Search Documents

By G. K. Jorgenson, S. H. Chung

"IntroductionThe SABREX Blast Modelling Program was developed jointly by the companies of the ICI Explosives Group, of which C-I-L Inc. is a member. SABREX (Scientific Approach to Breaking Rock with Explosives) is a modular computer program which incorporates new technology with a number of tested programs that have been in use world wide.SABREX predicts the performance of blasts in terms of (I) fragment size and distribution; (2) muckpile profile and face velocity; (3) grade fracture; (4) collar breakage; (5) a rupture envelope which depicts crack penetration behind and beneath blastholes; and (6) a complete cost analysis including explosives, drilling and accessory costs. The predicted blast results are displayed as dynamic colour graphics and in tabular form.SABREX uses data on the detailed geometry of the drilled and loaded pattern, detonation characteristics of the explosives and the dynamic properties of the rock to generate blast predictions. SABREX blasting calculations take into account the effects that shock and quasi-static pressures exert on the rock around the blastholes. While physical effects occur very rapidly in rock blasting, it is possible to view and model the sequence of events as discrete sections.The program can be run on a microcomputer and is currently operated by C-I-L technical service staff in Canada for the use of drilling and blasting operators.Figure I is a diagram representing the modules of the program and associated technology that is used to complement the program.Any, or all, of the modules may be used in a particular study or blast optimization. Because the BOBCAT module of the SABREX program has been described in previous papers(7.8.9), this discussion will concentrate on the newer modules: CRACK, HEAVE, RUPTURE ENVELOPE and to a limited extent, KUZ-RAM, which present a more detailed picture of the blasting process.Each of these modules is discussed in terms of the information they offer the operator in analyzing the blast. Specific examples of recent usage in Canadian mining situations are included to illustrate the ability of the model to produce practical results that can assist in optimizing actual blasting operations or solving problems that do exist."

Jan 1, 1987

By W. K. Coughlan

The Wabana deposit of Dosco Industries Limited is situated on the east coast of Newfoundland, at Bell Island in Conception Bay. It is a Clinton-type iron-formation of Lower Ordovician age. Five separate beds have been recognized, with others noted locally. Economic production has been obtained from the Lower, Middle and Upper beds, which are second, third and fifth in sequence, al-though at present only the Lower Bed is worked. The potential area of occurrence is about 70 square miles. It i;; bounded by major faults to the north, east and west and truncated by erosion at the south, where rocks of the de-posit crop out on the north side of the island. The iron is contained in oolitic hematite and chamosite, with minor siderite. As the deposit is submarine, conventional exploration methods are not applicable and much interpretation and projection from mined areas is necessary to guide exploration and development. With the interpretation of information from existing mined ores, it is possible, using a minimum of diamond drilling in advance of working faces, to maintain adequate ore reserves.

Jan 1, 1966

By K. Honkivaara, S. Junnikkala, J. Aho, K. Föhr, P. Lampinen

"Bubble area flux has been claimed to be a major tool to dimension flotation equipment. The paper describes laboratory scale (batch and 301 continuous cell using plant feed) and small-scale (1 ,8m3) industrial experiments with coarse-grained massive sulphide ore.Samples were taken with different froth thickness and air addition rates while the bubble size was measured with an UTC capillary device. Problems of averaging the bubble size measurements and the bubble area flux measurements are also discussed.Material balances were calculated using the commercial program BILCO. The flotation rate constants were calculated for pulp and for froth assuming that we can extrapolate the flotation rate constant of the pulp phase from tests using very thin froth thicknesses.The results indicate that the bubble area flux is not alone an adequate dimensioning tool. With fine sizes there was a nearly linear relationship between the bubble area flux and rate constant for constant impeller revolutions. For coarse sizes the form of the relationship is non-linear and seems to go through a maximum value. Thus the final flotation outcome is not a simple function of bubble area flux but depends on the particle size distribution and other more traditional flotation cell dimensioning variables. The effect of the froth residence time in the total recovery of coarse particles is large, but will not be treated in this paper."

