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By W. D. Guo

With an experimental apparatus developed recently, model tests on piles were conducted in sand subjected to triangular soil movement profiles. Four instrumented piles tests are reported, which show the pile behavior predominantly determined by soil sliding depth. Axial load can create additional bending moment and pile deflection, which also make mode of pile-soil interaction change with sliding depth. Limiting resistance was found 1.5~3 times higher than currently used for laterally loaded piles in sand.

Jan 1, 2006

By G. A. Brown

Major mining projects are developed with the assistance of lending institutions who provide hundreds of millions of dollars in funding over several years, and of course expect those funds to be returned with interest. Two Australian banks have adopted the Equator Principles, an emerging financial industry benchmark for assessing and managing environmental and social risk in project financing. Project financiers have encountered environmental and social issues that are both complex and challenging, particularly with respect to projects in the emerging markets of Asia-Pacific and elsewhere. There are many recent and historical examples of failures by resource companies to effectively manage their environmental, social, safety and security risks, some of which have caused the project to fail completely, and some of which have caused the temporary cessation of production. These events put the financial institutions' funds at risk through inadequate management capacity and non-compliance adversely affecting the ability of the borrowers to repay the loans. They can also reflect adversely on the reputation of the lending institutions. In assessing these risks, lenders are increasingly looking at the track record of the borrower in its country of origin and in other countries where it operates. Lenders are wary of companies that have one standard for operations in a developed country, where the regulatory environment may tightly control what they do, and another standard for operations in countries where the regulatory regime is perhaps less stringent. Lenders may require environmental and social reviews or audits to be conducted on their behalf by competent third parties prior to a loan being approved, and annually over the life of the relationship. The mining industry's concept of the unwritten `social licence to operate' is highly relevant in relation to the delivery of community benefits that are sustainable post-mine closure. This paper provides examples of recent practices that support financial viability and sustainable development, as well as examples of some failures that have put lenders at risk.

Jan 1, 2007

By Timothy C. Siegel

This report presents the results of a synthesis on the design and analysis of ground improvement for liquefaction mitigation. The synthesis included an industry survey concerning the practice of ground improvement for liquefaction mitigation. Participation in the survey was solicited by advertisements in several trade magazines and by e-mail for the DFI membership. The survey participants numbered 150. Their professional roles include consulting engineers, specialty contractors, design engineers, government engineers, and academicians. They represent a variety of geographical areas including North/Central/South America, United Kingdom, Middle East, Caribbean, Hawaii, Japan, India, Egypt, France, Australia and New Zealand. Upon completion of the survey, several professionals in the field of liquefaction and ground improvement were interviewed for them to elaborate on the survey results. The interviews are included in the Appendix of this report. Financial support for the project was provided by DFI and Dan Brown and Associates PC. The concept of the liquefaction mitigation synthesis was developed by DFI?s Ground Improvement Committee in recognition that: (a) The results of recent research and post-earthquake reconnaissance have challenged previously longheld beliefs about liquefaction and associated mitigation techniques, and; (b) The DFI membership and the engineering/construction industry are interested to know if and how engineers and designers are subsequently adjusting their practice in consideration of recent research and post-earthquake reconnaissance. For more detailed information on recent research and post-earthquake reconnaissance, presentations are available from the State-of-the-Art Forum: Liquefaction Consequences and Mitigation that was held in St. Louis in 2012. A commentary of the state-of-practice in ground improvement for liquefaction mitigation (prepared by DFI?s Ground Improvement Committee) is included in this issue of the DFI Journal. The author would like to thank the participants of the survey and especially Mr. Mike Jeffries, Dr. Les Youd, and Dr. Ikuo Towhata for their willingness to share their expertise in interviews. The author also acknowledges Mary Ellen Bruce of DFI, Billy Camp of S&ME, Inc., and Marty Taube of DGI Menard (and Chair of DFI?s Ground Improvement Committee) for their signifi cant contributions.

