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By Costa

The fly-in-fly-out (FIFO) mining model has significant implications for the industry as it plays an important role in fulfilling the economic, social and workforce needs of the contemporary mining industry. It has increasingly been adopted in countries such as Canada and Australia, but is the current nature of the FIFO model challenging the place women have achieved in the mining workforce? Research in the mining and oil and gas industries reveals that major sources of stress for fly-in-fly-out mining workers are the times of parting and of reunion, the challenges in defining roles within the family, parenting, and conflict between spouses over the use of the leave time and money. So how are women in the industry coping with the FIFO schedules and consequent intermittent relationship with families and partners? How is the mining industry adapting to recruit and maintain female employees in FIFO operations? This paper describes an exploratory study conducted in Canada, which intended to provide some initial insights that might help us answer the questions above. There are several inferences made from this exploratory study. It is clear that FIFO poses significant challenges for both female and male workers. It is largely seen as rigid, extremely challenging for employees with young families and workers who are single mothers, and it is generally incompatible with starting a family and caring for small children. FIFO creates severe stress on relationships and on workers psychological well-being. It seems to be indeed harder for women, since they are often in lower paying positions and therefore have less financial reward for the FIFO lifestyle. On the other hand, FIFO creates the opportunity for young women, including Aboriginal women, to jump-start their careers, as well as opportunities for mature women to work while pursuing other personal interests during their time off. This paper concludes with recommendations to improve the FIFO system in order to increase the ability of mining companies to hire and retain women

May 1, 2006

By H. J. Siriwardane

This paper presents results from three case studies involving longwall mine panels at which the measured ground movements were compared with the numerical model predictions based on the finite element method. A new approach called the "displacement approach" was used in this study. The general concept of this method is based on the assumption that total roof collapse occurs behind the mine face as it advances. This assumption appears to be true for almost all longwall mining conditions. The prediction based on the numerical model appears to compare well with the measurements.

Jan 1, 1988

By Prosser A. P

The conditions under which vanadium is rendered insoluble by silica in the alkali-roast process have been investigated starting with both slag and reagent-grade materials. The inert phase is a glass formed slowlyfrom soluble NaV03 produced at lower temperatures. It contains approximately 30 per cent V in a partly reduced state; iron is not a principal component. Some of the vanadium in the inert phase is slowly returned to a soluble form by heating in an oxidizing atmosphere below the temperature at which the glass is formed (750°C). As the reaction leading to the required, soluble form of vanadium is also slow between 600 and 750° optimization and control of the temperature profile and atmosphere in the furnace, and the residence time of the solids, are necessary to ensure high vanadium extraction during subsequent leaching.

Jan 1, 1976

The mineral industry is an important element in the human environment and in varying degrees contributes to the general standard of living throughout most of the world, both by supplying the basic materials required for heavy industry, transportation, construction, scientific equipment, and many labour saving tools and also by its contribution to the international economy.When projecting population growth and per capita resource utilization against a finite amount of nonrenewable mineral resources, it is apparent that at some future time, if the established trend continues, the supply of industrial minerals will progressively become exhausted according to their relative scarcity and world demand.In one way or another all of nature's mineral resources are used in the sel'vice of man. Some of the products of their manufacture are essential to the survival and further development of our civilization, others are luxuries, desirable but not essential. Marine vessels are essential to maintain a flow of resollrces around the world, and as trade increases the size of the fleet will grow and the quantities of metals needed will be greater.The commodities they transport, may be used in an inefficient or extravagant manner causing unnecessary depletion which may adversely affect the activities of future generations. An example that comes readily to mind is fuel oil, the international transport of which uses a vast tanker fleet. When refined, large quantities of motor spirit are used in motor vehicles. The U.S.A. alone uses 70 billion gallons annually in the 90,000,000 automobiles in use.Much of this is used in private cars-of which there is one for every 2'3 people-for transport between home and city. Well organized community transport would serve the same purpose, conserve a scarce commodity, take some of the stress out of livingdriving in a major city can hardly be considered a relaxing experience-and minimize the problem of atmospheric pollution.Whilst man has demonstrated his great versatility...

