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By D. L. Petersen, C. R. Nelson, B. K. Nelson, B. D. Wagener

The Lafayette Bluff tunnel, currently under construction for the Minnesota Department of Transportation (MnDOT), will be among the widest highway tunnels in the United States. The 199-meter tunnel is being constructed in a closely jointed, variably weathered diabase rock mass. Cover above the tunnel crown ranges from 4 meters to 27 meters, and is less than the tunnel excavated width of 18.3 meters for about 60 percent of its length. These factors dictated special support and lining design, limitations on excavation sizes and required sequences for support installation. Tunnel excavation is by controlled blasting, with multiple top headings and bench. Rock support and lining consists of external portal beams, rockbolts and reinforced shotcrete. A final concrete lining provides structural support for the rock mass and the membrane waterproofing system.

Jan 1, 1991

By Jim Bruce

The Transformation AGO project, constructed between 2005 and 2008, featured a foundation trade contract that included design of pile caps and grade beams and construction of 138 permanent micropiles. The new foundation works were constructed within seven different settings ? each featuring a host of attributes challenging to constructability ? inside and outside the existing Art Gallery of Ontario, all while the gallery remained open for business. Transformation AGO resulted in several firsts for micropiles in the Toronto construction market: this was the first micropile trade contract with a multimillion dollar contract value; it featured the first static compressive load test performed beyond 7000 kN on a single micropile; the first static compressive load test beyond 8000 kN on an experimental pile cap supported by two test micropiles; and it was the first publicly funded project to go to tender with micropiles listed as the preferred foundation option. This paper outlines the successful application of micropiles at the landmark Transformation AGO project.

Jan 1, 2011

By Steve Hubbard, Brad Marchant, Rolando Cuadra

"Triton Mining Corporation acquired the rights to Mina El Limon in Nicaragua in 1993 by international bid. The bid included the gold operations at Limon and an exploration concession of approximately 4000 km2. Triton assumed control of operations and exploration in May 1994.The Limon mine is located in west-central Nicaragua, approximately 100 kilometers northwest of Managua. The climate is tropical, characterized by a wet season from May through October, and a dry season November through April. Gold at Limon is associated with both banded quartz and silicified breccia veins in Tertiary volcanic rocks, belonging to the lower Coyol Group. Mining is from two open pits and one mechanized underground operation. A second underground mine is currently under development for production during 1997.This paper describes the expansion of the milling facility at El Limon from a nominal capacity of 400 tonnes/day, producing approximately 20,000 ounces of gold annually, to the existing 900 tonne per day mill operation. Engineering of the new mill facility was initiated in September 1994 and construction was completed a year later."

Jan 1, 1997

By T. R. Curr, W. A. Gericke, J. Basson

South Africa is a leading player in the international ferro alloys industry. Historical factors that have contributed to this dominant position include an abundance of natural resources and relatively low cost electricity. A number of relatively recent developments are potentially threatening this position. These include new legislation affecting the mining and minerals industry, a shortage of some types of suitable reductants, depletion of surplus electricity generation capacity with resultant threat of real escalation of electricity prices and pressure resulting from the recent strengthening of the South African Rand. The industry is addressing these challenges in a number of ways to ensure long-term viability. Some of these measures include investments in more efficient technologies that have economy of scale benefits and are less dependent on expensive reductants and electricity. Local macro-economic impacts include new legislation regarding ownership of enter-prises, mineral rights and royalties on mineral sales, development plans for port and rail infrastructure, as well as initiatives to expand electricity generation and coke production capacity. The fundamentals for being a successful ferro alloy producer are still largely in place for South African producers. Therefore the South African ferro alloy industry will remain competitive and is well placed for continued growth in line with the international growth in ferro alloy demand. The industry should emerge leaner, more efficient and ready to respond to any future demands of the industry. This paper will cover the present status of the industry, the factors that are impacting thereon and a view on its future outlook.

Jan 1, 2007

By Kenneth Wardell

Criteria have been fully developed for determining the optimum size of oil and gas well blocks. The criteria lead to the formation of well barrier pillars which are, of themselves, inherently stable and take account of variable mine roof and floor conditions. The criteria ensure, through considerations of ground movement, that strains transmitted to well casings, are within tolerable limits of casing specifications. The criteria cater for well barrier pillars in multi-seam mining situations and where previous old mining has taken place. The criteria maintain flexibility in being adaptable to local mine design situations. The criteria are applicable to proposed extraction thicknesses up to 15 feet at depths up to 2,400 feet. The criteria are related to producing wells and to abandoned wells. In the latter connection, various states of well abandonment are recognised.

