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By S. Read, G. Cook

The Hoek-Brown failure criterion is often applied to a wider range of rocks than the isotropic rock masses to which it is strictly applicable. This paper evaluates the patterns of defects in rock masses using spherical projection contour plots of samples of randomly-generated orientations and datasets from mapping of New Zealand closely-jointed greywacke rock masses. Two indices from the contour plots - the area within the 1% contour (A1%) and maximum concentration (Cmax) are introduced for distinguishing uniform (isotropic), random or regular defect patterns. The indices provide a potential extension to current guidelines on the use of the Hoek-Brown failure criterion. The paper also outlines kinematic checks to assess the influence of defect clusters on rock mass strength. Das Hoek-Brown Bruchkriterium, das strikte nur fuer isotrope Gefuege gilt, findet oft einen viel weiteren Anwendungsbereich. Diese Arbeit bewertet diverse Dispersionsmuster der Defekte einer Gesteinsmasse. Wir vergleichen in sphaerischer Projektion (1) Beispiele zufaelliger Orientierung von Defekten und (2) Felddaten ueber neuseelaendisache engstaendig geklueftete Grauwacken. Die Projektionen werden durch die Indices A1% (Flaechenanteil des 1%-Bereichs) and Cmax (Hoechstkonzentration) gekennzeichnet, welche isotrope, zufaellige und regulaere Muster unterscheiden und die aktuellen Richtlinien zum Hoek-Brown Kriterium ergaenzen. Wir testen ferner Defektgruppen der Gesteine kinematisch auf ihren Einfluss auf Massenfestigkeit. Le critère de rupture de Hoek-Brown est souvent utilisé sur une variété de roches plus étendue que les masses rocheuses auxquelles il est strictement applicable. Ce travail évalue la distribution des défauts au sein d'une masse rocheuse en utilisant une projection sphérique des contours d'échantillons d'orientations générées aléatoirement et de données de cartographie provenant de greywackes à joints rapprochés de Nouvelle Zélande. Deux indices de cette projection - la zone des contours en dessous de 1 % (A1%) et celle de concentration maximum (Cmax) sont introduites pour distinguer les répartitions uniformes (isotropes), aléatoires ou régulières. Ces indices fournissent une extension potentielle aux règles d'utilisation du critère de rupture de Hoek-Brown. Ce travail utilisent également les contrôles cinématiques pour évaluer l'influence des groupes de défauts sur la résistance de la masse rocheuse.

Jan 1, 2003

By T. D. Parris

Within a 30-mile radius of Sudbury, Ontario, the Ontario division of the International Nickel Co. of Canada, Ltd., operates nine underground mines and two open pits. Prior to 1966, ore removal from the underground workings was mainly by scraping, using 125-hp electric slushers in blasthole and caving mining, and 30-hp or less air-operated slushers for fill- method mining. The development and evaluation of low-profile, diesel-powered front-end loaders, designed specifically for underground operations, was followed with keen interest during the period 1964-1965.

Jan 6, 1969

Session 1 ? Intro to MiHR ? Business Case for Aboriginal Inclusion ? Overview of the Mining HR Guide for Aboriginal Communities ? Two presentations of Programs featured in the Guide ?? The RAP Program from NWCC ?? First Nations Youth Employment Program PDAC-MM Session 2 ? Presentation from MAC ? Taking up the AFN Corporate Challenge ? Presentation on Mastering Aboriginal Inclusion in Mining About MiHR Who we are: ? National Sector Council for the Minerals and Metals Sector ? 18-person Board of Directors ? 100+ Industry Leaders volunteer on our project committees ? PPP - Funded by HRSDC and industry What we do: ? Identify national HR challenges and opportunities for the minerals and metals industry ? Create national solutions through collaboration, partnerships and Synergy

May 1, 2009

The Greymouth Coal field is situated on the West Coast of New Zealand's South Island and has been mined for coal for more than 120 years. The area covered in this paper is within the Rapahoe Sector of this field and contains >200 million tonnes of low ash, low sulphur, bituminous rank coal. Paper No 6, presented to the 19th Annual Conference of the New Zealand Branch of The Australasian Institute of Mining and Metallurgy in Christchurch in August 1985 by R G Bowman, explained 'A Geologist's View' of the 'Economic Potential of the Greymouth Coalfield', and describes previous geological assessments of the Rapahoe Sector.

