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By S. Ramachandran, N. J. Grant, T. B. King

MANY investigations of the rate of the sulfur transfer reaction between carbon-saturated iron and blast furnace type slags have been made." It is evident that the reaction is complex, the rate being affected by the presence of elements dissolved in the metal that are readily oxidized and therefore capable of existing in the slag phase. Thus Goldman, Derge, and Philbrook- have shown that carbon, silicon, manganese, and aluminum, in order of increasing effectiveness, accelerate sulfur transfer from iron containing these elements to blast furnace type slags. Quantitative information is still, however, not available on the relation between what have been termed side reactions, such as silicon transfer and CO evolution, and the sulfur transfer reaction itself. In other words, the stoichiometry of the reaction has not been investigated. In the present investigation, the transfer of all reacting elements and the evolution of CO have been measured simultaneously in order to establish the mechanism of the reaction which occurs in practice. Information of this nature cannot be deduced from equilibrium studies. It should be pointed out that in kinetic studies of this type quantitative conclusions are applicable only to the system studied. This restriction should be borne in mind when attempts are made to compare results from different investigations. Apparatus The apparatus used enables slag and metal samples to be taken at frequent intervals and also provides a continuous record of the amount of gas evolved. A sketch of the apparatus is given in Fig. 1. It may be considered in three sections: 1) furnace section, 2) blank volume section, and 3) pressure measuring section. The furnace section is shown in detail in Fig. 2. It consists of two graphite crucibles, C and D, super-

Jan 1, 1957

By B. G. D. Smart

An understanding of the nature of yield zones surrounding coal mine excavations is fundamental to the design of mine support systems. Various methods have been designed for investigation of underground rock masses and an extensometric technique, the Magnetic Rod Extensometer, has been developed to overcome inherent design limitations in existing equipment of this type. This paper refers to the prototype form of the extensometer and details changes designed to overcome a variety of drawbacks indicated by routine use of the equipment. The principal change has been one of manual to computerised data acquisition and presentation in the laboratory phase of the system. This has dramatically reduced the time taken to process underground measurements and produce numerical and graphical results. The revised Magnetic Rod Extensometer represents an integrated instrumentation system that combines speed and accuracy in all areas of data handling.

Jan 1, 1984

By K A. Campbell, K A. Rodgers

The Plumduff sinter occurs at Whenuaroa, near Puhipuhi, approximately 30 km north of Whangarei. It is one of three residual sinters in the southern portion of a mid- to late-Pliocene geothermal system. The deposit consists of many large sinter breccia boulders, including rudrocks (coarse breccias), scattered around the flanks and summit of the small conical hill of Plumduff. Three types of sinter breccia occur: (i) rudrocks consisting of large, angular to sub-angular clasts of layered sinter up to 0.8 m across, as well as smaller clasts of sinter (20 - 100 mm dia), and fragments of stromatolitic structures; all clasts are supported in a matrix of microcrystalline, transparent to translucent to milky quartz; (ii) fragments of layered angular to irregularly mottled sinter of white to grey or bluish hue supported in a translucent to opaque silica matrix; (iii) smaller, matrix-supported breccias with clasts both partially surrounded and/or penetrated, by a clay-like weathering rind, and sinter conglomerates with rounded to oblate clasts. Three principal types of fabrics constitute the bulk of the sinter: (i) stromatolites, including columnar, palisade and filamentous networks, showing progressive silicification, in fenestral, tufted to clotted fabrics; (ii) peloids and pisoids; (iii) plant-rich facies in which various silicified plant species occur in a silica matrix. All fabrics have counterparts in hot spring deposits in the Taupo Volcanic Zone formed at temperatures from 75¦C to 35¦C. Also present is steam-condensate-produced alteration: kaolinite and alunite as well as boulders of quartz lattice texture. Cinnabar only occurs in sinter on the north and south central slopes of the hillside. No quartz veins or geyserite were recognised.

