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By J. Nell

An overview is given of the matte melting process used for the beneficiation of South African platinum group metal (PGM) ores. Most producers use six-electrode furnaces to melt the concentrate and Pierce Smith converters to oxidize excess iron sulphide from the furnace matte. Concentrates from two reef types (the so-called Merensky and UG-2 reefs) dominate the feedstock supply. Concentrate from the Merensky Reef is low in chromium and does not pose significant melting problems. Concentrates from the UG-2reef contain much higher levels of chromium, which results in the formation of chromium-rich spinels during melting. This is attributed to the low solubility of chromium in furnace slag under typical operating conditions (an oxygen partial pressure of 10-8?10-9bar at temperatures of 1550°C to 1600°C). During the converting process, care is needed to avoid excessively oxidizing conditions, which result in cobalt, nickel and copper losses to the slag. High nickel losses result in the formation of Fe2NiO4 (trevorite), which often forms solid solutions with FeCr2O4and Fe3O4. In future, the main challenge in the processing of South African PGM ores will be to cope with ever-increasing levels of chromium in the concentrate. A short-term solution to the problem would be to melt the concentrate under slightly reducing conditions to promote the formation of CrO, which is more soluble in the slag than Cr2O3.A longer-term solution to the problem would be to abandon the current matte-smelting process in favour of an alloy-based process, which would offer total flexibility with respect to the amount of chromium that can be tolerated in the feed. Keywords: Merensky, UG-2, furnace, slag, matte, converting, spinel, chromium

Jan 1, 2004

By A. D. Pienaar

The aqueous chemistry of niobium and tantalum compounds with hydrofluoric acid is a mature field of investigation. In contrast, very little attention has been paid to reactions of these compounds in non-aqueous environments. Similarly, reactions of elemental fluorine with niobium and tantalum compounds have received little more than cursory attention in literature. This work discusses the isothermal reaction kinetics derived from thermogravimetry, using a less redundant approach than is currently the standard. We also discuss the most likely kinetic models for this reaction.

Jan 1, 2012

By Neil T. Davie, Thomas K. Blanchat, Thomas C. Togami, Joe R. Weatherby, Dale S. Preece, Robert A. Benham, James J. Calderone

"Geotechnical structures ,such as underground bunkers, tunnels, and building foundations aresubjected to stress fields produced by..the gravity load on the structure and/or any overlyingstrata. These stress fields may be.. reproduced on a scaled model of the structure byproportionally increasing the gravity field through the use of a centrifuge. This technology canthen be used to assess the vulnerability of various geotechnical structures to explosive loading.Applications of this technology include assessing the effectiveness of earth penetrating weapons,evaluating the vulnerability of various structures, counter-terrorism, and model validation. Thisdocument describes the development of expertise in scale model explosive testing ongeotechnical structures using Sandia’s large scale centrifuge facility. This study focused onburied structures such as hardened storage bunkers or tunnels. Data from this study was used toevaluate the predictive capabilities oft existing hydrocodes and structural dynamics codesdeveloped at Sandia National Laboratories (such as Pronto/SPH, Pronto/CTH, and ALEGRA)."

Jan 1, 1998

By Charles W. Daugherty, James P. Gould, Kenneth R. Ware

INTRODUCTION As illustrated in Figure 1, the Washington Metropolitan Area Transit Authority's (WMATA) rapid transit system (METRO) ultimately will comprise 100 miles of line divided among 10 routes. At this time about 46 per cent of the system is under construction or in operation. Planning and design of an additional 38 per cent is at an advanced stage. Of the 84 miles under development or construction, about 10.4 miles consist of soft ground tunnels, and another 1600 feet of mixed face. This paper describes most of the factors considered by designers in setting grades for such tunnels. It is hoped the paper will be a useful guide to planners and engineers in developing similar transit systems. The problems faced in Washington, including those related to geology, are not so unique that the solutions cannot be applied to other systems. The paper also may be of interest to contractors who have not perceived the logic behind the selection of a particular vertical alignment. An attempt is made to explain the background constraints that make most tunnel alignments a compromise among competing alternatives. Readers might assume that the choice of alignments is largely controlled by geological conditions. In fact this is merely one of many factors to be considered.