Jan 1, 1980

By Laura Mottola

Process Design and Change Management for Successful Deployment of Technology in Mining Over the last 30 years Canada has been successful in developing but not deploying hardrockmining automation. Our opinion is that the current lack of R&D investment and implementation capacity places Canada at risk as a future global mining leader A white elephant A burdensome possession; creating more trouble than it is worth. White (albino) elephants were regarded as holy in ancient times in Thailand and other Asian countries. Keeping a white elephant was a very expensive undertaking, since the owner had to provide the elephant with special food and provide access for people who wanted to worship it. If a Thai King became dissatisfied with a subordinate, he would give him a white elephant. The gift would, in most cases, ruin the recipient.

May 1, 2010

By Heramb M. Bal

This paper will underpin the future development of intellectuals having greater understanding of patent law and legislation, IP rights, and innovation. To understand this idea, I present a case study of China?s progress in the last 31 years in the rare earth research, innovation, and simultaneously patents area. Rare earth elements (REE) are at the centre of high technology and are the next wave of world innovation. Much of modern society depends on rare earth elements through their use in computers, lasers, telecommunications, iPods, medical technology, military applications, and so on (Long et al, 2010). The rare earth research, a large research body is being provided by Chinese sources. China devoted three or four university centers to the study of rare earths (Lifton, 2009). These measures are all designed to keep China at the forefront of REE production, materials, technology, and innovation. As a result in the last fifteen years there has been a shift from a US-dominated REE industry patents to Chinese patents. The world must identify strategic areas of rare earth innovation and provide funding to firms and universities that conduct such research. Not only research and innovation is vital but filing patents and preserving IP rights for research and innovation is even more important. We (rest of the world) need a comprehensive strategy to guide the development of patent and IP rights for research and innovation. To achieve this, the development of intellectuals with superior knowledge of patents and IP rights are the future need of minerals industry. Keywords: innovation, rare earth, patent, IP rights

Sep 1, 2012

By Herbert H. Einstein

This report contains the documentation for 11 computer programs representing the entire computer documentation for the eight-volume report entitled "Risk Analysis for Rock Slopes in Open Pit Mines." A detailed summary of the programs is included.

Jan 1, 1979

By Zoë Mullard

Just as a mine has a lifecycle, employees working within the mining sector also make several transitions throughout their career, from initial recruitment to retirement from the industry. Throughout the employment lifecycle, employees bring skills and knowledge that significantly contribute to the global economy. These skills are developed through education, professional training, coaching and through hands-on experience. Despite the current economic conditions and the demand for minerals, the mining industry is facing a substantial skills shortage due to the disparity between the number of new workers entering the mining industry and a largely ?graying workforce?. Although educational programs continue to evolve to attract people with a wide range of skills, the diversity of jobs and the strains of working in remote mining operations continue to present challenges for recruitment and retention of employees. This gap also presents challenges around knowledge transfer at a corporate and mine-site level; employers will require cultural and techno-sociological approaches to ease through these transitions. At the same time, there has been an explosion of social media tools that facilitate information sharing, cross-organizational collaboration, distance learning and knowledge capture. These tools have become increasingly popular in the last few years and their applications vary widely. The mining sector has started to adopt these tools for a number of purposes, including opportunities to harness social media to enhance human resources interactions, outreach and oversight. This paper will outline several case studies that explore leading practices for how the application of new media can assist organizations and individuals as they progress through their careers. This paper will illustrate how new social media communication technologies can be used to increase employee engagement and build organizational capacity in the mining industry. The paper will also include strategies for how to implement social media to enhance human resources applications and will cover ideas for monitoring and evaluation.

