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By Jesus Garcia Iglesias, Jorge Loredo

"Abstract -The Asturian fluorspar district consists of vein and stratiform deposits where mineralization is controlled by a combination of lithological and tectonic factors.It is postulated that these fluorspar deposits have been formed under disequilibrium conditions created during circulation of ascending hydrothermal solutions along faults and other high permeability conduits. Mixing of solutions is inferred from fluid inclusion studies. Cavity filling and replacement processes are very important in localizing the ore deposits and in determining their morphology.Permian volcanic rocks in the area yield a regional positive geochemical anomaly in fluorine implying that Permian vulcanism may be a possible primary source of fluorine.On a regional scale a relationship can be established between some of the ore deposits and important tectonic lineaments. The stratiform deposits preferentially occur within a calcareous-detrital facies located at the margins of basins. These basin margins are related to important synsedimentary faults.Fluorite is the only economic mineral in these deposits. Quartz, carbonates, barite and pyrite are common minerals accompanying fluorite. Other minerals that may occasionally be present as minor components are: marcasite, chalcopyrite, fahlore, sphalerite, galena and related supergene minerals."

Jan 1, 1994

By A. Desbiens, R. del Villar

"This two-part paper summarizes the design and implementation of a distributed PIbased control strategy installed at the B grinding circuit, at the Kidd Creek Division of Falconbridge Ltd. Part I details the design of the control strategy using a grinding circuit dynamic simulator (DYNAFRAG). The first step consisted of sampling campaigns and data processing to calibrate DYNAFRAG. Then, several control alternatives were designed and tested with the simulator. The main feature of these strategies is their ability to regulate or keep within an upper and lower limit five output variables (circulating load, rod mill density, cyclone feed and overflow densities and pump box level) with only three manipulated variables (rod mill water, pump box water and rod mill tonnage). By simulation on DYNAFRAG, it was possible to discriminate among several control structures. The preferred control strategy uses a saturation algorithm, which allows the adequate regulation of two measured variables with only one actuator. Controllers located in interacting loops are appropriately tuned, taking into account the existing process coupling. Part II will present the implementation of the selected control strategy.IntroductionSteady state simulators are used to predict the stationary state of a given process under specific operating conditions. Tradi - tionally, steady state simulation has been applied for process flowsheet design, for evaluating process modification benefits or for determining key operating parameters in process operation optimization. Dynamic simulators add a new dimension to process simulation since they allow the prediction of the process transient behaviour, resulting from the application of a different set of operating conditions and/or from natural disturbances or equipment failure. Dynamic simulators can also be used for the training of new operators or for the design of control strategies."

Jan 1, 1997

By William B. Hetherington

Communities are the foundation upon which the whole structure of society rests and upon which the nation builds its hope for the future. They are not established to serve any one particular generation, nor any one element or group, but should be erected to render a lasting service to all who are to follow. They play a very vital and important role in the lives and welfare of the people, in their industrial, business, and social relations, and in the economy of the nation, of which they are the fundamental assets. Communities and civic governments are destined to be vital factors in the national welfare in the days that are to come. Any improvement in national or world conditions must have its origin within the communities. Any attempt at solution of the community problem must give some consideration to the fundamental elements which exist in every community, and to the underlying principles, and ways of life and thought, upon which community life is based. The community is, in its essence, a number of people living and working more or less closely together, sharing common rights, privileges, conveniences, and comforts, which would be impossible for the individual to obtain for himself by his own efforts alone, or in any other way than by the mutual exchange of persona! services and resources. In this way, men have increased the returns from their labour and commerce, have raised the standard of their living, with better social, educational, and recreational facilities, and enjoy a greater personal security.

