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By L. Juteau

"""The north coast of the St. Lawrence River will be the scene of an industrial development during the coming decades"". The facts which underlie this statement are the occurrences of iron and titanium ore, the abundance of hydro-power and the availability of deep-water ports in this region. Havre St-Pierre, Sept-Iles, Port Cartier and Baie Corneau already exist as major ports and urban centers. The huge quartz deposit at Baie Comeau will be a decisive contributing factor in the development of a metallurgical plant in this area. Due to its purity, it lends itself, first of all, to the manufacture of glass of different kinds, being comparable to the quartz sands now used by the plate glass and glass container industries in the Montreal area, Moncton, N.B., Trois-Rivieres and - in the future - at Bécancour, Quebec. However, its high quality will also make it possible to use it as one of the main basic materials for the production of silicon carbide and ferrosilicon, and as a flux in metallurgical processes. It is intended, in this report, to offer conclusive proof of the economical importance of this large quartz deposit by presenting the results of the studies made to date."

Jan 1, 1971

By E. P. Klier, Taylor Lyman

THE structures formed when austenite is quenched to subcritical temperatures and allowed to transform isothermally have been the subject of intensive study since the work of Davenport and Bain.1 Isothermal transformation diagrams summarizing the results of many of these studies have become widely familiar to metallurgists. Of particular interest to metallographers are the dark-etching, acicular products of transformation formed by isothermal reaction below the temperature of maximum velocity of the austenite to pearlite reaction. These products, the bainite structures, can be formed in a wide variety of steels. However, the constitution of bainite is not well understood and divergent views have been expressed as to its mode of formation. In this investigation a combination of dilatometric, microscopic and X-ray methods has been brought to bear upon the problem in the hope of some elucidation of the bainite reaction as it occurs in hypoeutectoid steels. MECHANISM OF BAINITE FORMATION Davenport and Bain1 considered the mechanism of bainite formation to consist of two steps-an allotropic transformation followed by precipitation of carbide. The separation in time of the two processes was considered to be very slight in the upper temperature range and very marked at temperatures just above the martensite range. This concept has been restated by Vilella, Guellich and Bain2 in the form of a definition of the acicular mode of transformation as: The successive, abrupt formation of flat plates of supersaturated ferrite along certain crystallographic planes of the austenite grains; this supersaturated ferrite begins at once to reject carbide particles, (not lamellae), at a rate depending upon temperature. In effect, this is the acicular mode of transformation, even though the temperature be such as to limit the actual life of the quasi-martensite to millionths of a second. The investigation of isothermal decomposition of austenite in certain alloy steels (notably those containing chromium or molybdenum) has revealed that there may be a range of temperatures between the pearlite and bainite reactions in which the austenite decomposes at a relatively low rate.3-6 Further, it is characteristic that in the second region of fast reaction the decomposition of the austenite is incomplete by one reaction but goes to completion by a second reaction. These observations led Wever7 to a description of the bainite reaction as follows: I. The reaction takes place by initial precipitation of a martensitic intermediate structure. 2. In the upper temperature range this structure readily decomposes into ferrite and cementite. In the lower range carbon separates in an unknown form. 3. In the upper temperature range the precipitated carbide nucleates the precipitation

Jan 1, 1944

By J. M. Paxton, R. L. Roscoe, G. A. McCreary, W. W. Muir, T. J. Drown, D. A. Barr, T. W. Law

