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By J. A. Finch, J. Vergouw

"Flotation selectivity becomes progressively more difficult to achieve with decreasing particle size. One of the possible problems is agglomeration, i.e. particles clustering together. One mechanism derives from the surface charge all particles develop in water. Agglomeration driven by surface charge is known as coagulation. One form is coagulation between particles of two different minerals of opposite charge. Another is coagulation between particles of the same mineral when conditions are such that the charge approaches zero.The paper describes the method of measuring charge and a new automated settling technique for measuring agglomeration. The phenomena are illustrated with galena and pyrite. Methods of assessing the importance of agglomeration in the plant environment are still to be developed.IntroductionFine particles can agglomerate (i.e. adhere to each other) under certain conditions. This is counter-productive for any physical separation process, including flotation. One cause of agglomeration derives from the surface charge that all particles develop in water. Agglomeration due to surface charge effects is referred to as coagulation. There are two forms of coagulation. If the surface charge is brought to near zero then the force of repulsion is lost and particles coagulate. This usually applies to particles of one mineral type and the technical tenn is homocoagulation. On the other hand, if two particles have opposite charge there is an attractive force. Since the particles in this case are usually different minerals this is known as heterocoagulation.Both types of coagulation can cause minerals to be misplaced. In the case of heterocoagulation this is fairly obvious. One example that may be familiar is slime coating (fines of one mineral coating larger particles of another) But even homocoagulation can be a problem an agglomerate of the same mineral particles can entrap particles of another mineral."

Jan 1, 1997

By Robert A. Cummings

A rock mass classification system has been developed for support estimation in mines using caving methods. The developed system (MBR System) accepts readily-obtainable geotechnical properties, and mining geometry, to develop a rating that permits recommendations for drift support in block caving mines. The data base includes major active United States caving mines. The method is intended to be used for planning and estimating purposes and for preliminary support design. The Manual explains the organization and nature of the MBR System, its derivations, details of required input data, methods for assessing the data and for developing rock mass ratings, and techniques for selecting the most appropriate mine support recognizing mine requirements and desired stability. A worked example is provided.

Jan 1, 1984

By F. D. Ford, Z. Dai, A. Byers

Manitoba Mining and Milling operations consist of three underground mines (Thompson T1, T3 and Birchtree), feeding the Thompson Mill. Three years ago, a collaborative effort involving Mines Exploration, Mines Project Development Group, Mill Technical Services and Vale Base Metals Technical Excellence Center was initiated to establish and verify the cause of high variability in concentrate quality and Ni recovery at the Thompson Mill. One outcome of this work was a program to systematically characterize the mineralogy and metallurgical performance of current and future orebodies feeding the mill. Mineralogy results show that high value enabling ores typically have a high pentlandite to pyrrhotite ratio and benign silicate mineralogy (mostly quartz and feldspar from sedimentary host rocks), while metallurgically challenging ores contain some combination of pyrite and/or hexagonal (non-magnetic) pyrrhotite and/or elevated quantities of talc (with associated carbonates) derived from altered ultramafic host rocks. The metallurgical performance of these two ore types has been simulated by an Excel particle flotation model, which calculates the relative floatability of particles based on the particle’s mineral composition and mineral locking determined from MLA images. The relationship between these mineral properties measured by MLA and metallurgical performance was established using 13 monthly composite samples from Thompson Mill. The model was then validated with results of laboratory flotation experiments on individual orebodies submitted for evaluation. The validated model can be used to predict plant metallurgical performance based on individual ore bodies feeding the mill. Individual orebody’s grade-recovery curves are assumed to be additive, and can be weighted in proportion to the mill feed to predict mill recovery over the same time period. The ore mixing can be done with a simple Excel spreadsheet and comes with a graphical output for easy visualization of the resulting grade-recovery curve.

