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By Jack G. Hazan

The Critical Path Method is the modern scientific answer for solving the planning and scheduling problems inherent in today's complex projects. With this method, nothing is left to chance. All resources are controlled and kept to the minimum. The various phases are properly planned and strategically determined. Optimum conditions are evaluated for the most economical and fastest way to complete a definite project. The method must be fully understood and implemented with positive data and continuous feedback to obtain the best results. This paper covers the various aspects of the Critical Path Method and mentions some of its applications in the mining and metallurgical fields. T 0 progress to a higher state of human welfare necessarily involves sacrifices. The greatest sacrifice is to relinquish social freedom in favour of economic freedom. In the old days, for example, a cobbler was free to work at whatever time of the day he chose; today, he can't. He is now forced to adapt himself to environment and to work at stand-

Jan 1, 1965

By P. C. Sui

Numerical investigation and parametric simulations of the coupled electrical conduction and mass diffusion in the GDL of a PEMFC are reported. The coupled transport is solved using a 2D, "under-the-rib" computational domain for the cathode GDL. The current density on the GDL/catalyst layer interface, which constitutes one of the boundary conditions for the GDL domain and reflects the activation overpotential in the catalyst layer and the ohmic loss in the membrane, is solved iteratively using a novel numerical algorithm. A parametric study is performed to investigate the effects on current density distribution of various operating conditions such as oxygen concentration and membrane resistance, and of design factors such as GDL geometry, anisotropic transport properties, and deformation under the land area. The results show that the current density distribution under the land area can be dominated by either electron transport or mass transport, depending on the operating regime.

Jan 1, 2005

By Randolph A. Pax, Brian Cornish

The operation of grinding mills in an ore processing circuit is supported by monitoring the input and output variables. These can include the feed ore size distributions, ore feed and water addition rates. The outputs can include the discharge undersize density, oversize tonnage rate and the P80 of the discharge. The grinding mill performance is judged by the power draw, recycle rates and discharge grind size. Conditions inside the mill are inferred from loads cells or bearing pressures and past histories. An overall noise value is sometimes used to evaluate the load as well as the occurrence of excessive impacting of steel balls onto the liners/lifters of the mill. This paper presents results of the internal behaviour of a mill using non-contact stationary microphones located close to the mill outer shell (Pax, 2012). The noise generated by a mill can be attributed to a number of events that occur inside these mills and suitably analysed can provide real-time determinations of in-mill behaviour and can provide powerful insights into the operation of the primary comminution tumbling mills. The acoustically determined signals including a specific 'steel' signal, water hold-up, integrated area together with a classification of impact events. Specific results from case studies will show information of the trajectories inside a mill, steel to rock ratio as well as rheology effects. By incorporating a self-consistent understanding methodology for the in-mill processes from an array of microphones, the information can be used to diagnose the dynamic conditions inside a mill.

Jan 1, 2016

By I. Le May

"The assessment of integrity in plants is discussed, together with the codes that are being developed for in service evaluation of engineering fitness for service. The use of Risk Based Inspection is described and some examples are provided of the evaluation of in service components in which flaws have been detected. An example of the assessment of the structure of a mine processing facility is described, and application of Risk Based Inspection and plant assessment procedures to mines is discussed. Periodic assessment of large plants and components to determine their integrity for continued safe operation is becoming a more accepted approach than formerly when regular shutdowns were the normal practice. This is on the way to becoming the preferred procedure for petrochemical plants and power generating plants, and the same philosophy is appropriate for many mining operations. Both the American Petroleum Institute (API) and the American Society of Mechanical Engineers (ASME) have committees developing codes for the continued operation of equipment as distinct from the existing design codes. The philosophy is one of risk-based inspection, which can be on a purely qualitative basis or more quantitatively based.The purpose is to reduce the inspection of unnecessary and non-critical items and to concentrate on the most critical components, reducing costs and downtime and increasing safety. The approach differs from that considered by many maintenance engineers, in that defects that are identified during an integrity evaluation do not automatically cause a component or structure to be condemned or require that repairs are made right away. The seriousness of the defect must be considered and the safe operating life can be estimated before it becomes necessary to replace or repair the unit or component. This is no different from what is done today with passenger aircraft and, to an increasing extent, with pressure vessels, reactor vessels and similar components in the petrochemical and power generating industries."