"This paper reviews the complete cycle of a small mining operation in a remote section of northern British Columbia, including discovery, exploration, development and production. The discovery of high-grade epithermal gold-silver mineralization occurred in 1969 following a regional geochemical reconnaissance program designed to search for porphyry copper mineralization in the Cassiar-Omineca Mountains. Exploration and development from 1971 to 1979 included geological, geochemical and geophysical surveys; trenching, almost 30 000 feet of surface and underground drilling in about 100 holes and cross-cutting, drifting and raising on the principal goldsilver- bearing vein. This led to the delineation of 100000 tons at an estimated grade of0.9 oz gold per ton and 18 oz silver per [on to an average depth of 120 feet below surface. of a 100-ton per day mining operation employing about 50 personnel with all supporting infrastructure transported to the site by a Hercules aircraft. The operation was subsequently supported by its own Twin Otter aircraft with periodic Hercules campaigns supplying major items including fuel.The mining operation included both open-pit and cut-and-fill methods. The milling operation employed conventional cyanide leach process with cyanide destruction initially by alkali chlorination and subsequently by the Inco SOl /Air process.The fly-in operation, initially structured on a 21-day-in and 7-day-out basis was modified to al-t-day-in and Z-day-out basis with no loss in efficiency and with a significant increase in employee satisfaction. The operation, which earned the B.C. Small Mines Safety A ward in two consecutive years in its Ll-month operating history, emphasized safety and process hazard awareness. Wildlife studies in the environmentally sensitive mine area also showed that industry and wildlife can coexist in harmony.Most importantly, the paper compares the feasibility assumptions with actual operating experience."

Jan 1, 1986

By Org de Wet

This paper summarises the strategy for selection between a two module coal plant incorporating large, but less equipment, and a three module coal plant with more but smaller equipment. The two options were evaluated in terms of three main categories: ? Size ? size of the equipment and the effect on the process efficiency as well as the difference in physical dimensions of the plant to accommodate the larger equipment; ? Cost ? capital savings between a two and a three module plant, processing the same ROM (run-of-mine) tons per hour (t/hr); and ? Practicality ? in terms of constructability of the plant, safety of using larger equipment and maintainability of the equipment. Decisions that were taken to reduce the risk associated with size, cost and practicality on the chosen option of a two module plant will be highlighted.

Jan 1, 2006

By Joseph Perry

MAGNESITE is found in 22 California counties, but many of the deposits are too small or too impure to be of commercial value. Several of sub-stantial size and quality were entirely exhausted by wartime operation. At present, three properties comprise the only known workable deposits in the state. Of these, the Western mine and the Patterson mine have been known and worked for many years, and have been described in con-siderable detail in various publications, therefore need only brief mention here, because of their proximity to the Bald Eagle mine. The latter, recently developed, is unusual in type of ore deposit, plant design and operation, as well as products made, and very little has been written concerning it. WESTERN MINE The Western mine, 32 miles south of Livermore, Calif., was formerly operated by C. S. Maltby. It has been a consistent producer for many years.1 The ore is of amorphous variety, occurring along fracture zones in serpentine. The veins vary greatly in width, the average being perhaps 8 ft., with the maximum indicated in one early stope of 40 ft.; 2 ft. is considered the minimum for economical mining. The strike of the veins is predominantly north and south, with dip to the west varying from 40° to 75°. Walls are well defined and as a rule firm and easily supported, Veins range in length from a few hundred feet to 1000 or more. Their maximum vertical extent is about 350 ft., but many run less. Early mining consisted of open-cut and glory-hole work on the larger outcrops. This was followed underground by a modified shrinkage system, the waste and low-grade horses being removed by hand sorting on the tramming levels and transported to surface dumps. Filled-stope mining is used now, in order to eliminate the handling of waste, which has

Jan 1, 1938

By Joseph B. Perry, G. M. Kirwan

MAGNESITE is found in 22 California counties, but many of the deposits are too small or too impure to be of commercial value. Several of substantial size and quality were entirely exhausted by wartime operation. At present, three properties comprise the only known workable deposits in the state. Of these, the Western mine and the Patterson mine have been known and worked for many years, and have been described in considerable detail in various publications, therefore need only brief mention here, because of their proximity to the Bald Eagle mine. The latter, recently developed, is unusual in type of ore deposit, plant design and operation, as well as products made, and very little has been written concerning it. WESTERN MINE The Western mine, 32 miles south of Livermore, Calif., was formerly operated by C. S. Maltby. It has been a consistent producer for many years.1 The ore is of amorphous variety, occurring along fracture zones in serpentine. The veins vary greatly in width, the average being perhaps 8 ft., with the maximum indicated in one early stope of 40 ft.; 2 ft. is considered the minimum for economical mining. The strike of the veins is predominantly north and south, with dip to the west varying from 40º to 75 º. Walls are well defined and as a rule firm and easily supported. Veins range in length from a few hundred feet to 1000 or more. Their maximum vertical extent is about 350 ft., but many run less. Early mining consisted of open-cut and glory-hole work on the larger outcrops. This was followed underground by a modified shrinkage system, the waste and low-grade horses being removed by hand sorting on the tramming levels and transported to surface dumps. Filled-stope mining is used now, in order to eliminate the handling of waste, which has