Aug 1, 2013

By D. Grgic, A. Giraud, F. Homand

RESUME : Le comportement mécanique partiellement saturé du minerai de fer a été étudié à partir d’essais de compression simple sur des éprouvettes à pression capillaire imposée par les solutions salines. Les échantillons restent peu saturés (32 %) même pour une humidité relative de 94 %, du fait de la présence de mésopores. Jusqu’à 90 % d’humidité relative la résistance diminue régulièrement. De 90 % à 94 % une forte chute est observée et pourrait être liée à la fois aux effets capillaires et à l’hydratation de certains minéraux. Le cycle hydrique subit par la roche dans la mine a été modélisé en 1D à l’aide d’un code de calcul entièrement couplé pour les milieux poreux partiellement saturés. Les calculs ont montré notamment une diminution importante en paroi des contraintes totales au cours de la phase de désaturation et une augmentation importante au cours de la phase de resaturation. Ces variations pourraient induire un endommagement du massif et être à l’origine d’instabilités, et soulignent l’intérêt d’une modélisation avec une géométrie plus adaptée. MOTS-CLEFS : mines de fer, partiellement saturé, pression capillaire, résistance, modélisation. ABSTRACT : The partially saturated mechanical behavior of iron ore has been studied from uniaxial compression tests on samples in which the suction is imposed with aqueous solutions. Samples are little saturated (32 %) even for a 94 % relative humidity because pores are too large. Up to 90 % relative humidity the strength decreases regularly. From 90 % to 94 % a great decrease is observed ; it could be explained by the capillary effects and the moisturizing of some minerals. The hydrous cycle imposed to the rocks in the mine has been modeled with an 1D fully coupled code for partially saturated porous media. The computations have shown an important decrease in the total stresses at the wall during the desaturation stage and an important increase during the re-saturation stage. These variations could induce a rock mass damage and instabilities, and highlight the necessity of a modeling with a well-adapted geometry. KEY-WORDS : iron mines, partially saturated, suction, strength, modeling. ZUSAMMENFASSUNG : Das mechanische Verhalten von teilweise gesättigten Eisenerz wird durch einachsige Druckversuche untergesucht. Die Prüfkörper haben einen durch Salzlösungen gestimmten kapillarischen Druck. Sie bleiben kaum gesättigt (32 %), sogar bei einer relativen Feuchtigkeit von 94 %, aufgrund der Anwesenheit von Mesoporen. Bis eine relative Feuchtigkeit von 90 % verringert sich gleichmässig die Druckfestigkeit und zwischen 90 % und 94 % merkt man eine starke Abnahme in Verbindung, möglicherweise, mit kapillarischen Effekten und Hydratation von bestimmten Mineralen. Die nümerische 1D Modellisierung des gezwungenen Wasserzyklus im Stein der Mine ist mit einem für porösen Medien ganz vernetzten Rechnungcode geführt. Sie zeigt besonders ein bedeutendes Sinken der Gesamtspannung während der Entwässerung und eine bedeutende Steigerung während der Sättigung. Diese Veränderungen könnten die Beschädigung des Gesteines herbeiführen und die Grundlage von Unstabilität sein. Sie unterstreichen die Wichtigkeit eine Modellisierung mit einer gut geeigneten Geometrie. STICHWÖRTER : Eisenminen, teilweise gesättigt, kapillarischer Druck, Druckfestigkeit, Modellisierung.

