Search Documents

Australia has a long history of underground mining. Even withadvances in open cut mining equipment, techniques andeconomics, many orebodies are still best mined by undergroundmeans. In addition, modern exploration tools are æuncoveringÆorebodies that are at increasing depths. South African mines arecurrently producing from below 3 km, and developing down to5 km depths û it is likely that Australian mines will also becomemuch deeper over the next 20 years. One of the most significanttechnical challenges in deep mines is the problem of heat.Community expectations and legislated standards continue todrive operations towards improving the working conditions inmines. The hazards and costs associated with chronic hotworking conditions (heat illness, poor safety, poor productivity,higher operating costs and poor morale) are also becomingincreasingly recognised (Brake, Donoghue and Bates, 1998). Theexposure of miners to many other occupational hazards has beenreduced over the past 50 years. However, despite air-conditionedcabins greatly reducing the heat stress on mobile plant operators,there are still many Australian mine workers subject to levels ofthermal stress that existed a century ago. There are severalreasons for this, including a frequently-poor understanding of thephysiology of working in heat by mine management, no agreedmining code of practice for working in heat, the lack of a robust,practical-sized instrument to measure heat stress, the costpressures on the industry and, to some extent, deep-seatedtraditional management and worker practices. Howeversignificant progress has been made in many of these areas (Brakeand Bates, in press), with the net result that there is likely to be a trend towards installation of refrigeration of some form in manyAustralian mines in the future. This will add directly to the costof operation, but will also have direct and indirect benefits,including cost benefits. It should also be noted that Australia isnot at the forefront of adopting practices to manage temperaturesin the workplace: South African metal mines usually haverefrigerated cooling, and Canadian mines spend large sums onheating, with heating costs (averaged over a full year) of up to$A1 per tonne mined (Bandopadhyay et al, 1997). The history of mine refrigeration dates back to 1919 when thefirst plant was installed at Morro Velho, Brazil. By 1965, the totalinstalled capacity (worldwide) reached about 100 MW(R)i. Since 1965 the growth in mine refrigeration capacity has beenexponential, with a doubling every six or seven years (Howes andNixon, 1997). South Africa is by far the largest user of minerefrigeration, with over 300 refrigeration machines installed. This paper discusses the key design issues associated with theapplication of refrigeration in underground metal or coal mines.Whilst the emphasis is on large, surface plants, small, surface orunderground refrigeration plants can also be very effective in thecorrect application and many of the principles of design andoperation are the same.

Jan 1, 2001

By Elders. Wilfred A.

Petrological and geochemical methods, the utility of which has long been established in the mining industry, are proving useful and cost-effective in elucidating the thermal evolution of active geothermal fields. In return, they yield insights into sulfide-silicate equilibria, mass and energy transfer in convecting hydrothermal systems, and the genesis of hydrothermal ore bodies. Within the Plio-Pleistocene sediments of the delta of the Colorado River, in the Salton Trough, several active geothermal systems are known. Temperatures vary from 100-365°C, at less than 2 km depth, and salinities vary from 3,000 to 280,000 ppm, total dissolved solids. The hydrothermal alteration causes marked induration of the sediments, producing greenschist facies metamorphic minerals, including hydrothermal ore minerals. Subsurface authigenic minerals show strong correlation with increasing temperature. A typical sequence in sandstones is (below 150°=C) montmoril-lonite-kaolinite, (above 180°C) chlorite + illite, (above 225°C) calc-alumino-silicates, (above 325°C) biotite. There is a transition from porosity-dominated\to fracture-dominated permeability in the hottest and deepest geothermal reservoirs. This regular series of minerals provides a practical tool during exploration drilling. From drill cuttings, we can make predictions on reservoir temperatures, useful in making decisions on well completion. Other types of geothermometry we have employed include light stable isotopes, fluid inclusions and vitrinite reflectance measurements. A combination of these techniques not only improves our temperature predictions, but together with fission tack annealing studies, permits us to model the dynamics of temperature change and fluid flow in these geothermal reservoirs.