Jan 1, 2015

By L. A. Cornish, S. N. Prins, R. Süss

The work is being done using the Thermo-CalcTM software, and the database is being built up by obtaining good thermodynamic descriptions of all of the possible phases in the system. The database supplied did not cover all of the phases, and these had to be gleaned from literature, or modelled using experimental data. Similarly, not all of the experimental data were known, and where there were gaps or inconsistencies, experiments had to be undertaken. A preliminary version of the database was constructed from assessed thermodynamic data-sets for the binary systems only. The binary descriptions were combined allowing extrapolation into the ternary systems, and experimental phase equilibrium data were compared with calculated results. Very good agreement was obtained for the Pt-Al-Ru and Pt-Cr-Ru systems, which was encouraging and confirmed that the higher-order systems could be calculated from the binary systems with confidence. Since some of the phase models in databases were different, these phases had to be remodelled. However, more work is ongoing for information concerning the ternary phases present in the Al-Cr-Ru, Pt-Al-Ru (two ternary compounds in each) and Pt-Al-Cr (possibly more than three ternary compounds) systems. At later stage of the work, problems with the thermodynamic descriptions of the Cr-Ru and Pt-Cr binary systems were found. A programme of experimental work to overcome these has been devised, and is being undertaken. Keywords: Pt-based alloys, phase diagram calculations.

Jan 1, 2006

By E. A. Lowe, A. F. Bellamy, J. W. Smith

"In the autumn of 1977 Bethlehem management initiated feasibility studies on recovery of by-product molybdenum from concentrate produced at the existing Highland Valley mining operation. Over the fall and winter months test work was carried forward concurrent with design, flowsheet, equipment specification and cost studies. The decision was made to go ahead with a 200 ton-per-day treatment plant. Construction started in early 1978 and progressed to an initial start-up stage in mid-June. Full operational status was reached in August 1978. Operational results through August 1979 are presented. INTRODUCTIONBethlehem Copper Corporation operates a 20,000 ton-per-day Open Pit Mine and Flotation Plant located in the Highland Valley, some 30 air miles Southwest of Kamloops and 20 miles Southeast of Ashcroft, B.C.Two open pits are worked; the Iona Pit with limited reserves of higher Mo content, and the lower grade, more extensive Jersey Pit. Upwards of 150 tons per day of bornite-chalcopyrite bulk concentrate is produced, ranging 0.25% to 1.5% in molybdenum grade depending on the area mined."

Jan 1, 1980

By J. A. Lamonica

The Bureau of Mines conducted an environmental noise survey to determine the noise levels to which underground coal mine employees are exposed, to evaluate noise survey techniques and equipment, and to compare noise exposures using two criteria, Walsh-Healey and CHABA, for determining allowable exposures that were under consideration for the Federal Coal Mine Health and Safety Act of 1969- Time study techniques and Bureau-approved standard sound level meters were employed. The shift exposures of 20 percent of the miners studied were in excess of the safe standards established by both criteria. The shift exposures calculated using the Walsh-Healey criteria were greater than those calculated using the CHABA criteria owing to the intermittent nature of the exposure. Ultimately the CHABA criteria were rejected, and the Walsh-Healey criteria were adopted.

Jan 1, 1971

By Phil N

A large number of experiments have been carried out by many workers on the recrystallization of deformed and subsequently annealed metals and alloys. Although observations on single crystals are of great importance in the study of the recrystallization textures of deformed and annealed metals, very little of this work deals with material in this form.Since, in deformed metals, the stress concentration is greatest at the grain boundaries and along the planes of slipping, it is to be expected that recrystallization will start in these regions. For example, in polycrystalline aluminium (1),:1: (2), copper (3), a-iron (4) and brass (5), (6), which had been deformed by cold-rolling, drawing, pressing or stretching and then annealed, the new grains first appeared in the boundaries of the original crystals, whilst in the case of cupronickel (7) and iron (8), recrystallization commenced along the slip planes of the deformed material. Deformed and annealed single crystals of aluminium (9) and cadmium (10) first start to recrystallize along slip planes and in deformation twins.The present work deals with the process of recrystallization of single crystals of lead after deformatjon by creep.Two factors enter into these experiments that were not met with in other work on this subject. Firstly, lead...

