Search Documents

By Michael Rieber

The increase in f.o.b. mine prices of coal from $5/ton to over $18/ton in five years [1] has increased the significance of transportation costs. Coals produced in the vicinity of the consumer bear a much lower transport cost than those produced in the west. This differential may be used for flue gas desulfurization, other cleaning, or further processing of local coals. To the extent that western coals are cheaper to produce and have a lower sulfur content, they offset the locational disadvantage. To the extent that they have a lower heating value, the disadvantage is exercabated. Given the other conditions, an accurate analysis of transport costs will help suggest the location of coal mining and the moue of transport both transport costs and tariffs have risen. Together they have increased delivered coal prices, altered the balance between the use of coal and other fuels, helped to alter the location of mining activity, and put pressure on consumers to examine the cost effectiveness of alternative transport modes. Transportation options for long distance coal movements include rail, barge, pipeline, and EHV transmission lines. A summary of system parameters is shown in Table 2.1. Barge transport, pneumatic and slurry pipelines are discussed elsewhere in this report. Together with EHV, they have been the subject of previous studies [2,3,4]. Slurry pipelines have been shown to be especially useful where rails are not available [2] but the technical problems of dewatering, handling, and utilization of lines [5] remain unresolved. They are discussed in Section 3. Barge transportation depends on the location of the mine and consumer with respect to the waterway system. One drawback of barge shipment is interruptions due to winter, and low or high water conditions. Mine mouth power generation followed by EHV transmission of over 500 miles has been shown to be the most expensive means of delivering an equivalent amount of energy to consumers [2].

Jan 1, 1977

By Malek Smadi, Yazen A. Khasawneh

"New embankments were constructed mostly on soft clays as part of interstate I69 extension in southern Indiana. The embankments serve as bridge abutments and as part of the fill sections along the interstate extension alignment. The height of the embankments range from 50-ft to 125-ft with a maximum foundation thickness of about 75-ft. The foundation soils comprise relatively high compressible fine grained soils. A fully coupled Hydro-Mechanical numerical simulations were conducted for optimizing the construction stages of the embankments. The objective of the staged construction is to allow for sufficient effective stress and undrained shear strength gain to ensure foundation stability under the stage load. Wick drains were utilized to shorten the drainage path and thus accelerate achieving the required undrained shear strength. The extensive field investigation and laboratory testing programs provided a good understanding of the subsurface conditions and allowed the use of a relatively advanced soil constitutive model in the numerical simulations of the staged construction. The effectively designed instrumentation program allowed for monitoring the settlement and pore water dissipation during construction. The pore water pressure, and surface and subsurface settlements from the numerical model predictions reasonably agreed with the instrumentation data over the construction period.INTRODUCTIONThe stability of soft fine grained foundation soils due to embankment construction is dependent on the undrained shear strength of such soils. The permeability, compressibility, and drainage boundaries control the foundation soils response (settlement magnitude and rate) to loading. The settlement magnitude is a function of minerology and soil structure. The settlement rate which is equivalent to the rate of excess pore water pressure dissipation is a function of the soil permeability and drainage boundary. The dissipation rate control the evolution of effective stress and thus the gain of undrained shear strength. As such, if the increase in total applied load is controlled such that enough time is granted for the evolution of the total stresses into effective stresses, then the stability of the foundation soils is enhanced by the gain of the undrained shear strength. The controlled application of the total stress is the definition of the staged construction. From the definition of the staged construction, it is obvious that the process is a coupling of the hydraulic and mechanical responses of the foundation soils."