Jan 1, 1981

By J K. Irwin

The authors discuss the application of drum and friction hoists under modern conditions and give four examples of friction hoists proposed for various applications. The paper concludes with a summary of the advantages and limitations of friction hoists relative to drum hoists. Introduction T H~ introduction of the multiple-rope friction hoist m the late 1940's has complicated the se-lection of the right hoist for a given job. Once such considerations as rope safety factor, drum to rope ratio, hoisting distance, tons per hour and/or service duty have been decided upon, the selection of a drum hoist is relatively simple. We now ask our-selves "which hoist -drum or friction? (See Figure 1 and Figure 2). When a friction hoist is a possibility we are immediately concerned with how many ropes to use, whether to hoist balanced or counter-balanced, whether a friction hoist will be flexible enough for the application and, of course, what the relative costs will be.

Jan 1, 1964

By Oliver Q. Leone

Three electrorefining cells were designed to investigate various factors associated with the electrorefining of reject - grade titanium sponge . Operation of the cells provided information on cell design as well as on how design and operating variables affected the quality of the titanium product . A sodium chloride - titanium chloride electrolyte was used , and the electrolyte chambers had capacities ranging from 400 to 3,500 pounds of molten salt . Major factors investigated were electrolyte composition , temperature and useful life , effect of various cathode shapes and materials of construction , methods for removing cathode deposits , effect of current density and cell potential , and the mechanics of deposit growth and crystal morphology . One of the cells was in intermittent operation over a 4 - year period and produced 2 tons of refined titanium . A product with a hardness of 80 or less Bhn (Brinell hardness number ) was consistently and easily obtained . Some metal with a hardness of less than 60 Bhn was produced . In one of the cells in which the electrolyte was held at operating temperature with an internal heater an ac input of 25 kw maintained 3,500 pounds of electrolyte at 850 ° C , but with an external heater 35 kw was required to maintain 400 pounds at 850° C.

Jan 1, 1964

By D. S. Burgess

An investigation of the hazard of spillage of liquefied natural gas (LNG) onto water is described. About 2,000 gallons of LNG were consumed in various tests. The initial vaporization rate of LNG following spillage was found to be 0.037 lb/ft2 sec; when the spill was confined, this vaporization rate was moderated after about 20 seconds by the growth of an ice layer on the water surface; when the spill was unconfined, a coherent ice floe was not observed and the vaporization rate was essentially time independent. The maximum diameter (in feet) of the spreading LNG pool was found to be given by 6.25 Wo 1/3, where Wo is the weight of LNG in pounds, Downwind of a natural gas source, time-averaged methane concentrations were given in good approximation by standard air pollution equations. However, peak concentrations were as much as twentyfold higher than average, adding an additional factor to the assessment of hazard. The effect of layering by the cold vaporized natural gas was similar to the effect of a temperature inversion on normal gases in the atmosphere. Small-scale explosions were observed on pouring LNG onto a water surface; no single explanation seems pertinent to all of the incidents observed.

Jan 1, 1970

By Hans E. Madeisky, Bruce W. Downing

Abstract-The acid rock drainage (ARD) buffering capacity of mine waste is governed by its bulk chemical composition and its mineral assemblage. Conventional acid base accounting (ABA) tests can be used to predict short-term buffering, but should be used with caution to model or predict the long-term ARD buffering capacity of mine waste. ABA data for mine waste samples from four different deposit types: anorthosite-hosted magmatic sulfide nickel, dunite-hosted magmatic sulfide nickel, porphyry copper-gold, and volcanic-hosted high sulfidation epithermal silver, were compared with whole-rock geochemical and petrographic data obtained from the same samples. Our objective was to devise and test a method of predicting ARD buffering capacity based on bulk chemistry and modal mineralogy. In other words, we developed a quantitative theoretical method for calculating neutralizing potential, relying on easily obtainable and relatively inexpensive whole-rock and sulfur XRF analyses, which could substitute for conventional ABA procedures in situations where these procedures are either too costly or too time consuming. For each deposit type, models were devised that reasonably approximate the net neutralization potential estimated by the ABA data obtained from laboratory tests. Once an appropriate model has been developed and tested, portable X-ray fluorescence equipment, already used for grade control at many mine sites, could provide the wholerock and sulfur analyses required to estimate the ARD potential of the waste material. Although this approach is not intended as a substitute for the legally mandated ABA test procedure, it could facilitate the timely and cost-effective management and mitigation of ARD at a mine site.

