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By N. N. Malila, N. R. Shoko

The ever-increasing pressure on the profit margins of ferro-chrome producers and the gradual depletion of deposits of rich hard lumpy chrome ores calls for the ferrochrome industry to maximise the use of fine fractions of concentrates and friable chromite ores. Zimbabwe is endowed with huge deposits of refractory and friable ores that occur on and off the Great Dyke complex. The conventional metallurgical process of smelting of chromite ores in submerged arc furnaces is favoured by the use of refractory hard lumpy ores. The requirement to use all lumpy ore has been circumvented to a large extent at Zimbabwe Alloys. The use of briquetted chrome ore fines in the production of Ferrosilicon Chrome and High Carbon Ferrochrome has yielded positive results over a period in excess of twenty-five years. Of the three industrially used methods of agglomeration of chromite ores; sintering, pelletisation and briquetting, briquetting is preferred because the other two are associated with higher capital and operational cost. Zimbabwe Alloys has developed operational and technical expertise on the briquetting and utilisation of chromite ore fines and concentrates. Variations in the quality of available chromite ore fines imply that their amenability to briquetting is a dynamic problem. Appropriate briquetting parameters to guarantee quality briquettes are essential to the successful use of briquetted chromite ore fines. In developing a technology for briquetting of chromite ores, it is important not only to study the mineralogical and grain-size characteristics of the chromite ore fines but also to make an informed choice of the type and quantity of the binder and the conditions for producing a physically and chemically competent green and cured briquette. This paper discusses Zimbabwe Alloys' experience on the briquetting process and the advantages derived in the smelting of the briquetted chromite ore fines in comparison to the use of conventional lumpy chromite ore with respect to improvements in chromium recovery and as a consequence related efficiencies and unit cost of production.

Jan 1, 2004

By E. Swartzman

This paper presents a general re-view of the various methods of briquetting coals, with and without the aid of a binder, with special reference to the production of a suitable briquette from Nova Scotia 'fines' for re-blending with industrial coal. From the economic and technical viewpoints, either small stoker-sized briquettes made with about 4 per cent asphalt in standard low-pressure double-roll presses, or briquettes made without binder in high-pressure double-roll presses, appear to be the most reasonable solution at present.

Jan 1, 1959

By G. Ozbayoglu, Z. Ozdemir

Turkey is the main boron minerals producing country in the world. The most important boron minerals are tincal, colemanite and ulexite. All mining, beneficiation and handling operations generate fines which cause ecological and economical problems. Utilization of this accumulated material requires both upgrading and agglomeration. The aim of this research was to exploit the ulexite fines by improving their grade and size. Attrition-scrubbing followed by washing and screening was employed for upgrading the fines. It was found that the grade can be increased from 23-25% B2O3 to 29% B2O3 with 73% recovery. Briquetting was applied as the size enlargement process. During the briquetting, the effect of moisture content, pressure, amount and type of binder, and drying on the quality of briquettes were investigated. The tests showed the possibility of production of strong briquettes by adding water alone, but the briquettes had no resistance to abrasion and water. Binders, namely boric acid and borax have been added to improve the properties of briquettes. The results showed that the compressive strengths and abrasive resistances of briquettes obtained with both binders were acceptable. However, the briquettes have no water resistance properties.

Jan 1, 2004

By A Reschke

The Thiess John Holland Group is undertaking the design and construction of Brisbane’s Airport Link Project, the largest single investment in transportation infrastructure in Australian history. Twin Herrenknecht TBMs are being used to bore parallel road tunnels from Kalinga Part in Toombul through to Lutwyche, a distance of 2.45 km. At 12.48 m, these tunnel boring machines (TBM) are the largest diameter machines, outside of Japan, to incorporate annular two-component type grouting through the tailskins.Grout design, preparation and injection have been given particular attention in this project in order to push the boundaries of achievement. Laboratory testing was conducted on various mix designs to ensure the contract specifi cations for grout strength could be met. To study the mechanics of the grout injection process, Herrenknecht supplied a test rig which duplicates the grout injection systems on the TBMs. Multiple recipes were tested, carefully selected to balance the requirements of rapid strength development with high mobility (to completely fill the void between the segmental lining and the ground) and minimal bleed.Team Mixing Technologies, Canada, was selected as the grout plant provider based on the technical performance of their high shear colloidal mill mixers. Field results have shown that the colloidal mixer prepared grout gives almost double the strength of an identical grout prepared by a paddle mixer.

