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By G. Shore

"The development of a DC resistivity instrumentation system for data acquisition in extreme topography yielded an unexpected bonus in the quality and information content of the type of raw data gathered. Not only were traditionally too-rough areas being investigated systematically for the first time, the unique high-density, multi-directional raw data were providing the opportunity to greatly expand the range of conductive and resistive signatures that could be accurately recognized. Using a true 3-D inversion algorithm, 3-D earth resistivity imagery began to show distinctive anomaly patterns for hydrothermal mineralization at the seldom-visited resistive end of the spectrum, successfully imaging epithermal gold systems in conditions that had defied conventional ground and airborne geophysics for years.The traditional mode of designing a resistivity survey to test a specific target concept was shown to be an unnecessary limitation on exploration thinking when a single sweep acquisition of dense, multi-directional 3-D raw data could effectively provide the all-targets “shotgun” coverage that would take 10 or 12 conventional surveys to duplicate. Exploration planning has the opportunity to move from single steps of trial and error geophysical testing to a mode of mapping everything at the outset, and then sorting out what might be of exploration interest in the results. Survey parameterization becomes the non-technical process of marking an outline on a map and declaring “survey here.” Operational and interpretational reasons for not testing where the exploration interest lies have all but disappeared. With any-terrain capabilities and unprecedented raw data density and overlap to support interpretation of complex conditions, that outline can be drawn through extreme rough terrain, including lakes, cliffs, industrial facilities, and grounded installations to test for generally unknown sub-surface features of potential interest.As more is learned about the larger-scale signatures of ore settings and the district-scale geo-electric imprint of hydrothermal processes on lithology, it appears that the only thing certain about ore signatures is their uncertainty. This is not bad news. New opportunities abound as the advanced 3-D technology allows a first effective look at the previously unexplorable rough terrain or complicated settings, and a second look at areas where older results may now be known to be non-definitive."

Jan 1, 2002

By Rob Boom, Yasuyuki Tozaki, Greg Traquair

The objectives of the business case are to examine a proposed metallurgical project and answer fundamental questions about project feasibility, risks, opportunities, and value. A business case fulfills these basic functions: estimates economic value; helps to understand competitiveness; serves as a risk management tool; and serves as a communication tool. A business case evolves with the project life cycle, and supports the gate reviews at the end of each phase of engineering, through to project construction and operations. A business case must be holistic, including all elements of scope that can impinge on project risk and value.

Jan 1, 2015

By Shi Wang, Hongbin Liu, Meiliang Wei, Wu Liu, Xiaojun Wang, Yuxian Ke, Xuepeng Song, Tiejun Tao

The study investigates the influence of water migration on the fluidity of fresh cemented paste backfill (CPB) with and without flocculant under variable shear rates. The research utilizes nuclear magnetic resonance (NMR), rheological tests, and scanning electron microscopy (SEM) to analyze water migration, rheological properties, and microstructure evolution. The findings reveal that water migrates to more stable states as shear rate increases, and the addition of flocculant enhances water migration and increases shear stress and apparent viscosity. The study establishes relationships between water content and rheological parameters, providing insights into the flow characteristics of fresh CPB for pipeline transportation.

May 4, 2022

By Alex Matheson, Nick W. D. Massey, Peter T. Bobrowsky

Crowing pressures on aggregate resources include diminishing reserves, high transportation costs, sterilization and land use conflicts. In the absence of detailed resource knowledge for a particular region, aggregate resource potential maps provide the best "first approximation" regarding the surficial distribution of sand and gravel. The 1:50 000 scale Level Ill aggregate potential map integrates several important factors which influence the management of sand and gravel. Data used to generate this type of thematic map is readily available in most areas, fieldwork required is minimal, there is a logical quantitative evaluation of the data layers and integration is easily accomplished on a desktop PC-based platform. Also the aggregate potential map, with its focus on identifying areas of potential future aggregate exploitation as well as present inventory, provides a useful tool for the aggregate explorationist.