Jan 1, 1943

By W. A. Jones

THE estimation of the average value of gold ore involves many considerations, among them the correct sampling of the deposit, the dilution by waste, and the loss of high-grade fines. It is a common experience that, after all these factors have been evaluated, adjustment of the assays is necessary before satisfactory agreement between the calculated mine grade and the mill heads is obtained. In fact, at many mines the latter correction overshadows all others in the preparation of routine estimates. For this reason it is proposed to deal only with the mathematical treatment of mine assays and the problem of bringing estimates into conformity with the corrected mill heads. Mine assays differ from physical measurements because the range of values is very great and these are not symmetrically distributed above and below the average, there being fewer high than low results. There is no widely accepted mathematical procedure for determining the average of series of measurements which exhibit these characteristics. Customary practice consists in empirically reducing high assays until a satisfactory agreement with mill heads is reached. It was thought that more confidence could be placed in grade estimates if a logical basis for calculations could be devised .. In an attempt to find a fundamentally sound procedure, amenable to practical application, many series of assays comprising over 235,000 channel samples (1) were studied at Hollinger Consolidated Gold Mines, Limited. Such an investigation could only be made where records covering many years of operation are available and where tabulating and calculating machines are in use. The results are recorded in the hope that the relationships noted for the large groups of assays used are of fundamental character and that the data will be useful to others dealing with the problem of grade estimation.

Jan 1, 1943

By Edward Sampson

Bases of National Power At a time when the economy of the world is in a particularly troubled state it is appropriate to examine some problems of the distribution of natural resources. I should like particularly to call attention to the remarkable increasing demand for natural resources, to give an analysis of the demand for certain mineral resources, and to direct attention to some problems in satisfying this demand. All industrial power is based on natural resources and the most basic of these are soils, energy resources, and mineral resources. There is a strong interrelation of these resources, more than is obvious, and I shall take up certain aspects from the point of view of a geologist. Few nations are well endowed with all three of the kinds of natural resources I have mentioned and much has been done by some small countries whose peoples are industrious and enterprising and where conditions for free world trade have been favourable. However, major industrial power is dependent on a substantial endowment of all three classes.

Jan 1, 1949

By Balmer Neilly

In these days of arrested prosperity, when patience is tried and the future but dimly outlined, Canada's gold mining industry stands out as a beacon light shedding its rays of hope and confidence and demonstrating that there is still one product unaffected by Customs barriers and eagerly sought by all the people of the world. Some other forms of industry have hesitated and side-stepped. Some have cried for help, and in spite of public assistance, generously extended, they are still unable to demonstrate definitely their ability to resume the onward march. But gold mining has never hesitated. As an industry, it has bad an unique experience. When prices are high and conditions are generally referred to as prosperous, this industry is adversely affected. The cost of production goes up; profits are diminished; public sympathy is lacking; and, thrown upon its own resources, the industry tightens up its belt and throws its whole energy into an effort to improve operating conditions, and offset high prices by increased efficiency. When, in due course, depression follows inflation and prices ebb, the gold miner, through necessity, finds himself physically and mentally prepared to meet the situation.

Jan 1, 1932

By Y. Q. Li, Z. C. Shen, C. H. Zhao

The dynamic properties of the KYF-320 flotation machine which is one of the biggest flotation machines in the world were tested and then verified by the computational fluid dynamics (CFD) simulation. Aeration rate testing results suggest that he effect of circulation holes on the fluid state in the flotation cell becomes gradually smaller when the impeller speed is greater than 107 r/min. The dispersion degree of air increases with the increasing impeller speed and decreases with the increasing aeration rate, and it increases slightly when the impeller speed is greater than 107 r/min. The air holdup increases and then decreases with the increasing impeller speeds and aeration rates, and a maximum value of air holdup is shown at impeller speed of 107 r/min with a value of 12.28%. CFD simulation results are in good agreement with these testing results. Industrial-scale test was carried out using this 320 m3 flotation machine for the flotation of Cu ores. The results show that Cu content increases from 0.06% of crude ore to 1.26% of concentrate, and the S content increases from 0.39% of crude ore to 24.83% of concentrate. Moreover, using this flotation machine 5.88% of power is saved compared to other type of large flotation machine.

