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By Raphael Victor

The construction and modification of tunnels brings a requirement for precise measurement of convergence and divergence to safeguard the structure, maintain safety and provide the assurance needed to maintain efficient progress. Established methods include manual measurement using tape extensometers and automated methods using photogrammetry and automated total stations. Drawbacks include the need for frequent access, power supply, cabling, and cost. The paper describes how the development of reliable optical displacement sensors (ODS) has changed the landscape. ODS sensors are connected to a long-range wireless mesh communications network via a solar-powered gateway outside the tunnel, with data instantly transmitted to the internet. A sensor and its reflector target can be installed in 20 minutes and is maintenance free for a decade. Tunnel movement is measured to sub-millimeter precision with repeatability of ±0.15 mm. Integration of a triaxial tilt sensor allows slope distance to be converted to horizontal and vertical changes and allows rotational movement to be determined. Applications include new-build and long-term structural health monitoring. Case studies will be given, including the refurbishment of rail tunnels in Spain where the ODS measured movement during track lowering in a situation where no other automated system was considered viable.

Jun 13, 2023

By Y. Nahmad- Molinari

We present a novel on line inductive sensor for the determination of the quality of the concentrates of iron ores. This device is coupled with a cheap USB Data Acquisition System that makes it versatile enough to simultaneously control up to seven fluxes at a very low cost (< $300 US dollars), and achieves a resolution better than 0.5 % on the determination of the magnetic iron content in the concentrate. A RLC circuit with its inductive element placed surrounding a sample of pure magnetite concentrate is tuned at its resonance frequency, by means of adjusting, the feeding voltage of a voltage-controlled oscillator (VCO) and several samples with mixtures of different contents of silica and magnetite are placed in order to get a calibration curve. After some signal conditioning, a National Instruments USB-DAQ NI-6008, acquires the amplitude of the signal via USB port on a PC using a Lab-View program designed for such purpose, in which the calibration curve is used for on-screen data presentation directly in percent of magnetite content. The implementation of this device for control purposes on line directly placed on the concentrators would allow better efficiency of the process and higher quality of the final concentrate by con-trolling; the rotation speed, the rising or dilution water fluxes or bypasses towards milling recirculation cycles.

Jan 1, 2014

By M. Maldonado

A flotation bank is a serial arrangement of cells. How to optimally operate a bank remains a challenge. This article reviews three reported strategies: air profiling, mass-pull (froth velocity) profiling and Peak Air Recovery (PAR) profiling. These are all ways of manipulating the recovery profile down a bank, which may be the property being exploited. Mathematical analysis has shown that a flat cell-by-cell recovery profile maximizes the separation of two floatable minerals for a given target bank recovery when the relative floatability is constant down the bank. Available bank survey data are analyzed with respect to recovery profiling. Possible variations on recovery profile to minimize entrainment are discussed.

Sep 1, 2012

By R. Baker

A novel electrochemical half-cell and corresponding working electrode were designed to evaluate the electro-catalytic activities of catalysts in an environment close to that of an operating proton exchange or polymer electrolyte fuel cell (PEMFC). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were employed using the novel cell to characterize various methanol electro-oxidation parameters that contribute to the overall reaction on a fuel cell anode. The effect of temperature on methanol oxidation kinetics was examined in the potential range of 0.31 to 0.65V (vs. NHE). The data was collected in the temperature range of 20 to 80°C. Based on the experimental analysis and literature data, an equivalent circuit model (ECM) for methanol oxidation was proposed and was used to fit the EIS experimental data. The experimental data and ECM electrochemical data was used to extract electrochemical kinetic parameters for methanol oxidation such as the exchange current density, Tafel slope, and energy of activation for the reaction. Kinetic data, especially at different temperatures, is very limited in the literature.

Jan 1, 2005

By Philip C. Tully

This bibliography contains 3,062 different citations to technical and scientific literature about helium and alpha-particles abstracted by 13 abstract service publications during 1963. Multiple subject classification has increased the total number of entries to almost 5,000. Helium citations are listed by 23 major classifications. The number of subclassifications has been greatly increased to minimize the time required for literature search. The use of automatic data processing has been extended in compiling the bibliography.

