Search Documents

By T. Lee

Ongoing economic success for mining companies is dramatically enhanced when they really know what they are harvesting, such that they can accurately forecast their head grades for any time period in excess of a month. This is an uncommon experience. It is a very common scenario for resource/reserve estimates to overstate the concentration (grade). Grade is a critical input of revenue, and hence, it is to cashflow projections. With the current direction being taken by the legal climate, it is no longer adequate for directors to accept the resource/reserve estimates of experts at face value. This is because resource/reserve estimates are the foundation of primary mineral economic decisions. Directors of mining assets need to undertake their own due diligence analysis of these estimates, in the best interest of themselves, and the company's shareholders. In the light of the industry's past achievements, this is quite a challenge. This paper suggests a set of new objective tools for directors to undertake an overview of the unique commodity concentration pattern and assess associated economic dynamics of each mineralization. These tools allow the examination of global graphical trends that can be helpful to directors and others in undertaking due diligence of resource/reserve statements. Ensure that it smells right.

Jan 1, 1995

By W. H. Holtzhausen

The purpose of this project was to compare two underground, batch coal haulers ? battery haulers and shuttle cars ? in order to determine the more viable machine to implement. The specific standards for battery haulers were investigated and compared to the requirements of shuttle cars in order to identify the unnecessary expenses related to the legal requirements that are attached to the machines. Costs such as running costs, capital costs, and maintenance costs were researched and compared over a typical life of machine. Average production rates and breakdown times were obtained and used to determine which machine would be more reliable in achieving the required annual production.

Jan 1, 2014

By N. M. Soonawala

Detailed regional geophysical and geochemical surveys, ground surveys and drilling were undertaken to follow-up the federal-provincial Uranium Reconnaissance Program (URP) over the 27,OOO-km2 Kasmere-Munroe area in northwestern Manitoba. An analysis of the URP data showed a fair correlation between the regional airborne radiometric results and lake-bottom geochemical results, both of which also correlated with the regional geology. More detailed surveys defined anomalies with greater precision within the broad zones outlined by the URP. The ground follow-up indicated that URP anomalies can be caused by varying degrees of uranium concentration in the rocks. Mineralization of interest was found in leucogranites at several locations within the survey area. Anomalous uranium concentrations were also found in coarse pegmatites and Hudsonian granitic intrusions. It can be concluded that large-scale regional surveys can be followed up in relatively short periods of time to yield meaningful results if a properly planned exploration sequence is employed, each stage of which successively narrows the area of interest.

Jan 1, 1979

By Dong Hoon Han

The sulfation rates of magnesium oxide and calcium oxide (molar ratio 7:3) contained in calcined CMA ( calcium magnesium acetate) by SO2 were measured. The experiments were carried out in the temperature range 700 to 1100 °C and under the SO2 concentrations of 0.3 to I mol % (5 % 02). In the low-temperature range below 830 °C the reaction produced CaSO4.3MgSO4 and unreacted MgO, but no MgSO4 phase. The formation of CaSO4.3MgSO4 phase has a significant implication in that it allows the utilization of MgO for SO2 removal whereas the sulfation of MgO from conventional sources is so slow that it is of no practical interest. Thus, the calcined CMA can remove SO2 at lower temperatures than conventional SO2 absorbents and at a greater capacity. Above 950 °C only CaO reacts with SO2, but at a much greater rate than the calcined Ca(OH)2, which is one of the most reactive SO2 absorbents.

Jan 1, 1998

By J. J. Foster

MOST of us will, I think, agree that never before in the history of the coal industry has the human side of our business been so important as today. Since, even in wholly mechanized mining, labor cost is such a large percentage of out total cost we are all deeply concerned not only about the present attitude of our employees but particularly about the future, when the industry returns to a "survival of the fittest" basis. Many things could and should be done about our employee relations in the coal business. Failure to recognize these obligations and do something about them may lead to serious consequences, the least serious of which will be the loss not only of many of our better employees but a large portion of our potential employees, as they graduate from our schools to other in¬dustries. Some of these things should be handled by the industry as a whole whereas others should be done by individual companies. Due to varying conditions and size of organizations it would, at best, be necessary to vary a program to meet the individual needs of each operator.