Jan 1, 1989

The disasters between 1920 and 1979 in coal mines in Queensland and New South Wales due to underground fire, gas or coal dust explosion or to gas or coal outbursts, have been assessed. The evidence relating to disasters caused by gas explosion points strongly to divergence from safe mining practice as the main cause. There is a need for greater training and education of personnel, closer analysis of gas reports, better monitoring and testing procedures, improved ventilation standards and a policy where safe working practice is actively encouraged. Conditions in the New South Wales occurrences of gas explosion were similar to those at Collinsville, Queensland in that dykes, igneous sills, burnt out coal and faulting were common to all. Information on outbursts indicates that contributing factors were intrusions, depth of cover, fault zones and other geological disturbances, methods of work, pressure and type of gas.

Jan 1, 1982

By A F. Wilson

The use of stable isotopic measurements as a technique for elucidating the origin and history of the water in hydrothermal fluids is relatively new. Recent studies have emphasised the importance of meteoric water in the formation of many hydrothermal ore deposits including many epithermal gold-base metal deposits which occur in faulted volcanic terrane. Other vein-type gold ores are believed to have formed from fluids of magmatic or metamorphic origin and exhibit characteristic d180 values. These values also give information regarding temperatures and the degree of equilibrium. Preliminary oxygen data for some important gold deposits of eastern Australia are evaluated in the context of styles of mineralisation.

Jan 1, 1980

By Anil K. Ray

This paper discusses in situ studies conducted at an Illinois Basin room-and-pillar coal mine to evaluate the performances of three different types of bolts under similar geologic conditions. The bolt types considered were the fully grouted passive rebar (FGPR), the resin-assisted mechanical anchor (RMAB), and the fully grouted tension rebar (FGTR). During the evaluations, the three types of bolts were installed in a single entry covering a span of three contiguous pillars with almost identical geologic conditions. The performances of the three types of bolts were investigated by instrumentting the bolts prior to installation as primary supports on cycle. Additional data on roof behavior was collected with extensometers and shear meters placed near the instrumented bolts. Excluding some time lapse right after installation, the performance evaluation of the three bolt systems was based on the data collected for over a year. Based on this study, it was found that the axial loads measured in the different bolt types did not show any identifiable patterns under the prevailing geological conditions at the mine. Therefore, the assumption that active bolts must be superior to passive ones is not always valid. Even though the studied mine did not have any thinly laminated, weak rocks in the immediate roof, the passive bolts performed as well as the active systems.

Jan 1, 2012

By J. Hansen

This paper has been written for presentation during the Open Pit Mining Session at the SME Annual Meeting and Exhibit, Denver, Colorado, February 26 to 28, 2001. The paper addresses the application of automated monitoring of electric rope shovels to improve performance and blasting technique.

Jan 1, 2001

By D. Settles, R. Rose, P. L. Dunn

"A new mineral sands operation is being developed in Georgia by Southern Ionics, Inc. (SII). Prevailing mineralogy and certain design constraints required detailed testing and circuit analysis to create a robust separation processes. The floating wet concentrator plant (WCP) and mineral separation plant (MSP) flow sheets were designed based on historical testing information and recent SII test campaigns on various composite feed samples. The flow sheets were finalized through rigorous process and orebody sequence modeling.The process uses traditional physical separation equipment; however a new MT spiral, the MG12, was selected for use on board the WCP for roughing duty. The MG12 spiral is a two-stage, twelve-turn spiral that has been proven to achieve very high recoveries of heavy minerals. The floating plant includes feed desliming operations, a central MT surge bin for optimum spiral circuit feed control and ancillary operations for concentrate and tailings handling. Scrubbed heavy mineral concentrate (HMC) is then transported to the MSP for concentration of the titanium and zirconium bearing mineral fractions.The testing, flowsheet development, and plant design will be described and explained, and a brief summary of the current project status will be given.IntroductionSouthern Ionics Inc. (SII) is a privately held chemical manufacturing company, founded in 1980 by Milton Sundbeck. SII focuses primarily on the sale of specialty and intermediate inorganic chemicals. Core markets include cement and refinery catalysts, molecular sieves, zeolites, pulp and paper, pharmaceuticals, TiO2 and water treatment. SII is built on the four cornerstones of service, quality, technology and delivery with all SII facilities ISO certified and key products used in potable water treatment certified to NSF standards. SII owns and operates its own transportation fleet and is focused on being a low cost producer, committed to safety and the environment."

