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By C. L. Brown

"INTRODUCTION The heavy loss of life from mine fires in some coal mines recently has focused attention on the importance of maintaining reliable communication systems between the active working sections of mines and the surface. A study of conditions following disasters in mines indicates that in several instances lives could have been saved if telephone communication had been available. Communication systems were not installed in some of these mines where disasters occurred, and in other mines they were installed in such a manner as to be rendered useless following a mine explosion or fire. Lives have been lost because of the inability of the rescue crews or persons di-recting the rescue to communicate with trapped men. Cases are known where many lives might have been saved had it been possible to give instructions for escaping or for location of barricades.More than 500 major disasters in which 5 or more lives have been lost have occurred in mines in the United States. The total number of lives lost in these disasters has exceeded 13,000. Some of the victims died instantly; but for many it was hours and in some instances days before death occurred. Evidence found in recovery operations following some of the disasters indi¬cates that many died needlessly because of the lack of suitable means of communication between the underground working areas and the surface.A localized gas and dust explosion in a coal mine in 1930 resulted in the death of 82 men; 2 were killed outright by the force of the explosion, 6 by a combination of burns and afterdamp, and 74 by afterdamp. About 140 men escaped or were rescued following the explosion, Of these, 119 escaped with little or no assistance, 2 were rescued promptly following the explosion, and 19 were rescued from behind a barricade. Seven bodies were re-covered from behind an ineffective barricade in another place; subsequent investigation proved that these men might have been guided to a safe location had an effective communication system been available."

Oct 1, 1946

By C. Carlson, W. Muir

"The oxygen demand of the complex lead-zinc-iron feed at the Cyuro Anvil concentrator was determined denendent on the cyanide ion con-contration of the pulp. By redistribution of the cyanide [ ] the grinding circuit in direct proportion to the amount of surface area created, a more activated flotation feed in obtained.Monitoring the oxygen demand of the flotation feed and grinding mill discharge has proved useful in diagnosing metallurgical problems day to day operation."

Jan 1, 1976

Smarter Gravity Separation Using the Kelsey Centrifugal Jig With relatively coarse grained and easy-to-process ore sources rapidly dwindling, smarter techniques are becoming more necessary for the continued success of mineral processing operations, while increasing environmental pressures also require more environmentally friendly solutions. Gravity concentration has long been employed to pre-concentrate minerals using water, reducing or eliminating the need for less environmentally friendly processing techniques such as flotation. Conventional gravity recovery devices however, operate in a 1 g environment with limited efficiency in the separation of fine particles of heavy and gangue minerals. More recently developed centrifugal concentrators operate in a multi-g environment and enable finer heavy minerals to be recovered, but also exhibit limited separation efficiency due to the separations being based on solid particle mass differentials. Further enhancement of gravity separation has been achieved using the Kelsey Centrifugal Jig (KCJ), which also operates in a multi-g environment, but separates minerals on the basis of specific gravity differentials, using 'ragging' media and a pulsation mechanism, which maximises the effect of differential particle accelerations. This enables the efficient separation/recovery of minerals down to a particle size of ~6 ¦m and/or separation of minerals with a low specific gravity differential. This paper presents details on the principals of operation of the KCJ, recent improvements in the technology and recent developments in modular KCJ plants, as well as some KCJ application areas, which offer smarter, environmentally friendly processing opportunities for the mineral processing industry.

Sep 13, 2010

By R. V. Ramani

This report is volume 10 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Ventilation subsystem of the Master Design Simulator. The Ventilation subsystem has the capabilities to handle: (1) branches in parallel or series, (2) fans in parallel or series, (3) multiple fans, (4) methane, compressed air, or other injections into the system, (5) leakages and fixed quantities, and (6) calculations of absolute pressure at nodes. The program uses the Kirchoff's Junction and mesh laws, and the Hardy-Cross iterative technique to converge to the desired accuracy in solving fox the head quantity. A case study is included in the report illustrating the use of the model. The appendices of the report constitute a user's manual for the Ventilation subsystem, and include a program listing.

Jan 1, 1975

By J. H. Jones

The original term of grant No. 1115174 was September 1980 through December 1983. An extended progress report, covering this time period, was forwarded to the Bureau of Hines in January 1984. The principal investigators were given a no-cost extension of their grant to cover the period January through December 1984. The report which follows covers this latter time period only.

Jan 1, 1985

By Guo Junfeng

The strength of coal mass saturated with gas is an essential parameter in studying the mechanism of gas and coal outburst, and its prediction method. Up to now, there has not been a method for determining the strength of coal mass saturated with gas. This paper describes a new method whereby the strength of in-situ coal mass can be determined and stored continuously and automatically. The simulation results obtained in the laboratory indicate that the new method allows a fast, reliable, inexpensive and convenient determination of the strength of coal mass.