Jan 1, 2000

"Energy efficiency in mining and minerals processing has attracted considerable public and industry attention because of the significant quantities of energy consumption involved. In this context the question of what are worthwhile targets for energy efficiency improvements ought to be of the highest priority. It is however worth taking a step back to avoid falling in the trap of taking preconceived ideas that have been reiterated repeatedly before as gospel. The aim of this paper is to highlight areas where new or alternative approaches could potentially be the better way forward. Some may come as a surprise to conventional industry thinking. Ultimately any such solutions are attractive to practitioners not just in an environmental but also in an economic sense, and hence should be targeted through applied research and development efforts. This paper highlights key aspects of each group of opportunities and some of the individual approaches to provide an overview of the current status quo.MINING INDUSTRY POWER UTILISATION – WHERE IS THE BIGGEST BANG FOR THE BUCK?The question of where is the biggest bang for the buck when trying to determine worthwhile targets for energy efficiency improvements has not always been reported on broadly enough, typically because industry practitioners operate in specific areas of expertise and comfort zone. Looking beyond the familiar doesn’t always come easy. Any technology or methodology consideration to address energy efficiency needs to take into account the context of alternative opportunities of superior value or risks not achieving desired uptake. The following sub-chapters have been ordered by magnitude of improvement potential as best as is possible, starting with the biggest first, and the smallest last. Some may be a surprise relative to conventional mining industry thinking."

Jan 1, 2016

By Peter Florian

At 5:50 am on October 1, 1992, the new $800 million Pittsburgh International Airport Midfield Terminal opened its gates to the world after five years of construction and more than 24 years of planning. Despite numerous design changes, this massive project was completed on time and substantially within budget. The importance of this airport to Allegheny County and the Pittsburgh region was recognized 24 years earlier by Allegheny County Commissioners Tom Foerster and the late Leonard Staisey. Staisey and Foerster established a program to acquire land for the "Airport of the Future".

Jan 1, 1993

As requested by my fellow members I shall endeavour to read a paper on the Treatment of the Auriferous Sulphide Ores of Kalgoorlie from a metallurgical standpoint. Before going into the subject it will be necessary for me to make some slight explanations. As most of you are aware many of our London friends holding interests in some of these mines think it necessary that their doings should be shrouded in mystery. The result of this is that in some cases it is impossible to get any official figures from the mines for this paper. I must ask you not to lose sight of the fact that in treating the sulphide ores of the Kalgoorlie mines we had absolutely no data to start on, and that to-day. we are just beginning to get a fair grip of tbe subject; and though very high extractions were announced when the first plants were started on sulphide ore, it was well known that this was only to maintain the public confidence in the mines to allow time to make necessary adjustments; and, as showing the advance made in the treatment of the ore, I notice several of the mines have published the results of the final or re-treatment of the residues of their first sulphide treatment. I have also had the opportunity afforded me of thoroughly sampling the residues of several of the principal mines, and find the results as now published absolutely correct.