Mar 8, 2011

By I Coombes, M Trim, Y Sun, M McRae, A Spiegl, H Lagger, A Amon, P Barraclough, M Villeneuve

The Brisbane Airport Link Project (AirportlinkM7) includes the design and construction of more than 12.5 km of tunnels, with the Kedron interchange including four ramp tunnels that intersect with mainline tunnels and result in caverns with spans of up to 26 m. These caverns are in highly variable ground conditions with less than 35 m of cover underlying residential neighbourhoods and commercial properties. The Kedron caverns were constructed using the sequential excavation method (SEM). Owing to complex geometry and excavation sequence, the caverns were designed based on numerical modelling methods, including both two- and three-dimensional models. These numerical methods were used to develop a suite of support types with excavation sequences for the expected range of ground conditions. A combination of methods that included in-tunnel monitoring (convergence monitoring and extensometers), probe holes, endoscope probes, face mapping and ground settlement measurements were used to verify performance of the tunnel support systems and to select and refine the appropriate support system for each section of the caverns. The construction monitoring data indicated that numerical modelling can provide a good basis for predicting the performance of large-span underground openings in highly variable ground conditions. This paper presents a comparison of the performance of the caverns predicted by state-of-the-art numerical models and the actual measured performance.CITATION:McRae, M, Villeneuve, M, Trim, M, Sun, Y, Barraclough, P, Spiegl, A, Amon, A, Lagger, H and Coombes, I, 2014. Brisbane Airport Link Project – design and construction of the 26 m span Kedron Caverns: comparing monitoring data with the design, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 295–306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By G. R. MANSON

The Brisco Barite Mine lies 70 km south-southeast of Golden, British Columbia. Barile mineralization occurs in a northstriking brecciation zone within Ordovician-Silurian Beaver/ oot dolomites and quartzites. Brecciation was caused by faulting related to the Mount Forster-Steamboat Fault. The main barite vein occupies a fault zone and is up to 12 m wide and over 250 m long. It is light grey to white, fine grained and compact; BaSO4 content is 9/. 70 per cent. Production started in 1945 and has continued to the present. Barile originally was removed from an open pit; later, an adit, begun in 1957, reached more than 240 m along the vein, 15 m below the pit floor. Today ore is hoisted from a decline resting some 37 m below the pit floor.

Jan 1, 1984

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 D. J. Buchanan

British Coal's mining research programme is directed towards the strategic objectives of reducing production costs, improving product quality and resolving health, safety and environmental issues. The strategy for R&D is described and selected parts of the programme are reviewed. Two major initiatives are directed towards reducing production costs: geotechnics and automation. Integrated exploration techniques are used to delineate geological structures as an aid to mine planning. Rockbolting is being rapidly introduced and the in situ stress field has been found to be of significant influence. Automation is the subject of a major programme. A strategy for coal quality has been devised. The health, safety and environmental programme concentrates on the traditional hazards together with surface environmental problems.

Jan 12, 1992

By R. V. Wheeler

A MATTER of much concern at present to the coal-mining industry of-Great Britain is the effect of the working of the Coal Mines Act, 1930. This Act, which received the Royal Assent on Aug. 1, 1930, contains five parts: (I) production, supply and sale of coal; (II) the reorganization of the coal-mining industry; (III) hours of work; (IV) the Coal Mines National Industrial Board; (V) general. The first three parts are of major interest and discussion can be confined to them.

