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By Pierre Roy, Claude Gosselin, Maryam Sadeghi, Michel Bourassa, Christian Rochefort, Claude Bazin, Gautier Mahieu, François Lavoie, Marilène Renaud, David Cataford

"Spirals are gravity concentrators used for the concentration of iron oxide minerals from ores. This paper presents the mineral size recovery curves observed for spirals operating in two Canadian iron ore processing plants. The size recovery curves are presented for rougher, cleaner and re-cleaner spirals. The partition curves observed for the spirals are significantly different than those observed for typical gravity concentration devices such as hydrocyclones or hydraulic classifiers. The size recovery curves show the complex behaviour of the minerals as they flow down a spiral and are analysed with a view toward process modelling and simulation. Initial simulation results show that gains in the iron recovery can be achieved by increasing the recovery of coarse iron oxide particles in the rougher spirals.INTRODUCTION Spiral concentrators are gravity based separation devices used for the preparation of coal, iron and different heavy minerals ores (Wills, 1992). The classification of the particles in spirals is based on the combination of gravity, centrifuge, drag, lift and Bagnold forces (Atasoy and Spottiswood, 1995; Burt, 1984; Bouchard, 2001). Several papers are dedicated to the analysis of the forces acting on the particles flowing down a spiral (Das and al., 2007; Sivamohan and Forssberg, 1985; Holland-Batt and Holtham, 1991; Holtham , 1992). Most of these papers aim at the development of a general model for the simulation of the classification of the particles for coal ore processing. Few papers deal with the operation of spirals for processing iron ores (Hyma and Meech, 1989; Srivastava, 2001; Dallaire et al., 1978) and fewer papers present results for spirals used as cleaners following a rougher stage. Since the classification in spiral classifiers is dependent on the particle size and specific gravity a partition or performance curve commonly applied to classifiers (Mai Manga et al., 2012) is used here to analyse spiral operation. Few papers were found to describe the operation of spirals in terms of partition curves (Atasoy and Spottiswood, 1995; Holland-Batt and Holtham, 1991; Richards et al., 2000). Most of the investigations presented the application of a model to simulate the position of coal particles of various sizes and specific gravities along the trough of a spiral (Kapur et al., 1996; Holland-Batt and Holtham, 1991). In addition most of the available literature on spirals deals with one stage of concentration by spirals (Dallaire et al., 1978; Das and al., 2007; Sivamohan and Forssberg, 1985) while industrial circuits usually consist of rougher and cleaner spirals."

Jan 1, 2014

By J. Osterberg

A new device has been developed for load testing driven piles and drilled shafts which consists of an hydraulic jack or bellows which has a telltale rod fastended to the bottom. The rod extends upward to the surface through a pressure pipe. When pressure is applied, the jack or bellows expands, applying an equal upward and downward load at the bottom. The downward movement at the bottom is indicated by the rod and the upward movement is indicated by the movement at the top. Thus, upward and downward load-deflection curves can be drawn. As load increases, failure will occur either in end bearing or friction. Results of field installations are described. Total loads of up to 1,100 tons metric have been used. The method obviates the need for the reaction load required for the conventional pile loading test and separates friction and end bearing. It is especially advantageous for use over water, in crowded spaces and for inclined piles.

Jan 1, 1989

By G. W. Jones

During the course of an investigation by the Bureau of Mines into the causes, behavior, end control of anthracite-line fires, it was observed that the carbon monoxide disappeared from a scaled fire area much more rapidly than could be explained oil the basis of leakage of gases. Two suggestions were offered for this high rate of disappearance; (1) That the carbon monoxide was oxidized at temperatures below 150° C, by either the anthracite or its ash (tests on many anthracites have shown that at temperatures above 150° C carbon monoxide is liberated in the oxidation products when air is passed through it); (2) that the carbon monoxide was oxidized by micro-organisms present in the sealed area.