Jan 1, 1992

By D Craw, J Becker

Post-metamorphic structural evolution of Otago Schist resulted in a pattern of northwest and northeast striking faults and fractures cutting the basement rocks. These faults have been reactivated several times since Mesozoic metamorphism. Gold-bearing quartz veins which have been exploited sporadically over the past 130 years are almost invariably hosted by northwest striking structures, and most exploration has been focussed on these structures. There is evidence for hydrothermal activity and mineralisation along some of the northeast striking structures, although there has been very little work done on these structures. Our study is attempting to characterise the hydrothermal processes in the northeast structures, in comparison to the northwest structures, in order to see if further detailed exploration is warranted. There is evidence for both normal and reverse senses of movement on northeast striking faults, and some of the faults have evidence for early ductile deformation overprinted by later brittle structures. Northeast striking structures host stibnite mineralisation in places, and faults are locally silicified or extensively impregnated with ankeritic carbonate. Sulphides are rare in veins, but do occur in some hydrothermally altered host rocks. Hydrothermal haematite accompanies extensive silicification along the Manuherikia fault zone near Alexandra. Anomalous gold concentrations occur in some hydrothennal zones, and in downslope sediments in some localities.

Jan 1, 1998

By G. van den Berg

Anglo Platinum has initiated a project to investigate hydraulic hoisting technology for platinum mines. Hydraulic hoisting systems are categorized as pumping, fluidizing feeder or displacement feeder systems. Positive displacement piston diaphragm pumps are most suitable for pumping systems but they require that the ore be milled prior to pumping. Fluidizing feeders are unsuitable for platinum ore applications due to the large percentage of fines in the ore. The three-chamber pipe displacement feeder has been most widely used for hydraulic hoisting and is the most suitable technology for platinum mines. Eight hydraulic hoisting applications covering pumping and displacement feeder technologies are reviewed. The key factors to be assessed in selecting a hydraulic hoisting system for a platinum mine are discussed. A typical platinum mine configuration will comprise an ore preparation plant (to produce -15mm material through screening or crushing), motive water pump on surface, high pressure water pipeline from surface to underground, ore slurrification plant, three-chamber displacement feeder, and a high pressure slurry pipeline to surface. The water and slurry pipelines are housed in a purpose drilled borehole. A hydraulic hoisting system selection chart is presented. A 150mm diameter system with a 25 MPa pressure rating is required to hoist 60 000 t/m from a depth of 1 200 m. Generic capital and operating costs are presented. A major potential advantage of hydraulic hoisting is that the fines, which contain a high percentage of PGMs, are captured underground and transported directly to the concentrator. Hydraulic hoisting technology is ideally suited to providing supplementary hoisting capacity to existing shafts that have reached the skip hoisting capacity limit. The main advantage for new shafts is the potential to significantly simplify underground rock handling and transportation. All hydraulic hoisting system components are proven. The only risk area is the wear rates of the valves and piping. Current estimates are based on gold ore. The business cases investigated show that the financial viability of the installations are not sensitive to wear rate. Hydraulic hoisting is technically feasible and financially attractive for platinum mines. Keywords: hydraulic hoisting, slurry

Jan 1, 2005

In the estimation of reserves the known values of the variables of interest from surrounding drill holes are used to compute or estimate the unknown value of the orebody over a given region or at a given point of interest. The classical means of doing this are: 1. The Polygonal Method û where the region is divided into polygons centred on bore holes, each variable is then assumed to have constant value over each polygon. 2. Inverse distance methods, where the variable is assumed to vary linearly with the distance between the known values of the drill holes. 3. Inverse distance squared method û a quadratic variation is assumed for the variables between the bore holes.

Jan 1, 1983

By David A. Brence, Andrew D. Marti, Richard P. Stahura, Ronald J. Valentine

The development of an effective belt-cleaning system for a new conveyor system seemed a fairly conventional assignment. But a closer examination of the project showed a number of “fine print” details: •High altitude location (with resulting cold weather and low humidity conditions). •Long conveyor length. •Troublesome material (very sticky and capable of hardening like concrete). •Limited water. These difficulties are spelled out the challenge of developing a cleaning system for the production conveyor2 (PC2) belt at Climax Molybdenum’s Henderson Mine.