Jan 1, 2017

By C. M. Harrer

The location, features, qualities, and extent of iron occurrences and the associated resources--limestone and dolomite, bentonite, coal-lignite, petroleum and natural gas, power, and water--are evaluated. The results of pioneer beneficiation tests on South Dakota taconite are discussed. In addition, pertinent features of taconite development, cost factors, the Western and Central United States trade area and markets are reported. The State's production of iron ores until 1963 has been small and for purposes other than the manufacture of iron. This investigation disclosed the probability of large resources of taconite in Pennington and Lawrence Counties. The average iron content is 29 percent, and a 65-percent or better iron concentrate might be produced. Ample resources are available for mining and processing taconite. An investment of at least $26 million would be required for a plant capable of turning out 1 million tons of agglomerated iron concentrate per year. The feasibility of such an enterprise is indicated, but intensive investigation and research must be completed to justify such an investment,

Jan 1, 1966

By AIME AIME

PURSUANT to a recommendation made by the Section delegates at their conference at the Annual Meeting of the A.I.M.E. last February, the Directors, at their meeting on March 15, 1944, appointed a committee charged with the duty of investigating the present status of licensing and registration of engineers, and to make a report on the whole subject for the information of the mining fraternity. The committee consisted of E. W. Ellis, chairman, H. D. Keiser, Henry T. Mudd, J. J. Croston, and Simon Strauss. Messrs. Keiser and Strauss were unable to assist in the work of the committee, and Mr. Mudd was forced to resign in July, his place being taken by A. F. Greaves-Walker. Able assistance was given the committee by T. Keith Legare, executive secretary of the National Council of State Boards of Engineering Examiners, and by Ed. ward Larson, executive secretary of the National Society of Professional Engineers. The accompanying somewhat condensed version of the report of Mr. Ellis's committee, dated Oct. 15, 1944, is confined to facts rather than to recommendations. The "Model Law" to which reference is made was first drafted by repre¬sentatives of six national engineering societies in 1911. It has since been amended many times, the latest version dated June 1943 is recommended to the State Licensing Boards as a pattern for formulating or amending state laws. A copy of the "Model Law" in pamphlet form will be sent to any member on request from A.I.M.E. headquarters while the supply lasts. The report:

Jan 1, 1945

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

At long last, mining is on the rebound in Minnesota?s Iron Range and the excitement is starting to show. The SME Minnesota Section?s annual meeting was once again held in the heart of Iron Range country, at the Duluth Entertainment and Conference Center on the Duluth waterfront. The conference boasted a record attendance of 475 people and its largest-ever trade show. Appearances by Governor Mark Dayton?s new Iron Range Resources & Rehabilitation Board (IRRRB) appointee, Tony Sertich, as well as a local Fox news crew (see clip on SME website [link: http://fox21online.com/news/duluth-mining-conference-breeds-optimism-tech-innovation]) made clear that a lot of eyes [ ] are on the industry as it dusts itself off from the 2008-2009 recession. While the early years of the 21st century were very good to the Iron Range, the global drop in commodities prices and production left many companies reeling and brought back bad memories of the collapse of the industry in the 1980s. However, two years of solid growth and a rebound to above pre-2008 production levels have let the Minnesota mining industry to relax a little and talk seriously about long-term growth and stability.

Jan 1, 2011

By Jr. Gabler

Because of concern over the availability and reliability of an uninterrupted supply of manganese and other materials, the U.S. Congress requested that the U.S. Bureau of Mines (USBM) study the /low of strategic and critical materials in the economy to delineate and quantify the production areas where metal values are lost. As a result, the USBM developed a generic computerized commodity flow model that is readily amenable to updating. The original model developed for cobalt, with slight modifications, was used to track the flow of manganese. This report follows the flow of manganese through its metallurgical and chemical applications and highlights areas where significant losses occur owing to downgrading, export, or disposal. The study indicates that materials containing 695,000 short tons (st) of manganese were consumed domestically in 1990. Scrap recovery specifically for manganese recycling was insignificant. However, considerable manganese was recycled through processing operations as a minor component of ferrous and nonferrous scrap and steel slag. The major loss category is manganese lost in steel processing, 323,156 st or 46 pet of the 1990 apparent consumption. Most of this loss reports to steelmaking slags. Recovery from slags is technically feasible, but is not economically feasible.