Aug 1, 2013

By Bern Klein, Randy Blaskovich, Reem Roufail

"Morphology is a tool that is rarely used for mineral breakage mechanism evaluation. Ground particles are typically assessed for their size distribution. They are also visually analyzed using image analysis. However, image analysis is not a comprehensive evaluation of the particle surface texture. It evaluates particle’s size parameters such as area, diameter, and perimeter amongst other features. On the other hand, morphology analysis takes the particle assessment to another level of detail. Morphology analysis evaluates particles’ roundness, elongation and angularity that would indicate the degree of roughness of the particle. According to Roufail and Klein (2009), rougher surfaces are generated due to breakage along grain boundaries – intergranular breakage. Mill operation, particularly mill speed, dictates the dynamics in the mill. Stirred mills are known to break the particles via abrasion under standard operation. However, if the dynamics of the grinding media in the mill are changed, the particles could be more exposed to impact and compression loading that would lead to a different mode of breakage.In this paper, the effect of material properties and mill operating conditions on particle morphology will be studied. Hard non-sulfide versus soft sulfide minerals are compared, namely quartz and galena, respectively. Extreme mill speeds are tested covering the range of 1000 to 2000 rpm for a 4-litre Netzsch (ISA) mill. In addition to particle size distribution, micro-analysis is executed in the form of morphological analysis using a tested manual roughness point counting technique.INTRODUCTIONGrinding in general and stirred milling in particular are processes that are used to break particles to liberate metal-bearing minerals for further separation downstream. The energy required to achieve the target particle size versus maximum possible liberation has been studied intensively and it is usually the breaking point for the grinding system chosen in a process flowsheet. Operating conditions are dictated by the energy consumption. Becker et al. (2001) related different forms of energy such as input, specific, volume/mass specific energies to stress intensities and final product fineness. Other research studies focused on energy input in a stirred mill (Zheng, Harris and Somasundaran, 1996)."

Jan 1, 2011

By Jack E. Brockway

As tunnel boring machine technology has expanded, so has its range of application. Tunneling machines (TBM's) are tackling tasks today that fifteen years ago were considered "inappropriate". A case in point is incline/decline TBM boring. An incline or decline bore presents peculiar design considerations that differentiate it from a horizontal bore. This paper reviews those design considerations as they apply to TBM's, backup, muck handling and other tunneling subsystems. In addition, several abbreviated case studies are presented. By the review of real life tunneling techniques as well as design considerations, the "appropriateness" of TBM incline/ decline boring today becomes apparent. INCLINE Introduction In contemplating the impact of incline versus horizontal tunnel boring system design, the obvious consideration is gravity. Up-hill boring can be quite different than horizontal boring. Muck, water and machine weight all tend to slide down the incline. In addition, hydraulic and lubrication systems if unaltered, will find their fluids pooled in the lower corners contentedly ignoring such higher elevation items as gears and bearings. In order to address this inherent gravity problem, a review of

Jan 1, 1983

By Robert Louis Adams

A general discussion of the structure of the junk automobile recycling system shows that the generation of stripped automobile hulks and scrapped automobiles is price inelastic. As a result, it is extremely difficult for the price mechanism to automatically achieve an equilibrium that will prevent the accumulation of excessive automobile wrecker inventories and vehicle abandonment by the last owners of scrapped cars. The new shredder processing technology and the new portable flattener technology have altered the structure of the junk automobile recycling system. The shredder technology has increased the demand for processed automobile scrap. This increased demand is reflected in higher prices paid for hulks by scrap processors. The portable flattener has reduced the transportation cost of shipping hulks to processors. The two new technologies have eliminated, at least potentially, the net cost of shipping stripped hulks so frequently incurred by wreckers in the past. The elimination of this cost eliminates the economic incentive for excessive wrecker inventories. Unfortunately, the incentive for last owners to abandon their cars does not appear to have been eliminated by the new technologies. The last owner of an automobile with no spare parts value is still likely to incur a cost by delivering his automobile to the recycling system. Although a subsidy payment is probably unnecessary to reduce excessive wrecker inventories, such a payment might be one solution to the problem of automobile abandonment. However, there are a wide variety of subsidy programs that could be introduced. Before any Federal subsidy program is introduced to reduce automobile abandonment, it is recommended that the program be tested on a limited basis in many different parts of the country.

