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By J E. (Boet) Coetzee

SAFEX International, as the name suggests, is a global organisation, which has the fundamental objective of improving the safety of operations concerned with the manufacture, storage, transport, and use of commercial and military explosives and pyrotechnic products throughout the world. It is a nonprofit making organisation of manufacturers of explosives from all parts of the world, founded in 1954 with the aim of exchanging experiences within the explosives industry. Every third year SAFEX organises a Congress during which members present papers on selected themes and discuss reports of significant incidents that occurred since the previous Congress. Admission is for SAFEX members only, thereby creating a safe environment for discussing problems “within the family”. The XV Congress will celebrate the Association’s 50th anniversary in Geneva where it was founded. An overview of the Congress indicates its structure and covers aspects such as the training event, technical seminars and the themes for the plenary sessions and associated workshops. The paper also highlights the special event for the chief executives of member companies and the review of incidents that occurred in the industry since the last Congress. The Congress concludes with a social programme for delegates and their partners on the last day.

Jan 1, 2005

By Jane Wright, Brent Blanchard

Question: When it comes to demolition projects, what could be more demanding than asking a blaster to explosively demolish a stubby, heavily-reinforced concrete structure in the heart of a third-world country? Answer: Asking them to fell only half. Such was the charge recently put forth to Controlled Demolition Group (CDG), Yorkshire, UK when they were called to Casablanca, Morocco to provide a stunning demolition effect for the upcoming Universal Pictures film Spy Game, starring Robert Redford and Brad Pitt. Director Tony Scott (True Romance, Enemy of the State) contacted the renowned demolition firm after seeing their work on television and receiving recommendations from explosives manufacturers. The film’s producers then asked the CDG team if they could bring down half of an apartment block as part of a dramatic suicide bomber sequence.

Jan 1, 2002

By Tam Tran

Over the last decade, halide (chloride, bromide and iodide) systems have been evaluated as alternative lixiviants for the processing of gold to replace cyanidation which has been widely used in commercial practice. This paper first reviews the development of processes promoted by Kaljas Ltd / Lachlan Resources (Australia) and Great Lakes Corp (USA) using different bromide/bromine systems in the early 1990's. Several research groups subsequently evaluated the use of iodide/iodine and chloride/chlorine for gold extraction, showing similar characteristics of gold/silver dissolution and recovery. A critique is :given on the advantages and the ,shortfalls of halide systems as alternative lixiviants. The stability of gold? halide complexes is discussed, based on practical experience and thermodynamic modelling of their speciation, The iodide system provides the most stable gold / silver complex for easier handling. However, the cost of iodide inhibits its application for are processing. In this critique, emphasis is given on the cheapest system, which involves the use of chloride for leaching (in conjunction with an appropriate oxidant). However the chloride-base leachant has a major drawback which is related to the unstable nature of gold chloride in a reducing environment.

Jan 1, 1998

By T. Egleston

The necessity of using a refractory material capable of much greater resistance to chemical action and having a far higher melting-point than those which contain silica, which melt and sweat off in the furnace even when not exposed to bases forming with silica more or less fusible compounds, has led to a careful practical study of all those materials which contain very refractory bases. The results of these researches, extending over several years, and made on a very large scale in many of the largest works in Europe, are of the highest interest, not only considered as a step in the progress of the study of the materials themselves, but in the application of refractory materials to metallurgical uses in general. The result of the experience of the last seven years with these basic materials, as in general with all such substanccs, is that natural products cannot be used as such. They are either too uncertain in their quality, contain substances which may in certain cases be very injurious, or, when in a condition in which they might be used, are so rare as to become practically unavailable for employment on a large scale. The materials that may he used are therefore not only limited in number. but they must be prepared artificially. When the use of basic artificial material is further extended, no doubt the number of these substances will not only be greatly increased, but the methods of preparation will be both perfected and cheapened to such an extent as to permit their application in processes for which they have hitherto proved too expensive. The quantity of refractory materials required for making ingots will he from 130 to 150 Ibs. per ton, or between 6 and 8 per cent. of the metal produced. In an establishment producing 2000 to 3000 tons of steel per week, considerable space is required to handle the basic materials properly. It is proposed in this paper to briefly discuss these basic materials and their application in the only two metallurgical processes where they have as yet been applied. These are the basic Bessemer and the basic open-hearth process, known as the Thomas-Gilchrist processes.

