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By A. M. Hearn, J. G. Roos

Energy consumption, being a large proportion of the input of the ferroalloy production process, can be measured in terms of the efficiency with which the energy is utilized and the effectiveness with which it is used. The efficiency of the usage of energy revolves around the specific consumption of the energy for the production of the alloy, which encompasses the thermodynamic aspects of the process and is more of a metallurgical function that will not be addressed further in this paper. The effectiveness with which the energy is utilized is determined by the optimisation of the electricity supply from the utility (in this case Eskom). The South African electricity supply industry is on the brink of considerable restructuring, implying changes in ownership, structure and regulation. In other countries, however, restructuring has often seen higher prices. Owing to the diversity of growth prospects in South African markets, Eskom is turning to new market management and generation strategies. In future, Eskom will develop pricing strategies to increase demand from attractive customer segments such as paper & pulp, iron & steel, aluminium, and other metallurgical industries. There will be a broader spectrum of product offerings, including dynamic pricing options and demand-side management incentives. In a future electricity market that will become more dynamic and demanding, it will become increasingly important for electricity consumers to optimise their electricity supply. There are many facets in optimising the electricity supply, which include optimal utilisation of the tariff, integrating energy cost management into the production planning process, implementation of demand-side management actions, modelling, scenario planning (.what-ifs?.), optimisation, maintenance scheduling coordinated with the tariff periods, etc. This paper gives consideration to the status of the development of technology at the manganese alloy works of Samancor at Meyerton, South Africa in order to increase the effectiveness with which energy is utilized.

Jan 1, 2004

By W. H. Schiffbauer

NIOSH has developed an active proximity warning system called HASARD (Hazardous Area Signaling and Ranging Device) for warning workers as they approach known dangerous areas around heavy mining equipment and other dangerous work zones. HASARD is composed of a transmitter and a receiver. The transmitter generates a 60-kHz magnetic field using one or more wire loop antennas. Each antenna is adjusted to establish a magnetic field pattern for each hazardous area. The receiver, worn by the worker, is a magnetic field strength meter. The received signal is compared against preset levels which are calibrated to identify levels of danger. The receiver outputs can include visual, audible, and vibratory indicators and it can also be made to disable machine functions. HASARD was field tested on a Joy 12 continuous miner, a Komatsu 210 M Haulpak, and on a highwall launch vehicle. Slight modifications were made for each application. HASARD provided warnings as designed and proved to be rugged enough to withstand the harshest of production environments.

Jan 1, 2001

By J. K. Whyatt, W. P. Blake, T. J. Williams

A study at the Idaho mine revealed that, despite the apparent randomness of seismic events, common characteristics defined five recurring types. These characteristics included the geological structure that slipped, the first-motion pattern and the location and intensity of damage. Many large events caused little or no damage, and where it did occur it was concentrated at intersections between slipping structures and mine openings. Of 39 events between 1989 and 1994 with local magnitudes of 2.5 or more, 10 were caused by slip on bedding planes in the southern limb of the mine, 6 occurred near the vein along a set of near-vertical faults that form the central shear zone, 8 were strike-slip events on the Southern Control Fault, 4 were by slip on the vein itself and 10 involved strike-slip and/or dip-slip movement along the North Control Fault. Strategies for control of mining-induced seismicity need to consider all five types of event, lest a strategy to reduce one type increases others

Jun 19, 1905

By Kennedy G. L

Experience is reporled in the operation of the pilot Lurgi carbonization plant at Morwell, afler it had been reconstructed to obtain better control of the heating of the briquettes in order to produce a strong char suitable for use as a metallurgical fuel. The theoretical Ideal Heating Cycle, which had been designed from earlier laboratory research, was closely approached in the carbonizer, and up to 97 per cent of the whole dried briquettes entering the carbonizer were recovered unbroken in the char.The strength of the char produced in the pilot plant was limited by the performance of the drier where the cracking and breakage of the briquettes was more severe. Theoretical studies have indicated that this limitation could be removed by using a hot briquette feed to the pilot plant. Experience indicates that with a hot briquette feed to the drier and with ideal heating in the carbonizer, hard char could be produced from Yallourn briquettes in continuous operation.The project has been terminated for economic reasons...