Jan 1, 1973

By P. James

"INTRODUCTION Control of target stream pH is very important in leach mining and treatment of MIW (mining influenced water). On the production side, solution acidity can impact SX (solvent extraction) effectiveness through PLS (pregnant leach solution) and raffinate pH. Many older operations and legacy mining sites generate ARD (acid rock drainage) that is too weak for profitable metal production by conventional means and faces costly wastewater treatment for mitigation and disposal. For wastewater and environmental treatment, neutralization to precipitate and remove metal contaminants to clean the wastewater is the dominant approach. Traditional lime neutralization and precipitation is most often used but results in large amounts of mixed metal sludge requiring costly disposal. Blue Planet Strategies (BPS); which focuses on improved resource utilization targeting electrolytic treatment and waste conversion into resources, has developed a new “reagentless” neutralization process. Electricity is utilized in its proprietary DEMET™ (Dynamic Electrolytic Metal Effluent Treatment) platform capability to controllably raise target stream pH. The method offers a simple, low-cost approach yielding cleaner treatment chemistry. It can result in less sludge generation and enables possibilities to selectively recover contaminants as potentially saleable products for new revenue generation to offset further offset treatment costs. DEMET Overview BPS’s patented electrolytic DEMET platform leverages solid scientific and chemistry foundations through its advanced design to achieve capabilities and performance not previously realized. DEMET technology combines separated compartment electrolytic cell functionality with proprietary advanced dynamic electrodes and cell configurations to achieve a variety of chemistries and processing targets.[1-6] DEMET‘s unique elements can yield higher processing rates at practical efficiencies, lower energy consumption, plus improved processing stability and lower maintenance requirements due to enhanced resistance to cell fouling and shorting; while also thwarting cross stream (catholyte vs. anolyte) contamination. Consequently, DEMET can provide a superior, extremely versatile, and more cost-effective electrolytic treatment option where a multitude of FEED and PRODUCT stream combinations might be employed in comparison to traditional tankhouse electrolytic cells."

Jan 1, 2015

By B. Papilon

Dynamic pressures during blasting can affect performances of both electronic and non-electronic detonators. Boreholes can develop tremendous amount of pressures during blasting. The effect of such elevated pressure especially during electronic delay countdown is probably more acute in electronic detonators. Measuring the pressures during blasting can aid to understand the relationship between magnitude of the pressure developed and the multitude of blasting conditions.

Jan 1, 2013

By BRETTMANN TRACY

Jan 1, 2000

By S. L. Windes

"INTRODUCTION For a number of years, the Bureau of Mines conducted tests on various types of structures to ascertain the effect of seismic vibrations emanating from quarry blasting in an effort to determine an index of damage. Associat¬ed with these tests, occasional records were made of the characteristics of the air blast or concussion from the explosions. Although the importance of the air-blast problem was recognized, the equipment was not designed for airblast measurements, nor was the early research program concerned with the problem. After the ground-vibration tests had been completed, attention was turned to study of the air blast and its effect. The program was modified, however, in certain aspects by the imminence of war and the final entry of the United States into the conflict. These modifications were made to supply information pertaining to military and civilian defense problems.Detailed discussion of these problems is beyond the scope of this report, which attempts to present preliminary results of factual and fundamental character. However, it may be noted that airblast data are urgently needed for intelligent design of both Government and non-Government buildings, which must withstand the air blast from bombs and afford maximum protection for the occupants. The safety of vital equipment above and below ground necessitates consideration of damage from air blast. Protection against use of dynamite by saboteurs, moreover, hinges largely on the effect of air blast. Identification of a planned ""accident"" involving dynamite often entails knowledge of the characteristics and power of the airblast.The peacetime problem of damage from air blast resulting from quarry and mining blasting activities is of course exaggerated by the wartime requirements of increased production accelerated operation, and enlarged development."

Jun 1, 1943

By A. López-Valdivieso, M. A. Corona-Arroyo, M. Llamas-Bueno

Magnetite (Fe3O4) ore is concentrated by low-magnetic-field drums to recover a magnetite concentrate that is low in silica (SiO2). The presence of SiO2 in the magnetite concentrate for steel production increases the steel processing costs, so a major challenge in magnetic concentration is to lower the SiO2 grade in the Fe concentrate. This work presents studies that were carried out on the removal of SiO2 from the magnetite concentration at the plant scale. Studies were performed with a three 36 × 96″ drum unit processing 46 ton/h of rougher magnetite concentrate. These studies showed that silica appears in the magnetite concentrate by three mechanisms, namely SiO2 entrainment in Fe3O4 chains, heterocoagulation between Fe3O4 and SiO2 particles, and mineral locking of SiO2 to Fe3O4. The SiO2 entrainment mechanism had the highest contribution (75%) to the SiO2 recovered in the Fe concentrate. Electrokinetic studies on Fe3O4 and SiO2 showed that heterocoagulation occurs because of the low negative zeta potential of the minerals at the pH of the plant slurry. This study also showed that a high percentage of ultrafine size SiO2 particles trapped in Fe3O4 agglomerates was not removed by the dilution water for the slurry fed to the drum. To lower the SiO2 recovery in the drum magnetic concentration process, work should be directed towards the removal of trapped SiO2 in Fe3O4 agglomerates.