Jan 1, 2001

By Sarkis G. Ampian

Extraction of alumina was correlated with the sinter and leach products from the lime soda sinter process for anorthosite. The effect of composition and grain size of reactants, time and temperature of sintering, and techniques of sample preparation were investigated. Greater than 90 percent Al2O3 extractions were obtained from dry-mixed minus 200-mesh anorthosite sinter mixes having mole ratios of CaO/SiO2 = 1.8 and Na2O/Al2O3 = 0.8. These sinter mixes were briquetted at 15,000 psi and fired between 1,200° C and 1,320° C for 20 to 60 minutes. The sinter phases that contribute to low alumina recovery were determined by X-ray diffractometry, optical microscopy, and electron probe X-ray spectrography. The mechanism of the sintering reaction was investigated by high-temperature X-ray diffractometry. The contrast in the lime soda sinter process for clays and for anorthosites are discussed. Explanations and suggested solutions are presented for problems such as gelation and variable alumina recovery encountered by previous investigations.

Jan 1, 1967

By Thomas Varley

[For a year or more, statements have appeared in the technical press, and Especially in various trade journals, indicating that valuable metals such as gold, silver, platinum, and other rare metals, have been found and also have been successfully extracted from oil shales. These reports stated tat decarbonization and special methods of chlorination treatment, leaching and subsequent Precipitation, also cyanidation followed by table concentration of the residues after cyanidation, all indicated that told ad silver and other metals could be, and were, successfully recovered. Such articles have caused much misunderstanding, and as the correctness of some re of the statements made in them were questioned by some of the technical journals and by various chemists and metallurgists, an investigation of the subject. was begun by the metallurgical division of the Bureau of Mines, in order, if possible, to determine to what extent, if any, metals of value do occur in oil shales, and if so, the feasibility of attempting their recovery by tie processes said to have been used for teat Purpose. Inasmuch as the Bureau's station at Salt Lake City is investigating the recovery of oil from oil shales, the investigation of too recovery of metals from oil shales was assigned to my direction as superintendent 'of that station. An agreement had been entered into with the owner of m extensive oil shale deposit in Wyoming whereby I would personally collect the samples' of shales for use in the investigation.]

Jan 1, 1922

Radioisotope x-ray methods for the on-stream determination of copper, lead, and zinc in mineral product slurries were developed, and were successfully tested at the plant of Cobar Mines Pty. Ltd.The tests were made in three stages. Measurements to determine the precision of analysis were made initially on briquettes of the mineral products. The effect of slurry solids content variations was then determined by measurements on the mineral products in a recirculating slurry loop. The radioisotope analyser was finally tested in a series of on-stream measurements in the plant.Copper, lead, and zinc in flotation feed and in copper concentrate were determined to a precision ranging between 1·4 and 15 per cent of the mean element concentration in the slurry solids. These precisions are within limits required for plant control purposes at Cobar.

Jan 1, 1971

By Günter Petzow, Hans Leo Lukas, Hans Jürgen Seifert

"The CALPHAD method (CALculation of PHAse Diagrams) has been extensively developed in the last 25 years and became a useful tool in materials science. Thermodynamic descriptions for the functions of state of unary, binary and ternary phases are derived by the optimization of phase diagrams. These functions are stored in computerized thermochemical databases and can be combined to extrapolate to multi component systems. Depending on special demand, the actually most advantagous presentations of the calculated results can be chosen: tables or in a clear graphical form as phase diagrams, phase amount diagrams or volatility diagrams. The method will be desribed by the system Ti-Si-C-N-O including the ceramic subsystem Si3N4-SiC-TiCi,N1_1,-C-N-O which is very important for the development of ceramic composites. The calculations give the thermodynamic stabilities of the condensed phases as function of temperature, concentration and partial pressure of different gas species. Adjusting the sintering conditions to these results the formation of unfavourable compounds or liquid phases can be suppressed.IntroductionThe CALculation of PHAse Diagrams (CALPHAD-method) of multicomponent systems provides the possibility to plan experiments very efficiently and avoid the experimental trial and error approach for the development of materials. The main problem for best use of calculated results is their interpretation with regard to the specific applications under consideration. Tables give the exact quantitative data for the treated phenomena. However, most important to make best use of these thermodynamic data is their graphical representation especially designed for the solution of specific problems, scientific as well as application oriented. Only well chosen graphical representations support a comprehensive understanding of the thermodynamic interrelationships and the transfer to the problem."