Jan 1, 1998

By Y. P. Wu

Steeply dipping seam refers to the coal seam with dipping angle in the range of 35?55°, which is well recognized to be very hard to mine by the mining industry all the world. In the last two decades, some fundamental researches were focused on the strata behavior of long-wall panel, complicated rock mass breaking process of the steeply dipping seam, overburden stress field developing and evolution, rock strata breaking and moving process, rock structure stability mechanism and control. Results show that it?s presenting macro stress arch-shell (MSAS) of the stress distribution of the overlying rock in steeply dipping seam. The MSAS is the spatial distribution of intensity envelope line under the strength criterion and has the geometry shape asymmetry as well as the stress distribution heterogeneity. The arch- shell base will forward as the working face mine forward and the shell roof will extend to higher overlying strata above the gob. In this paper, the stress arch-shell analysis model and coordinate system were established and analyzed the inclined masonry structure at different zone. Analysis results show that the rock damage at the key part of the arch-shell is the main factor which causes whole overlying rock structure failure. The rock structure instability modes have tension instability of the shell roof, compression-shear instability of the shell shoulder and composite instability of the shell base, meantime, instability coefficient is proposed to determine instability condition. The above research results enrich the complex coal seams mining theory and provide a theoretical basis for mining safely and efficiently in steeply dipping seam.

Aug 1, 2013

By E. W. Vekris

Patents are playing an increasingly important role in the business world. A diverse patent portfolio can enable a company to secure a monopoly within the market, which can provide a competitive advantage over competitors. At the same time, possessing a diverse patent portfolio greatly increases the value of a company's intangible assets. This paper provides an overview of the patenting process as it pertains to the fields of metallurgy and mining, and summarizes some general patenting strategies. A review of new "green technology" initiatives recently adopted by Patent Offices around the world is also provided.

Jan 1, 2011

By G. M. Furnival

A PROGRAMME of structure drilling was commenced in the Southern Alberta Plains in June, 1943, for the purpose of determining the geological structure of the underlying sediments. More than 270 holes have been drilled throughout an area of some 1,800 square miles or 1,000,000 acres (see Figure 1). The Southern Plains of Alberta are covered by a mantle of glacial drift,' at places exceeding 200 feet in thickness. Only where this mantle has been dissected by deep drainage channels is bed-rock exposed to any great extent. Along such channels, surface geological mapping can be conducted to ad- vantage. Accordingly, geological mapping was commenced _in 1942 and continued each season to the present. To supplement this information, a survey of the water wells was carried on in conjunction with the mapping. However, to obtain more positive and evenly distributed structural control throughout the area as a whole and to define more adequately structural trends indicated by the preliminary mapping, it was necessary to resort to the use of drills to penetrate the glacial mantle. Various types of light drills are commonly used for this purpose and provide geological information in the form of drill cuttings, cores, drilling time rates, etc. Correlation of information is generally obtained through comparison of cored sections, drill cuttings, micro-fossils, and drilling time rates. However, in this case the holes were electrologged and correlations were made chiefly by comparison of such logs. The data so obtained is plotted and portrayed in the form of structure contour maps on recognizable stratigraphic horizons and in the form of isopach maps of the recognizable stratigraphic intervals penetrated in the holes. This method had not been widely used in Alberta previously and the technique employed was necessarily developed after the project began.