Jan 1, 2015

By Robert Jakiel

The following paper is being presented to provide a basic understanding of the equipment and procedures used in multi-auger deep soil mixing as part of the program for the Deep Foundations Institute (DFI) Deep Soil Mix Seminar. The paper is written as a summary of the author's experience using multi-auger deep soil mixing equipment while working with SMW Seiko, Inc. on several east coast projects in the United States, particularly the soil-cement mixing for the soil stabilization of the Fort Point Channel area in Boston, Massachusetts, one of the largest and most difficult soil mixing projects completed thus far in the United States. The summary provides a brief summary and insight into some of the operational aspects of the equipment and procedures, and some of the important considerations when using multi-auger deep soil mixing. This paper is intended for use by both the contractor and the designer involved in selecting appropriate soil mixing equipment and procedures for various types of soils, depths or applications, or for a better understanding of the operational aspects, potential benefits, and impacts that the performance criteria may have on the operational capabilities of the soil mix equipment, when specifying multi-auger soil mixing for a particular project. Prior to reading this article it is important to become more familiar with the various acronyms and terminology used in soil mixing technology. A Definitions section has been provided at the end of the paper that will help the reader become more familiar with some of the terms used throughout this paper.

Jan 1, 2001

By H. Hurkchand

Background: A cross-sectional study was conducted in November2001 to establish the prevalence rates of Human Immunodeficiency Virus (HIV) and sexually transmitted infections (STIs) (Chlamydia trachomatis and Neisseria gonorrhoea) in a coalmining town in Mpumalanga. Methods: 155 adults were recruited (79 males and 76 females), by holding community meetings, and by door-to-door recruitment. Saliva and urine specimens were collected for the analysis of HIV and STI prevalence, respectively. Results: The mean age for males was 31.35 years (min = 19 yrs and max = 50 yrs) and the mean age of the female participants was31.90 years (min = 17 yrs, max = 49 yrs). The prevalence of HIV was found to be 22.78% [95% CI (14.09?33.59)] in the males vs. 47.37%[95% CI (35.79?55.16)] in the females, [p = 0.001, OR = 3.05, 95%CI(1.49?6.26)]. The prevalence of C. trachomatis was 7.90% [95% CI(2.95?16.39)] in the males vs. 12.86% [95% CI (6.05?23.00)] in the females, p = 0.324. The prevalence of N. gonorrhoea was 3.79%[95% CI (0.79?1.08)] in the males vs. 9.86% [95% CI (4.06?19.26)]in the females, p = 0.137. HIV was significantly associated with C. trachomatis, [p = 0.032, OR = 3.18, 95% CI (1.04?9.72)], but was not significant when stratified by gender. HIV was not significantly associated with N. gonorrhoea (p = 0.072) but it was significantly associated when stratified by gender, p = 0.001 for females. There were no significant associations between HIV and age (p = 0.408), even upon stratification by gender. Conclusions: HIV prevalence in this community is high, and corresponds to national figures. However, the prevalence of STIs is surprisingly low as it would be expected to be high in a migrant population. Although communities are exposed to expanding peer-education activities that encourage behaviour change, the prevalence of HIV in this group. There is an urgent need for interventions designed to treat or prevent HIV infection in women generally and in women at high risk. Keywords: HIV prevalence, STI prevalence, antenatal, mining