Jan 1, 1886

By F. W. Clark

At the present time, when lixiviation versus amalgamation is being so thoroughly discussed by practical men, and published information is so meagre, the following tests, made by students in the mining laboratory of the Massachusetts Institute of Technology, may be of interest to others. The ore experimented upon was obtained from the Sombrerete mines near Zacatecas, Mexico. A careful analysis of the dried sample resulted as follows : Per cent. SiO2,............62.79 S.............13.86 Al2O3............4.39 Fe,............11.26 Zn,............1.57 CaO.............2.91 MgO,........... 0.06 Cu,.............0.12 Pb,.............0.40 Sb and As,..........trace CO2,............2.35 Ag,.............0.16 99.87

Jan 1, 1886

By J. C. Bayles

Jan 1, 1886

By James Herbert Bartlett

The MANUFACTURE of Iron in the PROVINCE of Quebec. The St. Maurice Forges.—The deposits of iron-ore in the St. Maurice district, in the rear of Three Rivers, were probably known to the Indians and .Jesuits, but it is not till 1667 that any discovery is reported. The affairs of the colony were then in the control of the " West India Company," who amongst other monopolies had a right to all mines and minerals." Specimens of the iron-ore were examined in Quebec. in 1668 by the Sieur la Potardière, who reported unfavorably on them. In 1671, Louis de Buade, Comte de Frontenac, was appointed governor of La Nouvelle France ; and in the original manuscripts relating to his administration some allusion is occasionally found to the St. Maurice iron mines.? In a letter to the Imperial Government, dated 2d November, 1672, he says: "The iron mine of which I have already spoken is of great consequence. I have visited it myself, in order that I may be enabled to give a more accurate account of its nature. I am gratified to learn that another mine has been discovered in Champlain, which is much richer than the Cap de la Madelaine mine, and the ore is in greater

Jan 1, 1886

By Arthur V. Abbott

During the past four years I have had occasion to make quite extensive use of steel castings in the manufacture of testing-machines and large scales for Messrs. Fairbanks & Co. The failure of some of these' castings at stresses much below those which were claimed for them by the makers, induced me to institute a series of experiments to determine the actual constructive value of the steel castings now to be obtained in this country. The art of steel-casting is rapidly improving, almost every issue of the scientific press bringing accounts of some new development; consequently, the results of the following experiments are only exponents of the value of steel castings as at present made. In order to make the examination as thorough as possible, ten sets of patterns were made and forwarded to as many different firms in the country who advertised to make steel castings. The first part of the accompanying table gives a list of these manufactures, together with the price per pound. The order accompanying the patterns simply requested the manufacturer to supply two castings from each pattern of his ordinary product of steel. These castings were sent to me and paid for in the usual manner, so that it is probable that the samples fairly represent the quality of the average of steel castings, and are free from the suspicion of being "special runs." Two patterns were sent to each maker, one being a straight

Jan 1, 1886

By S. N. Titkov

Flotation of halite?new, recently begun to be developed method of processing water-soluble minerals. In the paper the results of studies of the new directions of the application of halite flotation are represented. Studies on the flotation separation of halite and sylvite in the salt solutions of different composition, showed the possibility of the halite flotation realization not only in the carnallite brine (content of salts: MgCl2 25.5% ~ 26.0 %, chlorides of potassium and sodium 5.5% ~ 6.0%), but in the sylvinite brine, which contains 10.5% ~ 10.8% KCl and 20.5% ~ 21% NaCl. On the basis obtained results are carried out experiences on the halite flotation from samples of the converted products of sylvinite ores by flotation method and by the method of the electrostatic separation. It is shown that in all cases it is possible to accomplish effective and selective recovery of halite. The halite recovery into the foam product of flotation makes 80% ~ 90% with an increase in the content of KCl in the cell product of flotation in comparison with a composition of flotation feed: - from the product after the electrostatic separation of ore ? from 76% KCl to 95% ~ 97% KCl; - from the small fraction of ore (- 0.25 + 0 mm) ? from 30% KCl to 60% ~ 64% KCl; - from middlings (intermediate products) of sylvite flotation from 16% ~ 31% KCl to 45% ~ 80% KCl. An increase in the molecular weight of alkylmorpholines increases the selectivity of the flotation separation of halite and sylvite. Halite recovery from small size fraction of ore or/and middling of sylvite flotation with the sub-sequent joint filtration halite product and tails of sylvite flotation allows to reduce considerably expenses for manufacture potash chloride from Pilot-industrial tests for the first time confirmed the possibility of the effective halite flotation in the saturated solutions of chlorides of potassium and sodium (sylvinite brine).