Jan 1, 1996

By A. Ignatow

"A review is made of some of the principal factors and conditions that are, and will be, important to the over-all market climate for asbestos fibre and for the future of Canada's asbestos industry: - health hazard associated with asbestos exposure;- uncertain international regulatory environment for continued asbestos use;- adverse public reaction to asbestos;- product liability/litigation costs (U.S.A. primarily);- promotion of substitution by governments and asbestos user industries; and- minimal product and market development efforts by asbestos producing and consuming industries.In addition, Canadian producers, who export some 95 per cent of their production, face additional constraints:- dramatically reduced integration with asbestos-consuming industries;- 60 per cent of exports to most rapidly declining markets (U.S.A., Europe);- increased competition from offshore producers favourably located to growth markets in developing countries;- increasing production costs;- a strong dollar;- disadvantageous freight rates; and- loss of price leadership and price erosion.Future market trends, as well as prospects for Canada's asbestos industry, will be projected in this paper.Economic FactorsTable 1 presents asbestos fibre production in all countries for the period 1980-82. In certain instances, e.g. U.S.S.R. and China, these are capacity estimates as production statistics are not officially published. The U.S.S.R, by far, is the world's largest producer accounting for some 50 per cent of world production, though most production is consumed internally or by COMECON countries. It is estimated that some 700 plants produce asbestos-containing products within the U.S.S.R.Canada accounts for some 25 per cent of world production though it ranks first in world trade. Other important producers are South Africa Zimbabwe, Brazil and Italy. Since 1979, Canada's asbestos mining industry has experienced a dramatic drop in production and exports of asbestos fibre, as demonstrated in Table 2."

Jan 1, 1985

By J. C. Harrison

Eldorado Gold Corporation of Vancouver, B.C. owns and operates three gold mines. The Sao Bento underground gold mine in Minas Gerais State, Brazil produced 105,907 ounces in 1997. The La Colorada and La Trinidad open pit, heap leach mines in Mexico produced over 83,000 ounces in 1997. With a deteriorating gold market plaguing the industry throughout 1997 Eldorado had to take critical measures at each mine to enhance gold production while lowering cash operating costs. Each mine had its own unique problems to confront. This case study will discuss three distinct courses of action taken at the three mine sites.

Jan 1, 1999

By Andrew B. Cecala

This U.S. Bureau of Mines report provides a detailed description of the Bureau-designed modified shearer clearer system. Engineering drawings are provided for all major components of this system. The modified shearer clearer system is a revised version of the original system and is intended to improve the ventilation around both cutting drums. The original shearer clearer technique was solely a dust control technique that has been effective in lowering shearer operators' dust exposures. The technique uses a series of water sprays that not only knock down a portion of the dust cloud but also act as small fans that move a substantial amount of air and keep the dust cloud from dispersing over the shearer body. The modified version is composed of two additional spray blocks for improved air movement around both cutting drums, thus lowering methane levels and the likelihood of an ignition. A laboratory study performed with the modified version in a full-scale longwall gallery resulted in a 73-pet reduction in methane concentrations at the shearer machine for both cut directions. The air-moving capabilities of the system provide more turbulence at the cutting drums and reduce methane levels.