Jan 1, 1973

Building the Unified Comminution Model The Unified Comminution Model (UCM) was formulated with the vision of bringing all comminution models onto a common base. The structure of the model relies on knowledge of the mechanical environment in the comminution devices to predict the modes and rates of collision in a device. A detailed understanding of the breakage modes and an ability to correctly test these modes for the ores in question is then required to feed into the UCM. A model structure has been developed that has the capability of dealing with multiple modes of breakage, such as low energy impact surface damage, chipping, sliding abrasion, cumulative impact body breakage and the transition of rock between modes. A critical review is presented on the shortcomings and limitations of utilising the discrete element method (DEM) to provide the mechanical environments. The assumptions and applicability of utilising DEM in milling models are presented and proposed routes to building a realistic mechanistic model are proposed. Based on this more realistic measures of collision energy have been derived from the DEM simulations, which better mimic the real breakage tests. Generic forms of the collision energy distributions have been observed and developed into functional forms for use in the simulation environment. The method of application of this model to a pilot SAG mill is presented.

Sep 13, 2010

By G. Couture

"The Glencore Raglan mine Concentrator, located in Quebec’s Nunavik region, has been in operation since 1997. The nickel metallurgical plant was originally designed to process 100 tonnes per hour of ore to produce 130 000 tonnes of nickel concentrate per year at 16% Ni. The increased grinding capacity and the discovery of rich ore bodies have increased the annual production to more than 190 000 tonnes of concentrate at 19% Ni. In 2014, the Metallurgical group, with support from BBA, implemented an expert control system on the flotation circuit. This project was initiated to cope with the high variability of the concentrator’s feed. Increasing the plant recovery and final concentrate grade were also important project objectives. The implementation of the expert system ensures better control of concentrate inventory while maintaining maximum plant throughput. This paper describes the successful implementation of the new control system, the control technology selection and the flotation circuit optimization. It will also discuss the performances obtained with this new approach and the improved process stability.IntroductionThe Raglan Mine is located in Northern Quebec along the 62th parallel. It has been in operation since 1997 and was originally designed to produce 130 000 tonnes of concentrate annually at 16% Ni. The increasing of the grinding capacity and the discovery of rich ore bodies have increased the annual production to more than 190 000 tonnes of concentrate between 18 and 20% Ni."

Jan 1, 2015

By Walter Valery, Peter Radziszewski

"The NewCrest Cadia operation boasts the largest SAG mill commissioned last June 1998. A request was made to shed some more light on possible SAG mill charge behaviour. Three different software were used to simulate SAG mill charge behaviour:Mishra/Rajamanis MillSoft DEM charge motion program, Radziszewskis agglomerated DEM charge motion program and Powell/Nuricks MillTraj outer trajectories program. The contexts simulated are: 20/30 % charge volume, 65/75/85 % critical speed using the Hi-Lo lifter configuration specified for the mill as well as a Hi-Lo 60 degre lifter face configuration. Further, lifter interval was also studied to determine the effect on power draft. Power predictions are compared with those obtained during the commissioning period.INTRODUCTIONThe NewCrest Cadia operation is located outside of Orange, New South Wales, Australia. With proven reserves of 190 million tonnes at a grade of 0.75 g/t Au, the mill was designed to process 17 Mtpa (2065 tph) of ore with an 86% copper and 73% gold recovery. The grinding circuit (Fig. 1, Table I) boasts the largest SAG mill (Fig. 2) and was commissioned last June 1998."

Jan 1, 1999

By Jorge Navarrete

La Corporación Nacional del Cobre de Chile produce cobre y otros subproductos a través de sus yacimientos y líneas de producción como las pirometalúrgica, hidrometalúrgica y biohidrometalúrgica. En este sentido, el presente texto señala la implantación de un LIMS para la industria minera de cobre. LIMS es una abreviatura genérica para los software de Administración de Información de Laboratorio, cuyo objetivo es relacionar la Informática, Quimiometría y Calidad.De forma que cumpla con los objetivos de adquisición y gestión de la información de pesaje, muestreo y análisis químico producida por diferentes áreas, tanto internos como externos y unidades funcionales.