Jan 1, 1939

By Maurice J. Peterson

The applications of optical spectrochemical methods of analysis for determining trace impurities in metals are described, and the need for developing analytical procedures capable of accurately determining fractional parts per million of impurity elements in metals is stressed. Factors which determine sensitivity of detection and means to extend sensitivity levels in spectrochemical methods are discussed. Examples from the current literature illustrate the diversity of spectrochemical techniques that have been applied to the analyses of varied sample types, Many of the methods use preconcentration procedures to increase sensitivity limits. A bibliography containing abstracts of recent methods in included. Optical spectrochemical analysis is based upon the measurement of radiant energy emitted by atoms of the elements to be determined when a sample is subjected to a suitable source of excitation. The behavior of the valence electrons during excitation, usually by an arc, spark, or flame, produces radiant energy of specific wavelengths. This is recorded as spectral line images on a photographic film or plate by the spectrograph; for direct-reading instruments, the spectral lines are detected with photomultiplier tubes. The spectral lines result from the excitation of atoms in the sample. Each variety of atom produces its own characteristic set of lines, thus serving to identify the elements in the sample. Increased concentrations of elements in the excited sample results in increased blackening of the spectral line images.

Jan 1, 1961

By F. Hassani, K. Moozar, J. Ouellet, P. Gauthier

"This paper describes a sudden spill of waste rock used for backfilling from a waste pass at an underground mine in Canada, thus causing a major failure/accident. The mine operator immediately launched a detailed investigation to understand the causes of this accident and develop procedures to prevent any recurrence of such events in the future. The authors from McGill University were invited to collaborate with the engineers at the mine to examine this accident. The events leading to the accident were studied, appropriate measurements were taken and samples of the waste material were collected for further testing and analysis.The field visit and the interview of the witnesses allowed the detailed documentation of the events. The sequence of events related to the incident, along with the experimental results obtained in the course of the investigation, are presented. The waste material was characterized in the laboratory with regard to its behaviour in the presence of water. This information is discussed and the failure mechanism involved in the accident is identified. Finally, the full recommendations as well as the immediate operational measures implemented by the mine to prevent the future occurrence of such events are presented and discussed."

Jan 1, 2004

By K. Barr, F. Grenier, J. Hettinger

"To reach the Hemlo Gold Inc. objective of becoming the lowest cost, safest Canadian gold producer while causing no environmental damage, management embarked from its inception on a strategy to build an organization which would foster employee involvement wherever possible. This paper describes the organizational structure and how various innovative concepts have been implemented.BACKGROUNDThe Golden Giant Mine in the Hemlo area of North Western Ontario is owned by Hemlo Gold Mines Inc. 50.1% is controlled by Noranda. The mine commenced operations in March 1985 at a modest production rate. After it reaches full production by the end of 1988, with completion of underground development work, the mine is expected to operate at 3000 t/d and produce in excess of 300,000 ounces of gold per annum. This makes it one of the three largest producing gold mines in North America.Two other companies, Lac Minerals and Teck-Corona, operate mines on either side of the Golden Giant Mine. Noranda Geco Division is located 55 kilometers to the north at Manitouwadge. The majority of Hemlo Gold's 270 employees live in Manitouwadge where a mix of accommodation was constructed and made available for purchase by employees. Bus transportation is provided to and from the workplace with modern coaches. The housing and transportation policies were implemented prior to start-up and designed to help attract and maintain good employees.As shown in Figure 1, the operation is divided into five operating and support departments with each reflecting a high degree of departmental control and responsibility. For example, the mill department is responsible for all aspects directly relating to the milling complex including safety, operation, mechanical maintenance, assaying, instrumentation, and environmental control. Similarly, the mine department is responsible for all phases of operation, mine engineering, geology, and maintenance of underground mobile equipment. The plant department is responsible for maintenance of hoisting plants and conveyances, underground stationary equipment, all site electrical services, surface buildings, housing and yard maintenance. Efforts are made at every level of the organization, from departmental organization to individual job assignments, to ensure responsibilities are clear and that they encompass complete functions."