Jan 1, 1940

By V. N. Rampton, C. F. Gleeson

"Exploration results over three overburden drilling anomalies defined by the Ontario Geological Survey in 1981 in the Kirkland Lake area, Ontario are presented. The anomalies come from lowland areas where overburden is thickest. By mapping the bedrock and surficial geology, by prospecting, humus sampling and shallow till sampling over the surrounding upland surfaces, one can initially evaluate such overburden drill anomalies without costly reverse circulation drilling. The drilling should follow, if necessary, only after surficial base data has been obtained. Preliminary work on these three properties has defined the presence of at least two styles of gold mineralization. One occurs in silicified zones in intermediate volcanics closely associated with northwesterly trending faults and shear zones. The second occurs in quartz-carbonate alternation zones in volcanics intruded by quartz-feldspar porphyry dykes. IntroductionThe three examples presented in this paper present first-hand information on an approach to the follow up of several geochemical anomalies that were found by the Ontario Geological Survey when they carried out reverse circulation overburden drilling as part of the Kirkland Lake Initiative Program (KLIP) in 1980 (Routledge et al., 1981). The initial approach is relatively simple, systematic, and cost and technically effective. It readies the properties for further exploration, or conversely, it could downgrade the properties as viable gold targets."

Jan 1, 1987

By R. P. Singh

A mine fire model gallery has been designed and constructed on the premises of the Central Mining Research Institute, Dhanbad, India to perform systematic in-depth studies on various aspects of mine fires. The gallery is 65.5 m long and 5.86 m2in cross-section and it is divided into firing and non-firing zones. It is equipped with a computer-aided online telemonitoring system that has 130 sensors, two data loggers and computer peripherals for continuous recording of various fire parameters. A fan to generate airflow through the gallery has been installed at its end. Two sliding doors and one rolling shutter were also provided for sealing and regulation of airflow. Two sets of experiments have been carried out in the model gallery maintaining air velocity of 1 and 1.5 m/s through it. In the experiments, the inner sides of the firing zone, 22 m in length, were lined with a thin layer (8?10 cm thick) of coal slabs. Two fire suppression techniques viz. flushing of liquid nitrogen (LN2) and infusion of high pressure high stability (HPHS) nitrogen foam were tried to quantify their effectiveness under dynamic fire conditions. The paper addresses important design features of the gallery, its instrumentation system, the experimental procedure adopted and important findings from the experiments. It has been observed that the intensity of the fire was very high after one hour of its initiation and continued for 3?4 hours. During the period, frequent backlash with smoke and flame was noticed. The efficacy of the fire suppression techniques has been assessed interms of reduction in temperature, generation rate of CO2and CO, and heat release rate. The study reveals that high pressure high stability (HPHS) nitrogen foam is more effective in controlling open fires than liquid nitrogen is. Keywords: Model gallery, telemonitoring system, velocity, temperature, pressure, gas concentration, intensity, liquid nitrogen, high pressure high stability nitrogen foam.

Jan 1, 2004

To George Orwell the year of 1984 was the inspiration for a book. To most New Zealanders it was the year that the fourth Labour Government was elected to power. It was also the year that the review of mining legislation commenced. While Orwell's book and the election of Labour are clearly events of some historic note, one could be excused for classifying the review of minerals legislation somewhat differently in terms of its present achievements! Since the review began it has led a tortuous path through a rapidly evolving policy environment to a point three years hence where no major policies have been determined.

Jan 1, 1987

By D. Mohan

Soft to medium dense silty and clayey soils are found in many parts of India and conventional friction piles have normally been used for foundations of high rise buildings and other structures on such soils. The author investigated the use of Bored Compaction Piles and these have been used on these soils achieving substantial economies in cost over conventional friction piles. Similarly highly expansive clays, commonly known as Indian Black Cotton Soils occupy about 20 percent of the Indian land area. Short bored underreamed piles have been developed for such soils and a very large construction of various types of buildings and other structures have come up on such piles over the last thirty years in various parts of the country. The paper describes investigations leading to the design and development of both these type of foundations.