Jan 1, 2015

By R. J. Munday

Although uranium deposits in northern Saskatchewan are clustered around the Athabasca basin, basement lithostructure determines their distribution. Basal Wollaston Group pelites are invariably graphitic and carry uraninite in felsic segregations and biotitic pegmatite. Where these intersect the Athabasca Formation, remobilized uranium concentrated as pitchblende. Uranium is also concentrated in silicified and hematized sandstone where the Athabasca Formation overlies post-orogenic faults. Presumably, pregnant solutions associated with the fault were stripped of their metals as they emerged into the contrasting physico-chemical environment of the sandstone basin. Both these types of mineralization correlate with a Grenvillian (-1,000 m.y.) heating event and associated diabase intrusions. However, the rich pitchblende veins at Uranium City appear to predate the Athabasca Formation, but display spatial correlation with the Martin Formation. They are tentatively associated with a syn- to post-D3 retrograde metamorphic event which thoroughly leached crystalline basement and generated uraniferous fluids which escaped, and precipitated metals, into fractures associated with faults that define the grabens in which the Martin Formation was deposited. Remobilization events allowed some of this uranium to move upward into fractures within Martin sediments.

Jan 1, 1979

By E. Adam, B. Milkereit, M. Salisbury, L. E. Reed, G. Perron

Integrating seismic reflection, borehole geophysical, and physical rock property studies is an effective means of mapping lithological contacts and structures in the crystalline crust. At Les Mines Selbaie in the northern volcanic zone of the Late Archean Abitibi Subprovince, a high-frequency seismic reflection profile has provided the first images of deep crustal structures of this important polymetallic mine site. Physical rock property and borehole geophysical studies confirm that prominent seismic reflections can be caused by lithological contacts, faults and sulphide mineralization. At Les Mines Selbaie, the first two of these are shown by this study. Clearly identifiable reflection images from sulphide mineralization have not been demonstrated in analysis of the profile. The seismic images provide useful information about gross structure in the vicinity of Les Mines Selbaie. They can also place important constraints on the sequence of tectonic events and, therefore, can aid future deep exploration programs.

Jan 1, 1997

By M. S. Badollet

"IntroductionASBESTOS FLOATS may be defined briefly as blends of air-borne particles of fibrous asbestos and dusts produced during the milling stages and collected by Cottrell precipitators, dust sheds, or bag-houses.The various grades of asbestos floats on the market contain fibrous asbestos particles ranging in length from microscopic to approximately 1/4-inch. The fines or dusts present in the floats are from 40 microns to 2 microns or less in cross-section.Airborne asbestos particles are of diverse length because they are collected at numerous places in the mill. There are: (1) dusts removed from dry rock storage bins, (2) dusts removed from rock and fiber screens, (3) particles from the tops of collectors, and (4) fines removed by suction from the processing equipment. Sometimes the airborne particles are kept segregated, so that there is a partial separation by gravity. This is accomplished by a series of dust chambers enclosed in a long, rectangular building. The longest and heaviest particles fall nearest to the air flow entrance, the smallest at a point farthest away and nearest the exit. Sometimes the air from the dust chamber building is passed through a series of bag-houses or electric :precipitators ,to collect the extremely fine particles which normally escape to the atmosphere."

Jan 1, 1952

By T. S. Heah, S. T. Bishop

"The Lorraine property is located in the northern Intermontane Belt, north-central British Columbia. The property is underlain by intrusive rocks of the Duckling Creek Syenite Complex, an Early Jurassic, alkaline phase of the Late Triassic-Early Cretaceous Hogem Batholith. Two significant zones of copper-gold mineralization have been explored to date; the Main zone (historical Upper and Lower deposits) and the recently discovered Extension zone. A combined geological resource was estimated in 1975 for the Main zone deposits at 10 million tonnes averaging 0.7% Cu, and from 0.1 g/t Au to 0.34 g/t Au. The Extension zone, still at an exploration stage, is estimated to be considerably smaller than the Main zone.Copper-gold mineralization at Lorraine Mountain exhibits characteristics suggestive of both magmatic and hydrothermal origins, and may be related to orthomagmatic-hydrothermal fluid flow contemporaneous with magmatism and development of migmatitic fabrics. A depth greater than the depth of formation of classical porphyries may explain many of the variations displayed by mineralization at Lorraine. These characteristics distinguish Lorraine from other members of the alkalic suite of porphyry Cu-Au deposits in the Canadian Cordillera.IntroductionThe Lorraine prospect is located in the Omineca Mountains, at the headwaters of Duckling Creek, 56 km northwest of Germansen Landing (Fig. 1). The property is centred at latitude 55°55'N, longitude l25°26'W on NTS mapsheet 93N/14W. The area is typified by mountains of moderate relief, with elevations ranging from 1150 m in the valleys to peaks of 2000 m. Valleys are U-shaped and blanketed by glacial till which give way to steep, talus covered slopes and sharp ridges. Outcrop is generally limited to elevations above 1600 m (Fig. 2)."