Jan 1, 1988

Investigation on Comprehensive Utilisation of Nickel Slag from JNMC

Sep 13, 2010

By H. C. van Zyl

Mine water in the Upper Olifants River Catchment in Mpumalanga(upstream of Loskop Dam) is at times discharged into local streams, resulting in local acidification and regional salination of surface water resources. Pollution of surface water can be prevented by collecting and treating mine water to a quality where it could be re-used without restriction (Cleanwater 2020 Initiative). Mine water in the Olifants River Catchment currently amounts to only 4,6% of the total water usage, but contributes 78,4% of the sulphate load. Limestone and lime treatment is the most cost-effective technology for neutralization and partial sulphate removal of acidic/sulphate-rich water to sulphate levels of less than 1500 mg/l due to precipitation of magnesium and removal of the associated sulphate fraction (through gypsum crystallization). Neutralized mine water of this quality may be suitable for irrigation. A number of alternative desalination treatment technologies were investigated (subsequent to gypsum crystallization pre-treatment) where treated mine water must meet more stringent quality requirements (e.g. less than 200 mg/lSO4). The capital cost of these processes varied between R4 million/(Ml/d) and R10million/(Ml/d) and the running cost between R2/m3and R5/m3. Water usage in the Upper Olifants River Catchment currently amounts to 947 Ml/d (including the power stations), and will increase to an estimated 1385 Ml/d by 2020. The additional water demand by2020 (438 Ml/d) will have to be supplied by importation from neighbouring catchments, and more efficient utilization of the local water resources, including excess mine water. Various levels of treatment are required to make mine water suitable for the following potential applications (acceptable treated water sulphate concentration shown in brackets): irrigation (2000 mg/l), coal processing plant (1000 mg/l), general industrial use (500 mg/l), discharge to public streams (500 mg/l), potable use (200 mg/l) and cooling water in power stations (20 to 40 mg/l). The following two options, or a combination thereof, can be considered for management of excess mine water in the Upper Olifants River Catchment: ?Collection and treatment of excess mine water to a quality suitable for selected urban and industrial applications (Option A) ?Collection and treatment of mine water to a quality suitable for irrigation (Option B). The estimated capital and running cost for Option A amounts to R528.5 million and R55.7 million/year, respectively, compared with R68,2 million and R11,9 million/year for Option B. It is recommended that Option B be investigated for implementation in the short to medium-term. Option B was selected due to cost benefits and the initial favourable results obtained by a joint Water Research Commission and Coal Industry initiative where mine water is used for irrigation. Option A may become feasible in the long-term to ensure maximum environ-mental protection and reduced treatment cost as a result of anticipated technological improvements over the next 5 to 10 years.

Jan 1, 2001

By W. McMahon

Following the Sago Mine accident, the Mine Safety and Health Administration (MSHA) asked the U.S. Army Engineer Research and Development Center to study several possible methane explosion scenarios in the Sago coal mine. The study used a 1-ft resolution map of the mine to produce a 3-dimensional (3-D) model of a portion of the mine, including the sealed area where the explosion occurred. An advanced 3-D computational fluid dynamics (CFD) code was used to calculate the explosion pressures within the sealed area, on the mine seals, and in nearby regions of the mine. Based on the best available information on methane concentrations and assumptions on homogeneity and on layering and mix composition, three separate initial conditions of methane-air concentrations and location were studied. This paper discusses the CFD modeling technique, the results of the calculations, the challenges of conducting this type of modeling, and the advantages and limitations of CFD modeling of accident investigations of mine explosions.