Jan 1, 2005

By A. R. Gaba

Phase I of the Canary Wharf development in London's docklands involves the construction of six fifteen storey buildings located predominantly over water of the West India Docks. The buildings are supported on some 1000 No., 25m long, open ended steel tubular piles driven through 10m of dock water to found in dense sand at a depth of about 15m below dock bed level. The piles are of composite section with reinforced concrete within the upper 17m of the steel tube. Three trial piles were installed in the dock to investigate the driveability and performance of the driven steel tubular piles. The piles were subjected to dynamic and static load testing. Loads were applied in both vertical and horizontal directions. Vibrating wire strain gauges were installed on the inside of the steel piles, on the reinforcement and in the concrete to determine the relative proportions of the applied load carried by the steel tube and concrete infill and to establish how these proportions varied along the length of the piles. Inclinometers were also installed to monitor the lateral deflection of the piles. This paper describes the driving, construction and testing of the three trial piles. The results of the vertical and horizontal loading tests are discussed and comparisons are made between dynamic and static tests carried out on the piles.

Jan 1, 1989

By Edward A. Metz, R. Larry Grayson, Douglas F. Scott

We describe inconsistencies in disease and illness reporting in U.S. mining, identify under-reporting of disease and illness in U.S. mining, and summarize selected disease and illness in U.S. mining from 1983 through 2001. Methods: We summarized information on mining-related disease and illness data for the years 1983-2001 from the Mining Safety and Health Administration database (MSHA). Results: Discrepancies exist in types of information collected by the Centers for Disease and Control, the National Institute for Occupational Safety and Health, and the Mining Safety and Health Admin¬istration database. Several factors, including a worker's fear of losing his or her job, health insurance, or other job-related benefits contribute to under-reporting of disease and illness information in the US mining industry. Conclusions: Since 1997, both number of workers employed in mining and disease and illness rates have decreased; however, the highest disease and illness rates in mining continue to be coal worker's pneumoconiosis and hearing loss.

By C. Swart

Automation technologies are increasingly adopted in different mines world-wide. This paper presents the technical aspects of vehicle automation applications at two Noranda operating mines. Teleoperation of 5 LHDs at Noranda?s Bell Allard mine is used in order to meet aggressive mining requirements under difficult conditions. The equipment is performing under high demand for reliability and performance. In order to further increase performance, automated loading has been commissioned on one of the LHDs and is being tested. Results to date indicate improved performance with respect to an operator through better filling of the bucket, fewer passes at the muck pile and shorter cycles. Noranda?s Brunswick mine is currently commissioning an automated haulage zone where two optically guided trucks transport ore from a remotely operated chute to two ore passes. Expected operational advantages include increased system capacity and enhanced safety and comfort for the operator. Monitoring to date indicates that the trucks can operate reliably under the conditions imposed by mine production.

Jan 1, 2002

By Forrest T. Moyer

Frequency rates of injuries per million man-hours of exposure were improved during 1965 slightly to moderately over those of 1964 at metal mines, nonferrous reduction and refining plants, nonmetal mills, stone quarries and mills, sand and gravel operations, and slag operations. However, at metal mills and nonmetal mines the rates of occurrence of work injuries were less favorable. The severity rates of injuries during 1965 were better than in 1964 at metal mines and mills, stone quarries and mills, and slag operations. Conversely, severity rates were worse at nonferrous reduction and refining plants, nonmetal mines and mills, and sand and gravel operations.

Jan 1, 1966

Today computers are accepted as a standard item in industry and they perform a variety of tasks over a wide spectrum of activities from mine planning and CAD to data processing and spreadsheet work. However many problems particularly in the. area of decision making where there are no clear mathematical models available and usually the output or answer is dependent to some extent on a heuristic approach, don't lend themselves to conventional solutions using standard procedural algorithms. Recently a number of techniques have evolved primarily from the enhanced capabilities of modem equipment, which are capable of solving these problems. This paper is a brief overview of these rather unconventional developments of computer technology in the area of artificial intelligence with reference to their application in mining.