Jan 1, 1945

By A. F. Brock

Introduction During the past ten years, shaft sinking has been going on continuously at Inco and new shafts and shaft extensions have been sunk under a broad diversity of conditions. The Murray mine and the Stobie section of the Frood-Stobie mine have?been opened and a main hoisting and supply shaft has been sunk at each of these mines; No. 2 shaft at Murray was sunk initially from surface to 1,960 feet and is now being extended; No. 7 shaft at Stobie was sunk from surface to 3,105 feet. No. 2 shaft at Garson has been extended from 2,200 feet to 3,200 feet in depth. At Levack, No. 2 shaft is being extended from 1,860 feet to 2,850 feet for ore hoisting from the 2,650 lev el. At Creighton, No. 6 shaft, collared on 52 level, was sunk 1,740 feet to a total depth of 5,563 feet below surface. It is the deepest Inco working. At Creighton, also, No. 7 shaft is being sunk from surface to the 30 level to handle the ore from caving operations. Ail Inco main hoisting and supply shafts sunk during the past twenty years have been vertical rectangular shafts equipped with two cages and two ore skips. The cages are standard and interchangeable for all shafts except Garson No. 2; they are single-deck, 13 ft. 4 in. by 5 ft. 2 in. inside and are designed to carry a maximum material load of 16,000 lb. The man load is 48 men. Skip capacities at the several shafts vary from 8 to 15 tons. Forty-two hundred feet bas been established as the standard vertical lift, and the permanent hoisting equipment at each shaft is designed for eventual hoisting from that depth.

Jan 1, 1950

By J. Mackintosh Bell

External trade strongly influences the well being of all nations. In the modern economic mechanism, no country is so well endowed that it has not to import commodities from others and to export its products in turn to make good its deficiencies, to rectify or improve its financial structure. From the standpoint of international commerce, Canada is strategically well placed. On the south she is bounded by the richest country in the world. On the east she faces the Atlantic, on the west the Pacific. On both coasts there are fine harbours to which lead great lines of railway that span the continent. Canada is now fifth among the exporting nations of the world. For disposal abroad, she has enormous quantities of primary commodities and substantial amounts of manufactured goods as well. But she is far from being self-sustaining. She is unusually dependent on foreign trade, not only because of the commodities she has to sell but because of the lack of many essential articles she does not or cannot produce. To Canada, external commerce is vastly more important than internal trade. The wealth of nations is decided by their ability to produce more than they need, to sell more than they buy, and to build up favourable balances resulting from trade or services. With few countries, however, are returns perennially satisfactory. Fruitful periods are followed by leaner years. In times of prosperity foreign credits are increased, monetary systems strengthened, reserves accumulated to withstand recurring days of strain. Today, the foundations of financial systems are being re-examined, "dogmas hitherto accepted as canonical are being questioned" . It is not only in Europe and America that men search for illumination in problems arising from monetary restrictions.