Jan 1, 1995

By A. Himsley

This paper presents a review of the existing ion exchange resin systems for treating unclarified pregnant liquor, with particular reference to uranium extraction. A new concept of a truly continuous ion exchange system is described and operating details are given,of a 0.6.-m (24 in.) diameter pilot plant treating unclarified acid leach liquor.

Jan 1, 1977

By R. A. Wyman

A comparison of the amount of minus-28-mesh product produced by a standard grinding test procedure is provided for 45 non-metallic materials. The percentage of product, the weight of product per unit of energy used and the weight of product per mill revolution are shown. The results exhibited excellent reproducibility and demonstrated an accurate comparison of grindability for non-metallic materials.

Jan 1, 1977

The system of keeping geological plans and sections for the Geco Mine at Manitouwadge, Ontario, is described. Special methods employed to save draughting time with-out sacrificing accuracy, such as the extensive use of black line prints, are discussed. The uses made of the plans and sections by the mine planning engineers in their designs of stopes, and by the blast-hole engineer in ~is preparation of blast-hole layouts, are noted. An unusual scheme for portraying the distribution of .copper, zinc and silver values within the ore zone is de-scribed. The method of estimating the grade of ore to be "blasted in each ring of blast holes is outlined, as is the method of estimating the annual ore reserves. The design of an effective but simple transparent geo-logical and mine development model, used as a display for -visitors, is discussed. A large-scale model used for the study of problems in geological structure is also de-scribed.

Jan 1, 1964

By M. L. Joy

The heat pipe is a self-contained, passive structure that uses a liquid-vapour fluid cycle to provide high thermal conductance . Through the proper selection of working fluids and container materials, heat pipes have been operated at temperatures ranging from less than -300°F to more than 3,000 °F. The passive nature, high efficiency and configuration flexibility of the heat pipe are presented. The application of McDonnell Douglas Astronautics Company Cryo-Anchor® heat pipes for foundation and support stabilization in permafrost regions is discussed. Using the proven Cryo-Anchor technology base. a proposed application of heat pipes in a cold -region mine ventilation system heat recovery heat exchanger is presented. Information obtained from the development of an air-cooled heat pipe steam condenser provides the technical basis for large -scale heat pipe applications.

Jan 1, 1978

By L. Ferland, D. LaRonde, J. C. Caron

"The free-world production of columbium ore concentrates has doubled in the last five years. St. Lawrence Columbium and Metals. Corporation has contributed largely to this expansion, its production rate increasing from 720 tons of concentrates per year in 1961 to 2 200 tons in 1965.To follow the normal market development, the Company initiated an engineering study aimed at establishing the most economical mining methods, thus permitting it to increase its milling rate from 1,000 tpd in 1964 to 2,000 tpd in 1967 and possibly to 3,000 tpd in 1968. The results of this study pointed out the advantages to be gained in converting from an open pit to an under-ground operation. This paper describes how the mining engineering department has successfully developed ""stopes"" from the walls of its No. 2 open pit, in order to assure continuity of its operation during the interval required to develop its underground mine."