Jan 1, 1938

By Donald E. Buck

In 1988, Albania's centrally planned economy continued to decline. The country's officially published yearend economic report did not contain concrete results such as the growth of national income or industrial output. 2 The shortfall for central budget earnings for 1988 amounted to 9% below the planned target. Losses in industry were attributed to poor management and organization, as well as to low technical standards and excessive consumption of fuels and raw materials. The construction, energy, and mining sectors of industry did not meet their annual production plans. As in 1987, within these sectors, the chromite and petroleum extracting and processing industries continued to lag in output. Both chromite and petroleum remained Albania's chief sources of foreign exchange; the production downturn of these commodities continued to negatively affect the country's foreign trade position, especially in view of constitutional prohibitions against using foreign credit to finance trade. The chief events in the minerals industry in 1988 included the construction startup of the first of four planned new concentrators at the Bulquize chromite mine, as well as the construction startup of new ferrochromium capacities at Elbasan. Also, the copper mining industry reported the completion of facility expansion at the Perlat mine in the Mid-rite district. Albania began new facility construction at the Dinamo heavy-equipment enterprise at Tirana to maximize self-sufficiency in mining equipment production. Upon completion, the new factory would double the out-put of mining equipment at the enterprise and would introduce new designs for electric trucks and pneumatic drills for the mining industry. The new facility would also increase the production of new machinery and equipment for the country's beneficiation plants.

Jan 1, 1990

By G. W. Phelps

This discussion deals with the geology o£ the Tennessee-Kentucky ball clay deposits; their mineralogy and chemistry; methods of finding, mining and refining; and makes observations on reserves of and future prospects for these clays. Ball clays appear in ceramic formulas for manufacture of vitreous china sanitary-ware, electrical porcelains, floor and wall tile, dinnerware and artwares(l). This type of clay is used for refractory (2) and abrasive products(3), and as a suspending agent for ceramic glazes(4), engobes(5) and porcelain enamel slips(6). Although some ball clay is imported, probably 85-90 percent of ball clay used in the USA(7) is obtained from deposits in Weakley, Henry and Carroll Counties in Tennessee(8), and in adjacent Graves County, Kentucky(9). The term "ball", as applied to clay, probably derives from former mining practice in England whereby conveniently-sized blocks of clay were cut from moist clay beds by spading(10), The expression "ball" has no other technological significance. ASTM(11) defines ball clay as "a secondary clay, commonly characterized by the presence of organic matter, high plasticity, high dry strength, long vitrification range, and a light color when fired." This, and similar(12) definitions, applies to English ball clays but is not satisfactory for many American ball clays. Geology of the Tennessee-Kentucky Ball Clay Deposits Figure 1 shows that most commercial clay areas of the eastern United States lie near the edge of the Coastal Plain; a skew-shaped configuration of its landward boundary outlines the Mississippi Embayment(13), Near the apex of this basin a broad plain, with a rolling, Bullied topography(14), dips gently westward from the Tennessee River to bluffs at the edge of the Mississippi River flood plain.

Jan 1, 1972

Historical exploration of the Ballarat East goldfield defined two primary quartz vein lode types. Tracking the intersection of these lodes with vertical lines of enrichment (or so-called æindicatorsÆ) was the basic practice for historical mining. This strategy proved highly successful in terms of identifying quartz veins associated with mineralisation. However, it provides little understanding of the timing or processes involved in the formation of these veins, or the associated emplacement of gold. Current underground mapping shows the Ballarat East gold deposit can be subdivided into four stages of vein formation. The earliest veins (V1 and V2) strike north-south and formed during bedding flexural slip and limb thrust fault propagation in parasitic chevron folds. V3 veins are subhorizontal and relate to further fold tightening involving a transition from east-west compression to north-south extension that initiated re-shear of bedded slip surfaces and additional strike-slip faults. Sporadic V4 veins overprint the shallow-dipping sections of V2 and V3 veins and are associated with weak north-south compression. The V4 veins mineralogy is distinguished by a high carbonate content and sphalerite-galena sulfide assemblage. Vein sampling indicates a significant increase in gold mineralisation where overprinting by the later deformation/veining has occurred. As a result of these observations, a new model is emerging that identifies the chronology, structural control and spatial distribution of respective quartz vein types. This is a major advance in terms of exploration targeting, resource modelling and mine planning.