Jan 1, 2001

By J. Kretschmann

Around the world, mining has been done for thousands of years for the benefit of humankind. The winning process in mining operations ends with the depletion of the deposit or its closure if the operation becomes economically unprofitable. After that, a period of post-mining follows which may last for a very long time and which is generally regarded as a period of hazards, risk and high cost. In the USA alone, approximately 500,000 abandoned mines do exist; worldwide, there are millions. In Germany, too, we have had to deal with abandoned mines for a considerable period of time now.

Jan 1, 2012

By Lawrence P. Goldfarb

This paper presents the results of the geotechnical investigation for the repair of the Fashion Island Boulevard Bridge, Bridge No. 350160, in San Mateo, California. The concrete, precast girder bridge suffered considerable damage during the Loma Prieta earthquake. The existing 36-inch, precast, prestressed concrete piles cracked and spalled at their tops. Based on analyses performed by Biggs Cardosa Associates, structural engineers, the piles did not have sufficient strength and ductility to resist the dead plus seismic loads specified in the Caltrans "Bridge Design Specifications". Additional support for the bridge was needed and the repair strategy consisted of installing large diameter pipe piles at the existing bent and abutment locations. This paper describes the geotechnical engineering analysis and design decisions for the large diameter pile design.

Jan 1, 1993

By B. Valentim

The methodology used to obtain fly ash subsamples of different sizes is generally based on wet or dry sieving methods. However, the worth of such methods is not certain if the methodology applied is not mentioned in the analytical procedure. After performing a fly ash mechanical dry sieving, the authors compared those results with the ones obtained by laser diffraction on the same samples and found unacceptable discrepancies. A preliminary study of a wet sieving analysis carried out on an economizer fly ash sample showed that this method was more effective than the dry sieving. The importance of standardizing the way samples are handled, pretreated and presented to the instrument of analysis are suggested and interlaboratory reproducibility trials are needed to create a common standard methodology to obtain large amounts of fly ash size fraction subsamples.

Jan 1, 2008

By A. M. Strachan

Capper Pass & Son Limited Was, until its recent closure, the world's largest producer of tin from secondary materials including solder drosses, non-ferrous smelter flue dusts, tin based metal alloys, residues and slags. Polonium-210, an alpha emitting radionuclide, was present in varying concentrations in some of the numerous feed materials processed by the smelter and refiner. The polonium-210 followed a complex path through the process flowsheet. This paper discusses the behaviour of polonium, both from its arisings in other smelters' process streams and through the entire Capper Pass smelting and refining circuit. The consequential personnel safety and environmental precautions necessarily taken in some areas of the process operation are outlined.

Jan 1, 1992

Recent literature is reviewed with emphasis on the design and scale up of mixers. Most important aspects of mixing have resulted from the study of Newtonian fluids and only a minor attempt has been made to extend the work to non-Newtonian materials.The rheology of non-Newtonian materials is outlined and the typical behaviour of mineral slurries is indicated.The importance of flow velocity, flow pattern, and fluid turbulence is discussed with relation to suspension of solids and rate of reaction.Data on experimental leaching of ore from Mary Kathleen, Queensland, show the effect of different mixing impellers.In conclusion, factors involved in the selection of a mixer are presented with emphasis on economic appraisal after pilot experimentation.INTRODUCTIONThe subject of mixing has attracted considerable attention during recent years, but relatively little work has been undertaken for the study of non-Newtonian materials. Most work has been restricted to Newtonian fluids because there are less inconsistencies in such study.Mixing, by definition, implies blending or combining, and ranges from gentle mixing which blends the contents of a large tank in 24 hours to violent mixing which completely homogenises the contents of a tank within seconds. Metzner and Otto (1957) have pointed out the present lack of knowledge on the degree (or quality) of mixing. Apart from this fact the design of mixers for Newtonian materials would seem to be reasonably certain.Both capital and operating costs rise rapidly with increasing mixer size. Therefore the design, or selection, of a mixer is a matter for economic consideration in the overall aspect of plant design and operation.