Jan 1, 1970

By W. A. Lang

"I.-IntroductionAn attempt bas been made in this paper to provide a basis for appraisal of the future of the coal briquetting industry in Alberta by outlining the processes used for briquetting various ranks of coal, by specifying the requirements of a briquetted fuel, by indicating .the status of the industry in the United States, by giving developments in Western Canada, by assessing costs of processing, and by discussing briquetting researches in progress. Much of .the detail bas been omitted since this might mask, rather than reveal, the more important phases of the problem. Reference will be made when possible to published articles where many of the details can be obtained.It should be stated at the outset that, in the writer’s opinion, there are three possible developments in Alberta as regards briquetting: (a) an expansion of the briquetting of the fines of • non-coking and coking coals of semi-anthracite, and of low and medium volatile bituminous rank; (b) the processing of the fines of high-volatile C bituminous coals; and (c) the upgrading of the lower rank high-moisture sub-bituminous coals. Details of the chemical and physical properties of these coals can be obtained in publications of the Research Council of Alberta (1, 2), and of the Fuel Research Station, Bureau of Mines, Ottawa (3).Semi-anthracite and low and medium volatile bituminons coals occur in the mountain areas of Alberta, where, during the upthrust of the Rocky mountains, the coal beds served as the sliding surface. This resulted in the coals being; crushed and consequently they contain a h1gh percentage of fines. In some cases they are high in mineral matter and require to be cleaned before being processed. However, the cleaning of fine coal is both difficult and costly. Both the amount of fines present in the mine-run coal and the amount of mineral matter associated with the coal have increased through the introduction of mechanized mining and through the recovery of coal by stripping operations."

Jan 1, 1950

By H. L. Bourne

The sand dunes which line the east shore of Lake Michigan resulted after the last, or Wisconsin, glacial period in Michigan. Melt-water streams carried vast quantities of glacial debris to the near shore areas of predecessors to Lake Michigan. As the lake levels receded, these vast quantities of sand were exposed to the prevailing westerly winds, which was the last major process that acted upon the sand and resulted in the formation of the dunes. 1 These dunes are one of the significant natural resources within the state. Michigan dune sands supply about 90% of the foundry sand used in the automotive industry, and 40% of the foundry sand used 2 for all purposes within the United States. The deposits owe their importance to the following factors: grain size distribution, grain shape, mineral composition and location with respect to the foundry sand market. In spite of their economic significance these I deposits are in jeopardy through legislative preemption.

Jan 1, 1975

By W. G. Pariseau

The U.S. Bureau of Mines has been conducting a series of rock mechanics investigations at the Lucky Friday Mine in the Coeur d&apos;Alene Mining District of northern Idaho. The present study uses rock deformation measurements to validate and calibrate a geomechanical model of the experimental Lucky Friday underhand longwall (LFUL) stope on the 5,100-ft level of the Lucky Friday Mine, Mullan, ID. The calibrated three-dimensional, finite-element model and measurements of rock mass displacement show a correlation of 0.795. The calibration reduces rock mass modulus to 14 to 17 pet of laboratory values and rock mass strength (with an energy rule) to 37 to 41 pet of laboratory values. This model suggested that stress-related ground control problems would be encountered west of the stope where the vein makes a right-angle turn and then splits. Rock burst activity was concentrated in this area during mining of the LFUL stope.