Jan 1, 2008

By D Craw, J Youngson

Recent exploration for mesothermal gold deposits in the Otago Schist has focussed largely on extensions of, or analogies to, the reverse fault-hosted Hyde-Macraes Shear Zone deposit. Abundant normal fault-hosted mesothermal and epithermal vein deposits in the Otago Schist have attracted less attention, largely because they have limited lateral extent and steeper dips. Northwest-striking normal fault-hosted vein sets near Barewood and Hindon in east Otago crosscut schist foliation on the Barewood-Hindon plateau at a high angle along a combined strike length in excess of 20 kilometres. The trend of the vein sets is not linear, but rather contains several right lateral steps. Almost all veins dip steeply to the northeast. Angular discordance between schist foliation and the plateau surface along the trend increases from near zero at the northwest end of the veins to about 30¦ at the southeast end. Crude formation depth estimates decrease from about 7.5 km at the Barewood end of the zone to

Jan 1, 2002

By Lester E. Sutton

The past three years have been the most difficult period in the modem history of the barge line industry. Having withstood the fuel cost run ups of the late 1970s and the imposition of inland waterways system user fees, the industry has struggled more recently with an overcapacity problem of unprecedented proportions. In responding to these challenges, the industry is undergoing important long-term structural changes, with the various individual barge lines pursuing an array of divergent long-term business strategies. This paper discusses these strategies in terms of their probable impact on the industry as a whole, and argues for the survival of a competitive number of large, national, independent barge lines as the outcome most in keeping with the long-term interests of the mining and minerals industry.

Jan 1, 1986

By W. M. Weigel

Economic deposits of barite occur in Missouri in two main districts. The most important, the Southeastern or Washington County district, is in the southeastern part of the state, mostly in Washington County with a small extension into the northeastern part of St. Francois County. Roughly, it embraces nine townships or about 200,000 acres and accounts for from 80 to 90 per cent. of the state production. The Central district, is in the central part of the state, includes most of Morgan and Miller counties, and parts of Camden; Benton, Moniteau and Cole counties. The area embraced is much larger than the Washington County district, but the deposits are more infrequent. The location and general area covered by the two districts is shown in Fig. 1. There is another small area in southern Franklin County but so far its production has been of small consequence. It might be considered as a northward extension of the Washington County field. An, area in the central part of Hickory County has also produced a small amount. The outline of the districts as shown indicates the general area in which deposits have been found. The total area covered by deposits of barite is only a small part of this, as, in the Central district especially, there may be miles of supposedly barren areas between ore-bearing areas of an acre or two in extent. The date when barite was first mined in Missouri cannot be definit stated, but the industry probably dates back to about 1860. The occurrence of barite was known long before this, as it was encountered in the lead mines in Washington County and mentioned by several earlier writers." Missouri is reported as producing 8000 tons in 1882 so it is evident the industry was well under way in the seventies in order to have arrived at this substantial production. By 1893 Missouri production had increased so that it ranked with that of Virginia, then the largest producer it increased until in 1914 Missouri accounted for about 65 per cent. of the total United States output.

Jan 1, 1929

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.   The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber.   With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.   This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By N. H. Mannakee