Jan 1, 2003

By David G. Adam

Introduction Syncrude Canada Ltd. is the operating company for a consortium of industry and government participants that produce synthetic crude oil from their leases in the Athabasca Oil Sands. Production from the $2.3 billion (1978) integrated mining, extraction, and bitumen upgrading and utility complex started in September 1978. Production is currently about 6.4 Mm3/a (40 million bbl per year) of high quality synthetic crude oil. This is done by upgrading the extracted bitumen from the oil sands mined. Plans are to increase the production to 8 Mm3/a (50 million bbl pier year) by 1989. At that time, the mining operation will be required to deliver 100 Mt/a (110 million stpy) of oil sand (ore) to the extraction plants, and handle quantities of waste ranging from 50 to 75 Mt/a (55 to 83 million stpy). The Syncrude plant is located at Mildred Lake, 40 km (25 miles) north of Fort McMurray and 480 km (300 miles) north of Edmonton, Alberta. Climate, particularly winter, is therefore a major factor affecting the design and operation of all the Syncrude production facilities. Bitumen production, consisting of overburden removal, oil/sand mining, bitumen extraction, and tailings disposal, account for about half the total SCO production costs. Considerable research and development, therefore, continues to be applied to improve both material handling and bitumen recovery methods. Potential applications for feeder breakers were identified in the material handling aspects of both overburden and oil sand mining to reduce cost and to attain planned production increments. Overburden removal Overburden materials on the leases comprise thin Pleistocene sands, gravel and fill, and sands, silts and clays of the thicker Clearwater Formation with the silt to clay components predominating. The latter contains multiple leases of hard siltstone with unconfined compressive strengths up to 148 MPa and thicknesses up 0.1 to 0.9 m (1 to 3ft). Characteristics of the overburden as well as the climatic environment and scale of operation present unique problems for the efficient removal of the material. In a bucketwheel/conveyor system, the weak silty clay formations require relatively flat working slopes for safe operation, while the siltstone lenses and frozen overburden require blasting or selective removal by other equipment. These factors, combined with the normal bucketwheel/conveyor design parameters, lead to high capital investment and relatively inefficient use of that capital. Hydraulic mining alternatives, including dredging, are constrained by severe clay settling problems in the waste disposal

Jan 6, 1986

In September, a fleet of 363-t (400-st) Liebherr trucks became operational in Brazil and have already begun moving iron ore in Para state. Prior to the arrival of the the trucks the Brazilian fleet relied on trucks up to 218 t (240 st). With the addition of the 363 t (400 st) trucks, the fleet has since experienced the high productivity offered by Liebherr T 282 B trucks.

Jan 1, 2010

Lime and Marble Limited was founded by the late T J McKee OBE and his family in 1935. The Company had its base in the high grade marble deposits on Takaka Hill, and was also shipping crushed limestone to the Auckland glass works, and supplying burnt lime for industry.

Jan 1, 1998

By A. D. Nicholson

This paper presents an approach to quantitatively calculate the neutralization of acid by silicate minerals, based on the chemical kinetics of acid reacting with silicates. This approach incorporates incongruent dissolution mechanisms and the effects of silicate iron content on net acid consumption, and offers guidelines for considering the extent to which specific silicate minerals will react. This approach differs from previous methods of estimating silicate buffering: it is based more on the fundamental chemistry of acid generation, and less on potentially misleading empirical measurements of acid neutralization.

Jan 1, 2002

By R. C. Adams

This report describes the feasibility of mining the oil-shale deposits of the Piceance Creek basin in Colorado by an integrated open pit system. The study is based upon a comprehensive analysis of pertinent environmental, economic, and engineering factors. Ten mining cases are investigated, and the mine design and cost estimates for each case are presented in this report. Nine of the cases represent three cutoff grades, defining oil shale ore as equal to and above 15 gallons per ton (gpt), 20 gpt, and 25 gpt, at three ore production levels of 500,000 tons per day (TPD), 1,250,000 TPD, and 2,500,000 TPD. The tenth case is an alternate design of the 500,000 TPD production rate at the above 15 gpt cutoff grade. The report consists of Volume I, a technical and cost comparison of the ten cases; Volume II-Part I, a detailed explanation of the estimating methods used; and Volume II-Part 2, a more detailed discussion of the technical and cost features of the ten cases than is presented in Volume I.