Jan 1, 1945

By W. E. Webb

This report describes a method the Bureau of Mines devised for measuring the dielectric constant and loss tangent of low-loss minerals at microwave frequencies. Determina-tion of these properties makes it possible to predict the effects of using microwave heating in potential mineral processing applications. The method uses a test cell and radio-frequency (RF) impedance analyzer with automated data acquisition and analysis. In this initial phase of microwave heating research, the Bureau measured dielectric constants and loss tangents at frequencies between 100 MHz and 1 GHz. The objective was to establish a reliable data base for use in predicting the effects of microwave heating on minerals. Comparison with previously measured data showed the Bureau's measurement method to be accurate to within ± 3 pct. This report describes the method and discusses the preliminary results of the Bureau's investigations. Typical comparative data are included.

Jan 1, 1986

By G. F. MacDonnell

THE Privateer mine consists of a group of mineral claims situated in the Zeballos area, on the west coast of Vancouver island, approximately 180 miles north of Victoria. Although Zeballos is a comparatively new mining camp, its transportation facilities can be considered exceptionally good. General freight and supplies are brought in by either C.P.R. or Frank Waterhouse steamers from either Victoria or Vancouver. Service by these boats varies from five to ten days and the trip from Victoria takes approximately two days. Passengers may use the C.P.R. boats, or, if speed is essential, they may fly, in which case they have the choice of two flying companies, namely, Canadian Air-ways, Limited, and Ginger Coote Airways. The average flight from Vancouver takes approximately two hours. Excellent unloading facilities are provided at the beach by a government dock for the steamers and a floating dock for aeroplanes. The mine, which is approximately five miles from the beach, is serviced by a fairly good gravel road, which has proved satisfactory for all haulage purposes. Zeballos has the reputation of having one of the heaviest rainfalls on the west coast, but as no accurate records have been kept, no comparisons can be made. H. C. Gunning, in his report, comments on the weather from 1929 to 1932, and one would judge that the practically continuous rainfall did not add to the pleasures of the field work. During the summer of 1938, the opposite condition prevailed and the area had exceptionally dry and pleasant weather. The snowfall is generally light at the lower elevations, but very heavy higher up. No extreme cold weather is encountered during the winter, which is generally short.

Jan 1, 1939

By Gabe McClain, Thomas Pallua, Joe Schrank, William C. Gates

Because of restrictions on blasting in urban areas and, more importantly, the proximity of this construction to national historic landmarks, blasting operations were extensively monitored to measure and correlate ground vibrations as peak particle velocity (PPV), frequency, and strain—these being the major factors that would impact the surrounding buildings. As a result, copious amounts of data were gathered and interpreted within a short time to estimate blasting parameters and optimize the subsequent blast rounds

Feb 1, 2020

By O. Salami, G. Xu

Fire accident is one of the most classic safety concerns in underground mines both in the USA and abroad. It may occur from pool fires due to leakages in hose or pipes, vehicle fires, or fires in tires and conveyor belts in the underground mines. It may also result from the storage of flammable materials such as gasoline, diesel, and explosives in the underground. When fire occurs in an underground mine, it releases heat, smoke, and other toxic gases such as carbon monoxide, and methane to the surrounding thereby making life unbearable to the miners. Furthermore, smoke greatly impact visibility in the underground which makes evacuation even more onerous and challenging. To this end, a thorough investigation of fire behavior and spread of toxic gases in a practical underground mine is imperative to develop a reliable emergency evacuation plan in an event of fire disaster in the underground mine. The objective of this study is to investigate temperature variation and CO spread along mine airways by conducting full-scale fire experiment in the underground mine. The results presented from this study are crucial to developing evacuation plans in underground mines. In addition, the findings from this study could be used to validate existing evacuation models.

Mar 2, 2022

By H. A. Schrecengost

Information presented herein was gathered by examination of 29 fluidized-bed thermal coal dryers and by conferences with manufacturers and users of such equipment to determine what safety features could b incorporated in design, installation, and op ration to minimize fire and explosion hazards. Fire and explosion hazards are inherent in certain types of coal dryers in that high temperatures are employed; the sizes and volatility of material handled are capable of propagating explosions; and drying gases are seldom, if ever, low enough in oxygen content to prevent ignitions of dust clouds, distilled gases, or their combinations. This is especially true for fluidized-bed dryers in which the coal is dried in air suspension and in which atmospheric air is constantly introduced to temper the heated furnace gases. Occurrence of fires on hated bedplates, in dust collectors, and in hot gas inlets was common in nearly all the dryers examined. Forceful explosions which produced external effects had occurred in 11 (39 percent), and internal "puffs" or ?bumps? had occurred in at least 24 (79 percent) of the plants examined in the study.