Jan 1, 1966

Fast Adsorption Phenomena at Air/Liquid Interfaces

Sep 13, 2010

By John F. MacDonald

This paper describes the driving of a 400 m long by 25 m diameter highway tunnel through sensitive, overconsolidated silts and clays. The design concept requires the construction of the permanent support system, consisting of 24 concrete filled perimeter drifts, before excavating the mass core. General construction procedures used during the construction of the perimeter drifts are described.

Jan 1, 1985

By John Gamble

This paper summarizes the weight of epidemiological evidence to evaluate the hypothesis that asbestos exposure is causally associated with increased risk of gastrointestinal (GI) cancers as suggested by Selikoff in an early study of insulation workers. This review looks at populations that develop GI cancers, namely stomach, colorectal, colon and rectal. Guidelines for assessing causality are strength of association, biological gradient and consistency of the associations. Exposure?response (E?R) was evaluated using three methods to estimate exposure. Rate Ratios (RRs) for lung cancer and percent of mesothelioma are used as surrogate measures of asbestos exposure for all the cohorts of exposed workers. Quantitative or semi-quantitative estimates of cumulative exposure to asbestos were also used to assess E?R trends and were compared to E?R trends for lung cancer and mesothelioma in individual studies. Surrogate measures are important since there are few individual studies that have assessed E?R. None of the various methods to estimate asbestos exposure yielded consistent E?R trends and the strength of the associations were consistently weak or non-existent for the four types of GI cancers. The epidemiological evidence detracts from the hypothesis that occupational asbestos exposure increases the risk of stomach, colorectal, colon, and rectal cancer. Findings are briefly summarized below. © 2007 Elsevier Inc. All rights reserved. Keywords: Asbestos; Colon cancer; Colorectal cancer; Gastrointestinal cancers; Ingestion; Lung cancer; Mesothelioma; Rectal cancer; Review; Stomach cancer

Jan 1, 2007

By José Vidalón

Dado que las lagunas de Papacocha y la Virreyna sufren los efectos de los drenajes ácidos de minas abandonadas, relaves y desmontes depositados en sus áreas de influencia, se ha previsto el control de los mismos. En este sentido, el presente texto evalúa los pasivos y propone soluciones dirigidas al control del drenaje ácido contaminado con metales disueltos, priorizando los métodos que no requieren la construcción y operación de una planta ni supervisión permanente.

Sep 13, 2001

By R. K. Dunham, D. J. Reddish, X. L. Yao

Paper presented at the conference: Risk assessment in the extractive industries, held in Exeter, UK, 23-24 March 1994, and first published London: IMM, 1994, preprint volume, 10pp., 10 refs. The integrated approach combines a powerful ground movement prediction program with a knowledge-based expert system. ESDAS (Expert Structural Damage Assessment System) was developed to evaluate mining subsidence damage in the form of risk and in terms of the three vital contributing components (mining factors, site factors and structural factors). Using a certainty factor risk assessment technique, the system can be used to predict the likely damage to a particular structure subjected to mining subsidence. A previously developed powerful ground movement prediction program, SWIFT (Subsidence With Influence Function Techniques), has been combined with the expert system to allow the mining factor to be more accurately determined in a broader range of mining layout. Since SWIFT can be calibrated to any particular coal field using local subsidence data, it is believed that the integrated system could be used in any coal field worldwide for the assessment and control of mining subsidence damage risks

Dec 1, 1995

By W. J. Kroll

This investigation was undertaken with the idea of studying a number of unconventional methods for making chromium to determine whether production cost could be lowered and to discuss some of the more recently described processes. These comprise carbon reduction of the oxide in vacuum, nitride dissociation, fusion electrolysis of the chloride, amalgam method, iodide dissociation, calcium reduction of the oxide, hydrogen reduction of the chloride, and reduction of this compound with zinc and with magnesium. Preference is given this latter method, which is shown in a flow sheet. Special attention is given purification of the chloride and separation of the vacuum at about 900° C. A reduction method for the elimination of traces of oxide contained in pure chromium by pure hydrogen obtained from the dissociation of zirconium hydride is described. The various methods are compared in a table in the appendix. Aluminothermic and silicothermic methods for the reduction of chromium oxide and the aqueous electrolysis have been disregarded in this investigation.