Jan 1, 1989

The principal activities of the Bureau of Mines Explosives Research Center during fiscal year 1967 (July 1, 1966, to June 30, 1967) arc reviewed in a part 1. Part 2 presents short abstracts of the publications issued during this period in the Bureau series and in other media. Part 3 describes a short study on the shock initiation of hydrogen peroxide not destined for publication elsewhere. ACKNOWLEDGMENTS The Bureau of Mines gratefully acknowledges the support received through cooperative agreement in fiscal year 1967 from The Dow Chemical Company Manufacturing Chemists' Association, Inc.

Jan 1, 1968

By D. Rutledge

Discrete (digital) signal processing techniques are proving to be very valuable tools for miners using the block cave method. Waveform analysis of different measured signals associated with active mining provides valuable information on production dynamics and safe operation of the mine. For example, correlation of the three-dimensional surface displacement velocity waveform and the production output waveform reveals a remarkably predictable time-varying physical process. In this paper, the authors discuss the signal processing techniques used to study these relationships, as well as the related implications for mining.

Jan 1, 2008

By Emil B. Milosavljevic

Problems associated with distillation and other classical methods for analyzing operationally defined cyanide (CATC, WAD, Total and Free Cyanide) will be discussed. These methods often achieve incomplete, species dependent cyanide recoveries and suffer from serious interferences. Depending on the relative concentrations of interferents and other matrix constituents, underestimation (ultimately Type II errors probability of not detecting a constituent when it is actually present) or overestimation (ultimately Type I errors -probability of deciding a constituent is present when it is actually absent) of the cyanide levels present in a ,given sample may occur, causing in the first case false security and in the second case, excessive cyanide treatment costs. Mahy, if not all, enumerated problems can be solved by using novel flow injection (FI) gas-diffusion amperometric methods. A modification of the recently approved FI ligand exchange (FIILE) method for determination of available cyanide (USEPA Method OIA-'l677) that obviates sulfide interference will be discussed. Eight laboratory round-robin data obtained for the FI UV -digestion (FIIUV) method that determines total cyanide (Proposed Method OIA-1678) will also be presented. In addition, some methods for cyanide speciation will be presented. Finally, research needed for developing reliable methods for determination of operationally defined cyanide in solid samples will be summarized.

Jan 1, 1998

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.

By Michael E. Berndt

Asbestos first became an issue to Minnesota?s iron industry when it was revealed that mineral fibers similar to those in Reserve Mining?s tailings were being found in drinking water for several communities that used Lake Superior as their primary water source. This discovery turned what had largely been an environmental court battle into a case concerning public health. The courts listened to much conflicting and uncertain scientific testimony on the size and distribution of the mineral fibers and on the potential health effects imposed by them. In April 1974, the plant was ordered to shut down by a federal judge but the company quickly appealed the decision. The appeals court granted a stay and ultimately ruled that the plant?s closure could not be justified based on the unknown health effects of the mineral fibers since the consequences of such an action would have immediate and severe social and economic impacts. The plant was allowed to continue operation, but ordered to abate emissions to air around the plant and to switch to a land-based tailings disposal system. Much of the scientific uncertainty and public concern over mineral fibers in Minnesota?s taconite industry remain today. ©2007 Elsevier Inc. All rights reserved. Keywords: Minnesota; Iron ore; Taconite; Asbestos; Amphibole; Reserve Mining; Tailings; Mesabi Iron Range