Jan 1, 2009

By Ahmed M. Yousif, Walid M. Abdellah, Galal M. Abdel Wahab, Amal E. Mubark

The present work is concerned with selective dissolution of niobium from Gabal El Faliq concentrate sample by using fluoridefree process. The chemical analysis of concentrate sample revealed the presence of high amount of ZrO2, Nb2O5, Re2O3, and HfO2 assaying 33.6, 1.99, 4.8, and 1.2%w/w respectively. Several economic minerals including zircon, samarskite, fergusonite, and xenotimewere recorded in the studied sample. About 98%of Nb content was selectively dissolved at the optimumconditions of 1:2 concentrate sample: KOH weight ratio, 2.5 h fusion time, and fusion temperature of 550 °C. Organic solvent extraction process using Aliquat 336S in xylene was effectively used for preparing pure Nb2O5 (98.95%).

Oct 22, 2019

By R. P. Vinson

Assessment of workplace exposures is an important tool for helping to minimize dust-related occupational illness and diseases. Real-time particulate monitoring can effectively locate areas where dust controls are needed and determine how well they are working. An affordable, person-wearable, real-time dust monitor is needed. The SKC Inc. Dust Detective (SKCDD) fulfills those requirements (Disclaimer: Mention of any company or product does not imply endorsement by NIOSH). The SKCDD consists of a disposable sampling tube (DST) connected to a small hand-held sampling pump. The SKCDD was developed through a Cooperative Research and Development Agreement (CRADA) between the National Institute of Occupational Safety and Health (NIOSH) and SKC Inc. The relationship of dust concentrations measured by personal gravimetric samplers to those measured by the SKCDD was determined in a laboratory aerosol chamber. A comparison of the means and the relative standard deviation of triplicate measurements of each type of sampling device demonstrated the SKCDD to be a viable alternative means for measuring dust. While it provides accurate measurements for specific coal types, it requires correction factors (those correction factors still need to be calculated) for other coal types.

By T Atchison

The Vale Ferro Carajßs S11D project in northern Brazil is based on the movement of unprecedented volumes of waste and ore for mobile in-pit crushing and conveying or ætrucklessÆ systems. In peak years, the system is intended to handle a combined 160 Mt of material.The planning and implementation of the first such system for Vale, in a remote greenfield site, utilising the services of a range of international study, design and supply partners has provided a unique set of technical and project delivery challenges. The lessons from these are of value to the industry as the trend to remote and high-volume operations continues.This paper describes the key features of the mining system and documents the challenges and mitigations for important technical, cultural and project delivery issues that have arisen. It is a combined description of the journey taken by both Vale (as owner) and SKM (as delivery partner) over the course of many years.CITATION:Atchison, T, 2013. Lessons from the S11D truckless mining project, in Proceedings Iron Ore 2013 , pp 177-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By R. Gunda

Due to the rapidly increasing production rates and deepening of mine working areas, there is a drastic rise in the number of thermal issues to be addressed for maintaining a safe mine environment. As high temperatures and humidity in underground mines could affect the health and performance of workers, and ultimately the production rate, it is necessary to provide a properly controlled safe environment. The backfilling of stopes in metal, non-metal mines results in different thermophysical properties for the hanging, side and foot walls, modeling of which is not provided by any existing mine climate simulation software. This paper presents the modeling of such a single stope using the MULTIFLUX (MF) software, developed at University of Nevada, Reno. A special case is presented in this paper, where a case study from the Homestake mine in the US with a drift and ramp connected to a stope with high Virgin Rock Temperature (VRT) and various spot heat sources is modeled in MULTIFLUX and CLIMSIM, and the results are compared against each other. Another case is presented in which the stope of the previous cases is modeled with walls, each having a different set of thermophysical properties. These results are compared with the former results to analyze the effect of anisotropic properties.