SINCE the publication of the paper of Mr. Scholz, The Effect of Humidity on Mine-Explosions,' I have undertaken a study of the meager available data of barometric and temperature conditions it times of mine-explosions, and have arranged these data in a manner which may be of interest to other students of mine-explosions. This study covers the period from 1898 to 1909, during which an ever-increasing percentage of collieries has been ventilated by fans giving air-currents of high efficiency. Previous to 1898 this percentage was smaller than at any time since. The vari¬ous States have become, from time to time, more exacting in their demands upon poorly-ventilated mines. This general im¬provement in ventilation throughout the Appalachian field has undoubtedly brought about a condition which is annually the cause; .or a very important attendant, of the high percentage of fatalities in mine-explosions, through the daily passage of from hundreds to thousands of gallons of water, invisibly suspended in the air, carried out of the mines by the ventilating-currents during the existence of certain temperature- and humidity-conditions. There is a wide-spread opinion that these conditions exist from November 1 to March 31; but it is more likely that they have a much wider range, which varies from year to year. Certain years show an increase or decrease of rain-fall from the mean ; the daily temperature may fall far below or rise far above the mean established by a record of a period of years; and the daily humidity varies likewise. If mine-explosions are influenced by a lack of moisture in the mines, certainly it may be expected that the influence will be felt at times when the

Nov 1, 1909

The "Line of Lade", a generic term by which the great Broken Hill orebodies are collectively known, lies in the County of Yancowinna, New South Wales (NSW) at the south eastern extrenity of the Barrier Ranges. As the township of Broken Hill grew to a city (incidentally it was officially named Willyama but by exerting an enterprising community independence which is still evident today it outplayed officialdom and retained its descriptive name), two major areas of population developed, Broken Hill and South Broken Hill. These two main civic divisions are respectively north west and south east of their dividing line, the surface expression of the orebody. See Fig. 1. The border between the States of NSW and South Australia (SA) is drawn along longitude 1410 East whilst the city of Broken hill's official longitude is 1410 28' 14" East which means it is only 50 km from this political boundary. A latitude of 310 57' 03" South contributes to the harsh climate of high summer temperatures which is not mollified by any significant increase in altitude for Broken Hill is only 300 m above sea level.

Jan 1, 1983

By R. M. Campoy

Mexico's mineral wealth has long been recognised and indeed has played a historically significant role on a world scale. The dynamics of the Mexican mineral industry have experienced a dramatic transformation especially over the last two decades. This transformation has mainly been instigated by the high growth rates and industrialisation of the Mexican economy since the 1960's. This paper focuses on the base metals sector of the industry which represents one of the major contributors to this transformation. The objective is to present a brief base metals review and to discuss some recent occurrences which pertain to this sector of the industry. This is followed by a discussion of mining's relevance in the current economic situation in Mexico. With this overview as background, the investment climate, primarily from a domestic investor's perspective and secondly in terms of foreign investment, is discussed. Finally, some recent government initiatives, including tax and accounting changes, are outlined. Any one of the sections of this paper can easily be developed into an extensive and indepth analysis; however, the intention of this paper is to provide the reader with a broad overview of the topics discussed.

Jan 1, 1985

An understanding of the origin of mineral deposits and their relationship to local and global geotectonics is essential if regional targets for mineral exploration are to be chosen. Volcanism, metamorphism and tectonism are especially significant for the origin and emplacement of mineral deposits, which, far from being fortuitous oddities of nature, occupy well defined positions within distinctive lithofacies. Thus, suggestions for mineral exploration targets can be made taking into consideration the position of 'fossil' convergent and divergent plate tectonic boundaries to indicate areas of specific types of mineralisation. To be borne in mind, though, that level of exposure, time and location of magma generation are all additional and important controlling factors. To further understand the importance of the above parameters, one must refer to the concept of paired metamorphic belts (Miyashiro 1973) which develop during an orognic cycle. These belts are generally constructed in such a way that an ophiolite type complex with metamorphic grades related to high pressure and moderate temperature regimes is flanked by an area of calc-alkaline volcanism and granitic activity with metamorphic grades within a region of high temperature and low pressure. The former situation is usually the seat of primary magmatic mineralisation, whereas the latter contains base metal. Deposits of acid plutonic and volcanic association. As will be seen later, this particular metamorphic-volcano-orogenic situation is well developed in some parts of New Zealand. For the present purpose a distribution of potential ores as related to plate tectonic processes is given below:a) Divergent plate boundaries: primary magmatic Ni-Cu, Pt,Cr, PeS2 and Cu, Pb,Zn in hot brines-hydrothermal environments Mn deposits.b) Convergent plate boundaries: stratabound Cu-Fb-Zn-Ag of felsic volcanogenic association. Porphyry eu-Au of island arc type, porphyry Cu-Mo of continental type. Cu, Au, Y, Sn, Hg, Sb of vein type and replacement lode related to granitic activity.c) Au of hydrothermal vein association, related to late dynamo-metamorphic events. By virtue of ocean floor spreading, regions of divergent plate boundaries are eventually juxtaposed or welded n to areas where plate collisions occur. This is then followed by partial melting due to various causes, just above the descending plate; thus creating a zone of acid to intermediate magmatism. The final picture is that of an orogenic zone with the paired metamorphic belts outlined above.