Jan 1, 1994

By Yoginder Paul Chugh, Jason E. Tinsley

"Over the last five years, the authors have compiled a database of Short Encapsulation Pull Test (SEPT) evaluations from Interior Basin (Basin) coal mines. Typically, SEPT data are analyzed to obtain peak load carrying capacity per unit length of resin encapsulation designated as the ""Grip Factor,"" or GF. In a previous paper, ""An Analysis of Short Encapsulation Bolt Pull Test (SEPT) Data From Interior Basin Coal Mines,"" authors analyzed tangent value of the load-displacement curve as Anchorage Stiffness at 50% (AS-50) of the peak load, or GF value, to assess reinforcement potential of an installed bolt system. This paper attempts to correlate the secant AS VALUES (of SEPT on 6 ft (1.8 m) long installed bolts at a lower load of about four tons from several different mines in the Basin with their MSHA-approved primary support requirements. Since the current regulatory environment requires plan changes dynamically to ensure that roof falls are minimized, the authors hypothesize that the practiced roof control plan must meet the minimum requirement of adequately supporting immediate roof strata. The analyses are based on 181 SEPT studies performed by Minova professionals. Analyses indicate a macrolevel correlation for both roof support density and roof support cost that may have the potential to be used by mine operators to compare their performance with other mines in the area. Limitations of the analyses include ignoring mining depth, mining height and required secondary supports as part of the requirements for a roof control plan. The authors recommend additional analyses to develop this concept further to develop guidelines that can be confidently used by coal companies.INTRODUCTIONPartially- and fully-grouted bolts are extensively used in coal mines for roof support as part of MSHA-approved roof control plans. Since grouted bolts have a larger area of contact with the rock, they can develop much greater anchorage capacity than conventional expansion shell (point-anchored) bolts. Load transfer characteristics and interaction mechanics between steel rebar, grout and rock mass around the bolt hole for grouted bolts are generally assessed in the laboratory or field though short-encapsulation pull tests (SEPT), which have been extensively researched by Aziz and Jalalifar (2005), Aziz (2004a), Serbousek and Signer (1987), Signer (1990), and Mark et al. (2002), among others. In a SEPT, about 12 in. (30 cm) of bolt length is typically encapsulated in resin and a pull test is performed to collect load-displacement data prior to failure and, in some cases, post-failure. A typical load-displacement data set for a bolt is shown in Figure 1. SEPT characteristics are designated by peak load carrying capacity, or grip factor, which is the peak load carrying capacity per unit length of resin encapsulation. SEPT is routinely used to assess anchorage performance characteristics of different lithologies overlying a coal seam to identify type of bolt, bolt diameter, length and spacing across and along an excavation. Anchorage stiffness, or AS, at any load may also be calculated as the tangent or secant value of the slope of the load displacement curve at a particular load level. Anchorage Stiffness characteristics of bolts from SEPT data have typically not been considered in any depth until recently (Chugh et al., 2014; Chugh et al., 2015)."

Jan 1, 2016

By S. R. Borrowman

Mill tailings from conventional uranium extraction processes contain nearly all of the radium originally in the ore. Such tailings require controlled storage in perpetuity to safeguard the surrounding environment from radioactive contamination. Alternatives to controlled storage of the tailings are (1) removal of the radium from the tailings for separate storage or use or (2) removal of the radium when processing the uranium ore. In laboratory tests conducted by the Federal Bureau of Mines, radium was leached from tailings using either hydrochloric acid or ethylenediamine tetraacetic acid. A hydrochloric acid leaching method was used to extract both radium and uranium from the ore to yield tailings containing less radium than those produced by either conventional sulfuric acid or alkaline leaching processes. From 77 to 94 percent of the radium in mill tailings was concentrated by sedimentation in slime fractions representing nearly 25 weight-percent of the original sample.