Jul 17, 2000

On the more important mines it is almost essential to have a general plan of the surface. A special feature of this plan should be the indication thereon of a suitable arrangement of contour lines, either wholly over the surface of the property or at parts where may seem most useful. The importance of having these contours marked on the plan will be best appreciated by the engineer, in selecting the best available site for a proposed new plant, in locating a tramway, in connecting the surface with the underground workings to the best advantage, or in solving many similar problems that come within his province. The closer the contours are together vertically the better, the limitation being the trouble and expense of getting them on to the plan. They may range from five to fifty feet apart but a distance of ten feet will be found, in most cases, to be the most useful.In deciding the datum level from which these contours are to be measured, it is best to depart from the ordinary sea level datum, and use instead the highest available point on the property. This datum will be called zero and all levels will be reckoned so many feet below it; thus by a contour marked 160 on the plan, it will be understood that the level of the plane of the contour is 160 feet below the highest available point on the property. This system of measuring levels downward is readily suggested from measuring the depths of shafts from the brace or of excavations from the original surface.

By Richard E. Gray

Subsidence due to coal mining is poorly understood by non-specialists. This has led to numerous misconceptions and myths based on limited observations and lack of knowledge. The three most common are: 1. Mine maps are inaccurate. 2. Deep mines are not a problem. 3. If no subsidence has occurred for many years after mining, there is no risk of future subsidence. Maps are important during mining and most are carefully prepared. Future use to evaluate conditions at mine level often includes drilling to confirm what the map shows. Usually, little or no effort is made to tie the surface survey of the property to the mine survey, to conduct a well designed drilling program to confirm the mine map, or to drill test borings vertically. When a mine entry is encountered rather than a coal pillar, or vice versa, and conditions at mine level appear different than anticipated, the first reaction is the mine map is inaccurate. The idea of a safe depth from subsidence is often based on the false premise that mining results in sufficient breakup of the overlying rock strata that bulking compensates for the coal extracted. The safe depth idea first appeared in the literature about 1880 and remained prevalent well into this century. Sadly, it is still encountered. The modern understanding of fragmentation of the immediate mine roof with the overlying beds sagging down on the broken roof rock was first described in 1900. With full extraction mining, either longwall or retreat room and pillar, surface subsidence occurs regardless of the depth of the mine. Subsidence over longwall mines at depths of 2000 feet can be 90 percent of the mined seam thickness. Numerous studies of undermined sites conclude that mining occurred many years ago and since no subsidence has occurred, there is no risk of future movement. This is true if sufficient coal pillars have been left to support the overlying strata. However, every year subsidence occurs over mines that have been closed for 100 years or more. In a study of subsidence incidents over the Pittsburgh Coal, the senior authors found that 50 percent of the incidents occurred above mines that had been closed for at least 50 years and 10 percent over mines closed for at least 80 years.

Jan 1, 1996

By P M. Hancock, Associates

Lacustrine sediments, hydrothermal explosion breccias and spring precipitates deposited 5200 - 1800 years BP as a result of geothermal activity at Lake Rotokaua, contain New Zealand's largest known sulphur reserves. Current drill indicated reserves are 2 600 000 tonnes of elemental sulphur, assuming a ten per cent (dry basis) cut-off, contained in some 17 000 000 tonnes of ore with an average grade of 214.0 per cent (dry basis) sulphur. Additional inferred ore containing 500 000 - 900 000 tonnes of sulphur has yet to be prospected by drilling. Geological factors will be important in exploitation of the deposit, particularly the extent and disposition of the orebody, sulphur grades and distribution, physical characteristics of the ore, permeability and stability of the overburden and the nature and extent of geothermal activity in the area. Trials to date indicate that Frasch mining and possibly opencutting are unlikely to be successful mining methods. Further mining feasibility studies will be required to ascertain the most likely mining system for the deposit.