Jan 1, 2014

"The 33rd annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Tucson Starr Pass Resort & Spa on Saturday, Dec. 5, 2015. Each year, one living Hall of Fame inductee, two Medal of Merit recipients, several honorees from Mining’s Past, an Industry Partnership Award and a Special Citation are recognized for their respective contributions to the mining industry.Conrad E. Huss, cofounder of M3 Engineering & Technology Corp. located in Tucson, AZ, will be honored as the 2015 Hall of Fame Inductee and will serve as the keynote speaker at the awards banquet. Huss has served his company as chairman of the board for its entire 30 years and guided M3 to become a full discipline firm. Now M3 offers complete project execution through engineering, procurement and construction management procedure and has become a major engineer of large observatories around the world. The company now has more than 1,000 employees with offices in Arizona, North Carolina, Mexico, Argentina and is incorporated in Guatemala, Peru and Canada.The Medal of Merit will be awarded to Charles Michael (Mick) Lownds, founder of his eponymous consulting firm in Salt Lake City, UT, for his 42 years in commercial explosives following tenure at Sasol and at Orica. Originally from South Africa, Lownds immigrated to the United States in 1998 and has made significant advancement on electronic initiation systems. Lownds has published numerous technical papers, is an inventor with 12 awarded United States patents and was also the recipient of the President’s Award from the International Society of Explosives Engineers in 2000.Medal of Merit for young professionals will be awarded to Fiorella Giana, Freeport- McMoRan Inc.’s (FCX) mine manager at Bagdad. Born in Buenos Aires, Argentina, Giana left the small cattle farm where she was raised in 2001 to pursue higher education in the United States. For the past decade at FCX, as a result of her extraordinary combination of technical skill, leadership and commitment to excellence, she has been given positions of progressively greater responsibility from an entry level engineer to senior mine engineer, to chief engineer and now as mine manager, a position rarely held by woman."

Jan 1, 2015

By Nickol Estrada, Maylin Mendoza, Jean Bueno

El objetivo de este trabajo fue determinar mediante las campañas de sondajes de perforación diamantina un nuevo dominio litológico, que hemos denominado- “Volcanico mineralizado” que sea económico y rentable para la producción, este volcanico mineralizado tiene características físicas, químicas y mineralógicas distintas a las que ya conocíamos cuya inclusión en los procesos de extracción y recuperación de mineral, significo un gran reto para los profesionales de Cerro Lindo, para esto fue necesario combinar varias herramientas geológicas para su caracterización (litológica, mineralógica, alteración y estructural), la estimación de las reservas así como la aplicación de las mismas en la Geometalurgia, para superar los desafíos encontrados.

Sep 29, 2023

By H. A. Zollinger

The Hallmark Distribution Center is one of the most sophisticated material handling and order filling facilities in the world. The 53 million cubic foot facility houses an ultra-modern, computer- monitored distribution complex that handles as many as 1/4 million orders per day. The Distribution Center replaces 16 leased buildings scattered through- out metropolitan Kansas City and, in addition, re-leased 4 floors in mid-town Kansas City needed for creative and administrative expansion. This new facility is the nerve center for distribution of Hallmark products in United States and Latin America. The size and gross numbers of all parts of the system is a significant accomplishment, but the purpose of this paper is to explain the technical advancements in the state-of-the-art of material handling and controls. The system iteself is made up of seven sub-systems including receiving, warehousing, picking rack stocking, towline, order filling, order sorting, and shipping. Significant techniques were used in each of these areas as well as technical advancements in the state-of-the- art. The most significant points are in 4 of the areas and are discussed in this paper.

Jan 1, 1973

By A. M. Bell

"Hallnor mine is in the township of Whitney, Porcupine district. To date, its production of gold has been second largest in the east Porcupine field. Ore was discovered in the property in 1936 by diamond drilling in overburdened country. This drilling was undertaken by Noranda Mines following the discovery of ore in conglomerate at Pamour 1 mile to the east.Milling commenced at the Hallnor in June 1938, and to the end of 1945 432,000 oz. gold had been produced from 889,000 tons of ore, giving an average recovery of 0.49 oz. a ton.The West mine of Pamour, the Broulan orebody, and the veins on the Hallnor and Bonetal are all parts of a mile long vein system that has been separated into three sections by cross faulting. In consequence, they could well have been described in one paper. In treating them individually the viewpoint obtained from each may lead to conflicting opinions, and any conclusions advanced in this paper on the general structure should be modified by the conclusions advanced in papers on the neighbouring properties.GENERAL GEOLOGYRock FormationsThe Hallnor orebodies occur within 400 feet of the contact between lavas and sediments, and may lie in either lavas or sediments. The lavas near the ore consist of flows of pillowed andesite and one flow of more acid and less sheared and chloritized lava locally named trachyte. These flows strike east-west and dip steeply. At the surface on the east side of the property the volcanics have been intensely altered to a massive carbonate rock having a north-south thickness in excess of 1,000 feet . This carbonate body extends west across the property with a plunge of 45° (Fig. 1)."

