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By C. Bucknam, M. McComb

Mercury and silver polythiocarbonate sludge that was generated from the pilot testing of optimized mercury removal from cyanidation pregnant eluate solutions prior to Merrill-Crowe recovery of gold and silver were tested for long term stability at Newmont Metallurgical Services. Sludge samples were mixed with heap leach residue to simulate disposal of the sludge in spent or active areas of the heaps and leached for twenty weeks with water and cyanide leaching solution, respectively. Leach testing results are presented as well as analysis of the sludge using scanning electron microscope techniques down to the <1000 nanometer scale.

Jan 1, 2007

By Claude Bazin

"Laboratory semi-batch flotation tests were conducted using two different sulphide ore samples. The size reduction was adjusted to cover a wide range of flotation feed size distributions. Results show that similar recoveries can be achieved independently of the fineness of grind. This result suggests that possible energy savings could be achieved by a redistribution of the power between the grinding and regrinding mills. The behaviour of the selectivity curves shows that some gangue minerals are more sensitive to particle size than other ones, implying the existence of preferential associations between minerals in the ore.INTRODUCTIONInteractions between grinding and flotation have been studied for many years, and still a robust model to link the two processes lacks to be developed (Girard et al., 2005; Bazin et al., 2001). The ore size reduction liberates mineral grains, while flotation separates them into valuable minerals and gangue. The more size reduction that is applied to the ore the more important is the mineral liberation but also the production of fine particles that can pose problems during flotation (Trahar and Warren, 1976). The definition of the grinding requirement for flotation is a complex problem (Rickelton and Dell, 1977; Sosa Blanca et al., 2000; Morrison, 1993; Wei and Gay, 1999).This paper analyzes the effect of the fineness of grind using semi-batch flotation test results. The first two sections describe the test procedure and the results. The third section analyzes the results in terms of liberation and selectivity, and proposes a possible redistribution of power between grinding and regrinding mills."

Jan 1, 2006

By Stephen H. Chung, Kevin Atherton

The main purpose behind this preliminary study was the reduction of costs while maintaining productivity. Finding a way to achieve this balance without compromising controls on safety and quality of blasting results is of continual interest to the mining industry and of particular interest when ore of lower grade is being mined.

Jan 1, 1998

By W. Langer

Of the 50 or so most often utilized industrial minerals, more than two thirds are, or have been, produced in the western states of Arizona, Colorado, Idaho, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wyoming. Some commodities, such as natural aggregate, currently are produced in all 13 states; others such as beryllium and iodine are produced in only Utah and Oklahoma, respectively. Together, the 13 western states make a significant contribution to the US industrial minerals industry.

Jan 1, 2007

By Xiang-yang Zhou

Keywords: Low-Grade Dolomite, Low CaO Content, High Specific Surface Area, MgO. A low energy consumption preparation technology of magnesium oxide with low calcium oxide content and high specific surface area from low-grade dolomite has been investigated. The optimum technical conditions for the preparation of magnesium oxide are the followings: dolomite is partially calcined at 750-800° for 2 h; the optimum solid-liquid ratio range in calcined dolomite slurry is 20-30 g?l?1; carbonation temperature, carbon dioxide pressure and end point pH value of carbonation are less than 40°, 0.4-0.6 MPa and 7 respectively during carbonation process; decomposition temperature of Mg(HCO3)2 solution is near 100°; calcination temperature of the precursor (i.e. precipitated basic magnesium carbonate) is less than 850°. More than 90% of magnesium can be extracted by the technology. The MgO product (CaO < 0.38%) with a specific surface area of near 50 m2?g?1 also can be obtained by the technology.

Jan 1, 2005

The common approach of designing blasts on a trial and error basis is quickly coming to an end. When utilizing the full scale blast environment, trial and error can quickly become cost prohibitive and leaves much to be desired in terms of true blast diagnostics. In these situations testing is usually only continued until a perceived improvement is achieved and when the gross undesirables in blast results are removed. This does not preclude, however, that further improvements of up to 100% or more can not be obtained.

