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By Christian L. Escalera

Over seven years ago, on October 29, 2012, Superstorm Sandy pummeled the Northeast of the United States inflicting heavy damage on New York City Transit’s (NYCT) system. Since then, NYCT has been methodically rehabilitating and hardening its assets to upgrade service and prevent future impacts caused by similar devasting storm surges. Part of these resiliency efforts, NYCT’s 207th St Yard Project is one of many projects that make up the Sandy Repair and Flood Mitigation Program. The work to be performed on the 207th Street Project includes building a perimeter Floodwall along the Harlem River, extending up 215th Street and 9th Avenue with the intent of having the ability to withstand a 500 Year Storm flooding event. The original 1,535 lineal feet of the marine side floodwall design consisted of 937 each W40x235 H-Piles continuously welded to PS 27.5 flat sheet to form an interlocked and composite steel seawall that would protect the NYCT 207th Yard from a storm surge of the Harlem River. However, after the Contract was awarded and a Notice to Proceed was issued, Walsh Construction Company II (WCCII) partnered with Mueser Rutledge Consulting Engineers (MRCE) to propose a redesign of the marine wall section as a Value Engineering Change Proposal (VECP). This VEP redesign is comprised of 279 each 54in Diameter Steel Pipe Piles that are interconnected with continuously welded PZ 35 sheet piles interlocks. The intent of the VEP was to provide a cost savings that could be shared by both parties as well as alleviate some constructability and alignment control concerns that WCCII had expressed to NYCT. The VEP allowed WCCII to substantially lower the total cost which was shared between NYCT and WCCII.

By R. Harris

Blister copper melts of 800 g to 1000 g containing less than 1 wt % S and up to 3 wt % Ni were desulfurized at 1523 K in air or by a pure oxygen jet blown at 75,500 and 1000 cm3/min, from 1 cm above the melt. Rates of desulfurization and oxygen pickup were measured and visible surface phenomena were photographed and videotaped. It was observed that SO2 was evolved from Cu-S melts in a manner reminiscent of the effervescence seen in carbonated drinks. The effervescence lasted up to 20 minutes and resulted in the ejection of material up to a height 50 cm above the melt surface. Sporadic discharge of large bubbles was also observed in a Ni containing melt top-blown with oxygen at 1000 cm3/min. The Cu-S melts top-blown with oxygen experienced faster sulfur elimination as compared to stagnant melts exposed to air and experienced only a single period of turbulent SO2 evolution, which occurred almost immediately after oxygen injection commenced. The Cu-S melts exposed to air experienced multiple episodes of effervescence. The stagnant blister copper melt containing nickel did not exhibit effervescent behaviour and experienced a lower rate of sulfur elimination compared to Cu-S melts tested under similar conditions. The present article examines the role of surface phenomena in determining the observed behaviour.

Jan 1, 1999

Except for uranium search, conventional oil well logging techniques are relatively little-used in mining exploration. The main reasons for this are cost and an apparent lack of awareness of the potential use of the methods in the search for ore. However, relatively inexpensive portable units are currently available for performing the simpler electrical and radiometric logs in diamond drill holes.The emphasis in oil exploration logging programmes is largely on the estimation of porosity. In most mineral work, however, porosity is not very significant, and factors such as mineral conductivity and radioactivity assume an important role.The Bureau of Mineral Resources (BMR) during a programme to explore for uranium and associated base metals in the area east of Rum Jungle, N.T., carried out electrical and radiometric logging of diamond drill holes as a routine part of their investigations. Case histories are described in which the logs were used to aid in defining stratigraphic sequences and transgressive structures in base-metal prospects. Some surface geophysicalanomalies were explained by the logging: induced polarization and electromagnetic anomalies were related to black slate; and self-potential anomalies were related to oxidation of pyrite black slate, or apparent electrokineticeffects in the black slate. The logs provided an objective appraisal of the rock units penetrated and thereby helped to differentiate lithologies.Borehole logging, including newer techniques such as downhole analysis, could be done in geological and geophysical investigations in other areas for a relatively small cost with a considerable potential gain of information.

Jan 1, 1978

By Kerry Lahti, Bryan Ulrich

On Feb. 11, 2005, more than 20 mining professionals gathered in Elko, NV for a day-long round-table discussion on heap leaching. Attendees included project managers, operators and environmental professionals. They represented 10 mining organizations. Knight Piésold sponsored the special event. Its seven representatives included three staff members from the company’s Elko Operation, and one each from its Denver, Cajamarca (Peru) and Vancouver offices. The roundtable format was chosen to allow people from the mining industry to share ideas and experiences in an open forum. Rather than presenting prepared talks, spontaneity was encouraged. This resulted in a lively and enjoyable discussion.