Jan 1, 1950

By Eric M. Klein

As part of the Woodrow Wilson Replacement Bridge project several damaged wetland and environmental areas were to be mitigated. One of the mitigation projects consisted of constructing a Denil fish ladder around Peirce Mill Dam in Rock Creek National Park, Washington, D.C. The dam is a historic structure operated by the National Park Service. The fish ladder is located between the east abutment of the dam and Beach Drive, a major collector road. Construction of the fish ladder required removal of a portion of the east abutment and an excavation that extended about 22-ft below the pavement of Beach Ave. It was not possible to close Beach Drive except for very brief intervals or at night; therefore, a support of excavation system that would minimize disruption to the public was required. The high groundwater required that the groundwater be cut off prior to excavation; the random rubble and soil fill, and shallow but erratic rock surface precluded driving sheet piling. A jet grout system was selected because the grout probe could penetrate the rubble fill, stabilize a variety of soil conditions, and cut off the ground water prior to excavation. It was not possible to construct a stable wall without tiebacks or soil nails. Given the schedule and tight working conditions it was decided that soil nails through the jet grout wall facing would be the most cost effective method, as it did not reduce the working space as rakers would and would be more cost effective than prestressed tiebacks.

Jan 1, 2006

By J. J. Bouillon

"Located in the northwestern portion of the Abitibi greenstone belt, Les Mines Selbaie is a copper-zinc (silver and gold) producer. Felsic tuffs host three are zones. Composed of sulphide veins and breccias, they are not exhalative massive sulphide deposits, except, probably, for the massive pyrite (fragments and lenses) localized close to the top of the volcanic sequence.The total of all (mineable and mined) ore in the three zones presently outlined on the property, is of the order of 29.9 x 106 tonnes with average grade of 0.63 g/t Au, 37.02 g/t Ag, 1.21% Cu, 1.91% Zn.The ore reserve calculations and the daily production procedures are computerized to various degrees. The data handling process is highly computerized.Various geophysical methods are, and have in the past, been successfully used on the property. The ""mise-à-la-masse"" surveys were used to perform the geological interpretation of an underground deposit (A-2 zone). Presently the PULSE-EM surveys are performed in all surface and underground exploration drill holes."

Jan 1, 1990

By McKinnon R. L

Laboratory and field work on the use of wetting agents for suppression of colliery dust is described. Although the results were inconclusive they were not discouraging and further investigation is required. The use of certain wetting agents may constitute a healthhazard.INTRODUCTIONCoal dust presents explosion and health hazards to the coal mining industry. The problem of dust suppression is particularly acute where water alone is unsatisfactory for this purpose. The addition of a surface active agent (wetting agent) to the water should enable the dust particles to be more easily wetted and thus more easily prevented from entering and spreading through the mine atmosphere.Investigations into this effect carried out at The University of Sydney mainly under research grants from The Joint Coal Board (Dawson and Hargraves, 1955; Charlton and Curnow, 1957) are summarized, and information on the possible harmful effects of certain wetting agents is given.Twelve local manufacturers and five importers supplied 52 wetting agents in liquid, solid, powder, and paste form.The active material content varied from approximately 10 per cent to 100 per cent and the cost per pound from 8d. to 14/3.LABORATORY TESTINGPossible test methodsThree methods of laboratory testing were considered.1. The standard method for comparing wetting agents is the Draves test, used in the textile industry on cotton...