Jan 1, 1997

By E. Yan, M. Mankosa, E. Wasmund

"Rougher flotation in sulfide ore applications is typically performed using conventional flotation machines. The trend over the last 100 years has been for these cells to become larger in volume with cells reaching sizes of 600 m3 and in some cases even larger. The associated foundation loadings, transport and installation requirements along with building size have also increased. In an economic environment where projects must be executed with dwindling capital supply, bigger is not always better. More recently, industry is being challenged to identify new technology that allows for improved flowsheets and financial returns through efficiency gains. To meet this challenge, a novel high-intensity two-stage flotation system known as the StackCell™ was tested to potentially achieve installation volume and required retention time gains when compared to conventional flotation circuits. The results from on-site pilot scale work conducted on typical copper concentrator rougher flotation feed showed retention time gains on the order of 6 to 9 times when compared with conventional flotation equipment. This finding has the potential of reducing capital demands for rougher flotation circuit designs when incorporating the StackCell. The results from test work will be discussed in this paper showing comparative test data generated with a Denver bench batch test, pilot StackCell and large conventional cells, all receiving the same feed.INTRODUCTION Over the last few years, a number of flotation devices have been described as two-stage or multi-stage flotation units. The idea behind multi-stage flotation devices is that flotation performance can be improved by utilizing cells with multiple specialized units in series, but not all units of the same type, as is practiced in trains of multiple tank cells or columns. Instead, each unit is specially designed to provide the optimized fluid environment for each stage of the sequential flotation process. This idea has been proposed based on a study of the fundamentals of the flotation process, and the realization that the process consists of discrete sequential processes, that are each optimized with dissimilar process conditions (Finch et al, 1995), (Zhou, 1996). Instead of executing each step simultaneously in a homogeneous fluid environment, where the conditions would be a compromise between particle collection and froth recovery, the multi-stage flotation unit operates in a set of segregated process environments, each with a set of conditions optimized for that step."

Jan 1, 2018

By D. E. Sullivan

The Minerals Availability Program of the Bureau of Mines conducts cost evaluations of current and potential mineral operations in the United States and foreign countries. The International Mining Cost Indexation System (IMCI) allows data of different time periods within a country to be updated to a common base year for analytical purposes. The IMCI comprises 12 factor cost indexes and an exchange rate series for 96 market economy countries, denominated in both local and U.S. currency. The IMCI for each country contains 12 time series indexes that measure the average annual rate of change in the cost of factor inputs to the mining industry within that country. Mining industry factor cost indexes include wages, plant and equipment, construction and mining materials, power and transportation, and other measures considered to comprise the majority of capital and operating costs. Cost data or proxies are collected in local currency. Index series within each country are constructed separately and indexed on a 1975 base year. The local currency index is converted to a U.S.-dollar-based currency index using an exchange ratio.

Jan 1, 1987

By Riggin P. R.

"IntroductionIndustrial Relations combines two very important relationships - employee relations and union relations.Employee relations always come into play when people are hired to perform tasks. Because mineral processing plants cannot be operated successfully without people, at least not yet, if they ever will be, employee relations must exist in an operatingplant.If the employees choose to be represented by a union, then a relationship with the union as an institution also comes into play. It is very important to note that unionization does not mean that the employee relationship is replaced by a relationship with the union. The latter is superimposed on the former, but it does not replace it. Similarities and overlaps in the two relationships will be present, some of which are of fundamental importance. Nevertheless, they are two different relationships and the reader should bear this in mind when reviewing those parts of this chapter which discuss unionization, collective bargaining, collective agreements, and work stoppages.These two important relationships, which we have chosen to combine and call industrial relations, have crucial roles to play in the social system which interrelates people performing the necessary tasks involved in the operation and maintenance of a plant. The technological organization - equipment, process layout and so forth - and this social system are interdependent and complementary. This chapter attempts to show that the potential level of effectiveness of both the technological organization and the social system depends on the recognition and nurturing of this nexus between them.Occupational health and safety and training are subjects for another chapter. But, both of these have been critical and longstanding employee relations topics . They are destined to take on added importance in the future. As issues in collective bargaining, they are also attracting increasing attention in all union relations. It is hoped that the reader will not isolate from industrial relations those topics which are being dealt with in another chapter. They are very much a part of it and we cannot refrain from making some reference to them."