Jan 1, 1975

By Bernardo J. Jiménez Vega, Edy L. T. Montalvan PhD

The experience gained during more than 900 Crosshole Sonic Logging (CSL) tests on drilled shafts shows the importance of establishing proper project acceptance and repair protocols. Drilled shaft evaluation is a multidisciplinary task that should not be left solely to the outcome of the CSL test. This test allows to characterize and delimit areas of different qualities of concrete, and it is important that all the interested parties understand the difference between flaws and defects. The information presented here is intended to give a guideline to contractors, inspectors, engineers, owners and clients on how to deal with acceptance and remediation of defective drilled shafts, detected using CSL tests. A database of flaws is presented depending on their location, intensity and remediation method. Procedures that allow the flaws to be analyzed are presented in order to dismiss or classify them as defects. In many cases, the CSL test may indicate an anomaly, but by coring the concrete and analyzing the structural demands and conditions, the flaw can be classified as non-severe. When flaws are classified as defects, their repair will depend on the area where they are located in the drilled shaft pile. In this document two procedures are described for repairing defects depending on their location. For defects in the drilled shaft head area, the procedure takes into account the interaction between the new and old concrete. For repairing the middle zone of the drilled shaft by grouting, the major concerns are the difficulty of accessing through the drilled shaft at deep depths and the communication between boreholes. For defects at the drilled shaft tip, two proposed remediation methods are presented. Finally, tomography tests are presented to compare the effectiveness of remediation by grouting.

Oct 1, 2022

By F I. Cox, D Peeler, T Bodisco

"Diesel particulate matter (DPM), in particular, has been likened in a somewhat inflammatory manner to be the ‘next asbestos’.From the business change perspective, there are three areas holding the industry back from fully engaging with the issue:There is no real feedback loop in any operational sense to assess the impact of investment or application of controls to manage diesel emissions.DPM are getting ever smaller and more numerous, but there is no practical way of measuring them to regulate them in the field. Mass, the current basis of regulation, is becoming less and less relevant.Diesel emissions management is generally wholly viewed as a cost, yet there are significant areas of benefit available from good management.This paper discusses a feedback approach to address these three areas to move the industry forward. The six main areas of benefit from providing a feedback loop by continuously monitoring diesel emissions have been identified: Condition-based maintenance. Emissions change instantaneously if engine condition changes. Operator performance. An operator can use a lot more fuel for little incremental work output through poor technique or discipline. Vehicle utilisation. Operating hours achieved and ratios of idling to under power affect the proportion of emissions produced with no economic value. Fuel efficiency. This allows visibility into other contributing configuration and environmental factors for the vehicle. Emission rates. This allows scope to directly address the required ratio of ventilation to diesel emissions. Total carbon emissions. For National Greenhouse Emissions Reporting (NGER)-type reporting requirements, calculating the emissions individually from each vehicle rather than just reporting on fuel delivered to a site.CITATION:Cox, F I, Bodisco, T and Peeler, D, 2014. Continuous remote emissions monitoring – the lynchpin for air quality management, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 137–142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

What is your assessment of the status of the mining industry as we see some evidence of an economic recovery? I am optimistic about the short and midterm prospects for the industry and, hence, for the professionals in the industry that constitute the majority of the SME membership. All who will read this interview recognize that the quality of life we enjoy today is largely a result of our achievements in the mining and minerals processing sectors. I believe that the sustainability of that quality of life and the aspirations of other sectors of the global community to attain that same lifestyle will significantly depend on the continued successes of these industries. Looking at some of the traditional economic indicators, we see predictions of continued increases in gold prices during the next 12 months as a new round of quantitative easing keeps real interest rates low and drives excess capital flows from countries with trade surpluses - who have traditionally parked their money in U.S. government bonds - into other investable assets, such as gold. On the fuel side of the industry, we have during the last decade seen a steady rise in the cost of coal, and some of the recent spot prices have seen dramatic increases. Some suggest that coal prices may rise sooner than anyone expects, as global reserves are revised downward. This is based on the hypothesis that some of the main coal-producing countries are overestimating supplies and that coal prices could start rising far sooner than anyone thinks - with obvious serious implications for energy policy. Those forecasters note that, for the past couple of decades, global supply has been dropping at a faster rate than consumption.