Jan 1, 1901

By Julie Shang, Tim Evans, Michael McDonald, Yu Guo, Bingfeng Xue

Effective chemical grouting represents a technical and economic solution to many challenges related to soil stabilization and blocking the flow of water. Chemical grouts are facing increasing demands in durability, environmental impact and value. To better meet these challenges, a novel and cost effective process was developed to produce a sodium silicate that increases the ratio (i.e. silica to alkali) beyond what has been used in traditional silicate-based grouts. The move to a lower sodium form of silicate was anticipated to have two desirable performance enhancements; a reduction in leachable sodium and improvement in the durability of the silicate grout. An in-depth study was performed at the University of Western Ontario Geotechnical Research Centre to quantify improvement in durability as well as other performance properties such as compressive strength. The study began by first modelling the gelation time and reaction kinetics of the high ratio sodium silicate over a range of silicate concentrations using two different setting agents as well as with/without a hardener. As expected, reducing the level of sodium produced a much more water resistant grout. These same formulations also showed a four order magnitude reduction in permeability. Somewhat surprising, test results showed the higher ratio silicate having much higher compressive strength. At the time of this abstract, the high ratio silicate was moving to the trial stage for geotechnical applications while the petroleum industry was further along with several successful field trials for water blocking as well as cement remediation. This paper will review the chemistry, testing and features of this next generation form of sodium silicate. Introduction Sodium silicate based grouts have been used for decades for soil stabilization and water control. Over the years, several silicate-based systems have been tailored for specific application conditions to maximize performance and reduce cost. Past research has also focused on the selection of setting agents and hardeners for silicate grouts. A constant in the development effort has been the grade of sodium silicate. The vast majority of chemical grouts have been formulated using a ~3.2 ratio sodium silicate. As a very brief overview on the meaning of “ratio” and why it is so important to performance properties. The ratio describes the proportion of sand to alkali or SiO2:Na2O used to make different grades of sodium silicate. Comparing a 2.2 ratio to a 3.2 ratio, it is easier to polymerize and set the 3.2 ratio. Upon setting and forming a silica gel, the system has higher compressive strength values and improved durability with a reduced level of syneresis (i.e. shrinkage). This leads to the question if 3.2 is better than 2.2 why not go to 4.2 or higher?

Jan 1, 2018

The influence of varying amounts of magnesia, silica, and alumina in iron ore sinter on its mineralogy, reducibility index (RI), reduction disintegration index (RDI), physical breakdown (AI and TI), and production properties (coke breeze rate) were examined. It was found that the mineralogy of iron sinter can more easily be predicted from its chemical composition than from the RI, RDI, AI or TI. Anticipating the consequence that varying amounts of MgO and SiO2would have on sinter properties is complex, and not necessarily predictable. High concentrations of Al2O3in the sinter result in high concentrations of the SFCA phase, but with drastically deteriorated properties. This study also confirmed that the form in which fluxes are added to the raw material sinter mixture affects the mineralogy and properties of the produced sinter.

Jan 1, 2010

By A. B. Hooker, L. C. IlsLey

"Observation of the use of trailing cables in ""mines shows that the chief limiting factor in the life of the cables and their safe use is the smashing or crushing of the cables in service, together with the effects of consequent splicing.Trailing cables are crushed when run over by cars, mining machines; and locomotives or when hit by falls of roof. Crushing damages the insulation and may cause failure at once or in later use. Failure may be either by short circuit between the conductors or by grounding to the track. The failure of a live cable causes electric arcs capable of igniting explosive mixtures of methane and air. Every cable failure in a gassy or dusty mine is, therefore, a real or potential hazard.Some mine operators do not allow the splicing of trailing cables for use in gassy mines, bet require that a damaged cable be immediately replaced and if repaired that it be used only in nongassy mines. Other operators allow the making of temporary splices to permit completion of the shift but require that such splices be remade and vulcanized before the cable is used again.Still other operators allow the continued use of temporary splices, which in general means that a cable is used until the splices give trouble in reeling, or overheat, or pull apart. Then the spliced sections are either cut out or the whole cable is replaced.Splices often determine the useful life of a cable. A splice poorly made may pull apart ueder mechanical strain and cause arcing that burn* the surrounding cable or ignites as or coal-dust. If it has lower conductivity a splice is the first part of the cable to heat; it may become so hot under load that it will burn apart and damage other parts of the cable, or, if it be a soldered splice, the solder may melt and allow parting of the cable. A poorly made splice often has insufficient insulation which may alloy short-circuiting between conductors or permit external contacts capable of giving an electric shock to one handling the cable. The splice is sometimes bulky from too much insulation and takes up too much room on the reel, causing uneven reeling; also by catching on the spooling device the oversized splice may receive expressive pulls and wear. Splicing is therefore a very important factor in the use of trailing cables."