Jan 1, 1989

By B. M. Larsen

A discussion based on three commercial furnace tests and electrical analogue calculations is presented. It shows that while regenerator efficiency is mainly dependent on loading or relative amount of heat exchange surface plus the heat transfer coefficients as effected by flow velocity, the actual air preheat temperature can be high or low, largely independent of regenerator efficiency, mainly due to the diluting or unbalancing effects of cold air leakage into various parts of the furnace system. THERE are many signs of a renewal of interest in the heat regeneration aspect of the open hearth process, among them being the recent paper by Marsh,' the introduction of auxiliary checkers in the stacks of the Isley furnace design, and a number of recent installations of two-pass checkers in new and old furnaces. However, there are also signs of yielding to the usual temptation of oversimplifying a problem. Faced with the job of obtaining better draft on a furnace, for example, a good designer always recognizes that focusing attention on some one factor, such as height of the stack or capacity of the exhaust fan, does not make his problem any easier; rather he must look at the whole system, including such items as valve resistances, bends in the flues, and flow resistance in the waste heat boiler; then he must make his design in relation to the available draft so as to avoid any serious bottleneck in the system. Yet this example is really much simpler than the problem of air preheating, and again, the latter problem is not really made easier by concentrating on air temperature in uptakes and on the more obvious methods for making this air as hot as possible. Also to be considered are such things as the total amount of air needed theoretically for complete combustion at any selected fuel rate, together with that needed for oxygen absorbed into the bath and for burning the combustible gases given out from the bath, plus some excess air. Furthermore, how does this total air requirement relate to the regenerator efficiency at various loadings? How much of the total air equivalent in stack gases will come from preheated air passed through the whole length of the incoming regenerator and how much from air leakage into various zones of the whole furnace system? Does the effect of leakage air differ depending on whether it leaks into the ingoing regenerator, the furnace above floor level, the outgoing regenerator, or the stack zone? Over a number of years we have in this Laboratory experimented with methods for measuring hot gas temperatures; we have measured, approximately, the efficiency of a few regenerators on commercial furnaces and we have developed an electrical analogue' for calculations of regenerator efficiency. The whole problem is too complex to cover in one paper even with a more complete background of data than we possess, but we can attempt here to clarify certain aspects in a general way, hoping to assist specific plant studies on individual furnaces. Some of our earlier experience has been incorporated into chaps. 4, 19, 20, and 21 in the book "Basic Open Hearth Steelmaking,"" and on the assumption that this text is available to most readers, this discussion has been shortened by references to that book. The most recent design of a flowing-gas thermocouple which we are now using for measurement

Jan 1, 1955

By K Zunica, A R. Penney

The principles of three-dimensional geological modelling are well understood and routinely used. Sample data is collated and geostatistical tools used to ensure that sample data is suitable for its end use, which is typically a block model that is appropriate for mine planning. What has become increasingly apparent is that physical rock properties and geotechnical parameters need to be incorporated into the three-dimensional geological model to create an integrated mine model.The approach to the collection of geotechnical information is not as highly prescribed and controlled as collection of geological data. Commonly, the geotechnical data set is incomplete and inconsistent, with little consideration of what the end use will be by those collecting the data, or how the geotechnical data might relate to the geological data. In some cases, specific geotechnical investigation programs are completed, yet correlation between those programs and previously collected data is rarely undertaken to the same level of diligence as found in the geology field.There are some obstacles that need to be considered when attempting to incorporate geological parameters, such as grade, lithology, and geological domains with geotechnical information such as rock quality designation (RQD), rock mass rating (RMR), rock strength, and geotechnical domains into the same three-dimensional block model. Interpolation or geostatistical estimation methods used for grade estimates might not be appropriate for many components in rock characterisation, particularly search geometries. A number of examples are provided to illustrate issues underlying some of the data collection procedures, and their effects on three-dimensional geotechnical modelling.The example presented attempts to highlight generally observed shortcomings in the collection of geotechnical information, parameters which need to be considered when combining geological and geotechnical data into the same model, and the benefits of having a combined block model from the beginning of a project.CITATION:Zunica, K and Penney, A R, 2014. Integration of geological and geotechnical data for three-dimensional modelling, in Proceedings Ninth International Mining Geology Conference 2014 , pp 291–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Thomas V. Falkie