Jan 1, 1933

By Stanislaw Trenczek

Natural hazards such as rock bumps, methane, coal dust explosions, airborne respirable dust, outbursts of gas and rocks, water, radiation caused by natural radioactive materials, spontaneous fires, and climatic hazards, occurring in the Polish hard coal mines, should be controlled. These hazards are characterized by different scale levels numbered from 2?5. To recognize the amount and levels of hazards, research works were carried out in 109 mining districts of mines belonging to Jastrzebska Spólka Weglowa, Katowicki Holding Weglowy and Kompania Weglowa. These are 86 % of all mines and could be regarded as representative of the majority of Polish mining. The hazards have been classified as regards the frequency of their occurrence as: commonly occurring ? with a frequency of 100 % (like airborne respirable dust and fire hazards), high occurrence frequency ? frequency from 60 to below 100 % (methane hazard ? 83.5 %, coal dust explosion hazard ? 92.0 %, and water hazard ? 99.1 %), medium occurrence frequency ? from 30 to below 60 % (rock-bump hazard ? 52.3 % and climatic hazards ? 51.4 %), and episodic occurrence frequency ? below 30 % (outburst of gas and rocks and radioactive hazards). The dynamics of effects of growth in hazard levels to their intolerable values is diverse. Some of them are passive in nature, which allows for longer observation of changes and appropriate early response (as for climatic and spontaneous fire hazards). However the majority of them take on the character of disasters, like methane or coal dust explosions and damage of the excavation structure ? as occurs after a rock-bump or rock outburst; and creation of an atmosphere unfit for breathing ? during open or spontaneous fires, or after gas outbursts containing methane. There are also latent hazards whose effects do not influence indeed a process of production; however they are detrimental to health when a worker is exposed for a long time to airborne respirable dust and radiation. For other types of hazards a level of danger may be only estimated. Since the systems monitoring allows a wider range of control, therefore, aside from rock-bump and methane hazards, there are monitored also fire hazards including measurements of other air parameters (velocity, pressure, humidity, temperature, O2, CO2 concentration). A few types of monitoring systems are used in Polish mines, like the monitoring systems for environmental parameters such as SMP-NT, SMP-NT/A, the telemetric systems CST-40, CST/A, including the computer-aided system for methanometry control officer SWµP, the computer-aided measuring systems KSP-1, KSP-2, KSP-2C, or the production and safety control system VENTURON. The underground part of the systems monitoring of natural hazards contains measuring devices and equipment for automatic control (power-off) of machines and electric devices in case of increased methane hazard. The surface part of the monitoring system allows the measuring data to be visualized and pre-alarm (warning) and alarm states to be displayed. Furthermore it makes it possible to archive and report the data and to control the underground supply and signalling devices. The EMAG Institute developed monitoring methods to extend a measuring range of monitored parameters (such as methane and fire hazards) as well as to monitor so far unmonitored hazards like dust hazards (by continuous monitoring of dust levels in mine air) and climatic hazards (by online monitoring climatic parameters of mine air).

Aug 1, 2013

By L. A. Ayres da Silva, J. P. G. Negri, A. L. M. Ayres da Silva

"Rock hardness is dependent on the type and quantity of the various mineral constituents of the rock and the bond strength that exists between the mineral grains. As the book “The Complete ISRM Suggested Methods For Rock Characterization, Testing and Monitoring:1974-2006” explains, hardness is a concept of material property. As such, the quantitative measure of hardness depends on the type of the test employed.Among the three types of tests that have been used to measure the hardness of rocks and minerals: 1) indentation tests; 2) dynamic and rebound tests; 3) scratch tests, the authors of this paper chose indentation tests, more specifically the Vickers test, and complementary verified the correlation between the results of the Schmidt sclerometer tests (rebound tests) and the Vickers microhardness tests in a set of the same 9 (nine) granite rocks.The objective of this research was to verif y the correlation of one created index, based on the Vickers test that can be able to represent the rock material hardness. We know that Vickers tests determine the microhardness of individual rock minerals. A pyramidal shaped diamond is applied to the surface with a specified force. The area of the permanent residual deformation divided by the applied force is a measure of the hardness. Using the relative participation of the mineral components of the rock, we established a hardness index denominated EVM (Equivalent Vickers Microhardness).The correlation of the EVM with others strength properties and application parameters like UCS (Uniaxial Compressive Strength) to study sawability of granite blocks have presented very good results. The association of equivalent microhardness with others strength parameters, allowed to find powerful algorithms for analyzes of the rock materials behavior under diversified circumstances, as the sawability of granite blocks, as we can see in Fig. 1.Other very interesting correlations were found as the EVM values and that were obtained by the use of the Schmidt impact hammer for the superficial hardness determination."