Jan 1, 1954

By S. Terry, W. Callender, R. J. Cornelius

When a dry ball-mill grinding circuit was in- stalled at the pellet plant of Hamersley Iron Pty. Ltd., it was something of a pioneering venture, since this was one of the first instances where such a circuit had been applied to iron ore on a major scale. The Hamersley pellet plant is located in Dampier on the coast of Western Australia. The feed for it consists of -8mm fines produced as a screened product at the Mt. Tom Price mine 186 miles inland from Dampier. It was these fines that encouraged the choice of a dry grinding facility for the plant. At the outset, tests had shown that the fines could not be filtered satisfactorily with a wet grinding system. At the pelletizing plant, the fines are stockpiled, reclaimed, dry ground in ball mills, formed into pellets on balling discs, hardened on an indurating line, and stockpiled for shipment overseas. These operations are shown in Fig. 1.

Jan 7, 1969

By James M. Krese

The West Kentucky Division of Island Creek Coal Company, which is a wholly owned subsidiary of Occidental Petroleum Corporation, operates the new Hamilton Mine. It is located six miles West of Morganfield, Kentucky, in the Northwest section of Union County, adjacent to the Ohio River in Lock 50. On July 15, 1968, a unique new coal conveying system was put in operation. This system consists of eight conveyor units carrying coal from the bottom of the mine slope ultimately to barges on the Ohio River. It is over two miles in length and has a total of 3175 connected horsepower. The river loading conveyor is the longest 72" wide conveyor in operation in this country.

Jan 1, 1969

By J. B. Malcolm

The discovery of tungsten-bearing quartz outcroppings in Vance County, N. C., by the Hamme brothers in 1942, made international news in the mining industry and was, in fact, one of the major ore discoveries made in the U.S. during the last 25 years. Operations began at the Hamme mine in 1942, but after 16 years of successful operation, the mine was closed down in 1958 under adverse market conditions. By that time, it had produced nearly 20 million lbs of metallic tungsten. Because of the square-set timber mining method then in use, mine operating expenses were high, actually representing 78% of the total operating expenses at the property. In timber work alone, 160 men were employed. Approximately 500,000 bd ft of timber were placed monthly at a direct supply cost of $1.00 per ton of ore mined. Late in 1959, following a slightly improved position in the tungsten market, company management decided that, by changing the mining method, the operation could be economically feasible. The major premise in this decision was that a reduction of from 25 to 30% of the mining costs could be achieved by the conversion of the mining method from square-sets to horizontal cut and fill. Reopening of the mine began in February 1960, Full production has now been reached and overall mine productivity has been doubled.

Jan 1, 1962

By E. F. Klein, R. L. Eacret

Introduction In contrast to the general type of crushing mechanism in which the crushing surfaces alternately approach and withdraw from each other, described earlier in this section, and continuous-pressure break¬ers such as rolls and roller mills that will be described in a later chapter, impact crushers load by striking pieces of rock while in free fall and hurling them at high speed against stationary surfaces. Because the impact crusher depends for its effectiveness upon high velocity, wear is greater than in the slower-moving jaw and cone¬type wear parts, and for this reason its use is strictly limited to rela¬tively soft, friable, and sticky rocks that are characteristic of many nonmetallic mineral deposits. A few of these are phosphates, lime¬stone, barite, clay, asbestos rock, and coal. However, several examples of their use on soft lead-zinc and precious metal ores have been known. Although the use of impact crushers is expanding today into the range of ores containing as much as 15-18% silica, Taggart16 set the practical limit at 5%, and in the 1940s and 1950s several installa¬tions in the US and western Europe exceeded the limits of economical maintenance and were quickly superseded by the slower-moving, con¬ventional crushers. A rock that tends to be plastic or bouncy in a jaw or gyratory crusher when the force is applied slowly to reach ultimate strength, may become brittle with rapid loading and thus increase the effective¬ness of the applied forces. For this reason it is to be expected that as the quality of hammers, grates, plates, and cages improves with advances in steel technology, the use of high-speed crushers of this kind will increase. Terminology Modern usage differentiates between the impactor and the hammer mill, the former relying primarily on the impact of hammers (fixed or free-swinging) and secondarily upon pieces striking one another or steel surfaces; the hammer mill relies on both the centrifugal impact force of free-swinging hammers and the attrition and shear action between these hammers and well-placed grates suspended at the bot¬tom just below the hammer circle. The hammer mill, because of its grate discharge, restricts discharge of oversize rock to the grate open¬ing, while at the same time providing a trap for removal of tramp iron or other uncrushables. The impactor discharges free, so generally works with a screen to control product sizes. The question of terminology, impactor vs, hammer mill, creates difficulties because the similarities appear to outweigh the differences by far; if one were to list the similarities in order of importance and then the differences, he would be forced to conclude that they would best be dealt with as a single kind of crusher. Taggart16 gave it four names and added "as it is variously known," but it must be remembered that in 1945 the machine was nearly exclusively of the flailing-hammer type, while today the fixed-hammer rotor is also com¬mon. In this chapter the terms impactor and hammer mill will be used where they seem to apply. It is perhaps unfortunate that this terminology is being confused with rock breaking at the mine, usually with hand-held tools, e.g., the article "High-Energy Impact Rockbreaking" by Grantmyre and Hawkes, CIM Bulletin, August 1975. General Description Impact breakers, impact crushers, and hammer mills accomplish material breaking and reduction primarily through impact action of the material with fixed or free-swinging hammers revolving about a central rotor. The material to be crushed enters through an opening at the top or top side known as the "feed opening" or "hopper opening" and falls into the path of rotation (hammer circle) of the hammers. Initial breakage is accomplished in midair by collision of the dropping feed material with high-speed hammers. The second stage of breakage occurs when the pieces hit plates or breaker bars which line the crusher boxlike frame. Hammer mills rely further on a shearing and attrition action between free-swinging hammers and grid bars or grates at the crusher bottom which restrict discharge of oversize material until it is broken sufficiently to pass through the grid opening. The term hammer is used in reference to the piece which strikes the material, whether it is fixed on the rotor or free-swinging. It