Jan 1, 1976

By Reynold Q. Shotts

A study was made of the coal resources of an area in Jackson County, Ala., forming a part of the Flat Rock, Henegar, and Stevenson quadrangles. The area studied is a portion of the Plateau coalfield on Sand Mountain and is near the Tennessee Valley Authority's Widows Creek steamplant. Since no detailed geological study of this area had been published, some reconnaissance work was done. The coalbeds and adjacent strata such as sandstones, conglomeratic sandstones, and conglomerates were studied. Available drill logs, together with the areal geology, provided sufficient information to permit correlation of the coalbeds and an estimation of coal reserves. For all categories of reserves, computed on a regional basis, a total of 72,920,000 tons of coal more than 14 inches thick is estimated for the areas studied in Stevenson. Flat Rock, and Henegar quadrangles. Of this tonnage, 40,001.000 tons is estimated to have less than 60 feet of overburden. The total measured coal reserves for the above three quadrangles are 16,359,000 tons, with 12,471,000 tons under less than 60 feet of cover.

Jan 1, 1966

By R. Unger, L. Mallett

The use of virtual reality (VR) technologies to train miners is an evolving area in research and development. In July 2006, representatives of 14 international organizations met to discuss current VR-related efforts and explore ways to employ VR in the future. This paper gives an overview of the various approaches presented at the meeting and discusses directions for future implementation. An example of a training package that teaches mine map-reading skills is presented. The meeting was the first step to building collaborations for furthering VR applications for mining. Planning has begun for a 2008 meeting open to broader participation.

Jan 1, 2007

By Dermot Winters

The Surface Mining Control and Reclamation Act (SMCRA, or the Act) was enacted on August 3, 1977. The Act was written, in part, to put an end to uneven environmental standards and to establish minimum national standards. Certainly, one of the motivating factors for passage of the Act was the success of the Federal Coal Mining Health and Safety Act of 1969 in reducing deaths and injuries in the coal industry nationwide. Section 516 (b) (1) of the Act requires *that subsidence be prevented from causing material damage to the extent technologically and economically feasible except in those instances where the mining technology requires planned subsidence in a predictable and controlled manner. Section 516 (c) of the Act authorizes the regulatory authority to suspend underground mining if there is imminent danger to inhabitants of urbanized areas, cities, towns, and communities. On December 13, 1977, the interim program, which applies a portion of the performance standards of the Act, was promulgated. Then on September 18, 1978, the proposed permanent program was published for public comment. Finally, on March 13, 1979, the final permanent program was promulgated and the States were given a period of time to submit their programs for approval.

Jan 1, 1986

By Refik Elibay, Lawrence A. Williamson, George D. Barnes

Under an extremely aggressive schedule, final design of 13.5 km (8.4 miles) miles of 8.2 m (27 ft) diameter deep rock tunnel, 322 ML/day (85 million gallons / day)submersible pumping station and associated facilities were accomplished ahead of a federal court mandated consent decree schedule. Challenges overcome by the project team in enabling timely completion of the construction documents will be presented. Discussion includes evolution of final design, consideration of future O&M requirements, and risks identified for construction and operations, together with measures to manage and proactively prepare for such risks.

Jan 1, 2005

By M. Rice, M. Stanley, J. Marlow

Arizona construction aggregate industry remains in the crosshairs of public debate, caught between the need for aggregate-based building materials and alternative, high-value land-uses. To better manage lands and improve land-use decisions, the Arizona State Land Department has need for a system to assess potential aggregate resources on State Trust lands, and assign dollar values accordingly. Thereafter aggregate values can be compared to residential, commercial, agricultural, recreational, and habitat values -- in a determination of highest and best land-use.