Jan 1, 1961

By J. Shang, P. Howarth, B. Morris

Tailings from the nickel refinery in Copper Cliff, Ontario, consist of fine silicates mixed with a variable amount of conductive and magnetic minerals mainly associated with sulphides and iron oxides. Subsequent oxidation of sulphide- rich phases within the tailings results in the formation of an acidic leachate that may contain significant concentrations of trace metals. Mapping the spatial distribution of regions of higher sulphide concentration therefore provides insight into the distribution of the acidgenerating potential within the tailings. Electrical conductivity is constrained by two parameters — the concentration of metallic sulphides and the ionic concentration of acid in groundwater. Magnetic susceptibility is directly related to the pyrrhotite and magnetite content. It is proposed that combining information derived from airborne electromagnetic and magnetic surveys can provide an indication of metallic sulphide distribution. Preliminary investigations of airborne electromagnetic and magnetic data acquired concurrently over the sulphide-rich Copper Cliff tailings site reveal that these parameters can provide information on mine tailing extent and permit separation of tailings with varying compositional and alteration levels. Airborne geophysical data provide information about the subsurface while a digital elevation model (DEM) and hyperspectral imagery record surface conditions. Integration of the two data sets can reduce ambiguity when interpreting mine tailing distributions and their subsequent alterations.

Jan 1, 2001

By Trevor R. Ellis

Minerals appraisers/valuers often find great difficulty in attempting to employ the sales comparison approach to the market value appraisal of development and operating stage mineral properties. An important factor generally overlooked is a comparison of net operating income (NOI) margins on a per-unit-of-production basis between mineral properties, whether these be demonstrated or forecast margins. NOI margins can vary greatly between mines or quarries that are producing similar products. Ultimately, the expected NOI margin determines what a buyer is willing to pay for an income-producing property. Here, common criticisms of the sales comparison approach by mineral appraisers are introduced. These are counterbalanced by raising some issues in the way the inputs for the income approach are usually derived by minerals appraisers and by review of some conspicuous examples of the much-too-common misuse or abuse of the income approach in market value mineral appraisals. Example transaction analyses and sales comparison analyses are used to demonstrate the author?s methodology for adjusting units of resource in his transaction adjustment tables. The examples are used as the basis for a discussion of ways to employ adjustments for operating economics and many other factors, while warning against the potential for double counting. The conclusions include a recommendation that minerals appraisers attempt to apply at least two of the three valuation approaches when appraising the market or fair value of development and operating stage mineral properties, the two being the sales comparison and income approaches.

Jan 1, 2011

By G. J. Colaizzi

The Bureau of Mines, at the request of local authorities in Rock Springs, Wyo., investigated and conducted through contracts a multistage program of exploratory drilling and pumped-slurry backfilling of 15 areas of potential subsidence in abandoned mine workings underneath that community. Initially, the Bureau in 1969 had recommended a program of gravity blind flushing of some of the inaccessible mine voids, and in 1970 a new technique, the pumped-slurry injection process, was tested for the first time in a site adjacent to the city's area of severe surface subsidence. Success of this initial testing program, and of a large-scale project in Scranton, Pa., led to further large- scale projects, funded by Congress, that resulted in the successful back- filling not only of all 15 target areas of potential subsidence in Rock Springs, but also of several areas in other States. Total cost of the projects in Rock Springs, including the original pumped-slurry test, was $3,243,993. A total of about 923,000 tons of sand was injected hydraulically into mine voids, rendering 178 acres of residential and central-downtown areas of Rock Springs less susceptible to subsidence damage. The pumped-slurry method was proved to be much superior to the gravity blind flushing method in term of the amount of solids that could be injected underground through a single borehole. However, there are special conditions that make this technique more or less applicable in different areas or underground configurations, as noted in the report's conclusions.