Jan 1, 1995

By C. Blawert

In spite of various corrosion studies on HPDC AZ91, there is no clear indication which microstructure gives the best corrosion performance. The skin with its fine microstructure is sometimes reported to have the best corrosion resistance, but there is no clear definition of the skin. If the skin is the outermost part of the casting and nothing is removed from it, then it is contaminated and the corrosion resistance is low. If the outermost skin is removed (about 25 µm) then a better corrosion resistance can be obtained. However this does not automatically mean that there is no other region in the bulk of the casting which could have a similar or even better corrosion resistance. Indeed, the corrosion measurements including potentiodynamic polarization and long term electrochemical impedance spectroscopy (EIS) revealed a lower corrosion resistance of the original as-cast skin about 100 pm thick. The thickness of this region is more or less independent from the thickness of the casting section. The surface region is free from any dendritic grain growth which influences the amount and distribution of the 13-phase and therefore the distribution of the most important alloying element Al. This could explain the different corrosion behavior. Further reason can be found in the enrichment of some impurities such as Fe in the near surface.

Jan 1, 2006

By Xiao Caimei

The method of Substance Flow Analysis (SFA) provides a helpful tool for the study of the industrial metabolism of a certain metal within a regional level, such as copper, lead etc. In this paper the flows and inventory of cobalt in China, 2008, were traced with the STAF model, and the situations of production, fabrication and manufacturing, use and waste management in China were introduced. The result revealed that the resource of cobalt in China was so poor that a large amount of cobalt material or cobalt products needed to be imported, and there was lack of recycling of cobalt resources.0

Jan 1, 2010

By T. J. Batchler, K. M. Mohamed, D. F. Gearhart, R. K. Zipf

Seals are explosion-resistant structures built in underground coal mines to isolate abandoned mining areas from the active workings. An equivalent single degree of freedom (SDOF) method such as the single-degree-of-freedom blast effects design spreadsheet (SBEDS) developed by the U.S. Army Corps of Engineers can be used to design seals to resist mine explosions. The critical input for the SDOF code is the seal resistance function. The objective for this study is to develop engineering data for design of plain concrete (PC) and reinforced concrete (RC) seals using finite element (FE) models. The FE models can then be used to generate resistance functions for different PC and RC seal designs, which can be used in the SDOF codes. The U.S. National Institute for Occupational Safety and Health (NIOSH) researchers designed and built a test fixture for use in conjunction with NIOSH’s Mine Roof Simulator to apply a four-point bending load on the face of the tested seal. Eight large-scale experiments for each PC and RC seal were conducted. The experimental design considered the effects of the foundation strength, hitching and roof-to-floor convergence. Calibrated FE models for PC and RC seals were developed using ANSYS Ver. 13. With a very limited number of engineering-based assumptions and a single set of data—including Young’s modulus, compressive strength, stress-strain relationships, etc.—the PC and RC seal models successfully calculated the recorded resistance functions and failure patterns for a wide range of boundary conditions. Plug and RC seals were assumed for a 1.83-m- (6-ft-) high entry to demonstrate the application of the calibrated finite element models for calculating the resistance functions of these seals. The resistance function of a particular plug seal case was found to be a bilinear relationship. The resistance function of a particular RC seal without shear reinforcement was found to be a nonlinear relationship.

Jan 1, 2013

By Derrick Dasenbrock, Mary C. Nodine, Benjamin Rivers

Up to 50 percent of major infrastructure projects suffer impacts to schedule or cost due to geotechnical issues, many of which correspond to risks related directly or indirectly to the scope and quality of site characterization work. The Federal Highway Administration (FHWA) in coordination with industry organizations seeks to address this issue through Every Day Counts (EDC), a program that identifies and deploys proven, yet underutilized innovations at the project level to save time, money and resources. The A-GaME (Advanced Geotechnical Methods in Exploration) is one of the innovations supported under EDC.