Jan 1, 2002

It has been proven theoretically and experimentally that the use of 10 - 30 per cent DRI in blast furnace along with iron ore or sinter results in lower coke rate and higher productivity. However, to-date this remains unpractised on a regular basis mainly because of economic reasons. The DRI produced by several methods are expensive and difficult to store/handle in large quantities because of its reactive nature and thus DRI in blast furnace remains unacceptable.

Jan 1, 1999

By AIME AIME

TWENTY-TWO sections and all four of the divisions sent delegates to the annual meeting. They became so interested in the wide ranging dis6ussion of old and yet ever-new problems of Institute affairs that three instead of two sessions scheduled were necessary. Monday morning the meeting assembled with President Bassett presiding in the absence of President-elect Tally, who had been called to Baltimore by the serious illness of a brother. Thursday morning Vice-president Turner presided until Mr. Tally appeared after which the latter guided the sessions. Since reports from all of the active sections save one had been mimeographed and sent in advance to the delegates, detailed reports from each were dispensed with. The discussions dealt largely with membership problems, both local and national, with financing, speakers and programs, visits from national officers, and the conduct of the annual meeting. Many interesting and constructive suggestions were made and will be reported back to the sections by the delegates.

Jan 1, 1931

By Peter J. Tarkoy

A great deal of attention has been directed toward the complexities and inadequacies of exploration and pre-bid geotechnical information for heavy construction projects, differing site conditions, and the adversary relationships which generally develop as a result. The adversary position has been maintained at all cost. The solution is simple, if not easy. The solution requires strict and equal adherence to given principles by all parties involved, throughout the life of the project, from conception to completion. It is necessary to review and redefine some basic concepts, without value judgements, from a context of getting the job done. In a recreated context, the role of truth, judgement, responsibility, and integrity, in exploration, engineering design, construction estimating, and project construction, will be examined. It is suggested that anticipated geotechnical conditions be defined unconditionally. The alternative choice is to give the bidder the opportunity of making the interpretive judgements based on geotechnical data. Similarly, a unilateral method of establishing encountered conditions that are agreeable to both owner and contractor, must be outlined prior to contracting. As anticipated and encountered conditions are firmly and accurately established, significant differences can evaluated based upon limitations specified in the contract documents. Impact of differences on project costs can be fixed by pre-defined methods.

Jan 1, 1983

By D Rattray, D Macfarlane, I Robb, N Halpin, G T. Dale

Mining faces many environmental, social and regulatory liabilities of which water management is just one. Others include site rehabilitation, carbon emissions, biodiversity offsets, strategic cropping land, subsidence, and noise and dust generation. Management of these liabilities is commonly seen as a cost of doing business and each is often independently addressed, bypassing the opportunity to reduce costs through integrated approaches. Furthermore, approaches to dealing with these liabilities tend to be constrained by a prevailing culture of engineered solutions and lack of appreciation of risk associated with alternative and hybrid alternative-engineered solutions. Suboptimal outcomes can also be reinforced by rigid regulatory constraints. While the cost of addressing operational liabilities may be a small proportion of overall mine management costs, failure to do so effectively may influence social licence to operate and, as recently demonstrated by the decision of the NSW Land and Environment Court to block expansion of the Warkworth Mine near Singleton, absolute licence to operate.Integration of environmental, social and regulatory liabilities with value-creating and risk-reduction opportunities such as beneficial water use, carbon bio-sequestration, habitat connectivity, keyline farming, improved grazing design and management systems, windbreaks and visual screens, presents opportunities to reduce risk and create value. This potential may achieve overall improved outcomes in both economic and non-economic mine performance criteria.Two case studies in beneficial use of waste water from the mining and coal seam gas (CSG) sectors (which operate under different legislation) will be used to illustrate the potential to address mine development, operational and closure liabilities by understanding opportunities to reduce risk and create value through a holistic water management framework. The technical requirements and alternative approaches to beneficial use of mine water are addressed, along with the direct economic benefits for mine operational costs and opportunities to positively engage communities and build resilience into social licence to operate. Regulatory barriers to achieving improved outcomes will be discussed.CITATION:Dale, G T, Robb, I, Halpin, N, Macfarlane, D and Rattray, D, 2013. Opportunities for integrated mine management to minimise risk and create value, in Proceedings Water in Mining 2013 , pp 227-234 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By Brendan Henry