Jan 1, 1994

By Y. Okita

The Goro Nickel Process, developed over a ten-year period, uses a number of novel processing steps and treats two ore types, limonite and saprolite, together. Nickel and cobalt are solubilized using a 270°C pressure acid leach in sulphuric acid, which rejects the bulk of the Fe into the leach residue as hematite particles. The leach liquor, after CCD, is aerated to oxidize any ferrous iron to the ferric form and is neutralized with limestone to precipitate iron as hydroxides together with gypsum from the neutralization of the free acid. Further neutralization with lime, together with steps to remove suspended solids, reduces the iron to trace concentrations. Nickel and cobalt are directly recovered from the low-iron leach solution by primary solvent extraction using Cyanex 301® (SXl) in a high-strength hydrochloric acid solution. Nickel is subsequently separated from cobalt in a secondary solvent extraction circuit using tri-isooctylamine. A granular nickel oxide is made by pyrohydrolysis, and this allows the recycling of hydrochloric acid to SXl. The process is currently being commercialized to produce approximately 60,000 t/y of nickel as nickel oxide granules and approximately 5,400 t/y of cobalt as cobalt carbonate. This paper describes the process development to control the Fe concentration in the SX1 feed solution.

Jan 1, 2006

By R. B. Pedersen, A. Filipa, A. Marques

"Shallow-depth (<200m) high temperature submarine hydrothermal systems are not commonly observed on mid-ocean ridge settings, as most known systems are located within arc - island-arc volcanic settings, often proximal to coastal areas (meteoric waters added). In 2013, during the Centre for Geobiology’s 2013 oceanographic cruise (R/V G.O. Sars), a dredge successfully sampled massive sulfides and hydrothermally altered rocks from the top of a volcanic edifice (~144-284 m depth) located on the northern sector of the Kolbeinsey Ridge. Dredged samples include vesicular altered basalts, and matrix supported anhydrite, barite and barite-pyrite-anhydrite volcaniclastic breccias. Sulfidesulfate breccias depict complex zoning where numerous small vent orifices are distributed with large blades of marcasite that appear intergrown with barite. Native sulfur was observed in one of these small vent orifices. On a microscopic scale, numerous spherical silica-rich structures appear associated to these breccias. These rocks are evidence for the presence of a relatively high temperature (minimum 150ºC) shallow-water seafloor hydrothermal system in the Arctic mid-ocean ridge, far from mainland influence. This new discovery presents a unique opportunity to study the dynamics of fluid chemistry, metal mobility and precipitation in shallow hydrothermal systems. The remote location of this system dictates that fluid recharge will be influenced solely by seawater and magmatic fluids, In July-August 2014 we expect to survey this new field and acquire new and comprehensive data."

Sep 1, 2014

This study was conducted to determine the effects of a machine-mounted scrubber and water sprays on face methane levels. Testing was conducted in the NIOSH ventilation test gallery which was designed to simulate a full-scale mine entry. In the test entry, a model mining machine, equipped with water sprays and a simulated dust scrubber, was located at the face of a 20-ft box cut. Blowing ventilation was provided using a curtain with a 40-ft setback distance. Methane released from a pipe manifold located inby the mining machine was monitored at six locations that were 1 ft outby the pipe manifold. Tests were first conducted to evaluate the effects of using sprays and scrubber separately on face methane levels. Additional tests were conducted to determine how a scrubber used with various water spray systems would affect face methane levels. The use of either sprays or scrubber reduced face methane levels significantly. The combined use of sprays with the scrubber further reduced face methane levels a small amount. Primarily the sprays affected methane levels by changing airflow distribution close to the face.