Jan 1, 1965

By Jos. R. Guiteras

This paper is one of r series published by the Bureau of Mines dealing with the mineral resources of western South Dakota. The mining of pegmatite minerals is described mainly from the standpoint of the feldspar industry, as most of the other .pegmatite minerals produced are recovered as byproducts from the mining of feldspar. Feldspar is shipped from the Black Hills by three companies, all operating in the southern Hills. Because the pegmatites of the northern Hills, represented by tae Tinton area, have been described in other papers3/ of this series, the present paper is confined to the pegmatite dikes of the southern Black Hills. Emphasis is placed upon the current activity in pegmatite mining; little attention is given to the history of many famous mines in the district, and information concerning them may be obtained by consulting resorts cited in the bibliography. The field work was carried on from July 28 to October 15, 1938. ACKNOWLEDGMENTS The geology of the Black Hills has been studied almost continuously during the last half century. A wealth of literature has attempted to explain the geology and mineralogy of the pegmatite dikes of this region. The writer acknowledges his indebtedness to all earlier investigators, as well as to the following men, whose assistance in the field was of particular value: F. C. Lincoln, professor of mining, South Dakota School of Mines; Mont Heumphreus, State mine inspector, South Dakota; Harold. H. Eyrich, superintendent, and Batemen Eilbeck, mine foreman, b. E. Schundler Feldspar Co.; J. W. Mitchell, field man, Consolidated Feldspar Corporation; John Wells, mine operator and local mineral buyer, Ouster, S. Dak.; Frank Hughes, general superintendent, and Harry Wasson, nine foreman, Hugo mine; D. W. Peterson, mine superintendent, Etta mine.; Lon Walker, Mine superintendent, Peerless

Jan 1, 1940

By Pritii Tam Wai Yin, Tony Leong, Neetu Bansal, James Vaughan, Amiel Boullemant

Mercury is a toxic element that is associated with many industrial activities including the Bayer process. Mercury is known to enter the Bayer process with the bauxite feed material and has the potential to accumulate as the process solution is recycled. This paper explores the speciation of mercury in Bayer process streams. The process parameters considered are the oxidising-reducing potential, basicity and temperature. The results of a refinery circuit survey are presented and compared with the thermodynamic predictions. Electrochemical measurements on relevant synthetic systems are also included.

Jan 1, 2014

By CHARLES COURT

I must tell you at the outset that I come to this conference deeply disturbed at the 'role of Government in international dealings in mineral and energy resources'. I am disturbed by- the confusion that now passes for policy. I am disturbed by the short- range view of critical problems taken by a majority of Governments. I am equally disturbed by the even shorter range of view taken by a growing army of industries. Many of them clamour for Governments to solve their problems in a specific way, with little regard for any other sector but their own-and with even less regard for the fact that every time a Government takes over some of their responsibilities they surrender some of their freedom. I would not say that longer range views don't exist. But I would say that they don't prevail at the present time. Instead, we are seeing the constant development of many policies for individual problems which don't tackle the fundamental causes. We must get back to basics without delay.

Jan 1, 1978

By K. C. Dean

During the course of the investigation of manganese mineral occurrences in the western United States, the Bureau of Mines collected several lots of ore' from properties in the vicinity of Winkelman, Ariz. As none of the ores would be marketable directly, an investigation was made to determine their amenability to concentration by ore dressing. The Geronimo group of claims is in Pinal County, 8 miles west of Winkelman, Ariz. The manganese oxides occur as cementing material in ore zones of conglomerate. Representative samples of a 2-ton lot of ore cut from outcrops of two lenticular deposits were laboratory-tested. Two 1-ton samples from the Benningfield property were similar in physical characteristics but differed in grade. This claim is 11-1/2 miles south of Winkelman and about 1 mile west of the San Pedro River on the south side of Putman, Wash. The manganese minerals occurred as nodules and lenses, replacing limestone, in a capping over a dark, igneous dike. The North Star group consists of five claims on the west side of the San Pedro River 14 miles south of Winkelman. The ore consists of a low-grade, manganese oxide-calcite occurrence interspersed with stringers of higher-grade material and is present as filling in a fissure zone in porphyry. Two samples were obtained by the examining engineer; one sample represented run-of-mine material, the other represented ore from the vein that could be hand-sorted or selectively mined.