Jan 1, 1931

What is the BC AMTA? ?What is an ASEP? ?Who are the partners? ?Critical Success Factors ?Questions/Answers Aboriginal Skills and Employment Program (ASEP) ?A collaborative partnership of industry, employers, post secondary, First Nations and government ?Working together to plan and implement training and education programs ?Demand-driven: targeted JOBS for participants

May 1, 2010

PRESENTATION PURPOSE ? Provide an overview of BC?s Environmental Assessment Actand environmental assessment process ? Identify key issues influencing environmental assessments in BC ENVIRONMENTAL ASSESSMENT ACT ? Major project proposals require an EA before a project can proceed ? Considers potential effects of proposed projects and ways to minimize or avoid adverse effects Minister of Environment and the Minister designated as responsible for project category decide whether or not to certify a project or order further assessment

May 1, 2006

By A. M. Richmond

Introduction The apparent commonplace, and prosaic, nature of building-stones, lime, cement, gypsum, and clay products, and many other miscellaneous non-metallic minerals, such as abrasives, barite, diatomite, magnesite, mica, slate, salts, etc., and their everyday appearance and necessary in our lives, has removed much of the glamour, romance, and speculative attractiveness so frequently associated with our gold, silver, lead, zinc, and copper mining ventures. However, it will be readily appreciated, with but a brief study of the thirty-five or more non-metallic minerals and products which are mined, prepared, or are known to occur, in British Columbia, that the 'industrial minerals' industry in the Province has an abundance of interesting technical problems, is fraught with speculative possibilities, and, as such, fully deserves much more technical attention than it has hitherro received. The brief notes presented in this paper show, in summary form, the magnitude of the British Columbia industrial and non-metallic mineral industry; outline in synoptically form the principal deposits of non-metallic minerals presently known; and indicate in a general way a few of the possibilities which exist in the Province for the expansion of the industry. For convenience in presentation, the assembled material has been divided into four sections: 1.-Sraristical information 2.-Strucrural non-metallic minerals 3.-Miscellaneous non-metallic minerals 4.-Non-Metallic mineral possibilities in British Columbia 1. -Statistical Information The writer does not propose to dwell at length on the statistical comparisons and deductions which may be drawn from the four tables which have been compiled for this section of the paper, nor is it considered essential, as the figures present a most emphatic story in themselves.

Jan 1, 1935

By George W. Harris

In the earlier period of anthracite-mining, much coal was wasted, both underground and in the culm-banks on the surface. Such waste is common in the development of new mining-districts, in which, as a rule, only the richest material can be profitably treated. In the anthracite-region, special causes operated to increase this evil. The mines were generally worked under 20-year leases, and royalties were paid upon such coal only as was actually marketed. The lessees consequently cared for immediate profit solely. They were not bound to win all the coal they exposed, or to leave it in such condition that their successors could win it. Nor was it their interest or duty to educate consumers in the use of their product. The market called for coal of large sizes; and such coal they furnished, throwing away the rest. Any pains taken by them to bring about a more rational use of coal by their consumers would have borne fruit, after their leases had expired, to the benefit of somebody else. A full statement of the situation was given in 1893, in the report of the State Commission, appointed in 1889 to investigate the subject.' That body included the names of Heber S. Thompson, William Griffith and the late Eckley B. Coxe.2 Its report gives special attention to the utilization of the old culm-banks.