Jan 1, 2001

A new personal respirable dust monitor developed by Rupprecht & Patashnick Co., Inc. in a multi-year project funded by the National Institute for Occupational Safety and Health (NIOSH) generated promising results in underground coal mine testing performed by NIOSH and industry representatives during the summer of 2003. The mine data showed that the personal dust monitor (PDM) performed similarly to co-located manual reference samplers for full-shift samples at all four underground coal mines at which the evaluation took place. The technology that forms the heart of the PDM, called the tapered element oscillating microbalance (TEOM system), is unique in its ability to collect suspended particles on a filter while simultaneously determining the accumulated mass with National Institute of Standards and Technology traceability. Because the monitor measures the true particle mass collected on its filter, its results do not exhibit the same sensitivity to water spray as do optically based measurement approaches. The technique achieves microgram-level mass resolution even in the hostile mine environment, and reports dust loading data on a continuous basis. Using the device, miners and mine operators have the ability to view both the cumulative and projected end-of-shift mass concentration values, as well as a short-term 15- or 30-minute running average. During underground mine trials in the summer of 2003, technical personnel used the readings from the PDM to identify and correct several abnormal dust generating scenarios. These events demonstrated the potential of the PDM to be used as an engineering tool to evaluate the effectiveness of various dust control strategies. In a separate evaluation performed by CONSOL Energy, Inc., the mine operator evaluated the benefit of a proposed new water spray-based dust control system. Engineers measured the dust concentration upstream and downstream of a production location under different dust control scenarios using two PDM units. By evaluating the change in the dust loading between the upstream and downstream monitoring sites, the company was able to determine in a few hours which hardware configuration would yield the greatest benefit to the workplace environment. BACKGROUND Measuring underground coal mine dust concentrations is an essential part of protecting miners&apos; health. The U.S. Secretary of Labor and the Federal Advisory Committee on the Elimination of Pneumoconiosis among Coal Mine Workers has recommended that better monitoring of coal miner dust exposures be used as a method to improve miner health. In consultation with labor, industry, and government, NIOSH issued a contract to Rupprecht & Patashnick Co., Inc. (R&P), Albany, N.Y., to develop a one-piece PDM. The object was to miniaturize TEOM technology into a form suitable for a person-wearable monitor that would enable accurate end-of-shift dust exposure information to be available to miners. Furthermore, any person-wearable dust monitor should minimize the burden to the wearer by incorporating the monitor into the mine worker&apos;s cap lamp battery, with exposure data continually displayed during the shift to enable workers and management to react to changes in dust exposure. In the summer of 2003, NIOSH conducted extensive testing of the PDM to determine its laboratory and in mine performance. In addition, anecdotal information collected in the mines showed several occasions where miners were able to identify situations that produced high levels of respirable coal mine dust The PDM&apos;s response to unplanned changes resulted in action being taken to keep dust exposures as low as possible. In another case that demonstrated the PDM&apos;s versatility, a mine was seeking to find a better dust control solution on its longwall headgate stageloader. In this instance, the PDM was used as a diagnostic tool by the miners to quickly evaluate the control technology. [ ] HOW DOES THE PDM WORK? The PDM is configured to provide accurate respirable dust personal exposure information in a form that is as convenient to wear as a normal cap lamp (See Figure 1). Respirable dust exposure data displayed by the device has two main objectives: providing the miner and mine operator with timely values to avoid overexposure to dust, allowing them to make any necessary changes during the course of a work shift; and computing an accurate end-of-shift statistic for a miner&apos;s average respirable dust exposure. The mass sensor embedded in the PDM, holds the key to the accurate, time-resolved dust concentration measurements. The inertial, gravimetric-equivalent, mass measurement technique used in the device typically provides a limit of detection on par with that of the most sensitive laboratory-based microbalances.

By Tom Martin

Mega projects present unique challenges with regard to estimating costs. With such projects, which may span decades, these challenges often begin as soon as a project is conceived. The importance of having a sound, resource based estimate avail-able early in the process cannot be overstated because it provides the basis for ongoing project decisions. For the final phase of providing an updated cost estimate, often while bidding by contractors is underway, the Engineer?s Estimate (EE) must incorporate present market conditions; account for possible volatile material price swings; be based on actual labor and fringe costs; rely on meaningful productivity rates; and accommodate any recent technology advances while identifying and allowing for risk factors. This paper explains the benefits associated with consultants adopting a contractor?s estimating approach when preparing the Engineer?s Estimate on mega projects like the various tunneling projects in New York City.