By Joseph Grumer

About a century ago Bunsen and his associates invented the famous burner that bears his name and was to become the ancestor of today's gas appliances. Over the years, Bunsen's invention became the starting point of a highly developed, practical technology that culminated in the gas industry as we now know it. However, it did not occur to the early workers to investigate the scientific potentialities of the new device, and as a result the science of gas-burner performance did not keep pace with the growing industry. It was with the objective of closing the rapidly widening gap between science and technology that the present research was undertaken Its immediate purpose was to provide basic information on the combustion characteristics of .fuel gases, in particular as they affect flashback, blowoff, and yellow tipping. Information obtained in the present research and contained within this report consists of the following: (1) Fundamental flashback and blowoff characteristics have been determined, it is believed, for all fuel-gas mixtures in which the gas industry may be interested. These are critical boundary velocity gradients for flames in free air, on burners with ports at room temperature and pressure. Burner aeration is characterized by the parameter, fraction of stoichiometric. These basic limits are explained, values are presented, and calculation procedure is given for deriving corresponding values of port loading and percent primary air (chs. I and II).

Jan 1, 1956

By Henry Kreisinger, WALTER T. RAY

In its investigation of more efficient methods for utilizing the coals and lignites in the United States, to the end that waste might be avoided, the value of low-grade coals increased, and the life of the nation's fuel resources prolonged, the technologic branch of the United States Geological Survey carried on a study of the factors involved in the manufacture and use of briquets, including the suitability of various coals for briquetting, the cheapest and most satisfactory binders, and the furnace behavior and evaporative efficiency of briquetted fuel. The investigations had their beginning in the work done at the coaltesting plant at the Louisiana Purchase Exposition, St. Louis, Mo., in 1904, and were continued at St. Louis and later at Norfolk, Va. Accounts of various tests and statements of the conclusions to be drawn from them have appeared in a number of bulletins. a In connection with the work at Norfolk, comparative steaming tests were made in stationary, marine, and locomotive boilers with run-ofmine coal and the same coal formed into briquets of two sizes. The tests in a locomotive boiler that are described in detail in this bulletin were undertaken to add cumulative evidence to work done at other places. They were made possible through the courtesy of the Seaboard Air Line Railway Company in supplying both the locomotive and the coal used. During the trials the locomotive stood on a side track in the shop yards of the railway company at Portsmonth, Va. No running tests were made.

Jan 1, 1911

By T. T. Read, F. C. Houghten

"The bad effects upon the health and output of miners that result when the ventilating current in a mine lacks sufficient cooling power have been described by Harrington and Sayers in a previous report (1)*** The normal temperature of the human body is about 98.5°F. and whenever work is done by the muscles, indeed even when sitting still, the normal bodily processes generate heat which must be given off, otherwise the body will become overheated and a number of bad effects will be produced. If it were possible to so enclose a man that he could continue to breathe and no heat could escape from his body he would die within a short time. In a series of experiments made at the Pittsburgh Station of the Bureau of McConnell and Houghton (2) found that a dry-bulb and a wet-bulb temperature of 112.5°F could he borne for only 35 minutes, even when the subject was at rest. A wet-bulb temperature of 100.4°F (dry-bulb 157°F) could only be tolerated for 45°F minute. Under such conditions the bodily temperature rises as much as 45°F above normal and the pulse is accelerated. Very uncomfortable sensations are felt when the pulse rate exceeds 135. The human body, like any other internal combustion engine, must be cooled in order to function properly.Under ordinary circumstances the air surroundings people is enough coder than themselves to permit this heat generated within the boiy to be river off with¬out difficulty. At higher temperatures, or when the rate of work, with its corresponding generation of heat is high, the body can not throw off heat fast enough, so it begins to sweat and the evaporation of the sweat cools the body. But the results of the experiments cited above indicate that in still air, even with the body at rent, it can not adjust its temperature when the air is above 90° wet- bulb. J. S. Haldane (4) says ""at a wet-bulb temperature of 60°F the actual amount of work done by the miner begins to fall off; as the wet bulb temperature rinse farther the work Bona gradually diminishes to the vanishing point. Then the temperatures indicated by the wet-bulb exceeds 85°F hard work in a mine seems hardly or the commercial working of a mine the wet-bulb thermometer should not in generaI, be allowed to rise above 80°F, unless perhaps where there it a good current."

Dec 1, 1923