Jan 1, 2010

By P Mitchell, S Pushpan, G Ferres, K Bobbermien, L Hudson

"Falling commodity prices and a rising supply surplus have ushered in a period of restraint in capital project investment across the global mining and metals sector. Competition for capital project funding has seen fewer projects progress through investment gates and a stronger focus on projects that deliver gains in capital productivity and strategic outcomes.Over the course of the 2015 financial year, EY conducted a study of 108 projects in the global mining and metals sector (EY analysis; Larsson and Ericsson, 2014; SNL Financial, 2015). The projects studied were at various life cycle stages and related to the development of copper, iron ore, gold, coal, nickel and other commodities. Each individual project investment exceeded US$1 B, and the studied group represented a cumulative investment value of US$367 B.The research found that the majority of projects were delayed and/or over budget when measured against the initial estimates made during the early stages of the project life cycle. Of the surveyed projects, 69 per cent were identified as facing cost overruns with an average overrun of 62 per cent above the initial estimate and 50 per cent reported schedule delays, even after remedial acceleration initiatives.The analysis found that budget and schedule overruns could be attributed to five key causes:project management factorsstakeholder conflictsresource constraintsregulatory, and policy-related challengesunfavourable external environment.Improving project delivery performance starts with successful planning, followed by rigorous management during delivery. From global experience on large and complex capital programs, EY has observed a consistent theme of underinvestment and a lack of focus in three often-overlooked but critical areas:implementing effective governance and reporting frameworks with lead indicators that reliably flag emerging risks while they can still be mitigatedallocating adequate cost and time contingency to account for risks across the life cycleenhancing the value of contingency by aligning contingency plans with scenario plans.This paper explores the surprising findings of the study, proposes a root cause model and examines key considerations in applying these critical enabling techniques.CITATION:Hudson, L, Mitchell, P, Ferres, G, Bobbermien, K and Pushpan, S, 2016. Are your megaproject schedules and costs under – or out of – control?, in Proceedings Project Evaluation 2016, pp 75–85 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By G. V. Henderson

The San Gabriel Valley contains some of the richest and most extensive sand and gravel deposits in California. Operating quarries within the San Gabriel area mine more than 15 million tons of high quality aggregate per year. This represents about 45 percent of the total mined in the greater Los Angeles area, one of the nation&apos;s largest aggregate markets and producing regions. Popular opposition to continued aggregate production in the San Gabriel Valley is high, especially in the city of Irwindale where 40 per-cent of the city&apos;s property is made up of "excavated holes," some 150-200 feet deep. Reclamation of 70 years of mining is now an almost impossible task. Zoning regulations have the effect of depleting these vast reserves rapidly by changing the definition of total reserves to include only "legally minable reserves." All but two or three of the aggregate mines now operating will be depleted or zoned out of business by the year 2000. Some studies indicate that there will be no aggregate mining operations by 1995. Recent studies show a drastic change in land use patterns within this valuable mineral resource area over the past 20 years. The San Gabriel Valley is a classic example of the lack of adequate regional planning with regard to urban development in MRA&apos;s and represents a "too little, too late" effort by local government and industry.

Jan 1, 1978

By Sean Gallagher

This report describes research by the Bureau of Mines on alternative materials-handling strategies for reducing the costs and incidence of back injuries in low-seam coal mines. Strategies recommended for redesigning materials-handling tasks include elimination of tasks, mechanization of tasks, and matching lifting tasks to the physical capabilities of underground miners. The report also discusses other methods that can be used by management to reduce the costs associated with back injuries.

Jan 1, 1989

By Martin Langenderfer, Catherine Johnson, Alexander Douglas

Mine haul roads degrade rapidly due to extreme loads on sub-optimal construction materials. Unmanned aerial vehicles (UAV) are suited to quantify large-area road-network conditions, such as surface roughness, defects, and grade to optimize remediation of poor conditions and reduce overall costs. Mine haul roads present unique challenges, such as material type and edge characteristics, to automatic road detection that often fail, requiring manual road input. This research proposes a new method for analysis using the road center determined by principal curve analysis of a haul truck’s Global Navigation Satellite System (GNSS) traces; analysis grids were created from this center line. A dense point cloud from UAV photogrammetry was generated, and multiple linear regression analysis was conducted on each individual grid. The root mean square error in each grid indicates the surface roughness, and the change of slope between grids indicates the road grade inconsistencies. This method was applied to 26 road sections, and the results were validated by images taken from the truck operator’s vantage point. Critical defects were identified including excessive pothole formation, corrugation, depressions retaining water, and narrowing of travel lane. The results demonstrate this is a valid method of road identification and quantification of road defects at a mine site.

Dec 19, 2023

A major hazard to workers in underground mines is fire and the resulting contaminated air. Fire reaches miners thousands of yards away with carbon monoxide gas and other toxic fumes. The same ventilation system that furnishes fresh air to miners can also be the vehicle to carry contaminated air to remote locations. To reduce these problems, the U.S. Department of the Interior&apos;s Bureau of Mines entered into Contract H0242016, "Mine Shaft Fire and Smoke Protection System," with FMC Corporation, Santa Clara, California, to evaluate mine shaft fire and smoke hazards and to develop and demonstrate a low-cost, reliable mine shaft fire and smoke protection system that would be applicable to a majority of metal and nonmetal mine shafts, including raises and winzes, especially in deep mines.