Jan 1, 1961

By G. J. Hasenfus

Although theoretical and conceptual knowledge regarding the impact of horizontal stress on underground coal mining excavations have existed since at least the mid-1900s, it wasn?t until the late 1970?s that the theory and practical understanding began to mesh. Since that time, particularly over the last 25 years of this Conference, increased empirical study, as well as advances in measurement technology, computer simulation, and bolt design, has significantly improved our understanding of horizontal stress impact, and provided coal mine operators with tools to reliably predict and manage it. This paper provides a retrospective review of some of the more important horizontal stress-related advancements made during the 25 years of Conference proceedings, particularly those for predicting and controlling horizontal stress impacts within underground coal mines. Relevant and significant CONSOL experiences and studies will be presented in context, with particular attention to horizontal stress considerations for longwall faces and gateroads. The significance of horizontal stress will also be placed in context with respect to local geology and structure, ground support measures, and mining configuration, method, and sequence.

Jan 1, 2006

By I Hustwick

New Zealand Steel Mining Limited operates two independent sand mining operations on the West Coast of the North Island of New Zealand. Waikato North Head 30 km south of Auckland supplies ironsand concentrate as the raw feed for New Zealand Steel's works at Glenbrook and Taharoa 70 km further south, exports ironsand concentrate to Japan.   Taharoa uses two sets of six low pressure Warman centrifugal pumps in series to load bulk ore carriers 3 km off shore through two underwater pipelines. Waikato North Head delivers the ironsand to Glenbrook 18 km through a 200 mm ID buried pipeline using two stages of high pressure positive displacement (HPPD) pumping.   A high level of operating and maintenance expertise has been developed since commissioning the two systems which are proving to be reliable, efficient and of minimal impact environmentally.

Jan 1, 1990

By J. M. Singer

In this Bureau of Mines study coal and rock dust beds were entrained by airblasts generated by gas explosions at the closed end of a 0.61-m-diameter explosion tunnel, 49.7 m long. The system was designed to simulate entrainment of mine dust deposits by accidental gas explosion at the coal face of nonintersecting mine passageways. Full-scale mine explosion trials confirmed many of the results of the explosion tunnel experiments and indicated several new features of dust entrainment. Dispersal of 20.3-cm-long stepped dust beds located 35 m from the closed end always began during the early portion of the ascending gradient of the first transient airflow (and pressure) wave, and was usually completed before the end of the first quarter-wave period. Bulk quantities of dust were entrained simultaneously by longitudinal regression from the leading edge of the dust bed and by surface lifting of the top layer. Instantaneous threshold air velocities for bulk quantities of coal and rock dust beds in separate, mixed, and layered configurations were in the same range (5 to 30 m/sec) as previously found under steady-state velocity conditions. Selective lifting of coal dust layers from rock dust occurred when the threshold dispersal velocity of coal dust but not of the underlying rock dust was exceeded.

Jan 1, 1976

By S. C. Langvik

The presentation named 'Dewatering of fines by Rotary Vacuum Disc Filters' has an opening why the filtration process is important to the Iron Ore Industry. It goes on to describe the various types of dewatering machines which have been used in this industry in the last 30-40 years, and where the vacuum disc filters now dominates. It presents also the most important design changes which have been made during this period to enhance performance. Further are discussed the principles of filtration and the factors and parameters which influence performance and operating costs. As a closing is presented today's ideas and thoughts about what can be foreseen of design modifications and improvements in disc filter design in the coming ten years.