Jan 1, 2011

By Shu Yan

The high resolution resistivity method (HRRM) is developed specifically for detecting underground cavities and tunnels. HRRM has a special feature in that it can recognize and cancel static shift, which makes it different &om the high density resistivity method (HDRM). In searching for various means for detecting underground cavities, we found that the detecting depth of the transient electromagnetic field method (EM) depends mainly on the measurement duration, not the loop area. In addition, TEM can also be used to locate the high-resistivity bodies. In order to use them for local working site conditions, we combine HRRM with TEM to become a combined electromagnetic method. Since the late 1980's this method has been used to locate abandoned mines and air passages and burning centers of mine fires with great success. This paper cites case studies for which this technique was successfully used.

Jan 1, 2005

By James Westfield

Bureau of Mines activities for safety and health in the mineral industries were reorganized during the fiscal year to provide direct supervision by the Assistant Director -Health and Safety. On December 19, 1954, the field offices conducting these activities were designated as district health and safety offices reporting to the Assistant Director. The functions of determining the causes of accidents and injuries in the mineral industries and recommending measures to eliminate them were continued, with satisfactory results in improved safety records. The inspection of coal mines and enforcement of the Federal Coal Mine Safety Act of 1952 were conducted as directed by the Congress, and safety conditions in the mines were notably improved. One coal-mine explosion classed as a major disaster occurred during the year. The causes of that explosion and means for preventing a recurrence were still under investigation because of the extreme difficulty in recovering several portions of the mine. Basic research on the nature of certain hazards and ways of eliminating them is continued. Training of individual workmen and supervisors in this knowledge is a major part of the work.

Jan 1, 1956

By K. Meyer, M. E. Goddfellow

"At Teck-Corona Operating Corporation's David Bell Mine, a water quality management strategy is employed to produce both a chemically and biologically clean effluent prior to discharge to the environment.The strategy includes operating methods to minimize contaminants leaving the concentrator and an effluent treatment plant for cyanide, antimony, and heavy metal removal of concentrator, mine and site waste streams.Concentrator practices, the effluent treatment plant, process chemistry and the present day performance of the water quality management strategy are reviewed.INTRODUCTIONThe David Bell Mine is located in the Hernia gold camp 35 km east of Marathon, Ontario. The concentrator has a design throughput of 1,000 tonnes per day. ROM ore (-6"") is ground in a semi-autogenous mill followed by a ball mill, thickener, leaching, and carbon-in-pulp gold recovery unit operations. The concentrator flow sheet is shown in Figure 1."

Jan 1, 1991

By James E. Cairelli

The NASA Lewis Research Center, under U.S. Bureau of Mines program direction, performed an assessment of alternative mobile power sources for mining applications. A wide variety of heat engines and energy systems was initially examined to ascertain which could be considered as potential alternatives to presently used power systems. The present mobile power systems are electrical trailing cable, electrical battery, and diesel - with diesel being largely limited in the United States to noncoal mines. Each candidate power source was evaluated in terms, of the following requirements: (1) Ability to achieve the duty cycle (2) Ability to meet Government regulations (MSHA certification) (3) Availability (production readiness) (4) Market availability (5) Packaging capability An initial screening reduced the list of candidates to the following: (1) Diesel (2) Stirling (3) Gas turbine (4) Rankine (steam) (5) Advanced electric (batteries) (6) Mechanical energy storage (flywheel) (7) Use of hydrogen evolved from metal hydrides This list of candidates was divided into two classes of alternative power sources for mining applications - heat engines and energy storage systems. A summary of each class follows.

Jan 1, 1981

By E. F. Divers

This Bureau of Mines report describes the results of a program to develop small, rugged mechanical dust collectors (scrubbers) with high dust collection efficiency and low energy comsumption for controlling dust in coal mining operations. All of the scrubbers described are similar in configuration and are powered by 6-hp, 2,000-ft3/min vane axial fans. Air pressure differential is less than 6 inches water column. Height of the scrubbers? including fan is less than 14 inches, width is less than 16 inches, and length is less than 45 inches. The flooded fibrous-bed scrubber achieved respirable (less than approximatey 7 µm) dust collection efficiencies of 95 percent. The small-diameter-cyclone scrubbers showed about 92 percent efficiency and can be best where excess water is a problem. The wetted brush scrubber showed 88 percent efficiency at low cost, and the wetted fan scrubber showed a slightly lower efficiency (87 percent) but offered the smallest size and cost. A suitable water droplet eliminator is described.