Mar 1, 1932

By Naresh Koirala

The Greater Vancouver Regional District completed installation of a 2.5 Km long, 2400 mm diameter concrete sewer in Delta, British Columbia in 2000. The sewer traverses through area of peat and soft ground. The ground investigation along the sewer alignment consisted of cone penetration tests and auger drilling with standard penetration tests. The gravity sewer is supported on precast, pretensioned spun concrete piles imported from Malaysia which had never been used for a major project in North America. The capacities of the installed piles were tested using pile driving analyzer (PDA) and three static load tests. A total of 46 PDA tests were carried out during pile installation. The paper describes the pile vetting process the owner went through prior to accepting the piles for use in the project and performance of the piles. It compares the pile capacity estimated from the PDA tests with that estimated from soil mechanics methods using data from cone penetration tests and standard penetration tests. The ranges of estimated capacities calculated by different methods are discussed from design capacity selection considerations.

Jan 1, 2004

By Jewel A. G. Gomes

Electrocoagulation (EC) has been performed with Al-Fe electrode system with changing polarity for the removal of arsenic from water. The removal process has been studied using ICP-AES and Anodic Stripping Voltammetry with a wide range of arsenic concentration (1-1000 ppm) at various pH (4-10) and residence times (1-60 min). Electrochemically generated by-products have been analyzed using XRD, FTIR, XPS, SEM/EDS and Mössbauer Spectroscopy. Results revealed expected crystalline iron oxides (magnetite (Fe3O4), lepidocrocite (FeO(OH)), iron oxide (FeO)) and aluminum oxides (bayerite (Al(OH)3), diaspore (AlO(OH)), mansfieldite (AlAsO4?2(H2O)), as well as some interaction between the phases. The amorphous or ultra-fine particular phase was also found in the floc. The substitution of Fe3+ ions by Al3+ ions in the solid surface has been observed, indicating an alternative removal mechanism of arsenic in these metal hydroxides and oxyhydroxides by providing larger surface area for arsenic adsorption via retarding the crystalline formation of iron oxides.

Jan 1, 2006

By R Munoz, R González, J Vallejos, A Delonca

In panel caving in underground mines, it is essential to characterise and monitor the stress and stability state of production level pillars to ensure the extraction of the mineralised ore column and the safety of workers. Pilar Norte is a sector in the El Teniente mine that forms a pillar between the undercut fronts of the adjacent Esmeralda and Reservas Norte sectors. It exists in a high-stress environment, which may induce damage to the rock mass production pillars. Generally, numerical models are calibrated using observed damage in galleries. This procedure does not discriminate between the structural condition and/or the blasting damage effects. This paper proposes a technique that uses borehole cameras to measure stress-induced damage. This has the advantage of being at the intact rock scale, meaning that the effect of geological structures is negligible and the blasting damage factor is eliminated. Comprehensive geotechnical characterisation and tomography monitoring has been undertaken at Pilar Norte to describe and determine the rock mass behaviour of the production pillars. By combining analytical, empirical and numerical models, a correlation between the measured overbreak recorded by the borehole cameras and the stress level of the pillar was developed. The methodology can be routinely applied to estimate the stress state in the production pillars.CITATION:González, R, Munoz, R, Vallejos, J and Delonca, A, 2016. Characterisation and monitoring of the stress state of production pillars at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 197–202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Lori A. Simpson