Jan 1, 1952

By R G. Moreby, S Bluhm, FávonáGlehn, C Pascoe

Resolution Copper Mine in Arizona, USA, is planned to be a 2000 m deep panel cave mine with virgin rock temperatures exceeding 80¦C in rock with high crystalline silica content, resulting in a very challenging ventilation and cooling system design. This is one of the largest copper orebodies ever found and, with a planned rock production rate of 120 kton/day. The project is currently in its prefeasibility phase and the paper discusses features of the ventilation and cooling system design which includes multiple ventilation shafts with total primary ventilation flow of about 3000 m3/s and both surface and underground refrigeration plants producing more than 140 MW refrigeration capacity. The cooling system features large surface bulk air coolers chilling all downcast air supplemented by an underground secondary air cooler system and a chilled service water system. This will be a very challenging mine to ventilate and cool but this work has demonstrated that it will be technically achievable with the application of existing technology.CITATION:Bluhm, S, Moreby, R G, von Glehn, F and Pascoe, C, 2013. Life-of-mine ventilation and refrigeration planning for Resolution Copper Mine, in Proceedings The Australian Mine Ventilation Conference , pp 125-138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Jacques Magnaudet, Julie Cranga, Didier Huin, Pascal Gardin

"With the aim of controlling steel grade in steelmaking reactors, IRSID and IMFT are developing a numerical description of the evolution of bubbles in the vicinity of a liquid steel/ slag interface. The objective is to identify the main parameters affecting the hydrodynamics of the various phases. The goals of the present paper are:• To describe the numerical technique developed to predict the multi phase flow including bubbles, liquid metal and slag layer.• To analyze the influence of the absolute pressure on the bursting of bubbles in a RH degasser. Validation is given by comparison with results available in the literature. The major point concerns the distinct behaviors observed whether the pressure is low or high.• To study the influence of the properties of the slag layer (thickness, viscosity and interfacial tension) on the entrainment of liquid metal in the wake of the bubble and on the nature of the projections from the bath surface.IntroductionMost of secondary steelmaking processes use gas stirring for homogenization, removal of nonmetallic inclusions or decarburization under reduced pressure. The bursting of gas bubbles at the metal or slag layer surface produces a beneficial ejection of metal droplets in the low pressure atmosphere, provided that there is no violent projection, which may have detrimental effects on the process.Our objective is to develop a numerical tool to study the phenomena occurring in the vicinity of the bath surface, in particular bubble bursting under reduced pressure and entrainment of metal in the slag layer. In this paper we report the first conclusions of our study. In the first section we describe the numerical model used to describe the three-phase flow and the expansion of the gas bubbles under the effect of the ferrostatic pressure. The second section is devoted to the study of pressure effects on bubble rise and bursting. The third section reports some computational results about the rise of a gas bubble through the interface between the two liquids."

Jan 1, 2001

How the Australasian and Canadian Codes (VALMIN and CIMVal) approach mineral property valuation is described. Brief comment is also made on the International Valuation Standards CommitteeÆs interest in a global valuation standard for Mineral (Extractive) Industries and the South African SAMREC initiatives to adopt a VALMIN-like Code. The conventional tripartite classification of valuation approaches into those that are Market-based, Income-based and Cost-based is outlined. It is best practice to use as many of these approaches as possible (and as many methods as reasonable in the particular circumstances), given the quantity and quality of the data available on the Mineral Asset (which depends upon the state of development of the mineral property). The use of specific methods must satisfy the basic considerations of logic and reasonableness and the purpose of the valuation. The competence, judgement and repute of the valuer are critical factors, since all valuations are time and circumstance specific. What constitutes æMarket ValueÆ in the different jurisdictions is discussed and definitions are given. Challenges facing the globalisation of a VALMIN-type Code for the international Minerals Industry are the influence of real estate valuers and the US jurisdictional idiosyncrasies. This is mainly due to a fixation on real property rights with a preference for using real estate-like comparative sales techniques (Market Approach) to the exclusion of Income-based approaches; a regulatory reluctance in the US to accept that Resources have considerable value; and the International Accounting Standards BoardÆs preference for Historical, rather than Current Value, accounting.