By Bianka Nani Venturelli

Estudou-se o efeito do tamanho de grão austenítico nas propriedades de tração do aço Hadfield refinado com Hf. Estas propriedades foram comparadas com as de um aço Hadfield sem refino, ambos com a composição química de acordo com a norma ASTM A128 – grau B2. Adicionalmente, foram usadas técnicas de caracterização macroestrutural, microestrutural e fractográfica. A caracterização macroestrutural mostrou que o aço Hadfield com adição de Hf apresentou tamanho do grão austenítico (600 ?m) aproximadamente cinco vezes menor do que o do aço Hadfield sem refino (3000 ?m). Os resultados do ensaio de tração mostraram um pequeno aumento (~6%) no valor do limite de escoamento com o refino do grão, em acordo com a Equação de Hall-Petch para materiais austeníticos. No entanto, os resultados dos ensaios de tração do aço Hadfield refinado mostraram aumentos que não foram previstos para as propriedades de resistência à tração (~37%), alongamento (~53%) e tenacidade (~88%). O exame fractográfico dos corpos de prova de tração indicou predominância do mecanismo de fratura dúctil para o aço Hadfield sem refino, enquanto que o aço Hadfield refinado apresentou predominância do mecanismo de fratura intergranular dúctil.

Oct 30, 2017

By Osamu Taki

This paper presents the system, the strength of column, the design concept, and the applications with four case histories from the past project as the general aspect of Geo-Column (trade mark of single soil-cement column by SCC Technology, Inc.). In the system, it shows the installation process and drilling/mixing tool with the mixing process. In the design concept, it shows how to design Geo-Column against the vertical and horizontal load. Finally, it shows the applications with four case histories, (1) building mat foundation, (2) isolated foundation on the pedestrian bridge, (3) bridge spread footing and slope erosion control wall in the channel, and (4) cut-off wall and shoring wall in the underpass roadway to the railroad.

Jan 1, 2000

Rutile – Zircon Mining on East Coast Surfing Beaches – Rutile-Zirconium Producing Companies in Australia

Jan 10, 1964

The EMEM Awards of the Department of Minerals and Energy (DME) were formally launched on 3 March 2000 by Ms Susan Shabangu, Deputy Minister at the Department?s Mineralia Centre in Pretoria. The launch was attended by invited guests from the mining and aggregate industries ,representatives of the Patron Organisations (see below),non- government and scientific organizations, the media, other government departments involved with mining environmental management and members of staff of the DME both nationally and regionally.

Jan 1, 2000

By Y. Boissonnas

INTRODUCTION, The transalpine rail routes in Switzerland are well over one hundred years old. As the established routes no longer meet the demands of the continually increasing volumes of rail traffic between north and south, two new routes through the Alps were planed. The old Gotthard rail line is in fact a mountain railway. The northern and the southern access ramps?with a maximum speed of 80 km/h and a maximum slope of 2.2%?reach the old Gotthard rail tunnel at an elevation of approximately 1,100 m above sea level. This is approximately 900 m higher than the city of Milan. In 1992, the Swiss electorate people voted with an overwhelming majority in favor of the project to build the new base routes through the Alps. The Swiss voted again in 1998 in favor of the financing proposal for the new infrastructure. Swiss Federal Railways together with the BLS Lötschbergbahn were commissioned for the realization and management of the Gotthard and Lötschberg routes. AlpTransit Gotthard Ltd., founded by Swiss Federal Railways, was given the task of managing the design and realization of the Gotthard route until the start of regular service. In the meantime the shorter Lötschberg Base Tunnel was open to traffic in 2007

A vital ingredient in ensuring that metals exploration companies, working in the developing countries of thePacific Rim, support the development of national geologists is making such a learning program cost-effective. There is a wide spectrum of learning needed in the development of these explorationists: the technical and conceptual skills to carry out exploration efficiently, the professional and managerial skills to apply the exploration in the work situation, the personal attributes required to manage their exploration effectively, and a company organisation that allows them to learn and use these skills and attributes.