Jan 1, 2011

By Nikhil Dhawan, Shrey Agrawal, Veeranjaneyulu Rayapudi

India’s steel vision of 2030 requires a huge amount of quality iron ore. The utilization of low-grade iron ores such as banded iron ores will play an important role to achieve the same production. The absence of alumina impurities in the banded hematite jasper (BHJ) ore provides it an edge over other low-grade iron ores. The conventional beneficiation techniques such as magnetic separation and washing were found to be ineffective to produce suitable feed (Fe ~ 60%) for the blast furnace. It was found that microwave exposure provides significant enrichment to the low-grade iron ore and can be used as a pretreatment step in the beneficiation of similar low-grade iron ores. The above study reveals that hematite phase is susceptible to microwave exposure which enhances the separation of iron values from impurities. Under optimum conditions, an iron-enriched concentrate with 61% Fe, 85% Fe recovery at 50% yield can be achieved from BHJ feed ~ 38% Fe. The pretreatment process for BHJ beneficiation includes only microwave exposure without any chemical additive and may prove economical and industrially feasible.

By S Logan, J Pu, J Milsom, G McDonald

Management of environmental issues is an integral part of the mine decommissioning process. In Queensland, miners must comply with environmental aspects of the Mineral Resources Act and Contaminated Land legislation. Successful decommissioning involves the integration of a final Plan of Operations, decommissioning report addressing the mineÆs commitments included in its Environmental Management Overview Strategy (EMOS), and Site Contamination Report for relinquishment of leases under the Contaminated Land Act (1991). Niugini MiningÆs Red Dome Mine is proceeding through the decommissioning process. This paper discusses the important environmental management issues including sampling programs, management of culturally significant areas, assessment of background concentrations of target analytes, the use of historical reviews and risk assessment techniques, the timing of works, and the remediation/management of large areas of impacted land. The importance of a clear communications plan between key stakeholders is also discussed.

Jan 1, 1998

By Irwan Halim, Stephane Polycarpe, Brian Hann

The Narragansett Bay Commission Phase III CSO Program includes construction of the 11,600-foot long, 30-foot ID, deep rock Pawtucket Tunnel in Rhode Island. This paper provides an overview of the Design Build Project features and highlight some of the important design considerations, features, and innovations, including geologic conditions and related TBM design, and deep shaft and tunnel segment designs. The paper provides the most recent updates on some of the project construction activities including TBM tunnel progress and retrieval schemes, tunnel pump station and deep vertical shaft liner installations, SEM construction, and microtunneling for the longest adit using Fiberglass Reinforced Polymer Mortar pipes.

Jun 23, 2024

By M. Shabbir

A study was made to determine the optimum conditions for precipitation of uranium from mill solutions using hydrogen peroxide. Precipitation tests were made on both synthetic and actual mill solutions. Parameters studied included amount of hydrogen peroxide, initial pH, reaction pH, time, and temperature. Also investigated was the effect of varied amounts of vanadium, molybdenum, and sulfate in the test solution on uranium precipitation and product quality. The optimum conditions for complete precipitation and high product quality were (1) the use of 150 percent of the stoichiometric requirement of hydrogen peroxide, (2) initial pH of 1.0, (3) reaction pH between 3.4 and 5.0, (4) 4 hours reaction time, and (5) ambient reaction temperature. The excess hydrogen peroxide requirement is partially dependent on the amount of impurities present in the feed solution. The hydrogen peroxide process appeared applicable to treatment of the several mill eluate and strip solutions tested. The experimental studies also indicated that the hydrogen peroxide technique gives substantially better product quality than that produced by ammonia precipitation.

Jan 1, 1974