Jan 1, 2011

By Laros T, Schoenbrunn F

Deep paste thickeners have been proven capable of consistently producing medium to low slump material for disposal without the need for filters. However, proper design of the entire system is critical for a paste project to he successful. Some of the factors that must be carefully considered in design of a paste system include thickener sizing, tailings inipoundineni design, underflow pumping, and control system.

Jan 1, 1998

By Charles Kingsley

THE PRESIDENT (DR. C. B. KINGSTON, member C.l.M.M.) expressed regret that neither of the authors of the paper was able to be present to submit the paper in person. In their absence, it would be introduced formally from the Chair. It was a clear, straightforward account of a fine piece of shaft sinking, cleverly conceived and boldly executed. He referred briefly to the distribution and nature of the Dome ore-bodies and stated that, for both the miner and the metallurgist, the mine had provided a wide range of problems of unusual interest. Discussion on the paper was then invited. MR. THOMAS PRYOR said the paper was most opportune, because the subject of internal shafts did not appear to be fully treated in current mining literature. Many members were not familiar with Canadian gold deposits and it would be of interest if the authors could give a brief description of the location of the ere deposits of the Dome mine. This information would doubtless explain why a new internal shaft was needed in a position which required such an exceptionally long cross-cut to connect it to the main hoisting shaft to surface. It would also add to the value of the paper if the authors would give some idea of the duty expected of the new shaft in terms of tons of rock hoisted and of trips engaged in the transport of men and materials, and it would be helpful if figures could be given of the total capital cost of the hoists and subsidiary excavations at the shaft top, and of the cost per foot for sinking and lining the shaft below the collar. Turning to details of the paper, one was favourably impressed by the care given to the provision of a good travelling way for men in the main cross-cut, as shown in Figure 1. It was by no means always that one could walk in comfort and safety in a working where there was a 20-in. ventilating pipe in the roof.

Jan 1, 1939

By Fergusson E.

An account is given of the history and operation of the Straits Tin market and the Penang price. The procedure by which the official ruling tin price is determined is presented and the way in which bids are treated is outlined: the price declared in Penang is the result of a joint operation by the two Malaysian smelters and is arrived at by finding the highest price at which the whole of the day's offerings for sale can be sold, thus reflecting the marriage of the offerings of the individual mine producers with the demand for Straits Tin from the consuming countries of the world. A system of accurate weighing, sampling and assaying of concentrates delivered to the smelters' premises enables the various ore-buying agencies of the two smelters to notify their central offices promptly of the estimated tin content of the concentrates their customers wish to price that day, so that by 11.00 a.m. both smelters will have exchanged with each other figures giving the total quantity of metal they have for inclusion in the day's market, at the same time exchanging particulars of the bids they have received. Miners are encouraged to sell regularly for cash and an evenness is thus achieved which avoids large daily fluctuations in overall quantity.

Dec 30, 1971

By Oren C. Baptist

[Several new oilfields have been developed in northwestern Wyoming during the past 10 years, production is obtained from discontinuous, permeable sands enclosed within impermeable shales. The energy to drive the oil to producing wells in supplied by gas in solution in the oil. Most of the wells had high-initial potentials, but rates of oil production have steadily declined, indicating a dissipation of the driving energy and the possibility that large volumes of oil will remain unrecovered in the reservoirs. The studies reported in this paper were undertaken to develop laboratory data of the type most likely to be needed by persons studying the susceptibility of the Newcastle sand reservoir to secondary-recovery methods.]

Jan 1, 1957

By NEFE NONE

Possible New U.S. Half-Dollar. - Tile George Washington Commemorative Coin Act, H.R. 3133, was introduced in the House and approved by the House Banking Committee. It would allow the minting of at least 10 million commemorative silver half-dollars the size of the same coin produced before 1965. A companion bill, S. 1228, was introduced in the Senate. Taxes and the U.S. Minerals Industry. - The General Accounting Office completed a report to Congress on "Assessing the Impact of Federal and State Taxes On the Domestic Minerals Industry." the study presents a quantitative method to assess the effect of taxes on profitability, and suggests ways to use taxes or tax credits to help marginal mine operations and possibly to increase mineral production, Limited copies of the 139-page report are available free of charge from U.S. General Accounting Office, Documents Handling & Information Sevices Facility, P.O. Box 6015 Gaithersburg, Md. 20760.