Jan 1, 2002

By Andrew Hyett

Over the last 30 years, a transition away from end-anchored bolts to fully grouted rock bolt systems has occurred in many underground mines. It seems geomechanically intuitive that the success of such bolts, which interfere with rock movements around underground excavations through a variety of complex interactions, is precisely why they remain challenging to instrument and monitor. Whereas measuring the load profile for an end-anchored mechanical bolt is trivial, for a fully grouted system, the load may vary dramatically due to discrete rock movement at cracks and joints. Despite the challenges, measuring the strain (i.e., load) along fully grouted rock bolts remains very appealing, and a lot of valuable research has been conducted using foil resistance strain gauges, particularly in US coal mines (Signer and Jones, 1990). Despite good intentions, more widespread adoption of this instrumentation remains unlikely for the following reasons: (i) The technology is expensive, partly because Intrinsically Safe (IS) requirements limit the number of suppliers and solutions. (ii) The technology is perceived as challenging to successfully implement except by those who are skilled in the art. (iii) The reliability of the technology is questionable in harsh environments. (iv) The technology relies on discrete pairs of strain gauges that may not capture the complete strain distribution along the bolt. No existing alternative technology can offer a solution to all of these limitations. However, in this paper, we introduce results from a new Distributed Optical Sensing technology that promises significant potential. Since the technology is capable of distributed sensing, our results suggest that this new technology can, for the first time, reveal the detailed strain profile along fully grouted rock bolts.

Jan 1, 2013

By K. M. Parida

The kinetics of dissolution of manganese dioxide in dilute sulphuric acid solution have been investigated using iron pyrites as a reductant. The dissolution rate of manganese is independent of the speed stirring but depends upon temperature, particle size, specific surface area of manganese ore, acid concentration, Fe(II) concentration and amount of pyrite. The activation energy is 43.6 KJ/mol and the linear relationship between the rate of dissolution and lido indicates that the reaction is chemically-controlled. The redox reactions of MnO2 with iron pyrites and Fe(II) are the rate-controlling reactions.

Jan 1, 1990

By D. A. Peacock

"INTRODUCTION Outer space technology and exploration have reached a tipping point so that mining and mineral processing in outer space is now a certainty and not a dream. Several competing companies, worldwide, are well on the way to building spaceships to land on the Moon and eventually mine the Moon and asteroids for volatiles, rare earth metals and Helium-3. The Google Lunar XPrize offers a $30 million prize1. China has recently landed a spacecraft on the Moon. The European Space Agency, with cooperation from the United States, has landed a spacecraft, Philae, on a comet. And, Mars One is planning a one-way trip to establish a settlement of humans on Mars. How and why are the Moon and asteroids and their resources of interest to private space industry and companies? Why are the Moon and asteroids viewed as a potential business venue? GEOLOGY OF THE MOON AND ASTEROIDS –WHY DO WE WANT TO MINE THERE? Space enterprises are actively working towards establishing and operating lunar and asteroid mining locations for resource extraction, resource processing, conversion to salable products, and distribution of the products and services in space and to Earth and beyond2. Forty-five years ago, the Apollo manned missions to the Moon returned rocks and regolith to Earth, which were studied and analyzed. What they found was that the Moon contains valuable minerals and resources. These minerals are largely due to meteor and asteroid impacts, which have, over eons, created this mineral rich regolith. These impacts have occurred on Earth as well, for billions of years, particularly early on in the history of the solar system. However, on Earth, wind, water, and vegetation have erased most of these impacts. On the Moon, in contrast, the only weathering is caused by subsequent impacts and the solar wind. The Moon regolith contains valuable rare earth minerals, platinum-group minerals (particularly where the Moon has been impacted by asteroids), volatiles (useful for processing and habitation), Helium-3 and titanium. Almost non-existent on earth, Helium-3 is abundant and accessible on the Moon and can be used in nuclear fusion power plants, producing much more energy than fission reactions and with much less radioactive waste. One of the main reasons Helium-3 is sought after as a fusion fuel is because there are no neutrons generated as a reaction product. Governments and private companies focus on mining of Helium-3 on the Moon as a basis for their economic models. Moon Express, one of the private companies who is planning on mining on the Moon, will recover moon rocks to fund its early operations25. Subsequently, it will recover Helium-3, platinum, and rare earth metals, as it engages in surface mining operations."

Jan 1, 2016