Jan 1, 1976

By R. A. Price

The base of the biozone of Olenellus is accepted as the most universally applicable criterion for defining the base of the Cambrian System. The use of this definitive criterion is restricted by important practical considerations. In the southeastern Canadian Cordillera this zone appears to truncate the basal ortho-quartzite of a west to east marine -transgression. This transgression began in Interior British Columbia in the Late Proterozoic and terminated in the region of the present Rockies in the Late Waucobian. Most of the material deposited by the transgressing sea originated in the eastern positive element 'Laurentia' and was transported over the intervening low Proterozoic-Windermere erosion surface. The configuration of the advancing shoreline and the distribution of the sediments were controlled by the tectonic activity of positive elements in northwestern Montana (Montania) and in the Fairmont Hot Springs-Radium area of British Columbia.

Jan 1, 1956

By PAUL H. SHAEFF

THIS paper is presented with the idea of discussing only the basic open-hearth charge. The importance of the charging operation in producing steel is more clearly understood by dividing the principal components into four groups and discussing each separately, thereby becoming acquainted with what constitutes a charge. The significance of these components in the charge itself will then be taken up. Classification of the charge components is as follows: steel scrap; pig iron ; limestone ; refractories and coke. Steel Scarp The first component, steel scrap, according to size, analysis and cleanliness, may be classified as heavy, medium and light. Heavy melting scrap includes crop ends such as are produced in blooming ingots or the heavy crops from bar mills abovely in. in diameter; railroad scrap, which comprises rails, side-plates, car-frames, draw- bars, etc.; and such automobile forgings as axles, crank- shafts, gears, etc. This class of scrap should give a four-box charging-car (box dimension 24 by 18 by 72 in.) an average load of 10,000 to 20,000 lb.

Jan 1, 1926

IN the decade beginning 1850, the development by William Kelly in I the U.S.A. and Henry Bessemer in England of the pneumatic method of refining pig iron, known as the Bessemer process, gave the world the first method of producing low-cost steel in large volumes. Briefly, the Bessemer process consists of blowing air through liquid blast furnace iron in a refractory-lined vessel known as a converter. The air enters the iron in the furnace bottom through tuyeres, and during its passage through the iron removes the carbon, manganese, and silicon by oxidation. The heat produced by oxidation is sufficient to raise the temperature of the liquid metal to normal steel casting temperatures and, in addition, to melt some scrap. In the 1860's, the open hearth process was introduced which in the early part of the twentieth century surpassed the Bessemer process in steel production. In the early 1870's, Thomas and Gilchrist discovered that phosphorus could also be removed if lime were added and the converter lined with basic refractory; the modification is known as the basic Bessemer process and is used in Europe. Bessemer steel usually contains between 0.010 and 0.020 per cent nitrogen and between 0.05 and 0.10 per cent phosphorus which influences the properties. Henry Bessemer,1 in 1856, recognized the possibility of using oxygen in the converter process, but the cost was prohibitive. This interest was associated with the theoretical balance of the Bessemer process. Experimental work' has indicated that bottom blowing with pure oxygen results in serious converter bottom and tuyere erosion. Dilution of the oxygen by steam has been observed to be an effective means of maintaining low-nitrogen content of the steel and at the same time reducing bottom and tuyere erosion. A further advantage is that the fume emission characteristic of Bessmer operation is reduced. The addition of steam to the oxygen, however, reduces scrap-melting capacity due to the endothermic reaction characteristics of steam. The possible advantages of refining methods for steel using high-purity oxygen have been recognized for over a hundred years, but the develop-

Jan 1, 1964