Of the various critics of federal energy and minerals policy we are hearing these days--and they are legion--few make their points more vividly than our fellow SME member and eloquent spokesman for the mineral industry. Mr. Eugene Guccione. In a moment of comparative mellowness. Mr. Guccione recently characterized Washington's time-honored legislative and bureaucratic machinery as a case of "...scientific illiterates asking the incompetents to do the unnecessary." I hope the prevailing industry view of government is not quite that harsh, and yet one cannot deny that government intervention is indeed pressing in on the mineral industry with increasing force. What is happening today in Washington and in state capitols will have enormous impact--both short and long term--on the future of coal and mineral production in the United States. Symptoms of this trend are everywhere. In the first place, there is a sentiment, widely held and still spreading, that the government must become involved-- that no matter what the problem, the solution lies in more government intervention. Free enterprise versus statist, reflex reaction organizations. When it cones to regulation in the resource field, there is too often a tendency to start out by assuming guilt on the part of the mineral industry. This can lead to laws governing mineral recovery that are more punitive than constructive...laws drawn up with little research into the scientific or economic considerations involved.

Jan 1, 1975

By Harold V. Pearce

(Chattanooga Meeting, October, 1908.) THE fire which occurred in the fall of 1906, at the works of the Boston & Colorado Smelting Co., Argo, Colo., destroyed entirely the gold- and silver-refinery of the plant; and in view of the development of modern practice in the refining of copper-mattes, etc., the management decided that it would be inadvisable to rebuild that part of the works for the continued use of the process which had been conducted therein for so many years as a metallurgical secret. This decision probably removes altogether from the sphere of practice the " Pearce " method for the separation of gold. At all events, it removes the business reasons which have prevented hitherto the publication of the principles involved. At the suggestion of Dr. Raymond, Secretary of the Institute, my father, Richard Pearce, the former manager of these works, has requested me to prepare a brief description of this process for the benefit of our members. Since I severed my connection with the Boston & Colorado Smelting Co. some time ago, I am indebted for some practical details to the present superintendent, Charles Rees, whose friendly assistance I would gratefully acknowledge. With regard to the history of the inception and development of this process by its inventor, Richard Pearce, I cannot do better than quote freely from his own notes and papers. HISTORY OF THE PEARCE PROCESS.' "In 1874 my entire time was directed to the improvements and additions to the plant at Black Hawk. The changes which I had made in the construction of the furnaces at Black Hawk proved so beneficial that I was requested to introduce the improvements at the branch works at Alma. These changes were carried out as speedily as possible, and proved of great advantage as compared with the old system. "The separation and refining of the gold from the matte now engaged my attention, and since previous experience in the treatment of gold-bearing matte and

Feb 1, 1909

By H. B. Miller

Contract Incentives have long been employed in the underground hardrock industry as a tool to influence employee performance, enhance productivity, and control labor costs. While traditionally structured to establish a direct correlation between performance and compensation, many contract programs have evolved into elaborate systems that promote strategies often viewed as independent of productivity. This paper presents the findings of research into these contract incentives and was conducted with the cooperation of 33 mines utilizing a spectrum of employee compensation and incentive programs. Emphasis of this analysis focuses on the types of production contracts observed and their role with respect to employee earnings.