Jan 1, 1906

By Thomas Leonard Watson

Jan 1, 1906

By G. R. Heffernan

"IntroductionTHE PURPOSE of this paper is to give a •brief history of iron and steel in British Columbia, a quick look at the present operations of Western Canada Steel, Limited, a review of iron ore resources and iron and steel markets, and a projection of what the future might hold for the industry in British Columbia.From the Past to the PresentWhile the paper is entitled Past, Present, and Future, in covering the past, which we shall call the time prior to 1947, there is very little to be said. Small shipments of iron ore were made from the Texada deposits by the Puget Sound Iron Company from 1886 to 1907. Total ore shipped did not exceed 70,000 tons. Part of this is believed to have been used in building a United States battleship in 1907 in the Bremerton Naval Yards in Seattle, Washington.In 1914 a small steel mill was started on Lulu island, rolling bars from •box piles and used shafting. This mill operated spasmodically for a few years but finally burned down in 1921. The rolling mill stands were sold to China and are no doubt in operation in China today.In 1916 the City of Port Moody assisted in the financing of a mill which operated on re-roll rails, box piles, and steel ingots made in an experimental electric furnace in Port Moody. This furnace also produced small quantities of pig iron scrap. The backers of the Port Moody mill showed a great deal of enterprise and must have been a very forward looking group, since this was one of the first recorded applications of the electric furnace to small ingot production. Despite their enterprise, the operation was unsuccessful and terminated in 1921."

Jan 1, 1953

By E. C. Harder

BRITISH Guiana, Great Britain's only South American colony, may be reached by very comfortable steamers, both from North America and Europe. The trip from North American Atlantic ports requires about 12 to 14 days; that from Europe about 18 to 20 days. A number of steamship lines, including Canadian, American, and Dutch, have regular sailings between North America and British Guiana, with calls en route at various interesting ports in the West Indies and northern South America. Moreover, several lines, including British, German, and French, have steamships operating regularly between Europe and the West Indies. Indeed, so popular have the West Indian voyages become in recent years that, during the winter months, special cruises in considerable number are organized for many vessels that ply in the trans-Atlantic service in the summer. A trip to British Guiana, therefore, has become a delightful experience. After visits at the various attractive Leeward and Windward islands and Trinidad, the approach to the low, flat, British Guiana coast, with its muddy coastal waters extending for many miles offshore, is somewhat of a contrast. Arrival in Guiana waters is signalled by the appearance of the modern high-power Demerara Light, located "on a shoal about twelve miles from the mouth of Demerara river. From this point, if the tide is right, a pilot takes the steamer across the bar, eight to ten miles offshore, and into Georgetown harbour. At high tide, the water above the bar ranges from 15 to 18 feet in depth, depending on whether it is neap tide or spring tide; at low tide, the corresponding depths are 9 to 11 feet. As the bar is of soft mud, however, it is usually possible for vessels to pass over it with a draught of about two feet in excess of that indicated by the tide tables. Upon nearing the shore, one sees first the Georgetown wireless towers, then the light-house and the tall chimneys of sugar mills and of various factories in Georgetown, and finally the palms and other tropical trees and the houses of Georgetown itself along the sea shore and the east bank of Demerara river. Extensive wharves operated by various exporting and importing companies stretch along the river bank and activity prevails in Georgetown harbour. The principal exports are sugar, rice, gold, diamonds, bauxite, balata, lumber, fruit and other tropical products. The imports are food-stuffs, wearing apparel, and manufactured materials of many kinds.

Jan 1, 1936

By Lloyd Emory

THE region known as. Guyana or Guiana stretches along the north coast of South America from the mouth of the Orinoco River in Venezuela to the mouth of the Amazon River in Brazil. Politically, it is divided into British, Dutch, and French Guiana, extend¬ ing into Venezuela on the north and into Brazil on the south. Because the area is within the sweep of the northeast trade winds and of approximately the same latitude, plant' and animal life are fairly uniform throughout. The geology is very similar as far as the northern coast is concerned. The drainage is taken care of by a number of large rivers that flow northward directly into the sea. The Courantyne River, which roughly divides the area into half, is the eastern boundary of British Guiana.1 The lower reaches of this river are also the center axis of an ancient bay that at one time indented the coast-line at this point. The old shore-line and, in fact, successive shore-lines can be traced from near the present coast-line in, the northwest district of British-Guiana, south-east and inland, crossing the Essequibo River near Dahli, the Demerara near Christianburg, the Berbice at the mouth of the Kuruduni River and the Courantyne at Vaka-Kuyaha Falls. The line then swings around to the northeast and again approaches the coast near St. Lau-rent in French Guiana. This article will be confined to British Guiana and largely to the valley of the Demerara River, but for geographic names .and topographic details it might, however, apply to Dutch Guiana as well. British Guiana, which comprises about 90,000 sq. mi. and is as large as England, Scotland, and Wales combined, may be divided into three belts, the alluvial belt or coastal plain, the foot-hill area (often spoken of as the sand clay belt), and the hinterland.