Jan 1, 2015

By Eric Toh, Michel David

"Geo-statistics was born from mining problems: grades not being what was expected; more tons of waste than expected; in other words, dilution. Geo-statisticians now claim to have solved many of these problems, but the solutions seem to have a hard time being picked up by practitionners. One of the reasons may be the jargon which geo-statisticians are using. The reason for jargon is that obtaining solutions required a strict formulation in a statistical framework. Practicing mining engineers and geologists are not used to such a framework, and they are not familiar with the jargon. In this paper, the authors re-examine dilution in operating mines and answer two extremely practical problems, using practical language as much as possible. Can dilution be reduced by improving the quality of blast hole samples? How many samples are needed to obtain a good ore-waste discrimination, i.e. to reduce dilution to acceptable levels? Citing real situations, this paper will try to show how fairly simple concepts can be used to answer both problems. It will try to present the solut ions using a minimum of jargon, even if the theoretical solution could be obtained in a few precisely worded paragraphs.The two problems considered are the following: the first one was encountered in the Panguna deposit of Bougainville Copper Limited, P.N .G., but it occurs in every open pit operation where selective mining is required. As the cut-off is lowered, more and more mining occurs in marginal areas. Grade control is mostly based on the grades obtained from blast holes, hence, it is essential that the quality of the blast hole samples be as good as possible in order to reduce dilution, waste being sent to the mill and ore being sent to the waste dump.The second example stemmed from the grade control technique used in many gold open-pit operations in Western Australia: channels are cut on lines 5 m apart and assays are taken every metre. The pattern in the same regardless of rock type, whether one is in the oxidized zone or not. The number of samples to be treated is enormous, hence, the question arises how to find an acceptable sampling grid, and whether changing it can reduce dilution at an acceptable cost.A solution will be given to each problem separately, although in fact it could be seen that the formal framework is the same in both situations."

Jan 1, 1989

By Lynne Bowen

"On the da y shift in Number One Mine at Nanaimo on Vancouver Island, on May 3, 1887, William Griffiths, a coal miner with many years experience, fired a shot to advance the face of the crosscut. A flame ran out for a distance of fifteen feet along the roof and then extended up the slope for ten to twelve feet, and although many would have called this a blowing out shot, Griffiths said it was just a feeder. ""A blower"", he said, ""would have caused an explosion."" 1There was no explosion. Griffiths reported gas and the area was cleared for three hours and then work resumed. When the shift changed at 3:00 p.m., the fireman reported all places clear of gas and the ventilation good.2The ventilation in Number One Mine was the best anyone had ever seen. The air in the mine was almost too cold. The current was so strong that it sometimes blew out the flame on the miners' fish oil lamps. It delivered five to six hundred cubic feet of air for every man and animal working in the mine. The law required only one hundred cubic feet 3The miners considered Number One to be relatively safe. The manager was proud of the mine and its up-to-date equipment"". Recently, there had been reports from France and America about the explosiveness of coal dust, but the manager did not think his mine was sufficiently dusty to be dangerous.5 The dust lay thick on the floor of the mine. Sometimes when a shot was fired the dust rose in great clouds. When a miner was shovelling it, the dust would billow up and be carried off by the current of air. The dust was also in the roof and in the stopings, put there intentionally to fill up the spaces and prevent the accumulation of methane gas."

Jan 1, 1992

By Hrayr Agnerian

The fair market value of an exploration property is determined by its potential to host a mineral deposit. This potential is gauged by the results of previous exploration, exploration stage, meaningful past expenditures and remaining targets that are not yet tested. Values of exploration properties can be viewed as distinct points in a three-dimensional space defined by orthogonal axes, namely: Exploration Stage (x-axis); Cumulative Expenditures (y-axis); and Property Value (z-axis). In general, these values are estimated by applying activity factors on previous exploration expenditures, e.g. an activity factor of 100% for an active property with good potential and a factor of 50% for an active property but past expenditures have not upgraded the property. At certain periods, a market factor may also be applied to reflect the activity of mineral property acquisitions. For properties that do not exhibit any exploration potential, only nominal values are applied.