Jan 1, 2005

By A. Salmoni, E. K. Gillin, T. Eger, A. Cann, P. Vi, M. Hunt

Kittusamy (Kittusamy & Buchholz, 2004) state that there have been few studies conducted to assess exposure to whole-body vibration (WBV) in the construction industry. They suggest that there is very little reliable data from the construction industry that characterizes exposure levels to various hazards including WBV or the health outcomes from such exposure and that there is a need for more exposure data. In a recent exploratory study of heavy construction equipment Cann (Cann, Salmoni, Vi, & Eger, 2003) looked at vibration levels for 14 different types of construction equipment. Eight of the 14 pieces of equipment tested exposed operators to levels of WBV that exceeded the recommended limits for an 8-hour period when comparing the measured VDV to the ISO 2631-1 standards. The purpose of the present research was not only to test a larger number of scrapers but also to investigate scraper operator exposure to whole body vibration (WBV) separately for each task. Methods 33 scrapers were evaluated for WBV in a variety of residential and road construction projects. Testing equipment consisted of triaxial accelerometers that allowed vibration data collection in all three orthogonal axes, with the x-axis positioned to measure vibration in the anterior-posterior direction, the y-axis in the medial-lateral direction, and the z-axis in the vertical direction. Root mean square accelerations (aRMS), vibration dose value (VDV), crest factor, and maximum transient vibration values (MTVV) were derived from this software and exported to an Excel™ spreadsheet for later data analysis. Test sessions for each piece of equipment lasted for approximately 20 minutes until at least three work cycles had been completed. Tasks included: idling while waiting for a bulldozer to push the scraper through the scraping phase, scraping, traveling loaded with dirt, dumping and traveling empty. Results Task breakdown by time reveals 25% of the work cycle was spent traveling fully loaded with dirt, 19% dumping, 21% traveling unloaded, 17% idling and 18% scraping. Calculation of aRMS vector sums gave values of 2.55 m/s2 during loaded transport, 2.46 m/s2 during dumping, 2.31 m/s2 during unloaded travel, 0.55 m/s2 during idling and 1.46 m/s2 during scraping (see Table 1). The highest acceleration values recorded were found in the z-axis during fully loaded transport reaching an average aRMS over three work cycles of 2.55 m/s2.

Jan 6, 2006

By Yavuz Ali Topkaya

Rare earth ferrosilicide is a versatile alloy mainly used to control the detrimental effects of sulfur in steel and to modify graphite structures in cast iron. The aim of this study was to determine the optimum conditions to make rare earth ferrosilicon alloy using a preconcentrate produced from a bastnasite type of ore present in the Beylikahir-Eskisehir region of Turkey. This concentrate contained 23.5%REO, 41.37% CaF2, 10.69% BaSO4, 8.50% CaCO3, 4.18%Fe2O3, 2.83% Al2O3, 2.74% SiO2, 1.20% P2O5 and small amount of other oxides. The initial metallothermic reduction of this concentrate using ferrosilicon and aluminum in a graphite crucible placed in a muffle furnace gave very low recoveries due to the difficulties encountered in adjusting the slag composition, temperature and amount of additives. Therefore, two batches of rare earth oxide concentrate containing 61.1% and 81.7% cerium oxide, respectively, that were procured from a Turkish glass producer, were used to optimize with respect to temperature, duration, slag-making additives and amount of reducers. In these experiments, smelting and reduction was done in an induction furnace with graphite crucible, and, ferrosilicon and aluminum were added after melting the charge. As a result, there was no difficulty in obtaining a rare earth ferrosilicon alloy containing 35-55% RE, 5-25% Fe and 20-40% Si, with about 80% metal recovery. When the optimum conditions were applied to the preconcentrate, alloys of similar compositions were obtained with 70-80% recovery. Experiments were also done with mixtures of preconcentrate and rich concentrate, and, recoveries as high as 95% were obtained. Only in this case, to increase the recovery, mixtures had to be charged to the empty graphite crucible after heating the crucible to the required temperature.