Jan 1, 1994

After some 50 years of worldwide research in relation to coal pillar mechanics and design as well as numerous workshops and technical papers related to these issues there is still some significant disagreement as to the approach one should adopt in the assessment and design of a coal pillar. Of course there are many different types of coal pillars that fulfil a wide range of roles at any particular mine and in this instance it is appropriate to have a 'tailored' approach for each pillar type in relation to the role it fulfils. However where it can become very difficult for the mine operators is when various researchers or consultants use or recommend significantly different approaches for the same type of pillar fulfilling the same role. By 1999 two pillar design techniques had been developed specifically for the Australian underground coal mining industry (ie The University of New South Wales Pillar Design Procedure, UNSW PDP and Analysis of Longwall Tailgate Serviceability, ALTS) and several other pillar design techniques were being practiced by individual consultants. The Australian industry hoped to resolve the issue of what technique to use for each pillar type and role, when it funded UNSW in 2000 to develop a 'Systems Approach to Pillar Design'. The findings of the abovementioned project were published in 2005 and while every attempt was made by UNSW to include the views of various local and overseas researchers and consultants it would be fair to say that a unified approach to pillar design in Australia was not adopted as a result of that project. This is the experience of one country where there has never been one central group solely undertaking such research in relation to pillar design (such as the Chamber of Mines in South Africa). This paper explores the Australian experience in terms of pillar research and what that experience may offer to researchers in Australia and other countries. At the First Australasian Ground Control in Mining Conference (2003) the first 'update' of the ALTS Design Methodology (ie ALTS II) was presented. In subsequent years the ALTS database was continually updated and significantly expanded such that it now includes detailed information in relation to both the tailgate (148 cases) and maingate belt road (58 cases). In addition to tailgate roof support and chain pillar design, the current version of ALTS (referred to as ALTS 2009) includes a maingate belt road roof support design module. This paper is also intended to update and summarise the development and application of the ALTS Design Methodology for longwall gateroad design over the last decade both directly and in the context of coal pillar research conducted in Australia over the last 15 years.

Nov 25, 2010

By Jose Luis Lopez Mendez

In May 1992, MEXICANA DE CANANEA, S.A. DE C.V. finalized the life of its Reverberatory Furnace which lasted 16 years. This created the need to prepare the Smelter for the next campaign.

Jan 1, 1994

By Adrian Fleming

Adrian Fleming is Executive Vice President of Exploration for Golden Star Resources Ltd., Denver. Adrian is an Australian who graduated in 1973 with an honors degree in geology from Newcastle University, New South Wales. His extensive international experience has spanned exploration, project development, and operations for both large and small companies in Australasia, Southeast Asia, North and South America, and Africa. Adrian has been with the Golden Star group of companies for four years and he is responsible for all exploration activity. ABSTRACT Golden Star acquired the rights to the Omai prospect in 1985 at a time when the country of Guyana was out of favor with the exploration fraternity. Subsequently in the late 1980s and early 1990s, Golden Star acquired exploration properties in Suriname and French Guiana well ahead of its competitors. Golden Star's strategy entailed identifying windows of opportunity and aggressively pursuing them. We also recognized that the Guiana Shield hosted a significant area of highly prospective greenstones which were comparable in metallogenic potential to similar terrains in eastern Canada, western Australia and west Africa. The geological skills Golden Star developed and the exploration techniques employed to explore deeply weathered rocks are described. The paper highlights the key elements of Golden Star's strategy and illustrates how some of the milestones reached by the company led Golden Star to establish an enviable portfolio of gold and diamond properties in the Guiana Shield.

Jan 1, 1998

By Markus A. Reuter, Yongxiang Yang, James R. Post

The packed coke bed in the lower part of an iron making blast furnace, the dead man, dissolves slowly in a pool of hot metal, which is tapped regularly. The coke particles of the dead man not only exhibit a size distribution, but also their size distribution is non-uniform throughout the dead man and as a result, the porosity of the dead man is non-uniform. This causes the flow of hot metal through the dead man to be irregular and non-uniform, bringing about channelling in the coke bed. Channelling is detrimental to the refractory lining life of the hearth of a blast furnace. Using population balance modelling and a porosity model it is possible to keep track of the local changes in size distribution and bed porosity during dissolution of coke particles. Numerical simulations show that carbon dissolution from a packed coke bed (with particles which exhibit a size distribution) increases the average porosity, decreases the mean particle size and changes the size distribution to a distribution with a smaller size range. Influence of the type of initial size distribution (mean, variance) is investigated. The calculated changes in porosity are used to dynamically adapt the flow and the mass transfer (kinetics) during calculations. This approach provides the possibility to implement dynamic porosity calculations for CFD applications, and thus simulate the results of various coke types and particle size distributions on dissolution and flow behaviour.