Jan 1, 1993

By A. D. Davis

Limestone-based material is effective for reducing arsenic concentrations below the current limit of 10 parts per billion for drinking water, typically resulting in final concentrations of about 4 to 6 ppb. However, in laboratory and field testing, further reductions to the 1 ppb range are difficult to achieve with limestone unless other material such as iron is added. The removal mechanism with untreated limestone appears to be the formation of a low-solubility precipitate of hydrated calcium arsenate, in the form of arsenate-apatite. Likely reactions and thermodynamic data indicate a theoretical removal limit of about 2 to 4 ppb for arsenic using raw limestone. Limestone also can reduce concentrations of cadmium and lead below 1 ppb in water, resulting in >99% removal efficiency. Thermodynamic constraints appear to be favorable for reactions involving the formation of otavite during cadmium removal and the formation of hydrocerussite during lead removal.

Feb 27, 2013

By S. E. Phillipson

Underground mine mapping is a critical component of understanding the controls on ground instability. Many relatively localized examples of ground failure are associated with geologic features, such as faults, joints, compaction zones, or sedimentological transition zones. In contrast, long-running, directional roof falls are associated with regionally directed horizontal stress fields, which are induced by tectonic plate interactions in the earth?s crust. When stress-related features are distinguished from geological features, underground mapping can be an effective method for inferring the direction of horizontal stress at individual mines. Comparisons with data compiled in the World Stress Map confirm that underground mapping can be a valid method for determining the orientation of maximum principal horizontal stress at a variety of scales, ranging from individual mines to an entire mining district or coal basin. Comparisons are presented between the maximum horizontal stress directions inferred by MSHA?s Roof Control Division through underground mapping and the azimuths of maximum horizontal stress in the World Stress Map database for North America?s Pennsylvanian-aged Appalachian, Illinois, Black Warrior, and Arkoma Basin coal fields. The comparison indicates that azimuths are similar for both data sets, even where variations in the direction of horizontal stress are present. It is interpreted that inconsistencies in direction are attributable to near-surface affects such as deeply incised stream valleys, or to fault zones that represent heterogeneities in the crust.

Jan 1, 2009

By Zhuokun Cao

Manufacture of aluminum foams still suffer from nonuniformity and poor reproductively for there is lack of basic knowledge of foaming process. In this paper, carbon fibers are used as novel stabilizing additive for aluminum foams, and the structure evolution of aluminum foams with different fiber content was studied. A laser rangefinder was used to detect the expansion rate of different al foams. Al foam samples are solidified at different foaming time to determine its relative density and cell size distribution. Results indicate that the cell size of foams linearly increases with the decrease of density, and the slope of the line is influenced by fiber content. The relationship between expansion ratio, density and cell size of the foams is discussed. It is concluded that the density of resulting foam is influenced by the rate of gravity driven drainage, and its cell size is determined by expansion ratio and foaming time.

Jan 1, 2010

By F. E. du Plessis

"The distinction between data suitable for process control and data subject to aliasing only becomes quantifiable with the availability of rapid real-time measurements. Expecting the dynamics of flotation to vary for different ore types, process flows and equipment types; a study was conducted to compare the dynamics of different flotation processes. The results shed light on the critical sampling intervals required for process control which in turn allows process stabilization and optimization. The technology used for the in-line measurements is based on diffuse reflective spectroscopy and has been introduced into the mineral processing industry over the past ten years. It has been widely implemented in the sulphide flotation industry in South Africa for the real-time measurement of grade.BACKGROUND AND OBJECTIVE A study was conducted by Du Plessis and Keet (2010) to quantify the minimum sample frequency required for grade and/or impurity control. The study was based on chromite data collected at 15 second intervals from the concentrate line of a flash float cell in the Platinum industry. The data captured the natural process variation of the entrained chromite through water recovery due to changes in feed parameters and flotation performance. It was found that the minimum rate of sampling required from the studied flash float concentrate was 2 minutes. This sampling interval time accounted for 90% of the variance in the process data. It was further found that a sampling interval time of longer than 4 minutes produced data with no significant correlation to reality. The dynamics of the flotation process has been misjudged in the past but can be quantified with the availability of real-time grade measurement based on diffuse reflective spectroscopy. The objective of the study was to compare the dynamics of different sulphide flotation processes through the comparison of maximum sampling interval times required to combat aliasing. All data were collected from single stream analyzers that are currently installed at mineral concentrators. The technology used is based on diffuse reflective spectroscopy."

Jan 1, 2012