Jan 1, 1967

By Dale C. H. Nevison

One of the most intensive of material rivalries is the confrontation between zinc die castings and plastic injection moldings. Pressed hard by the plastics industry, zinc die casters are learning how to make parts with less material yet without sacrificing quality. The key to this new trend is the technique of Thin Wall die casting. The obvious benefits of Thin Wall are lighter weight and lower cost. Again, obviously, these are the very selling points that put plastics into many appliance and automotive parts formerly made of zinc. One of the factors that has been most conducive to the outstanding growth of plastics has been the increasingly prevalent concept that "adequate" properties are sufficient, especially if there are cost advantages. Most of modern design today is oriented around the reasonable life of a product, rather than indefinitely extended life. This is simply an acknowledgment of the existence of a design environment that pervades many areas, reflecting the life-cyclic desire for change. Too often, so-called "weight-saving" materials end up being very costly - not only in production, but in durability and dependability. Change for the sake of change usually doesn't effect a change for the better. In the majority of cases, the best bet is to design in traditional materials and minimize the material needed, while maximizing the efficiency of the production process. Component prices of products to be produced from either plastics or zinc must be studied in detail to determine which material will produce the lowest cost of manufacture. It is not uncommon for two parts, similar in appearance at a casual look, to have a considerable difference in energy requirements and production costs. Detailed cost estimates of the advantages of each material should therefore be prepared for zinc and plastic parts before the final design and material selection decisions are made.

Jan 1, 1978

By G. H. Agnew

When water floods are initiated after gas-oil ratios have increased, the transition period from the start of injection until" the gas-oil ratios are returned to the solution gas-oil ratio may be important for either economic or technical reasons. The transition period is longest, and consequently most critical in water floods where injection is equal to withdrawals. This paper describes a theoretical basis for predicting the behavior of such a system and outlines a procedure for making the necessary calculations. The calculation procedure is illustrated for two actual cases: a line drive water flood and a five spot water flood. In each case there is a reasonable similarity between the actual and calculated performance.

Jan 1, 1960

By S. Steinlechner, G. Schneeberger, J. Antrekowitsch

The recycling of steel mill dusts is getting more and more important. The costs and requirements of land filling are rising and companies are interested in new recycling strategies. The rising of sustaina¬bility hand in hand with the high rate of valuable metals in these residues supports new research activities on the recycling sector. Especially zinc but also iron and lead are economical factors due to the treatment of steel mill dusts. This paper gives a small overview of fundamental studies concerning the chemical and physical composition of these dusts. Furthermore aggregates for the reduction of these dusts in the liquid phase are introduced and compared. The Flash-Reactor, the TBRC-Technology (Top Blown Rotary Converter) and submerged arc furnaces and there use for melting and treatment of these dusts are in the center of interest of this paper. The final conclusion gives an overview of possibilities for reduction of filter dusts in the liquid phase.

Jan 1, 2011

By The Staff

"IntroductionThe published information concerning treatment of uranium ores has been very limited as far as Canadian ores are concerned. Such information has dealt mainly with refining processes for concentrates or rich ores, designed to recover radium rather than uranium; these methods could not be economically applied to low-grade ores.The purpose of this paper is to describe treatment possibilities for some of the .ores that have been treated at the Mines Branch, and .to show how the character of these ores influences methods and results.What is a Uranium Ore?Prospecting for uranium has been extremely active during the past two years and a great many occurrences of radioactive minerals have been recorded. Such prospecting has been based to a large extent on the use of the Geiger counter in the fie1d. This equipment is an invaluable aid when the results are properly interpreted.Most definitely, indications of high radioactivity do not always prove the presence of a valuable orebody. First we have to determine:(1) Is the radioactivity due to uranium or to thorium. There is no immediate market for thorium.(2) Can the uranium in the ore be economically recovered.Chemical analysis is the most exact method of determining uranium content, but a fair estimate of the uranium, and also of the thorium, content can be made from the difference in gamma and beta activity. The Mines Branch guards against misinterpretation by determining both beta and gamma activities and, if more than a minor amount of thorium is indicated, then a Chemical analysis is made."

Jan 1, 1950