Jan 1, 1984

A series of flotation experiments were carried out in a 2.25-dm3 laboratory-scale Rushton turbine cell using hydrophobic quartz particles. Flotation was performed at a constant mean bubble diameter over a range of superficial gas velocities and impeller rotational speeds. The overall flotation rate constant increased linearly with increasing superficial gas velocity (and hence bubble surface area flux). The rate constant also increased linearly with increasing energy dissipation, until a maximum value was reached. A further increase in energy dissipation had little effect on the rate constant. The dependency of the rate constant on energy dissipation is a reflection of the size range and hydrophobicity of the particles used in this study. The flotation rate constant increased with increasing particle size, except at the highest energy dissipation value examined, for which the flotation rate of the larger particles reached a plateau and, in some cases, decreased. Good agreement was obtained between the experimental results and those predicted by a fundamental flotation model using experimentally measured values for mean energy dissipation and the Sauter mean bubble diameter. The bubble velocity was adjusted to obtain the best fit to the experimental data. The inferred bubble velocity, based on the flotation model, was found to increase with increasing superficial gas velocity (and bubble surface area flux) and was found to decrease with increasing impeller rotational speed. While the inferred bubble velocities were significantly lower than experimentally measured bubble velocities, and, except at low superficial gas velocity values, significantly higher than the bubble swarm velocity calculated from gas holdup measurements, similar trends with impeller rotational speed and superficial gas velocity were observed in all cases.

Jan 1, 2007

By S. C. Tadolini

Roof support systems have evolved from standing posts and timbers to a generation termed ?big nails? where steel bars are inserted into boreholes and anchored with expansion shells and/or resin cartridges. These systems have been effective but are limited to mining height. Additionally, the properties of steel do not resists shear forces or have the flexibility being required in difficult ground conditions. The next generation of roof support systems is coupling the best parts of the ?big nail? and resin grouted cable bolt systems. This paper will present the advanced technical solutions of the next generation of cable systems that includes an indented high-capacity PC-strand used with a variety of fixtures. Case histories of support applications will be presented.

Jan 1, 2012

By Edward L. McHugh, Charles Sabine, David G. Long

While less than 1% of reported mine accidents are associated with slope stability problems, slope failure accidents were responsible for about 15% of U.S. surface mine fatalities between 1995 and 2003. Small rockfalls, which may involve hand-sized rocks weighing only a few pounds, can cause fatal injuries to workers away from the protection of large machinery. Massive highwall failures containing a million cubic yards of material or more can be fatal even for heavy-equipment operators. As part of an ongoing study at the Spokane Research Laboratory, several remote sensing technologies are being evaluated as tools to assess slope stability and monitor slopes for hazards. An interferometric radar device capable of detecting very small displacements on slopes has been assembled and tested. Radar techniques can provide new tools to augment current methods for monitoring ground control hazards in mines.

By Harry R. Price, Behrooz Tahmasbi, Charles J. Roarty

The 2,408 meter (7,900-foot) long Middle Rouge Parkway Interceptor Extension varies in size from 1.52-meter (5-foot) to 2.36 meter (7-foot 9-inch) inside diameter. Most of the sewer was constructed in tunnel through fine sands and silts. Piping of these soils through the concrete liner eventually resulted in a loss of soil support, settlement and/or severe distress of the sewer, and the formation of several sinkholes. The repair and restoration was generally performed in the sewer and included cast-in-place concrete, shotcrete, cured in place pipe, soil stabilization, cement grouting, dewatering, and chemical grouting. As a part of the work, temporary pump stations and flow diversions were required to perform the work while minimizing discharges to the adjacent Rouge River.

Jan 1, 2007

A comprehensive axial test program has been undertaken at the WASM Dynamic Test Facility on the performance of 20mm threadbar. The threadbar tests had a double embedment configuration, with variation to the encapsulation lengths, debonded length and surface hardware and fixtures to examine failure mechanisms. Performance was significantly affected by the collar embedment length and type of fixture nut used. Results ranged from thread shearing occurring between the nut and bar at 1kJ of energy dissipated, to control plastic deformation of a central debonded length dissipating 22kJ.