Jan 1, 1980

By David Whalen

Mobile equipment in oil sand mining operations experience more maintenance problems than similar equipment in other surface mines, due to soft underfoot conditions. Oil sand properties are known to vary with temperature, bitumen content and previous loading cycles. One of the challenges is the widely variable underfoot pressure which supports shovels and trucks. In the case of a heavy hauler driving on in-pit roads, each tire is supported by a different ground stiffness resulting in an apparent uneven surface. Driving over uneven ground causes twist in the truck frame, which is transmitted to the dump body. Through a finite element analysis of a haul truck dump body, it was shown that slight frame twists produce localized stresses in the intersections of the floor stiffeners. These stresses are at times greater than those resulting from the maximum ore weight and are primarily responsible for cracking in these intersections. Syncrude maintains high quality haul roads, which are constructed of gravel, and makes every effort to keep the shovel pit roads as smooth as possible. This problem cannot be avoided through operational practices only and must also be accounted for in the design of haul truck bodies.

May 1, 2003

By Sukru Sumer

East Pit Lake is an artificially created lake that resulted from the remediation and reclamation of surface coal mining operations at TransAlta Utilities' Whitewood Mine in the Wabamun area west of Edmonton, Alberta. The original excavation resulted from the creation of a mine end cut at the northern extent of the mining operation. The area of the surficial drainage basin that feeds East Pit Lake was relatively small. Therefore, most of the inflow and outflow from the lake would result from regional ground water flow. There was a concern about the lake's ability to provide a suitable habitat for a sportfish population. To determine the final recovered water level and rates of recovery, a two-dimensional ground water flow model was used. Data supplied by nested piezometers in and around the mine were used to calibrate the computer simulation and assess predicted recovery.

Jan 1, 1995

By M. Feely, W. G. O'Keefe, C. O'Reilly, M. P. Holdstock

A petrographic and microthermometric study of fluid inclusions in the Kentstown Granite, crosscutting quartz (VI) and calcite+quartz (V 2) veins in the granite and calcite+quartz (V 2) veins in the overlying sediments was performed on samples taken from the borehole. Comparisons of the type 1, type 2 and type 3 fluid inclusion populations recorded in the present study with those from other Irish Caledonian granites strongly suggest a similar fluid evolutionary history. Furthermore, the low-temperature CaC12-rich brines (type 5) of this study, which must be syn- to post-Lower Carboniferous in age, have correlatives both in Irish Caledonian granites and in the Lower Carboniferous base-metal deposits of the Irish midlands

Jun 19, 1905

By K. L. Paciorek

The primary objective of this program was to determine the toxic fume and fire hazard of materials used in the construction of mine stoppings and in the sealing and reinforcing of mine ribs and roofs. The materials investigated were: silicone, phenolic, and isocyanate-based rigid foams, as well as epoxy and acrylate mine sealants. Of the rigid foams tested, the X-156 urethane foam presented the greatest toxic hazard based on toxic load values hydrogen chloride was the main toxic species evolved by this foam. In 'lone of the isocyanate-based compositions was hydrogen cyanide the major component, but its contribution increased with temperature. The FS-24 urethane and Celotex Max-Seal isocyanurate foams had the lowest toxic load values, although these two foams have different applications for in-mine use. Of the two mine sealants tested, the latex /acrylic coating presented the greater toxic hazard with acetic acid being the main toxic species evolved.

Jan 1, 1983

By Anibal Gajardo

Because of the Chilean Ministry of Mining's interest in the development of industrial minerals, the Chilean Geological and Mining Service (Servicio Nacional de Geología y Minería, SERNAGEOMIN) has carried out a research program during the last two years to identify projects that represent interesting investment opportunities for small- to medium-scale operations in Chile. Most important of these projects are: (1) Quebrada Lluta aluminum sulphate, for drinking- and industrial-water treatment, with a potential domestic and foreign mar- ket of almost 43,000 tonnes per year and investments of about US$1.8 million; (2) Quebrada Lluta-Quebrada Cardones pumice, for abrasives, filters, fillers, and light- weight aggregates, with a potential market of about 30,000 tonnes per year, and in- vestments of US$2.0 million; (3) El Maule dolomite, for soil conditioner and iron smelting, with a total potential domestic market of some 60,000 tonnes per year, and estimated investments of US$2.0 million; (4) Las Escaleras bentonite, for animal feed, pelletising, and oil absorbents, with a potential market of almost 6,000 tonnes per year, and investments of about US$2.4 million; (5) Laraquete-Carampangue andalucite, for alumina refractories, with a future total domestic and foreign demand of about 15,000 tonnes per year, and estimated investments of US$2-2.5 million; (6) Rio Lía garnet, for fillers and sand-blasting abrasives, whose domestic market represents 10,000 tonnes per year, with investments of US$2.3 million; and (7) Munilque pumice, for building bricks and panels, with a potential domestic market of 250,000 tonnes per year, and investments of US$1.4 million. The development of these projects will represent an important increase and a significant diversification in Chilean industrial-minerals production.