Jan 1, 2006

By M. D. Heresy, H. F. Coward

"Whenever a manometer has been used for recording explosion pressures it has been calibrated under a series of static pressures. Whether the readings taken during the rapidly changing pressures of an explosion (dynamic pressures) truly represent the actual pressures therefore is an open question. The authors had hoped to solve this problem by conducting the calibration with the aid of known pressures, applied at about the ammo rate as in an explosion, for example, by means of a cylinder and piston, the piston being driven in by an eccentric cam at a rate which would be determined accurately by the shape and rate of revolution of the cam. If the rate of compression were great enough, then the pressure in the cylinder (to which the manometer is attached) could be calculated from the laws of adiabatic changes of pressure and volume. It seems highly probably, however, from H. T. Tizard's observations on pressure changes in a cylinder during rapid compression (55) 4/ that there is much heat loss, therefore pressure loss, in the very small interval of time during compression; although Tizard was able to estimate the amount thereof, he did so only by relying on his nanometer, which is exactly the procedure that the authors challenge on the grounds that the manometer was not standardized under the conditions of its use. Hence the authors were driven from this scheme of calibration to another, namely, comparing records of ono and the same explosion taken simultaneously on several instruments of as varied a type as possible. If 2 of a number of instruments agree, perhaps both are accurate; if 3 agree, probably each of the 3 is accurate; if 4 agree, it is almost certain each of the 4 is accurate.There was a second objective in the present work. If the Bureau of Mines and the B.C.D. (British Coal Dust) manometers differ in their records, then from a sufficiently comprehensive series of experiments it may be possible to coordinate the extensive results already obtained at the American and British stations.Thirdly, it was hoped to learn which is the best available instrument for observing the pressures of coal-dust and as explosions and, if possible, to indicate means for improvement in manometry."

May 1, 1935

By D. L. Stevens

Following an in-depth scenario and strategic planning exercise in 1997, Noranda’s mine production goal was set at 500,000tonnes per year of both copper and zinc metal within five years. There had been no recent discoveries, reserves were shrinking and things had to be done differently and quickly. Change is now continual in our program but here is what we did first: - Combined the exploration and business development groups - Formed teams to search for and respond to opportunity - Made our geologists more business minded and our engineers more optimistic - Went global - Set clear thresholds, farmed out the marginal properties, fast tracked the others - Focussed reconnaissance exploration where we had a clear competitive advantage - Became a “flexible” partner to both juniors and seniors

Jan 1, 1999

By David Vergara Segura

Una empresa minera, en condiciones normales, maximiza su operación y minimiza sus pérdidas por tener operativos y equipos ligados a la producción. Por lo que es necesario la integración entre las áreas de la empresa, específicamente entre las de Mantenimiento y Logística. En este sentido, el presente texto señala la importancia del trabajo en equipo entre estas dos áreas, cuyo objetivo común es optimizar la gestión del activo que tiene un impacto significativo y directo en la producción. También se plantea bajo del esquema de una empresa minera ficticia, el desarrollo de estrategias conjuntas, y se define un modelo de gestión logístico, generador de ventaja competitiva, el cual está orientado a la optimización del uso del activo.

Sep 12, 2005

Good morning and thanks for the chance to talk to you. It's really pleasing to see so many industry representatives here I want to spend a few minutes talking about issues relating to your industry. At the end of today I would like to leave you with three strong messages from government. The first is that this government supports environmentally responsible mining and the endeavours of the mining industry. The second is that explorers and developers are wanted and welcomed in New Zealand. And the last is that it is up to the industry to keep the public properly informed about how your industry and to constantly work on improving your public image. The mining industry is a high-tech industry which fits snugly with our concept of a growing knowledge-based economy. It has particular value for regional development, the gold mining industry alone provides more than 4,000 jobs û mostly outside of the main cities. The industrial minerals industry is twice as large as that. As well as those people directly employed by the industry there are greater downstream effects for the community. One example from the broader extraction industry of this is of the local pie shop down the road from one of Taranaki's petroleum industry locations. The shop sells over $4,000 worth of pies a week to workers in the industry. That's just one example of the positive benefits the industry brings to its local community and is the sort of real positive benefit you need to be telling people about  

Jan 1, 2000

By L. M. Gould

"Syncrude Canada operates the largest oil sands crude oil production facility in the world and produces over 13% of Canada’s total oil requirements. To achieve this, Syncrude mines the oil sands in open pits, extracts the raw oil known as bitumen from the sand using water-based processes and upgrades it into sweet light crude oil by fluid coking, hydroprocessing, hydrotreating and reblending. The final product, Syncrude Sweet Blend (SSB), is sent by pipeline to three Edmonton area refineries and then to pipeline terminals which ship the SSB to refineries in Canada and the United States.As parts of the Mildred Lake base mine reached their economic life, they were replaced with new facilities at the Aurora Satellite mine. Aurora is situated on Oilsand Leases 10, 12 and 34, 35 km northeast of the Mildred Lake facility (Fig. 1).In 2000, the first hydrotransport low-energy extraction production train started up at Aurora. A second production train is scheduled for start-up in 2003. Open pit mining at Aurora occurs using two hydraulic shovels, two cable shovels, and trucks ranging from 320-ton to 380-ton payload capacities (Fig. 2).Once the oil sands is excavated, the trucks dump the ore into a crusher designed to break up the big lumps of oil sands and rock at peak rates of 11 000 t/hr. The ore is then transferred by conveyor to a surge pile and then to a mixing box which combines the oil sands with hot water. Following bitumen separation in the primary separation vessel, froth is delivered to Mildred Lake for processing via the intersite pipeline (Fig. 3).The goal of this paper is to illustrate how high precision shovel GPS (HPGPS) is being used at the Aurora mine to aid in mine planning. This can be accomplished by first describing the function of the mine planning department, describing the Aurora orebody, and finally explaining how the HPGPS system functions and how it is employed at Aurora.The short range mine planning department ensures a steady supply of ore is delivered to the plant at the desired grade in a sequenced and economical manner. This is done by creating a mine plan that consists of shovel dig locations that require the shovels to mine in a specified area at a specified elevation."