Jan 1, 1996

By Zhang Junzhi

This paper relates cross-border mergers and acquisitions (M&A) risk management theory to actual coal enterprises in China. The 3 phases of M&A are preparation, implementation and integration. By using the Analytic Hierarchy Process and fuzzy evaluation methods, we will try to establish a model to assess risks of the cross-border M&A of China?s coal enterprises. We then apply this model to the case of Yankuang Group acquisition of the Felix Company and receive the assessment results. There are significant reasons for quantitative research on risks of cross-border M&A of China?s coal enterprises, such as effective prevention and risk-aversion, and facilitation of cross-border M&As.

Aug 1, 2013

By M. Alvarez-Silva, A. Uribe-Salas, J. A. Finch, M. Mimezami

The point of zero charge (PZC) of electrokinetically anisotropic minerals (chlorite and serpentine) was determined using the Mular-Roberts (M-R) titration technique, and compared to isoelectric point (IEP) obtained from electrophoretic mobility measurements. To validate the M-R technique, the point of zero charge and isoelectric point of two isotropic minerals (alumina and silica) were shown to be comparable. For serpentine and chlorite, respectively the PZC was found at pH 4.3 and 4.6, while the IEP occurred at pH 3.2 and <3. Settling tests showed that the maximum settling rate, which corresponds to aggregated particles, for chlorite was around pH 3, i.e., close to the IEP; lizardite did not show a conclusive maximum.

Jan 1, 2009

By J. G. Cullain

Inco Limited is an integrated mining, smelting, refining and manufacturing company with operations located worldwide. The Ontario Division operations consist of 13 mines and 10 processing facilities located in Sudbury, Port Colborne and Shebandowan. The scope of our utilization of energy in the Ontario Division in 1976 included in excess of 2.2 billion kilowatt hours of electric power, 12 billion cubic feet of natural gas, 60 million Imperial gallons of residual oil and smaller quantities of other fuels. In addition to the primary energy consumption, waste-heat energy is recovered in various operations throughout the Division, thereby reducing our primary energy requirements. Total expenditures for primary energy alone in 1976 exceeded 60 million dollars. Energy management studies were initiated by Inco&apos;s Utilities Department in late 1972, and resulted initially in a program of electric power cost reduction. This program produced significant results by improving the use of the water available for our hydraulic generation facilities and by a comprehensive peak reduction program. Our experience showed that a program of peak power control creates an awareness of both peak and energy costs, and thereby encourages a general reduction in the electric energy consumption as well as lowering the peak demand. Energy management is a continuing program at Inco and, recently, a formal energy management policy and program was instituted. Energy management committees were formed in each plant or mine area to identify the major areas for energy; consumption, thereby isolating areas with large potential energy losses, and determining immediate action which will improve the energy efficiency or reduce the energy waste within their respective areas. A decentralized program with good cross-communication between all committees was felt to be the best method of providing an on-going effective energy management program. In the future, the projections of dwindling fossil-fuel supplies in Canada and the resultant spiralling energy costs will further emphasize the need of sound energy management practices for all Canadian industry.

Jan 1, 1977

By Jehan Rondot, Raymond Marleau

"Des quartzites trés pars ont été découverts au cours de la cartographie de la region du lac des Martres, étape de l'étude géologique de la region de Charlevoix.On distingue quatre groupes métasédimentaires, tons con tenant des niveaux de quartzite dans an mains deux domaines géologique différents, c'est à l'ouest, clans le do¬maine gneisso-charnockitique que se situent les quartzites du groupe des Martres. Quartzite et gneiss à, grenat et sillimanite, en banes épais, constituent la formation de La Galette. A Pest, dans un environnement gneisso-granitique, les deux groupes métasédimentaires de Saint-Siméon, et de La Malbaie comprennent, par contraste, des bancs pen épais et de compositions variées. Les niveaux de quartzite dépassent rarement 50 m d'épaisseur. L'autre groupe métasédimentaires, celui de Saint-Tite des Caps, recoupé de nombreuses intrusions charnockitiques et granitiques, ne possède que de minces niveaux de quartzite.La pureté et la grande épaisseur des quartzites de La Galette suppose une histoire complexe qui se termine par des depots continentaux de climat aride, par opposition aux depots marins des autres groupes. D'autre part, la presence de ces quartzites an sein de roches Presque anhy¬dres et de haute temperature que sont les charnockites leur confére des caractéristiques de fusion sans decrepitation.Parmi la multitude de depots de quartzite qui existe clans le monde, peu sont de qualité supérieure. Or, de par sa composition chimique, le quartzite de La Galette se compare avantageusement à ceux des meilleurs gisements des Etats-Unis, de l'Europe de l'Ouest et de l'Afrique du Sud. D'accès facile pour l'exploitation, les gisements ne sont qu'à une trentaine de milles de Baie Saint-Paul ou de La Malbaie, sur le Saint-Laurent.L'utilisation en metallurgic prévue pour le quartzite de La Galette comprend la production de silicium, de ferro¬silicium et d'autres alliages de silicium. La composition du quartzite est en outre appropriée pour la production de carbure de silicium et de silicate de sodium. Les fines peuvent être utilisées pour la fabrication du verre et comme matiere de charge"