Jan 1, 1976

By S. Rajendran

The area of the Exclusive Economic Zone (EEZ) of India is about 2.014 million km2 and the resource evaluation of placer deposits is one of the objectives of Government of India. Placers are detrital metallic minerals found on beaches and in the near shore areas. Quantitatively more important are placer deposits of light heavy minerals such as zircon, ilmenite and rutile. Rivers and other drainage channels are the main carriers of the placers which contain heavy minerals like magnetite, ilmenite, garnet, zircon, monazite, rutile etc. The present beach as well as part of the shelf was land during Pleistocene as a result of the world wide lowering of the sea levels. The coast line shifted a number of times. Hence, the heavy mineral placers on the beaches are expected to extend to offshore areas chiefly with Pleistocene lowered sea level strands. India has extensive deposits of heavy mineral placers along the beaches. Placer deposits of heavy minerals occur in discontinuous patches on the beaches along many parts of the east and west coasts. Along the central west coast of India (12??N - 19? N lat.) the placer containing 14 - 17% ilmenite form an estimated reserve of 4 million tons. On the Ratnagiri coast of Maharashtra, the proportion of heavy mineral varies between 54 and 70% in the bulk samples, consisting mainly of 14 - 39% magnetite and 16 - 30% ilmenite. The National Institute of Oceanography (NIO) surveys show that the sediments off the central west coast consist largely of silty sand, sand silt and clay. The core samples show that a reddish brown clay overlay olive gray clay which in turn overlay heavy mineral rich sands. The heavy mineral concentration ranges upto 90% and has mainly ilmenite and magnetite with minor quantities of apatite, rutile, zircon, kyanite etc. Siddiquie et al. reported 42 - 75% TiO2 in the ilmenite.

Jan 1, 1998

VISIT TO HENDRINA POWER STATION AND OPTIMUM COLLIERY A visit to Hendrina Power Station and the Optimum Colliery, contractually committed to supply the coal for the power station, took place on the 20th September, 1972. INTERNATIONAL IRON AND STEEL CONGRESS This congress will be held in Dlisseldorf from May 23rd to 30th, 1974. The main theme is "Metallurgical Technology of Iron and Steplml1king".

By J. McMurray

Introduction Uranium was recovered from mining of collapse breccia pipe deposits in the Arizona Strip district in northwestern Arizona (Figure 1) intermittently between 1956 and 1990, with cumulative production having totaled 23.3 million pounds of U3O8 (8960 tU) at an average grade of 0.6% U3O8. Production was suspended in 1990 because of low uranium prices, but the recent resurgence in market price once again makes the breccia pipe deposits potentially attractive exploration and development targets. This paper describes: (1) formation of the pipe structures and their metallogenesis; (2) mining and milling of breccia ore; and (3) potential roadblocks to development of new breccia pipe mines. Breccia Pipe Formation Formation of the breccia pipes began in cave systems formed during development of karst topography in the Mississippian Redwall Limestone. The karst Redwall surface was eventually covered by up to 900 meters of shallow marine to continental sediments ranging in age from Pennsylvanian to Triassic. The pipes were formed by progressive upward stoping caused by groundwater ascending under hydraulic head along near-vertical faults, joints and fractures. The stoping process involved both chemical disaggregation and mechanical failure of roof and wall rock. Upward stoping of successively younger units allowed for upward propagation of a pipe and resulted in a chimney-like column of breccia between the steep walls of the pipe. Syndepositional thickening of sedimentary units of varying ages indicates that pipe formation began as early as early Pennsylvanian time and continued intermittently through Triassic time.