Jan 1, 1981

By H. Kolcz, G. S. Dobby, R. Stratton-Crawley, S. W. Wilson

"The Matte Separation plant at Inco's Copper Cliff Smelter Complex is described. The continuing implementation of flotation column technology in the flowsheet in various applications is reviewed. Comparative studies on 0.038, 0.10, 1.1 and 1.8 m diameter columns have been carried out. It was demonstrated that consistent metallurgical performance was obtained with both pilot- and plant-scale units. Grade-recovery relationships for plant columns can be predicted with confidence from data obtained from test equipment. The work indicates further areas of the flowsheet in which columns present an attractive alternative to conventional cells. INCO’s MATTE SEPARATION PROCESSNickel concentrate from Inco’s Sudbury area mills has been processed in the Copper Cliff smelter for sixty years. Prior to that, Sudbury ores had been smelted directly. Historically, copper-nickel separation from smelter converter matte was achieved by the classical Orford process. In the mid-1940s Inco developed an improved separation scheme based on mineral processing methods, the Matte Separation Process. A generalized Copper Cliff Smelter Complex flowsheet is shown in Figure 1.Iron sulfide and gangue contained in the nickel concentrate are rejected in the smelting-converting process. The molten product, typically containing 50% Ni, 25% CU and 22% s, is cast at about 1000 ºC, into floor moulds and allowed to slowly cool for four days. During this period nickel sulfide (heazlewoodite, Ni,S,), copper sulfide (chalcocite, cu,S) and a copper-nickel metallic alloy precipitate and form a coarse grain structure that is amenable to separation by physical means. The phase chemistry of this system has been described previously by Sproule et al (1). This matte then becomes the feed to the Matte Separation Process.A simplified block flowsheet of the Matte Separation Process is shown in Figure 2. Matte ingots, typically weighing 20 tonnes each, are broken and crushed in a three stage crushing plant to approximately minus 0.01 m and conveyed to the Matte Separation building. Grinding is carried out in two parallel circuits each consisting of a rod and ball mill in series producing a flotation feed which is 65% minus 44 microns. Typical throughput of each grinding circuit is 650 tonnes/day. The metallic fraction of the feed is recovered by magnetic separation. This product, containing about 66% Ni and 15% CU, is a major component of the feed to the Copper Cliff Nickel Refinery."

Jan 1, 1990

By J. C. Hampton, L. A. Matzar, C. R. Gamwell

In geomechanics, conducting uniaxial or triaxial compression tests require samples to be prepared to a certain length-to-diameter ratio. This ratio is typically defined as 2:1 (length to diameter) and is accepted as a common standard for all materials on which mechanical properties testing is performed. Variations in sample length can cause changes in measured strength properties across multiple material types, such as cement, rock, or soil. Within the oil and gas industry, it is not uncommon to receive samples for technical services work that are slightly under or exactly the length requirement before surface grinding and sample preparation. Many of these samples are discarded from uniaxial and triaxial compression tests and used in another manner; therefore, it is necessary to study the length-to-diameter ratio in efforts to understand the limits and validity of testing samples that are slightly out of the 2:1 ratio. This paper discusses uniaxial compression tests performed using Berea sandstone and a standard cement mixture of 2.54-cm diameter to study changes in rock strength and properties. Compressive strength for each lengthto- diameter ratio over a range of 0.5:1 to 2.2:1 was measured. The investigation was extended to study near-end effects, where the sample length is near, but not exactly twice the diameter. It was discovered that the cement samples conformed reasonably well to the suggested ASTM correction factors. The sandstone did not conform to the correction factors and further analysis is required to develop a correction factor unique to the material. Near end effects, in both the cement and Berea, were found to increase compressive strengths, especially when the L/D of the samples was increased slightly over a 2:1 L/D.

Jan 1, 2015