Jan 1, 2001

The Tennant Creek goldfield is situated in the Northern Territory, 360 miles north of Alice Springs, or a tot~l distance of 1,300 miles north of Adelaide, and 600 miles south of Darwin. The auriferous area extends 20 miles north and south by 50 miles east and west. The overland telegraph line and the AIice Springs-Darwin road pass through the centre of the field.HISTORY, PRODUCTIONThe country comprising the goldfield was traversed by J. MacDouall Stuart between 1859 and 1861 in the course of his last three exploring expeditions, which terminated respectively at Attack Creek, Newcastle Waters and at the mouth of the Adelaide River. The explorer named Tennant Creek and also Mount Samuel, on which mining operations are now in progress. The overland telegraph line was completed in 1872 and a relaying station established eight miles north of the site of the present township. There was no other settlement in the adjacent country prior to the opening up of the goldfield.Gold was discovered in 1926 on what is known as the Great Northern lease, three miles north of the township. The field was remote; the nearest plant at which gold ore could be treated was at Peterborough, in South Australia, 1,186 miles distant, and it was not until 1932 that the development of the field actively commenced.The production of the field from its inception to December 31, 1939, was 57,895 QZ. of gold, valued at £522,000, recovered from 61,793 long tons of ore, won from 98 mines. In 1940 seven of these mines had reached depths between 100 ft. and 230 ft., the workings of the majority being less than 60 ft. below surface.TOPOGRAPHY, WATERThe country is traversed by parallel and sub-parallel lines of hills trending east and west and rising to altitudes varying from 50 ft. to 100 ft. above the intervening valleys. The low ranges and isolated hills owe their survival to the resistance offered by their indurated, harder rocks to erosion which has removed the softer intervening formations. Their elevation and area depend to a considerable extent upon the presence of; and, the size of, the more or less exposed haematite formations, or are due to the influence of extensive siliceous dykes which traverse the locality.Watercourses head from the hills and either flood out on the flats within a short distance, or in a few cases follow longer courses to the northward. In the channels of the larger creeks billaoongs, which form important water storages for a considerable part of the year, -are to be found. Tennant...

Jan 1, 1942

By J. Thompson

Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering) degree A study into the stability of strike gullies at TauTona mine was to be carried out. In reaching the conclusions to follow, a three-stage process was followed. ?A literature study as well as discussions with management and workers alike to gain their inputs and perceptions. ?An ESH Department survey into the history of transgression from proper mine standard in TauTona strike gullies. Unfortunately records were found to be scarce and obscure and the importance of better inter-departmental recordings cannot be stressed enough. ?An underground survey of 11 pre-selected gullies distributed in both the UCL and LCL reef horizons. This stage is to carry the greatest weight in the points to be brought forward in this report. The process highlighted and ranked the following areas as the most critical role players in the deterioration of strike gullies: ?Poor blasting practice ?Sub-standard siding depth and lead-lags ?Split sets ?Off line gully development ?Adverse geological features. The following has been suggested to the mine to help reduce strike gully instability. ?Where possible, maintain lead-lags below 7 m?else increase the siding depth to suit. ?Decrease the gully width standard to 1.2 m (especially in ?high risk areas?). ?Discourage drillers from drilling side holes in gully face blast pattern. This will allow for time in which tendon support can be kept up to date. ?Ensure split sets are installed 1 m behind the gully face so as to prevent opening up of fractures. ?Utilize the centre split set in the 1:2:1 pattern to maintain the proper gully line. ?When adverse conditions prevail, it is necessary to apply a special support plan not only to the panel face, but also (just as importantly) to the gully as well. Shotcreting of the gully hanging is a suitable long-term consideration for providing the additional a real coverage needed. List of Abbreviations [CL Carbon Leader M/O Mine Overseer UCL Upper Carbon Leader FOG Fall of Ground LCL Lower Carbon Leader H/W Hanging Wall ERR Energy Release Rate F/W Foot Wall WDL Western Deep Levels ESH Environmental Safety and Health ]

Jan 1, 2002

By Robert Martin

New Millennium ?a new project for an experienced mine building team ?Owns 100% of KeMag(Harris Lake) property ?Owns 80% of LabMag(Howells River) property -20% owned by Naskapi Nations of Kawawachikamah ?All founding directors are mining professionals : Geologists or Mining Engineers ?All have extensive experience in the iron ore industry ?The Project Office is located in Montreal, lead by a team of experienced iron-ore professionals Project Overview Geology & Resources Market Prospects Process & Product Development Development Plan Questions

May 1, 2007