Mission Bay is a 300-acre reclaimed site in San Francisco, California, that is currently being redeveloped. Plans include new neighborhoods, parks, a new University of California, San Francisco, research and development campus, a biotechnology campus, and commercial office buildings. New infrastructure is being constructed throughout the site, consisting of utilities, pump stations, and roadways. Previously, Mission Bay was a part of the San Francisco Bay. Reclamation of the shallow bay coincided with the booming development in San Francisco in the 1880s and continued through 1920. Subsurface conditions are extremely variable throughout the site. The stratigraphy generally consists of 5 to 45 feet of fill, up to 140 feet of weak, compressible clay (?Bay Mud?), dense sand, stiff clay, and bedrock of the Franciscan Complex that has been encountered 5 to 210 feet below the ground surface (bgs). Geotechnical issues related to these subsurface conditions include liquefaction, lateral spreading, settlement, and adequate foundation support. This paper presents case studies of the geotechnical aspects of design and construction of several buildings in Mission Bay, highlighting the similarities and variability in the subsurface conditions and the different conclusions and solutions developed for each project. The case studies will include: 1) a building supported on steel H-piles where the depth to bearing varies from about 70 feet bgs in one half of the site to 165 feet bgs in the other half; 2) a building supported on precast, prestressed, concrete piles bearing in a thick, very dense sand layer; 3) a building with over 100 feet of Bay Mud supported on 120- to 180-foot-long PCPS concrete piles driven to bedrock adjacent to buildings supported on steel H-piles driven to bedrock; and 4) sites where auger pressure grouted displacement piles (APGD) and Tubex piles were installed. Case studies will include results of pile driving analyzer (PDA) testing and static pile loads tests, where performed.

Jan 1, 2006

By Wilfrid Comeau

While researching for a theme lecture (Comeau, 1993l) on: 'The Mechanics and Physics Explosives', the author of Energy Transfer in Rock Fragmentaion by was confronted with many conflicting concepts regarding: the current explosive rock fragmentation theories, the physical principles governing energy transfers, the mechanical properties of rocks, and observations and data from full scale rock blasting.

Jan 1, 1995

By N. A. C. Smith, D. D. Stark

"Sulphur is apparently a normal Constituent of crude petroleum, but in most crudes is present in percentages of less than one-half of one per cent. Some crudes, however, contain more, and occurrences have been reported of heavy asphaltic oils with as much as five per cent of sulphur.Occurrences of Sulpher-bearing CrudesIn North America, the fields rest of the Mississippi River are almost entirely free from sulphur oils, the time oil from Northern Ohio and Indiana, and the Potrolia crude in Ontario, being practically the only ones which contain sulohur in amounts over 0.5. per cent. In the Mid-Continent district the production of high sulphur crude in general is small and unim¬portant. The two main excentions are the Healdton field in Oklahoma and the El Dorado field in Arkansas, both of which produce oils with considerable sulphur content. In the Wyoming field, one sand, the Ember Sandstone, pro¬duces a crude of high sulphur content, and it is probable that this crude rill be of considerable importance as production increases. At present, however, very little crude is produced from this formation. In the Gulf Coast conditions are irregular, some crudes being low in sulphur and others comparatively high. The same is largely true of California. The crudes of Mexico contain notable amounts of sulphur, and as they have been of great commercial importance in this country, a typical sample of light Mexican crude was selected for the present study. It is probable that the results obtained poly also (but to a lesser degree) to other sulphur-bearing oils. An analysis of this crude will be found in Table 3, also analyses of other typical sulphur-bearing crudes from different sections of the United States."

Mar 1, 1924

By G. L. Oldwright, Virgil Miller

"The data presented in this paper were collected at the smelter of the Consolidated Mining & Smelting Co. of Canada Limited, Trail (Tadanac), Brithish Columbia. The authors are greatly indicated to S.G. Blayrock, vice president and general manager; James Buchman, smelter superintendent; and the staff members mentioned in Report of Investigation 3243. The authors are exceedingly grateful to George Murray, assistant smelter superintendent, for his keen interest, suggestions, and help in carrying out this investigation.INTRODUCTIONThe methods of charign the blast furnaces at Toole and Kelloggs were noted in Report of Investigations 2957 and 3094 respectively. Report of Investigations 2957 cited (4 to 9 inclusive) Hofman's Metallurgy of Lead (p. 226) and the work of A.S. Dwight, Thompson and Sicka, the staff of the Engineering and Mining Journal, and L.D. Anderson, N.F. Collins, in The Metallurgy of Lead (Chas. Griffin, London, 1910) also gives (pp. 247 254) the principles that he believes govern the successful charging of the blast furnace."