The Canada Line is a 19km long automated light rapid transit system with 16 stations in Vancouver, BC, Canada. The Concession was awarded to InTransitBC to design, build, partially finance, operate, and maintain the system for 35 years. The project must be complete by November 2009 to be ready for the 2010 Winter Olympics to be held in Vancouver and Whistler, BC. The bored tunnel section consists of 2.45 km of twin bored tunnel and 3 stations. The station work is limited to the excavations and temporary support necessary to facilitate the bored tunnel works. A joint venture between SNC-Lavalin Constructors Pacific and SELI (SSJV) has recently completed the design and construction of this section. Work for the bored tunnel commenced in November 2005 with shoring and excavation works for the tunnelling operations pit that will become Olympic Village Station and will be completed in the spring of 2008. The tunnels were driven with a 6m diameter Earth Pressure Balance Tunnel Boring Machine (EPBM) and lined with 250mm thick, 5.3m diameter precast concrete segments. Seven hundred and fifty meters of each tunnel were driven through glacial and interglacial deposits of sand, silt, and clay with granitic boulders. The paper discusses the challenges faced in negotiating these soils which contained unforeseen geological conditions. These conditions were overcome by developing a systematic approach to Risk Management that included thorough risk assessments, regular risk management meetings with the participation of two of the world?s leading EPBM experts, Professor Eisenstein and Professor Kovári, and by the ability of the construction team to effectively analyze and mitigate problems.

Jan 1, 2008

By Witold M. Pytel

A simplified, three-dimensional, time-dependent, mechanistic model of the overburden-coal seam-floor interaction has been developed and validated at two Illinois coal mines. The model based on the thin plate theory can involve any complex layout of mine workings, time-dependent sequence of extraction and, rheological properties of immediate floor strata. The model output data consist of spatially distributed surface subsidence and its slope and curvature, as well as load acting on pillars in one or more panels. A comparison of calculated and monitored surface subsidence or in-mine convergence measurements has proven the model's effectiveness for surface subsidence and load transfer prediction.

Jan 1, 1992

By Adnan A. Malik, Tadashi Maejima, Jiro Kuwano

"ABSTRACTTheoretical approach to estimate the ultimate pile capacity gives a rough idea at the initial stage of design that later on strengthen by the execution of static pile load test at site. The static pile load test is the only best option for the estimation of ultimate capacity of various types of piles. There are various methods based on strength, serviceability, net deflection for end bearing, shaft adhesion, graphical and extrapolation approaches for the interpretation of pile load test data to calculate the ultimate capacity. In this paper an attempt is made to evaluate the best-fit method for the estimation of ultimate capacity of single helix screw pile. The pile load tests on model scale were performed on screw piles of different helix diameter. The purpose of adopting model scale of testing was to achieve a state at which settlement increases without further increase in vertical load. The ground was compacted with dry sand at denser state. It was observed from the test results that extrapolation methods such as Chin- Kondner and Decourt predict the load settlement curve of screw piles very well, however ultimate pile capacity was on higher side which may not be suitable for the strength of helix plate. Decourt approach to plot the pile load data showed clear indication of the deformation of helix due to strong subsurface condition. A modified approach in Decourt method is proposed for estimating the ultimate capacity of screw pile having deformed helix whereas reduction factor is suggested for Chin-Kondner method for the estimation of ultimate capacity of intact screw pile.INTRODUCTIONDeep foundations are used to avoid the soft ground at shallow depth that is not suitable for carrying the structural load. Different types of piles have been used to transfer the load to deeper stratum. The screw pile is one of the new piling method and its use is considerably increasing. It consists of a cylindrical steel shaft with one or more helices at various length of the shaft. The diameter of helices (Dw) is usually 2 – 2.5 times the shaft diameter (Ds). The pile is installed to the required depth through torque and pressure. The advantage of screw pile over other piling system is its quick installation mechanism, high end-bearing and uplift resistance, noise reduction and minimum use of man power."