Jan 1, 1978

By W. G. Payne, A. C. Richardson, B. L. Gandrud

"INTRODUCTION The Connellsville mine of the Yolande Coal & Coke Co. is in the southwestern part of Jefferson County, Ala., about 30 miles southwest of Birmingham. The mine is on the Blue Creek bed, which is about 6 feet thick and dips at a angle of 18º. The bed is worked by the room-and-pillar method and is mined by both machine and hand methods. The Blue Creek bed at this point yields a high ash, low-volatile coal with excellent coking properties. Because of its exceptionally low volatile content and high coking strength, this coal is excellent for blending with Alabama coals of higher volatile content and weaker coking properties to form blends suitable for production of metallurgical coke.A sample of washed coal taken during this investigation gave the following analysis on an as received"" basis: Moisture, 8.3 per cent; volatile matter-, 20.2 per cent; ash, 8.0 per cent; fixed carbon, 63.5 per cent. The high ash content of this coal limits the quantity which can be utilized when low-ash coke is required. In the Birmingham district it is usually difficult to sell as coking coal a product that contains more than 8.0 per cent ash. To produce a. coal with this ash content at Connellsville presents a somewhat difficult washing problem. This paper gives the results of an investigation that was conducted by the Southern Experiment Station of the U. S. Bureau of Mines in cooperation with the University of Alabama and the Yolane Coal & Coke Co. for the purpose of determining the washing characteristics of the coal and the possibility of reducing its ash content on coal-washing tables.The practice at the Connellsville washery at the time of beginning this investigation was to crush the run-of-mine coal to pass a 1 1/2-inch round-hole screen and to treat the satire output on two primary, 3-compartment jigs. A. middling product was recovered from the primary jigs which was re-treated on a single-compartment rougher jig. This system yields a product of acceptable ash content, but the yield is low and the loss of good coal in the refuse is high."

Feb 1, 1933

By S. J. Broderick

[Xuge d-mp heap co:lt:.ini9: tilcu?:na3s of tons of cad ~eP~se 2r3 a failiar sight in coal-mininc regior@:. T5ey reprecei~t considergole economic 1083, are very l.u.,si~hC,ly, ?:ld t?ke un m-lch vaL-x3le qace. Cor.sequentl;r thelr remcval i~ geatlyr dezir36, ax2 my ret-sn t?-at c,m be obtained would be er;pecic.llj .a~elconre&apos; t.7 the cod ir.S..r; kry. T?.e vaste rk.t~ri..tl conpl-ises large pieces of slr.t.e, hi~h-2s&apos;. bore c~al., luqs cf cle:., ,ad finer refuse conin,= fro3 the vrtskery, Tilt 1:zshcr:r refilsn contnins sone yood coal. Rig coal and the &apos;better p~lcs of bore ere the zat~rla2.s ~15:;~itiered in this in- vest ig:?.tion. 7% Il~avter frnctions of the w~~sherjr ref;lw aizd tts large 2ieces of slcte ?,".:I rgck contilin 1it:lei ccai-i-bcna.c~o~s caterial ad are vir- tu<dly worthiess nc, rz:. ::atcrin!. for .*=irin,= zct,iv?*teb cCvb~n. 13 the 3irniingh.m district, i13br.12, a-c.ju",P p?rcccn",f the c3sl r?.ir?ed is washed, ,md in tkis c?i.;trict nlz:~c rcfilce ecc;:?:lletcs ~t the r%tg of 1 to 2 million .! tons 2 yew.]

Jan 1, 1941