Jan 1, 2007

By Paul D. Tomlingson

There are huge benefits for mining operations that have a well-defined maintenance program that is understood and followed across the total operation. But for operations lacking a quality maintenance program, there is equal assurance that nearly every major maintenance problem can be traced to this omission. Few problems will be permanently corrected until such a program is implemented. Definition The maintenance program re-quires the interaction of all mine departments. Initially, the production department will request work and the maintenance department will identify work, principally through preventive maintenance inspection and testing efforts. Maintenance will then classify the new work to determine the best way to respond. Maintenance will plan selected major jobs to enable its crews to carry them out more effectively. Maintenance will schedule the planned work with operations. Supervisors will assign all types of work to their crews then, control the work through effective supervision. As work is completed, maintenance will measure the work using an accurate information system. Next, it will assess overall accomplishments against goals such as performance standards or budgets. In addition, the pro-gram would prescribe a means to evaluate every aspect of the operation as it affects maintenance so that necessary improvements or changes can be identified, prioritized and acted on. Such evaluations should be part of a mine-wide continuous improvement effort. A well-defined maintenance program is one of the best investments a mining operation can make to assure its profitability. Educating the total operation on the pro-gram assures long-term dividends from the investment.

Jan 1, 2008

By K B. Quast, A Schuurmans

Laboratory batch rod and ball milling tests were conducted on samples of Heavy Medium Separator (HMS) sinks from Renison Limited. The effects of mill rotation speed, rod volume and ball size on the resulting product size distribution were investigated. Between 48 and 69 per cent of critical speed, the product sizing distribution curves remained very similar, with a finer grind resulting from increasing the speed of rotation at constant grind time. Increasing the rod loading from ten to 53 per cent by volume caused the product size to become finer and more closely sized with a transition occurring at approximately 29 per cent. This was interpreted as a change of dominant grinding mechanism from abrasion to impact. No preferential grinding of the cassiterite was observed. The effect of increasing ball size at constant charge weight was to preferentially grind the coarser particles and generate more intermediate sized particles, whereas the product from a mixed ball charge gave a distribution similar to that obtained when a charge containing only smaller balls was used.

Jan 1, 1998

By Heidecker A

Several types of drainage structure providecost-effective environmental controls for water supply to Charters Towers and its mining industry. Drainage groves maintain bank-levee, channel, pool, and spring structures. Failure of drainage structures leads to anoxic fermentation of channel fill releasing residues, such as arsenic, which would otherwise pass harmlesly by fixed on sedimentary particles.Experiments along drainage structures indicate that productive agroforestry could be integrated with expeditious development of groves to cope with environmental change.

Jan 1, 1990

By ATF Publications

The following is a summary of the changes that were incorporated into the new Federal Explosives Regulations, 27 CFR Part 55, dated 9/2000. However, in light of the recent events of September 2001, additional changes in the Federal Explosives Laws and Regulations may be forthcoming. The nature and extent of any such potential changes are impossible to gauge at this time. However, this synopsis of the changes contained in the September 2000 Orange Book, ATF P 5400.7 was current at the time of this writing. Any questions regarding this paper should be directed to the Public Safety Branch in ATF Headquarters in Washington, D.C.

Jan 1, 2002

By W. H. Pomroy

In its 2001 diesel particulate matter (DPM) rule for metal and nonmetal underground mines, MSHA established an interim concentration limit of 400 micrograms of total carbon (TC) per cubic meter of air (400TCµg/m3), and a final concentration limit of 160TCµg/m3, to be phased in over five years. Following a court challenge to the 2001 rule, MSHA, industry and organized labor reached a partial settlement of the litigation under which the agency agreed to issue a proposal to amend the 2001 rule by, among other things, changing the surrogate from TC to elemental carbon (EC), applying MSHA's traditional hierarchy of controls, and revising requirements for one-year special extensions for complying with the final DPM exposure limit. MSHA issued a final rule in 2005 converting the interim concentration limit from 400TCµg/m3 to 308 micrograms of EC per cubic meter of air (308ECµg/m3) based on a miner?s personal exposure. Pending further rulemaking, MSHA retained the final concentration limit of 160TCµg/m3. In May 2006, MSHA issued a final rule that clarified that the final limit of 160TCµg/m3 would be based on a miner?s personal exposure rather than as a concentration limit. The 2006 rule also phased in the final DPM limit in three steps over two years, beginning in May 2006 at 308ECµg/m3, followed eight months later in January 2007 with a limit of 350TCµg/m3, and finally reaching 160TCµg/m3 in May 2008. Also in the 2006 rule, MSHA committed to converting the 160TCµg/m3 limit to an EC limit in future rulemaking. This paper reviews the DPM exposure limits in the context of the MSHA rulemakings and discusses the DPM engineering controls that were utilized by mine operators to attain compliance with each progressively lower limit.