Jan 1, 1928

By J. C. Jaeger

The study of brittle fracture of rocks has been a much neglected subject until quite recently and now is in a state of transition and rapid development. Historically, three methods of testing were used by engineers: uniaxial tension, bending, and, by far the most common, uniaxial compression of cubes. This latter was probably adequate for engineering requirements, but from the last century onwards there has been a demand from geologists for a study of the properties of materials under conditions comparable with those at depth in the earth's crust. King1 remarked that "in engineering practice a cube of the material is put into a testing machine and the stress required to crush the cube is measured. This gives the limiting stress difference for the material so long as the boundary conditions are similar to those existing during the test . . . this may by no means be the case when the boundary conditions are very different from those existing in the test, for instance, in the case of rupture in the neighbourhood of a cavity. . . ." Despite this very clear statement of principle, many writers until recently (e.g. Jeffreys2 used the uniaxial compressive strength as a measure of the 'strength' of rock. In the last century (Becker 3, it was both conjectured and, for some rocks, known qualitatively, that plastic deformation could occur under confining pres- sure; the demand from geologists has been for the study of flow rather than fracture of rocks.. From the time of von Karman (1911) and Böker5 (1915) onwards, apparatus has been built which could provide confining pressures sufficient to make some rocks plastic. Many experiments tended to be made on rocks such as marble, which readily become plastic, and the general tendency was to make relatively few experiments in the brittle range. This is particularly true of many experiments on combined stresses. As a result of this, there is not sufficient data to provide adequate information

Jan 1, 1967

By H. G. Denkhaus

Comment on ?The evaluation of rock brittleness concept on rotary blast hole drills? in the Journal of SAIMM, vol 102. no. 1. pp. 61?66 Comment on ?Correlation of specific energy with rock brittleness concepts on rock cutting? in the Journal of SAIMM, vol 103. no. 3. pp. 163?171by R. Altindag Foreword Some thirty years ago it was almost customary that articles in South African technical and scientific journals were followed up by discussions in which the reader(s) expressed criticism and/or added to the information contained in the article. This custom has obviously died out, be it that the articles are nowadays of such a high standard that nothing can be added or be it that the receivers of the Journal suffer from an information inflation and do not read the articles anymore. I now have the temerity to offer a discussion to an article that recently appeared in the journal, namely ?The evaluation of rock brittleness concept on rotary blast hole drills? by R. Altindag (J.S. Afr. Inst. Min. Metall., vol, 102(2002), pp. 61?66.

Jan 1, 2003

By C. L. Dake

AN insistent and steadily growing demand is evident for the broadening of undergraduate curricula in engineering. Among suggested additions are training in public speaking, report writing, business law and contracts, accounting, finance, money and banking, scientific management, economics, social and labor problems, psychology, and ethics. The demand for these subjects comes from the older engineers and from the industries that employ our graduates. Of course, many of the men who suggest such changes are influenced largely by their personal needs and contacts, but the demand is sufficiently widespread to merit serious study by educators. In fact, many educators themselves concur in the proposals for broader training. These matters were examined intensively a few years ago in an exhaustive study of engineering education. Opinion at that time was rather strongly against any profound change. Since then, however, the whole economic system has undergone violent disruption. Even if recommendations made a few years ago were appropriate to the conditions then- obtaining, the enormously changed conditions of the present make advisable a further careful study of this problem. In recent years, mergers, to reduce costs, have sharply limited the number of engineers employed and have thereby intensified the struggle to secure positions. In this stiffer competition, engineers with the most adequate training undoubtedly fare the best.

Jan 1, 1934