Jan 1, 2014

By Yasunori Kosaka, Junya Tokita, Aramaki Shosaku, Inoue Junji

Light ANFO that satisfies blasters and customers who want to reduce the amount of explosive consumption without changing blasting effects and designs and passes Cap sensitivity test regulated by law. The reduced loading density of light ANFO reduces the amount of explosive consumption. The loading density of conventional ANFO is 0.X-0.9g/ml, while the loading density of light ANFO is 0.7-OXgiml. The detonation velocity of light ANFO is maintained not to reduce blasting effects. Detonation velocity of conventional and light ANFO using steel tube of inside diameter 36 mm are 3200 - 37OOms. detonation velocities are the same though the loading density of light ANFO is reduced by O.lg/ml. This suggests that the reactivity of light ANFO improves.

Jan 1, 2002

By J. Walden, S. Rhoades, R. E. Miller, R. Gibbs, P. Boman

Accelerometers and pressure transducers mounted in suspension components can be used to monitor the ride of haulage trucks. Presently, it is difficult to tell what caused a jolt to the truck using either pressure or acceleration data alone. When information from a Global Positioning System is recorded at the same time as shock pressures or acceleration data, then the exact location of an event can be determined. Mine management can then determine what caused the jolt to the truck.

Jan 1, 1999

By Greg Barnes

Agenda ? The Mining Stock Life Cycle ? Current Environment ? Valuation ? Golds ? Valuation ? Base Metals ? Case Study ? Quebrada Blanca Hypogene Commodity Investment Cycle ? Macro-Economic Indicators ? LME Inventories ? watch the trend; rising inventories ? bad for prices, declining inventories good for prices ? OECD Leading Indicators ? PMIs ? Purchasing Manager Indices ? Industrial Production ? more important for metals consumption than GDP ? Housing Starts ? US, Europe ? Auto Sales ? All things China ? metal imports/exports; SHFE inventories; SRB stockpiling ? Seasonality ? it does play a role ? What is Chris Dutton (TDSI Quantitative Analyst) saying?

May 1, 2010

By Jörg Fischer-Bühner

Conventional 22ct Au jewellery alloys are comparably soft in the as-cast and soft-annealed state and hardening by cold-working is the only way of giving strength to the jewellery. The paper first focuses on hardening of 22ct jewellery alloys by conventional means, i.e. solid solution hardening with base metals (aiming particularly at an increased as-cast hardness) as well as precipitation hardening by alloying with base metals beyond the solubility limits and subsequent age-hardening heat treatment. Co-additions of ~2% turned out to result in most pronounced solid solution hardening up to ~100 HV1 in an investment cast & quenched state. Subsequent heat treatments, consisting of solution annealing at 850°C for 1h followed by water quenching and ageing at 300°C ? 400°C for ~ 1h lead to pronounced age-hardening with a peak hardness of ~ 260 HV1. In contrast, 22ct Au alloyed with Ni, Fe or Sb display no age-hardening effect within the same range of heat treatment parameters. The 2nd part of the paper reports on some preliminary trials to enhance the hardening effect of the base metals by additions of suitable elements, which possess a strong tendency to phase formation with the added base metal during ageing treatments. It is shown, that the age-hardening behavior of 22ct and 990/995 Au alloyed with Co or Ni can be remarkably influenced by additions of Sb. A total of only 10wt%0 of CoSb or NiSb-additions lead to a peak hardness of ~ 150 HV1 for a 22ct Au and ~ 100-120 HV1 for 990 Au , which is obtained already after very short ageing times (20-40min) at 300-400°C after solution annealing at 700°C / 1h / water quenching. It is suggested that the age-hardening mechanism in these alloys consists in precipitation of intermetallic CoSb- and NiSb-phases.

Oct 1, 2003