By Walter B. Hester

All persons and communities that have experienced strong-motion earthquakes are convinced of the importance and complexity of earthquake problems thatmust be solved in order to reduce the personal hazards and property losses to a reasonable minimum. It is also clear that absolute elimination of all risks is impossible. Reduction of existing hazards and precautionary measures which will minimize chances for disaster can be accomplished by realistic appraisal of the effects of recent earth- quakes on modern structures and installations. Localities that have reason to expect so-called strong- motion earthquakes can anticipate these effects by taking appropriate steps. Valid earthquake information can only be obtained from earthquakes. Each earthquake contributes to the body of knowledge by additional facts and by clarification of previous observations. Rational interpretation of the data followed by practical application of the conclusions can contribute greatly to the safety of persons and property. The general public expects the architectural and engineering profession to accept this obligation and render this service. Most earthquake hazards are man-made and arise from the imperfections of the works of man and his failure to anticipate the consequences when the natural characteristics of his environment are ignored. If it is not given to man to prevent such natural phenomena as earthquakes, it is sometimes within his power to control their destructive effects and to reduce to a minimum the toll of life and human suffering.

Jan 1, 1958

By E. W. Enqelmann

INCREASED metal consumption throughout the world in the past three years has brought greater activity in the concentrators and mills that treat the ores.' Comparatively low prices have made greater economies necessary, with a continuing search for more efficient flow sheets, equipment, processes, and reagents. Comminution GRINDING has long been too ex- pensive and even any small increment of saving has been eagerly sought. Although not recently new the use of rod mills to cover the gap between intermediate crushing and coarse grinding has made further headway. They eliminate dusting and the closed- circuit operation of fine crushers, either roll or Symons cone, and the rod-mill product is suitable for secondary mills which can be operated with smaller balls and iron liners instead of coarse balls and steel liners. The newer practice is radically different from the older application of rod mills where they at- tempted to use them instead of ball mills for fine grinders. For that purpose they were not well adapted, as they do not have sufficient grinding surface available per cubic foot of mill volume.

Jan 1, 1940

By Thomas P. Mucho, Dennis R. Dolinar, Anthony T. Iannacchione

The Chestnut Ridge Anticline is a prominent structure in southwestern Pennsylvania, USA. This structure has brought two economically valuable limestone formations to the surface, where they are easily accessible to room-and-pillar mining. Nine active crushed stone quarries, an underground research facility, and one industrial facility currently operate along the linear trend that represents the axis of the anticline. The National Institute for Occupational Safety and Health (NIOSH) has identified significant variation in levels of horizontal stress within relatively short distances at shallow overburdens along the anticline. At one quarry, the horizontal stress is high enough to shear strata with a modulus of approximately 77 Gpa. Conversely, zones of extension were observed in parts of another quarry, indicating very low horizontal stress conditions. This study found that high levels of horizontal stress are to be expected in this very stiff rock formation and that local geologic and topographic structures are capable of altering the magnitude and possibly the orientation of the horizontal stress field.

By M Scott, J J. McEwan

Silver and silver alloys tarnish readily by the formation of tarnish on the surface when exposed to a wide range of sulphur-containing atmospheres. This tarnish is unsightly and undesirable and can be removed either with a silver polish or a chemical dip. Polishes are, however, not suitable for irregular and embossed surfaces such as on coins, medallions and jewellery items, because of uneven removal of the tarnish layer and excessive wear. Successful tarnish protection can be achieved by either storing the items away from the aggressive atmosphere or by coating/treating the exposed surfaces with a protective layer. Storage is feasible for collections but is not suitable for items that are handled or worn regularly, such as jewellery. A number of commercial coatings and treatments have been developed, but to date there has not been a systematic evaluation of tarnish protection. This paper details the performance of a range of generic coatings in an accelerated tarnish test. The degree of tarnish was evaluated by means of loss in reflectivity and change in colour. Four coatings/treatments improved the tarnish resistance of silver by more than tenfold. These include an organic lacquer, rhodium electroplating and an organic self-assembled monolayer (SAM) conversion coating. Research is continuing to optimise these coatings. Keywords: silver alloys, tarnish resistant coatings, silver polishes.