Jan 1, 2009

By Peter G. Kovalchik, Rudy J. Matetic, Susan B. Bealko, Adam K. Smith

Overexposure to noise remains a widespread and serious health hazard in the U.S. service providing and goods producing industries. Excessive noise can lead to poor verbal communication and reduce the ability to recognize warning signals. These dangerous work conditions can also cause stress and fatigue. Occupational hearing loss is a permanent illness, with no recovery currently possible. Method: National Institute for Occupational Safety and Health (NIOSH) has recognized Noise Induced Hearing Loss (NIHL) as one of the ten leading work related diseases and injuries in the United States, and has emphasized its importance as one of the critical areas expressed in the National Occupational Research Agenda. Results: One of the most serious noise problems in the goods producing industries is the operation of continuous mining machines during underground coal mining. In order to minimize occupational hearing loss, noise hazards are “designed out” early in the design process. NIOSH is leading a national initiative called Prevention through Design (PTD) to promote this concept. This paper describes the quiet by design approach of a noise control that reduced noise exposures of continuous mining machine operators by 3dB(A) using the four functional areas of PTD, namely Practice, Policy, Research, and Education.

What decision making tools and methods are available to a project owner when there is no clear differentiator between construction alternatives? A team led by a joint venture of Parsons Brinckerhoff and PGH Wong Engineering (PB/Wong) has been providing preliminary engineering services to the San Francisco Municipal Transportation Agency (SFMTA). The SFMTA and PB/Wong team developed several alternative construction methods for the tunnels and stations of the San Francisco Central Subway Project, none of which could be judged clearly better than another using traditional approaches and metrics. The team employed a risk assessment and analysis frame-works as a means of comparative analysis, drawing upon the knowledge of industry experts in the geotechnical, tunneling and construction fields to assist in the effort. This paper presents the approach and results of a cost and schedule risk analysis for two such analyses designed to answer two different questions regarding the advisability of different construction approaches. These assessments paved the way for key decision making in the preliminary engineering phase of the project and formed the foundation for continuing risk management efforts on the project. The focus of this paper is primarily the first two stages of risk management?identification and assessment?and some of the organizational dynamic issues that arise in such efforts.

By K. G. Kebkal, R. Bannasch

"Because the operation of tethered underwater vehicles in the deep ocean or under drifting ice areas is very complicated or impossible, the application of autonomous underwater vehicles (AUV) is preferred or even the only possible solution. However, this implies the possibility of a direct and real-time control over all AUV functions, which is only achievable with the availability of accurate positioning/navigation and a high-speed communication link. This paper presents a flexible bottom- or surface-based solution enabling high positioning accuracy of underwater objects (harvester, AUVs, bottom nodes); specifically, a multifunctional system that combines Ultra Short Baseline (USBL) transceivers and Long BaseLine (LBL) stations deployed at a large depth. Moreover, each baseline transponder is equipped with a high-speed communication device to provide the means for real-time AUV control based on the information about its current position, e.g. navigate it with direct commands and operating its actuators and other mechanisms. Moreover a communication link with a high data rate can provide valuable visual information from the operation area.Depending on how many nodes the LBL grid comprise has, target transponder positions can be estimated with an accuracy of several to tens of centimetres. The purpose of the paper is to present the experiments with all key elements of the multifunctional Hydro-Acoustic USBL-aided LBL Positioning and Communication System."

Sep 1, 2014