Jan 1, 1999

By Olav K1omstad1ien

The lean, but extensive iron ore deposits of the Dunderland Valley north of Mo i Rana, Norway, is the raw material for the Rana Mines which is a division of the state owned steel mill A/S Norsk Jernverk. Activities for the exploitation of the orebodies were commenced in 1902 by the English Dunderland Iron Ore Company. During its operating period the company constructed a total of two large scale concentrating plants. The activities were strongly marked by technical problems and labor disputes. Thus actual production was limited to the years 1904-1908, 1928-1931 and 1937-1939. During these periods a total of 1.9 million tons of crude ore was mined and 0.6 million tons of concentrates produced for export. The present plant commenced operations in late fall of 1964. Up to and including 1976 about 26.6 million tons of crude have been put through the concentrating plant and about 10.7 million tons of concentrate produced.

Jan 1, 1978

By W Farnworth

The Huntly West Mine has undergone significant changes in the last two years, which will affect the remainder of the mine's life. The paper describes the evolvement of plans and an overview of the technical considerations made in planning for and implementing the first New Zealand longwall operation. The technical investigations involve the longwall equipment, exploration, ventilation and strata control. The focus on these areas was to ensure that unacceptable project risks were addressed. Implementation of longwall mining at West Mine is planned in three phases, Development, Panel One extraction trial, and Full Longwall operation.   At present the development phase is complete, longwall installation is in progress and production start-up is planned for the end of August, 1991.

Jan 1, 1991

By C. L. Reichardt

Mining companies are increasingly looking to the developing world for the next generation of mining projects, often in countries that have little or no previous history of large-scale mining. One of the major challenges for such projects is hiring?and retaining?personnel that have technical skills and experience in mining-related disciplines. Staffing a mine with an expatriate workforce is neither cost-effective nor sustainable, and many countries now insist that mining companies ?transform? the profile of their workforce to more closely mirror the demographic profile of the host population. The need to nurture mining-related skills in emerging mining nations is not solely limited to the workforce: there are also pressing economic and sustainability imperatives to develop capacity within local service providers such as consultants and contractors, as well as to facilitate informed engagement between mining companies, government and civil society. However, few educational institutions in emerging mining nations currently have the ability to offer practical training in mining-related disciplines. Local employees who are sponsored by companies to develop their skills through international study maybe impeded by language and cultural barriers, and may also be taught using course content that is of limited relevance to the specific challenges of their future working environment. This paper addresses the challenge of skills development and retention in emerging mining nations and uses examples from sub-Saharan Africa and the Asia Pacific region to explore practical means of developing capacity in mining-related disciplines. It examines the need for companies to implement strategies to develop local technical capacity in countries where they envisage a long-term operational future and also highlights the need to foster partnerships between academia, developmental institutions, mining companies, governments and civil society to establish the critical mass of mining-related skills required to nurture the development of a sustainable mining industry.

Jan 1, 2009

By C. Sun

In this study, numerical simulations of yield pillars employing the finite element method with time-dependent Drucker-Prager material model are conducted. The stress control mechanism of yield pillars on weak floor strata is studied. The development of pillar yield zone, the distribution of pillar stress and the development of failure zone in the weak floor strata are investigated. The study indicates that a properly selected yield pillar size may significantly reduce the peak stress induced in the weak floor strata and effectively control the development of failure zone in the floor.

Jan 1, 1999