Jan 1, 2002

By R. J. O'Dea

"The United States hat large reserves of titaniferous iron ores that are a potential future source of both iron and titanium. Although it is not now economically feasible to recover iron and titanium metals from these ores, they may become important in times of stress and, in some instances, already have served as a source of pigment-quality titania.The iron- and titanium-bearing constituents of the ores considered in this report are not completely separable from each other by ore-dressing methods, and chemical (or smelting) procedures must be employed. It is im¬portant, therefore, that information be available concerting their reactivities. The most important titanium-bearing constituent is ilmenite (FeTiO3), the thermodynamic properties of which were discussed in a previous publication.3/ The results of thermodynamic studies showed that both hydrogen and carbon monoxide are relatively ineffective reducing agents for the iron in limonite. On the other hand, carbon theoretically is effective at tempera¬tures above 8510C., at which. point the combined equilibrium pressures of CO and CO2 from the reactionsFeTiO3 + C = Fe+ TiO + COand200 = C+ CO2reach 1 atmosphere.This report gives results of small-scale tests of selective reduction by carbon of the iron in titaniferous iron ores, both with and without addition of sodium carbonate. It is shown that the bulk of the iron may be reduced and separated without serious reduction or loss of titanium. Three Wyoming ores, Iron Mountain, Shanton, and Taylor, wore studied. The principal factors investigated were temperature, time, carbon:ore ratio, particle size, and sodium carbon ore ratio.Two methods of investigation were employed. In the first, intimate mixtures of ore and carbon were roasted and the reduced iron and titanium evaluated by leaching with dilute sulfuric acid and analyzing the leach solution (and, in some instances, the dried residues).Twenty grams of ore were mixed thoroughly with carbon and tamped into an alundum thimble having a loosely fitting cover. The thimble and contents were placed in a test-tube end porcelain tube and heated to the desired temperature in a Globar tube furnace. The open end of the porcelain tube was connected to a bubbler containing sulfuric acid, in a manner that permitted complete shut-off of the tube when desired. This allowed removal of the tube from the furnace at the end of the roast period without exposure of the contents to the atmosphere."

Jun 1, 1946

By R. L. Gall

This report describes Bureau of Mines experiments in gasifying coal in a helium-heated tube-coil reactor. The purpose of this work was to investigate helium as a medium for transferring heat from a nuclear reactor to gasify coal or for use as high-temperature process heat. A laboratory-scale system was designed and constructed to demonstrate feasibility. In preliminary tests with this system, in which the coal was fed as a water slurry, the helium-heating and recycling equipment operated well. Considerable difficulty was experienced, however, in preheating coal slurry to the desired range of 400° - 1,000° F. without plugging the preheaters. Five different preheaters plugged with coke or with salts leached from the coal. The longest operating period wan 12 hours. These difficulties were partly due to the relatively small equipment and flow rates. The gasifier processed l pound per hour of low-rank coal at 300 p.s.i.g. and 1,800° F., with the carbon conversion limited to 20 to 30 percent by the short residence time and slow heat-transfer rate.

Jan 1, 1962

By F. Lindroos

A cornerstone in the LKAB Green Pellet concept is to produce pellets with a small footprint in terms of energy con-sumption, CO2 emission and emission of other elements harmful to the environment, like dust, sulphur dioxides, nitrogen oxides, chloride and fluorine. The concept also encompasses our determination to make pellet products that contribute to low environmental impact and low energy consumption in our customer?s processes. The presentation will focus on the pelletizing process. It will describe both how we have attempted to decrease the generation of unwanted components in the process gas, and how we have tested or evaluated equipment for external gas cleaning. We will discuss and give examples from recent and on-going efforts and outline some of the future challenges we see, to meet our own environmental standards and also the tough demands imposed by EU and national legislation, while striving to boost production.

May 1, 2011