Jan 1, 2007

Digital Simulation of Particulate Processes The inherent complexity of mineral particulates (shape, size and mineralogical texture) has challenged conventional simulation model approaches for decades. Much effort was expedited in using mathematical assumptions to accommodate stereological effect. With the advance of instrumental methods such as x-ray microtomography 3D structure can, in many cases, be measured directly. The information derived from such measurements provides direct input to building the structural digital model. In addition digital simulation methods that enable creation of process realistic particulate properties in an efficient digital computer space have demonstrated their effectiveness to model a variety of realistic packing, sorting and multi-phase processes. The paper reviews recent advances in the use of information derived from 3D micro-tomographic imaging and laser scanning technology can be coupled with digital methods to enable simulation of tablet compaction and dissolution, filtration and permeability, column packing and leaching kinetics, packing and cementation of nuclear waste. By assigning 'properties' to a digital zone (voxel) in the computational space it is possible to mimic the realistic characteristics of quite complex particulate mineral processing systems. The system self-adapts to correct the coherent particle characteristics (shape, size, compound, porosity) with time. Such simulations are useful to elucidate the sensitivity of system performance to variations in process parameters. Dimensional scaling of the approach is also possible, as the case studies will illustrate, in deploying the method to both small (micron) and large (m) features. The use of process realistic simulations presents experimental challenges in code validation. It is in this context that other tomographic methods play a role in direct 3D measurement of system behaviour such as electrical and optical sensors.

Sep 13, 2010

By H. Tomlinson

Fatalities from falls of roof and coal are responsible for the death Of more than 1,000 miners annually in the bituminous coal mines of the United States, or practically one-half of the total fatalities In and about these mines. The men are killed by falls singly or in small groups and little or no publicity is given these accidents as they lack the spectacular features of gas and dust explosions. As a result, the public and even the miners have the impression that accidents from falls of roof and coal are just one of the unavoidable hazards of the coal-mining industry. This belief is not true. Accidents caused by falls can be avoided largely by the application of sound engineering principles, by education, and by proper leadership in the industry, just as gas and dust explosions and accidents caused by explosives have been reduced in recent years. The necessity for studying falls of roof and coal becomes apparent by referring to the following data from a table by Adams and Chenoweth:3

Jan 1, 1933

By F. Habashi

"The rare earths industry started in Austria in 1887 by Carl Auer von Welsbach (1858-1929) Professor of Chemistry at the University of Vienna. The process was based on monazite sand transported from Brazil as shipping ballast free of charge. This made possible producing thorium, cerium, and other rare earths at a low cost, thus permitting the growth of the industry. However, once the Brazilian authorities realized the strategic importance of the sand, shipping was stopped. Brazil then started its own processing of the sand in 1949. The background for Auer’s work, the role of Robert Bunsen in Heidelberg, and the invention of the spectroscope will be presented. INTRODUCTIONHeidelberg on the Neckar (Figure 1) was the meeting place for chemistry students from all over Europe in the nineteenth century. Her university founded in 1386 had already a famous professor of chemistry and medecine in the Faculty of Medicine by the name Leopold Gmelin whose three - volume Handbuch der theoretischen Chemie appeared in 1817-1819, that became later a multi-volume monumental work. As successor to Gmelin came Robert Bunsen (Figure 2) in 1852 who made this university town the Mecca of chemistry students. One of his students, the English Henry Roscoe (1833-1915) who became later a distinguished professor in Manchester, described him as follows: ""As an investigator he was great, as a teacher he was greater, as a man and a friend he was greatest""."

Jan 1, 2012

Disseminated gold mineralization in the Vunda River area 12 km SE of Lautoka in Viti Levu occurs sporadically in shoshonite volcanics within an alteration area of some 6 km2. No definite intrusions have yet been located though possible intrusions occur toward the centre and on the eastern margin of the area. The nature and distribution of alteration suggests the presence of a co-magmatic mineralizing stock just below the surface.The gold occurs within close spaced fractures and occasionally around the c1asts of breccia and agglomerate.Various types of alteration compatible with porphyry mineralization occur, but to date show no zoning or defined correlation with incidence of gold which occurs in various alteration facies.It is suggested that the gold and trace copper mineralization at Vunda arises from the sub-volcanic intrusive phase (monzonite) of the Sambeto shoshonite (5 m.y.) and is part of an E-W zone of porphyry-type mineralizationtrending easterly to the Kingston porphyry copper deposit at Navilawa.There is a close similarity between the Vunda mineralization and some of the porphyry deposits of alkali affinity in British Columbia, Canada.

Jan 1, 1978