Jan 1, 1977

By Xiqing Wu, Liang Dai, Tao Yue, Longsheng Yi, Ruifang Wang

Magnetic seeding flotation (MSF), i.e. adding magnetic seeds and pre-magnetization-flotation, is a new flotation technology especially for fine particles, which improves the flotation performance by enlarging the apparent size of the particles in a way of magnetic agglomeration. Both the fine coal slimes with a size of 66.68% –38µm and the pyrite slimes with a size of 73.95% –23 µm were investigated by the MSF, respectively. Flotation tests with variable of dosages of magnetic seeds and polyacrylamide were conducted, and some measurements, such as laser diffraction size analysis, magnetic susceptibility by vibrating sample magnetometer (VSM) and infrared spectroscopy (IRS), were also applied in order to probe the mechanism of the MSF. Based on the tests, measurements and calculations it was found that both the recovery of coal and the flotation kinetics of pyrite slimes increased with the additions of the magnetic seeds, and in the presence of polyacrylamide the coal flotation was further strengthened due to a synergetic effect of magnetic seeds and polyacrylamide on the flotation and a relatively larger apparent size of slimes after additions of magnetic seeds and polyacrylamide. The reason for the MSF lies in fact that the presence of the polyacrylamide intensified the adsorption of magnetic seeds on the coal particles and increased the coverage of the magnetic seeds on the coal surface from 0.2 to 1.3 wt%, resulting in increased magnetic susceptibility of coal particles from 9.13×10-9 to 22.17×10-9 m3/kg and thus a low magnetic field strength of pre-magnetization needed for the magnetic agglomeration among the coal particles from 602 to 24 mT prior to proper flotation. IRS shows that polyacrylamide chemisorbed on the surfaces of both coal particles and magnetic seeds, thus acting as the bridging media between particles and seeds.

Jan 1, 2016

By G. F. Miller

ONLY IN THE Province of Saskatchewan is natural sodium sulphate found in Canada in amounts large enough to make recovery economically sound. Geologists have estimated that the numerous deposits within the Province contain upwards of 200 million tons of Glauber&apos;s salt. There are twenty-one deposits in the Province which contain 500,-000 or more tons and about two dozen with lesser amounts. The first recorded production of sodium sulphate in Saskatchewan was in 1918. The company concerned, and others that attempted to develop the industry in its early stages, were unsuccessful. Their failures were caused by two main factors -lack of knowledge of efficient operating methods and the unstable market situation for the finished product. Today, the situation is changed in both respects and the product, commonly referred to as &apos;saltcake", is a very important chemical requirement of many industries throughout the world. Before proceeding with remarks on manufacturing methods it should be stated that, although this is a general paper on the manufacturing methods and end uses of the saltcake produced in the Province, the writer is, of course, more familiar with the plants operated by Saskatchewan Minerals than with other operations and perhaps may be excused for dealing more particularly with the plants of that Compa11y.

Jan 1, 1958