Dec 1, 1934

By J. O?Shea

From the characteristics of the new (1976) electronic components and units that are being marketed, the author has tried to foresee the types and the performances of the near-future slope-monitoring equipment. Much-improved sensors, instruments and systems for pit use can now be developed - sun-powered telemetry remote stations are feasible, very sensitive as well as precise and drift-free liquid level inclinometers will be available, new techniques for distance measurement with lasers obviate the need for atmospheric corrections and the latest generation of desktop calculators have become easily programmed minicomputers. Thus, it is realistic to assume that fully automatic pit-slope monitoring systems will be operational in the foreseeable future.

Jan 1, 1978

By D. Michael Holloway

The California Department of Transportation (CALTRANS) evaluated several pile foundation schemes for supporting the structures along the realignment of Interstate 880. The project replaces the double-decked (Cypress) viaduct collapsed in Oakland, California during the 1989 Loma Prieta Earthquake. Structural support demands led to the selection of steel pipe piles (16-, 24-, and 42-inch-(406-, 610- and 1067-mm-)diameter), filled with concrete and steel reinforcement. Deep penetrations required through layers of very dense/cemented sands in some locations, caused serious drivability and pile integrity concerns. The need for large pile driving hammers and large diameter steel pipe piles pushed the engineers well beyond local experience. Such questions as the feasibility of driving the pipes closed-ended through dense upper strata and quantifying the effects of installation on the long-term capacities of the piles led Caltrans to develop a comprehensive pile test program to address the design and construction issues effectively. The results were furnished to prospective bidders on the production stages of the ensuing contracts.

Jan 1, 1995

By Leonard Obert

This report describes a gage which, when used with my procedure for producing strain relief, will measure the resulting borehole deformation, From the borehole deformation the magnitude and direction of the principal stresses in a plane normal to the axis of the borehole can be calculated. The design considerations, mechanical construction, sensitivity, and stability of the gage are discussed. INTRODUCTION During the past two decades an increasing mount of consideration has been given to the problem of measuring and evaluating stress in rock around underground openings. Several investigators have made theoretical and model studies of the stress and (or) strain concentrations around simulated mine openings or in structural members, such as mine pillars or immediate roof. Other investigators have developed gages for directly or indirectly measuring stress or strain, and a number of reports present the results of measurements made with these gages. Because various methods and instruments have been developed, factors involved in this type of measurement will be briefly considered.

Jan 1, 1962

The Tasman Orogenic Zone is regarded as a single metallogenic province (the Tasman Province) with four SUb-provinces corresponding with its major tectonic components: the Lachlan, New England, Hodgkinson.and North Queensland orogenic provinces. Within the Tasman Province there are four main ore-rock associations.These are1. manganese and iron with sedimentary and basic volcanic rocks,2. zinc-lead-copper and copper with intermediate-acid volcanic sequences,3. minor chromium, platinum, and osmiridium with ultramafic complexes, and4. tin, wolfram, gold, and copper with syn- and posttectonic granitic intrusions.Whereas the ores of ultramafic and volcanic associations form geographically-restricted metallogenic districts, the ubiquitous granitic ores may be subdivided into twenty-one districts that cover almost the entireOrogenic Zone. The Tasman Province is notably lacking in uranium ores and Mississippi Valley-type deposits.There is a distinct tendency for ores of each association to be progressively younger to the east and north, thus paralleling the progressive growth and stabilization of the Zone. Similar ore-rock associations are present in repeated phases of mineralization from the Cambrian to the Permian-Triassic, reflecting the essential homogeneity of the Tasman Province, and the similarity of the successive tectonic cycles.

Jan 1, 1972