Jan 1, 1995

By Jan W. Merks

"The settlements between mines and smelters are based on the mass of metal contained in concentrate lots. The mass of contained metal is a function of the wet mass of a lot, and its moisture content and metal grade while the variance of the mass of contained metal is a function of the same variables and their variances. Uncertainties in the measurement procedure applied to estimate each variable are quantified in terms of precision and bias. The absence of bias and an acceptable degree of precision are the keys to effective risk analysis and loss control.ISO Technical Committee 183-Copper, Lead and Zinc Sulfide Concentrates, has developed standard methods for sampling and weighing, estimating precision and testing for bias, the determination of mass loss on drying, the calculation of the mass of contained metal and its variance, and various analytical methods for major and minor metals. The variance for wet mass is calculated from the precision of the scale while the total variances of moisture and grade are estimated from pairs of interpenetrating primary samples. The variance of contained metal can be calculated either from mine data or from smelter data but the risk associated with the settlement is largely determined by the absence or presence of bias and the variance of differences between exchange assays.ISO/TC 183 does not deal with precision and bias for exchange assays but is developing guidelines to determine realistic splitting limits. Given that the exchange of assays between mines and smelters accounts for a large part of the risk associated with the settlement, precision and bias for exchange assays should be measured and monitored. The need for umpire services can be reduced by applying statistical quality control (SQC).Calibrating static scales, moisture balances and analytical balances, bias testing of sampling methods and sample preparation procedures, estimating the variance of a single variable or the variance of a function that a set of variables defines, and monitoring precision and bias for exchange assays, are the quintessence of metrology, the science of measurement, when applied in mining and metallurgy."

Jan 1, 1995

By M. Cai

A practical simple method is proposed to estimate the tensile strength (st) of strong brittle rocks from the strength ratio of R= sc/st = 8 sc/sci, where sc is the uniaxial compressive strength and sci is the crack initiation stress in an uniaxial compression test. 8 is the Griffith strength ratio and the term sc/sci accounts for the difference of crack growth or propagation in tension and compression in uniaxial compression tests. sci can be reliably obtained from volumetric strain measurement or acoustic emission (AE) monitoring. With the strength ratio R determined, the tensile strength can be indirectly obtained from the result of uniaxial compression tests. In addition, a practical estimate of the Hoek-Brown strength parameter mi is presented and it is suggested that mi = 12 sc/sci can be applied to strong, brittle rocks in high confinement zone and mi = 8 sc/sci can be applied to low confinement to tension zones. It is found that the predicted tensile strengths and Hoek-Brown strength parameter mi using this method are in good agreement with test data. The rock strength parameters like st and mi, which require specialty tests such as direct tensile (or Brazilian) and triaxial compression tests for their determination, can be reasonably estimated from uniaxial compression tests.

May 1, 2009

By W T. C Kendall, H D. Ngo

Garden Well is a shear-hosted Archaean orogenic gold deposit located 100 km north of Laverton, Western Australia. The Garden Well processing plant is designed for a nominal 491 t/h milling rate and annual capacity of 4 Mt. The plant has three key innovations:1. a scrubbing circuit, expected to reduce grinding power consumption by up to 20 per cent2. a secondary cycloning/gravity circuit, providing a second opportunity for gravity gold recovery (additionally, the circuit effectively increases the leach residence time of the coarse gold bearing fraction of the leach feed by approximately 60 per cent, without any additional tankage)3. the use of mid-stream oxygenation to enhance gold recovery.The Garden Well deposit is free-milling with overall laboratory gravity/leach gold recoveries exceeding 95 per cent at a P80 grind size of 150 ¦m. Three mineralogical domains have been identified: oxide, transition and fresh, with the fresh domain having subdomains of fresh ultramafic and fresh shale. There is a high component of gravity recoverable gold in all three domains.This paper will discuss these innovations and the design challenges and the risk mitigation strategies that were adopted to ameliorate the prototyping risk. The performance of the plant since commissioning together with lessons for the future will also be presented.CITATION:Smith, R J, Kendall, W T C and Ngo, H D, 2013. Treatment plant innovation at Garden Well, in Proceedings World Gold 2013 , pp 315-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013