tensile tests only determine mechanical properties to small strain, direct measurement of the constitutive behaviour of aluminium alloy spot welds at large strain remains a challenge. A technique was successfully developed using digital image correlation coupled with shear tests to directly measure the constitutive behaviour of an AA6022-T4 spot weld to large strains. The results show that the spot welding process not only decreases the yield strength but also lowers the work hardening rate of the nugget versus the base material. Details of sample preparation, experimental approach and results will be discussed.

Jan 1, 2011

By J. E. Amadi-Echendu, F. Stober, J. Ndlovu, L. R. Nelson

The Polokwane Smelter Complex (PSC) relies on a single 68MW high-intensity six-in-line furnace to smelt a planned 650 000 t/a dry concentrate to produce a platinum group metals (PGM)-bearing matte. As typical of a greenfields venture, considerable attention was paid to the project development and implementation stages of design, engineering, construction and commissioning. Somewhat unusual though, was the role of a dedicated multi-disciplinary "Operational Readiness" and support team, comprising the owners team and specialists from the furnace designer, HATCH, to effect a safe and rapid ramp-up to the design smelter capacity of 68MW. The challenges encountered in developing an effective partnership will be discussed. The modus operandi and roles of the "Operational Readiness" team during the design, procurement, construction and commissioning stages as well as that of the operational support team within the overall ramp-up objective will be presented. The "Operational Readiness" team was responsible for:

Jan 1, 2005

By S. Hopkins, R. Preston, S. Gillis

"This paper examines typical visual inspections of operational soft rock mine shafts and discusses some of the challenges involved, many of which are associated with inconsistent inspection practices. The paper presents the development of a more standardized approach to periodic shaft inspections that supplement the more frequent inspections performed by shaft crews at the mine. This approach helps to keep an accurate record of changing conditions, compare conditions between multiple mine sites, as well as prioritize and plan potential remedial work. INTRODUCTION Shaft inspections, whether they are performed daily or weekly by members of the shaft crew at the mine, or periodically by consultants, traditionally involve a visual inspection undertaken with personnel traveling on an inspection deck on the conveyance, taking notes and photos. Inspections are typically required by mining regulations and carried out to identify and address hazards before a safety incident occurs that could cause harm to people or damage to property, as well as to help plan required maintenance work. Depending on the site, there can be many challenges associated with inspections in the shaft, especially compared to a typical inspection at surface. Some of these challenges are associated with the shaft environment itself, while others are related to the subjectivity of inspections and a lack of standardization, particularly between multiple sites within the same operating company. Recognizing these challenges, a more consistent and repeatable approach to shaft inspections in soft rock mines is evolving. This approach involves reviewing available historical data, comparing sites with similar conditions, establishing survey control, documenting observations and measurements with locations, and updating as-built or condition drawings. Part of this standardized approach is the implementation of an innovative 360-degree camera with a high-power lighting system that can be used either remotely or alongside personnel completing a traditional visual inspection. The system uses six cameras to take photos at a rate of 15 frames per second, with the image data subsequently processed and stitched, then joined into a high-resolution video. This tool improves time-efficiency, objectivity, and repeatability of inspections."

Jan 1, 2019

By S. E. Wolfe

AKNOWLEDGE of the density of a pulp or suspension is frequently required by the millman, to whom fluctuations in density, which occur in all mill circuits, are of importance and interest. There ,are many w.ays currently in use to determine density and probably the most common method is to take samples of the pulp. The proper sampling of the material is no easy matter, particularly when the pulp contains a sand fraction which settles rapidly. For example, when filling a liter container from the overflow of a classifier, it is al-most impossible to fill the can completely and yet prevent overflow. If there is an overflow, the pulp remaining in the can invariably has an excess of sand and the indicated density will be too high. To surmount such difficulties, and to obtain a continuous indication of the density of a pulp at any desired depth, the simple indicator shown diagrammatically in Figure l was designed by the writer in 1951. Its component parts, numbered as in Figure 1, are as follows.

Jan 1, 1958