Jan 1, 1985

By P. -E. Boileau, P. Marcotte, Y. Aldien, S. Rakheja

A number of biodynamic models of the hand-arm system have evolved on the basis of measured driving-point mechanical impedance (DPMI) responses to facilitate analyses of the coupled hand-tool system [1]. The parameter identifications in such models are based upon minimization of an error function of the model and the target impedance data, which may not yield a unique solution. Consequently, a number of model structures and parameter sets could be realized that would equally satisfy the target curve. Moreover, the vast majority of the reported models exhibit acute deficiencies due to excessive static deflections of model masses, presence of a low frequency mode and very light masses in the order of 1.2- 4.8 grams. The models also do not characterize the dependency of the biodynamic responses on many factors, namely the hand forces, hand-arm posture and vibration intensity. This study aims at development of a hand-arm biodynamic model with considerations of the hand forces, and both the DPMI and power absorption measures, to enhance the uniqueness of the model. Methods Two different model structures are chosen for identifying the model parameters on the basis of measured DPMI and absorbed power characteristics of the hand-arm system under zh-axis vibration over a range of hand-grip and push forces. Owing to the strong influence of the hand-handle coupling forces, the models were initially derived for fixed hand forces, namely 30 N grip and 50 N push forces, as suggested in the ISO 10068 standard [2]. The equations of motion for the model are formulated and solved to compute both the DPMI and absorbed power responses. A constrained minimization function comprising weighted errors of both the DPMI and absorbed power is formulated and solved to identify the parameters. Alternate functions corresponding to different combinations of hand forces are then applied to identify hand-force dependent model parameters. Variations in the model parameters are investigated as functions of the grip, push and coupling forces through linear regression analysis. Regression-based models are formulated for deriving the hand-handle forces dependent model parameters. The validity of the model is also examined under selected combinations of hand forces. [ ]

Jan 6, 2006

By Y. G. Li

The design and construction of the hand-dug caisson pier foundation of the Shenzhen International Trade Centre are described in the paper. In addition discussions and inquires about the load-bearing capacity of the hard bedrock are offered.

Jan 1, 2010

By W. J. Grose

The Embankment Place office development over the platforms of Charing Cross Railway Station in London has presented many interesting and unusual problems to the engineers involved with the project. The main structure is supported on widely-spaced columns which penetrate the station platforms and underlying vaults, calling for high capacity foundations built in severely restricted spaces. Hand-dug underreamed piles were chosen. Whilst a conventional design approach was taken to size the piles, a detailed appraisal of ground movements was made to explore the effects of the new building loads on the existing foundations, not only beyond the site perimeter but also those amongst the new foundations. Before construction of the pile proper could take place, it was necessary to sink a caisson through the upper unstable and water-bearing soils. This being identified as a high-risk item, a full-scale trial was carried out prior to embarking on the main works. The twenty-one hand-dug piles were 2.5m diameter, over 30m deep and belled out to between 4.5m and 6.6m.

Jan 1, 1989