May 1, 2009

By William R. Yernberg

The 2003 Rapid Excavation and Tunneling Conference (RETC) was held at the New Orleans Marriott, New Orleans, LA, June 15-18. The New Orleans conference was the 16th since the RETC was formed in 1971. This year’s conference was sponsored by the Society for Mining, Metallurgy, and Exploration, Inc.(SME), with co-sponsorship of the Construction Institute of ASCE. Attendance at the meeting was 1,178, a conference record. This was up significantly from the771 attendees at the 2001 meeting in San Diego, CA. The RETC was formed to “advance the engineering and scientific knowledge of rapid underground excavation and tunneling through interdisciplinary meetings, publications, technical-educational exhibitions and encouragement of research.” The RETC conferences are now held every other year. They provide an opportunity for individuals to meet with designers, contractors and manufacturers associated with the tunneling industry to share experiences in all phases of tunnel design and construction.

Jan 1, 2003

Previous methods for measuring the flow of solids in Jnrdraulic conveying have not considered the important effects of slip velocity and particle concentration. In this paper an extension of the method proposed byShirato et al. (J. Chem. Engng. 'Japan, 1: 164-167) for determining mass flow in a vertical conduit is outlined.The present method consists of measuring' the volumetric flow of the slurry (by a magnetic flow meter for instance) and the density of the slurry in two pipe sections of different diameters. Effects of variation of slip withparticle concentration, not previously considered, are allowed.Problems involved in estimating the density of a slurry from differential pressure measurement are discussed.The major problem is the uncertainties in estimating frictional losses due to the wall in two-phase flows. The greater reliability of a more "direct" technique, such as by 'Y-ray absorption, for measuring solid concentration is emphasized.

Jan 1, 1971

By M. L. Goble

"Inco Metals Ltd. (Manitoba Division) operates a mining, milling, smelting and refining complex, 500 miles north of Winnipeg in central Manitoba. The Thompson Mill is presently operating at 12,000 S.T.P.D. on ore from both underground and open pit mines. The ore is treated in two separate milling and flotation circuits utilizing a common crushing system which is located inside the main mill building. The milling facility employs approximately 43 operating employees, 30 maintenance employees and 20 staff in supervisory or process development roles.In recent years an increasing awareness of the potential hazards of contaminants in the work place has made it mandatory that all employers maintain careful and accurate records of the work environment to which each employee has been exposed during his working career.The importance of this record keeping and general observation of the work place cannot be over emphasized. Proper monitoring of the work place provides an accurate and complete record of the contaminants and physical agents to which an employee is exposed during his work career. This can aid in studies which might be conducted in the future and can also be used as a basis for instituting improvements to the workplace."

Jan 1, 1980

By Patrick R. Stephenson

The current version of the JORC Code was issued in 2004 and since that date the Australian Securities Exchange, in collaboration with JORC, has issued a number of companies? updates to provide guidance on various reporting issues. An interim review will be undertaken during 2010 to meld these updates with the current 2004 Code. This will be followed by a full review during 2010/11 covering all aspects of the Code and focusing particular attention on: ? clauses / guidelines relating to Exploration Results1, exploration targets and the reporting of historical estimates; ? issues relating to the Public Report2, including definition, the requirements for Competent Person sign-off, level of disclosure and mandatory requirements; ? guidance on techniques to quantify resource / reserve estimation uncertainty; ? the level of study required to convert Mineral Resources to Ore Reserves, and disclosure of prices and economic factors; ? expansion of the requirements for reporting of marketable material for bulk commodities; ? the use of language and tone that anticipates new and emerging technologies and techniques for the qualitative and quantitative measurements of data; and ? linkages to valuation and the valuation code (The VALMIN Code). Although the Canadian and Australian reporting regimes for public statements on Exploration Results, Mineral Resources and Mineral (Ore) Reserves are similar in intent and coverage, they differ in detail, sometimes substantially. Canadian requirements are generally more wide-ranging and prescriptive than Australian requirements, including in the need in many situations to publicly lodge a Technical Report, a requirement that does not exist in Australia. Australian-listed companies seeking to list in Canada, and Competent Persons seeking to act as Qualified Persons in Canada, need to ensure that they are fully conversant with Canadian regulations and how they differ from those in Australia.

May 1, 2010