Jan 1, 2003

By Marco Castenetto

Some of the most significant Danieli innovations in the field of long products are the: i) The EWR® system, through automatic continuous head-to-tail flash welding of billets at reheating furnace exit side, enables uninterrupted production of the mill for endless rolling of straight bars, wire rod and bar in coils. The process is particularly beneficial to wire rod and bar-in-coil mills as it enables production of “customized-size coils” (any coil weight according to specific Customer request) and with extra-high final coil weight, even starting from low-weight billets; ii) The Spooler process is based on twistfree winding of hot-rolled rebars into highly-compact/ultra-heavy coils featuring a unique cobble-free un-coiling capability. This enables high-speed feeding of the downstream cold-processing lines with hot-rolled spooled coils coming directly from the rolling mill without the need of any traditional off-line operation (such as de-coiling, stretching & re-winding). The system results highly beneficial both to bar-in-coil producers and to the downstream lines operators. The latest step forward is the combined application of these two systems that has made it possible for endless rolling of spooled bar in coils, enabling to cumulate the benefits of the two processes, particularly as far as transformation costs are concerned.

Aug 16, 2017

By W. R. Webb, M. O. Peterson

WHEN men drive haulage equipment ranging up to 22 tons in an open pit operation, they must live with the realization that their safety is dependent upon the machines they drive and how well they operate them. The hazards inherent in their jobs must be recognized, met, and defeated. It comprises a never ending struggle toward perfection-an almost un- obtainable goal. The Jones & Laughlin Benson Mines, at Adirondack State Park in New York, created a safety program which resulted in only one three day lost time accident from April 1948 to April 1952. At the very start of the program, management of the open-pit operation recognized the hazards existing at Benson. The program was designed to meet each danger. With a knowledge of the problem faced, the process of minimizing each facet was planned along lines of maintenance of equipment and training of personnel. Its success is evident. In the ever-present struggle, care and maintenance of machines and application of experience to new equipment design are mainstays. Truck Haulage Benson produced 2.9 million tons of crude iron ore and 1.6 million tons of waste in 1951. To do the job, truck mileage reached 500,000 miles. The tremendous mileage emphasized to safety planners, the fact that the more work done, the greater the possibility of risk in haulage operations. Instrumenting the aim of the safest equipment possible is a methodical servicing program. Like other segments of the drive, the servicing program is based on greater production with fewer accidents. Every truck is serviced at least once per eight-hr shift. Examination includes inspecting and tightening wheel studs, checking tires, steering apparatus, lights, brakes, wipers, heaters, fire extinguishers, and refueling. A running history of the equipment's operating life is kept in the form of service and maintenance records. Machine operators are constantly on the alert for malfunctioning of units. At the first sign of trouble the truck is returned to the garage for exchange. No truck functioning incorrectly is kept on the line, regardless of its shift check schedule. The program resulted in a reduction of the number of costly overhauls and cut down the number of haulage accidents. Miscellaneous Mobile Equipment Auxiliary units, operating within the pit, have presented definite safety problems. The highest accident rate in the pit occurred on trucks carrying water and bits to the churn mills. The weight and awkwardness of bits and drill stems, combined with remote delivery points were direct causes of numerous accidents. Here, the problem has been one of equipment handling, rather than haulage. All air compressors for secondary drilling are truck mounted, facilitating mobility. In addition to making it easier to move the equipment, truck mounting has eliminated many of the hazards connected with relocating machinery. By making air compressors independent of other units, drilling operations have been speeded up considerably. Unseen rocks in the path of moving vehicles are a constant source of tire damage. At Benson the problem has been met by supplying each loading crew with a bulldozer for cleanup operations. The pitman directs the dozer operation, and when truck drivers back into loading areas, he serves as an extra set of eyes. Modern Truck Garage Provides Drive-Through Service Simplicity is the essence of any preventative maintenance program. At Benson, a modern garage, with a drive-through service bay simplifies servicing. Shift inspection of the 22-ton haulage units is accomplished with minimum delay and maximum thoroughness. Major repair work and periodic overhauls are done in the repair section of the truck garage. Crane facilities for handling heavy assemblies ease the job and add to the safety factor. Other mobile machinery,

Jan 1, 1952