Jan 1, 2006

By Scott, Turner

MY whole life has been spent in the mining business, PO I naturally tend to address my remarks particularly to the newly-graduated mining and metallurgical engineers among you. To a certain extent, all forms of engineering principles are involved in the training of the mining engineer, and most sorts of engineering are certainly utilized by him, so every one of this graduatins class is concerned with the field I propose to discuss.

Jan 1, 1932

By John D. Bardill

A cooperative project between the Bureau of Mines, Department of the Interior, and the Montana School of Mines, investigating results of hydraulic systems for transporting sand slurries for emplacement, was begun in August 1955. In such circumstances, the Bureau provides funds for a fellowship leading to a Master of Science degree as well as available instruments, tools, supplies and equipment. The School provides the ore-beneficiating laboratory with its equipment for use as a pilot plant. The success of a hydraulic backfilling method employing mill tailings depends largely upon the physical characteristics of the tailings. One of these characteristics is size distribution, especially in the finer size ranges. When being emplaced underground, almost impervious layers of slimes separate from some types of mill tailings containing a high percentage of slimes and settle on the top of the sand fill. These coatings may be so dense that the water in the slurry cannot percolate through them for proper drainage. Successive layers of fill in a stope, each with an impervious coating on top, sometimes build up a hydrostatic head, creating pressure on the bulkheads. This may cause breaks in the lining material, inducing sand runs and flooding the level and sumps below. Deleterious slimes flocculated and disseminated throughout the sands should help prevent the formation of impervious slime layers, increasing percolation and settling rates.

Jan 1, 1960

By William F. Boericke

KIRKLAND LAKE and Porcupine in 1931 accounted for more than $41,625,000 of Ontario's total gold production of $43,117,688. For the first time, the younger camp surpassed the older in gold output, producing $21,734,000 against $19,891,000 for Porcupine. Present output of both camps is increasing, and should pass the record figures of 1931 before the year is out. In May of this year, Porcupine mines milled 285,759 tons, with a bullion value of $1,810,009; the corresponding figures for Kirkland mines are 149,188 tons and $2,104,757. A much higher average value per ton for Kirkland ore, $14.10 against $6.33 average for Porcupine accounts for the difference. The two fields are about 100 miles apart by rail, and there are important differences in the character of the ores, which accounts largely for the difference in milling costs and in final tailing values, despite excellent metallurgical work in both the fields.

Jan 1, 1932

By F. K. Shelton, J. C. Stah, Ruth E. Churchward

A study of the hydrometallurgy and electrowinning of cobalt from various domestic ores has been in progress at the Boulder City, Nevada, Experiment Station since February 1940. Previous reports covering certain phases of this investigation have been published. This report covers the research and pilot-plant work on the production of cobalt metal from cobalt-copper ores from the initial experimental work on crude ore through continuous operation. The ore types were from the Blackbird District, Lemhi County, Idaho. The initial tests were made with concentrated ore which was received by air mail and these experiments were expanded both in size and scope. After the laboratory was continued, improved, and extended tests were reported. Sufficiently advanced, a continuously operated plant producing 250 pounds of electrolytic cobalt per day was operated from June 15 through July 15, 1944.

Jan 1, 1948

By A T. Spathis, M G. Wheatly

Some preliminary dynamic pressure data were obtained from several charges detonated in a tunnel situated in massive granite rock. The context of the work is the potential for desensitisation of explosives, failure of detonators, and sympathetic detonation due to the close proximity of inter-hole and inter-deck explosive charges to each other. Dynamic pressures were measured using piezoelectric gauges in water-filled 45 mm diameter holes adjacent to the charges. Some of the first arrival peak pressures were noisy, and although not fully resolved, may be due to reflections and the physical arrangement of the transducers and their size with respect to the monitoring holes. The estimated peak pressures were between 0.1 to 8.7 MPa at approximate distances of 2.8 to 0.8 m, respectively. Further work is planned with gauges that are disposable, have a higher pressure range, and can be used within a few borehole diameters rather than the piezoelectric gauges used in the present work.

Jan 1, 2016