Jan 1, 2005

By C Haughy, F F. Pitard

Blue Mountain Minerals is a large supplier of calcium carbonate products used by various manufacturers as a major raw material. Very small amounts of free carbon in the rock can have a huge impact in carbon-sensitive applications. The marble in the deposit at Blue Mountain Minerals contains variable amounts of free carbon in the form of trace amounts of the mineral graphite.To make quality improvements, variography was used to measure the impact of non-ideal sampling practices at the Blue Mountain Minerals operations in Columbia, California in the United States. A major investment in correct sampling systems and sampling protocols was implemented over a one-year period. Subsequent variography was used to measure the improvement on the predictability of the graphite content in marble produced by the quarry and as it is processed as an acceptable raw material for extremely carbon-sensitive applications. The improvements of the sampling protocols, control of long-range changes and better knowledge of process cycles are easily noticeable on variograms when they happen to exist. The economic impacts are discussed.CITATION:Haughy, C and Pitard, F F, 2017. Use of variography to measure improvement of sampling practices for the quality control of graphite consistency in marble used for carbon-sensitive applications, in Proceedings Eighth World Conference on Sampling and Blending , pp 255–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Lingyun Zou, Xinghai Lei, Tiezheng Li, Yifei Song, Nan Wang, Yang Li

The stability of key strata is of utmost importance in ensuring safe and effective coal seam mining operations. To minimize disturbance impacts on these strata and ensure their stability, it is crucial to assess the degree of disturbance caused by mining activities. This study proposes the evaluation index “disturbance degree of key stratum (KSDD)” and establishes a quantitative KSDD criterion to measure the degree of disturbance on key strata. To facilitate the assessment process, an intelligent calculation system for KSDD is developed. The classification criteria are derived by combining the measured three-zone heights from multiple mines. The reliability and accuracy of the KSDD quantitative criterion are validated using field measurement data. Furthermore, the KSDD quantitative criterion is applied to the Meihuajing mining area No. 23, and the distribution characteristics of KSDD are analyzed. The findings of this study can serve as a valuable reference for reducing disturbance and enhancing the stability of key strata during subsequent mining operations. Overall, this work contributes to the field of ground control in coal seam mining by providing a comprehensive approach to assess and mitigate the disturbance caused by mining activities on key strata.

Mar 8, 2024

By R. M. Goktan

Rock brittleness plays an important role in the cutting action of picks on rock surfaces. It controls the ease with which cracks can propagate through the rocks. Although rock brittleness is known as a property that contributes to the cuttability of rocks, despite considerable research effort, there is still much uncertainty about the relation between rock brittleness and rock cutting efficiency. This fact can be attributed to the lack of a universally accepted brittleness concept and a brittleness measurement method. The existing publications of some researchers have, in a way, tended to confuse the understanding of brittleness in the general field of rock excavation where it is expected that the energy consumption of cutting should decrease with increasing brittleness of rock, other conditions being equal. However, this sometimes conflicts with the brittleness concept commonly used in rock mechanics, where the more brittle the rock the higher its mechanical strength. The ratio of rock compressive strength to tensile strength is considered by many authors to give a valuable brittleness index for drag pick operations. Hence, in this contribution the ratio of uniaxial compressive strength to tensile strength BI is considered as an index of rock brittleness, and a new methodology is proposed for its use in rock cutting efficiency analyses of drag tool operations. Validation of the suggested approach is supported by available experimental data in the literature. Contrary to the conclusions reached previously by other authors, it is shown that an increase in rock brittleness is accompanied by an increase in the cutting efficiency, other conditions being equal. Keywords: brittleness index, rock brittleness, cutting efficiency, specific energy, rock excavation.

Jan 1, 2005

By W. F. McDermott

One of the major improvements in ore grinding economics in North America has been the introduction of autogenous grinding. The history of this has been well documented in previous AIME presentations and in the literature. Pickands Mather & Co. has been very active in the development of autogenous grinding since 1957. This early work led to the application of autogenous grinding to the Wabush Mines ore in 1965, with the installation of 6-24 ft. diameter by 8 ft. long - 1,750 HP mills. Development work recently completed in 1971 on another ore has led to the decision to install 5-36 ft. diameter by 15 ft. long - 12,000 HP mills when this project goes ahead. Between these two decisions lies a tremendous amount of research, development, and application of autogenous grinding to a variety of ores. The Pickands Mather Metallurgical and Research Laboratory in Hibbing, Minnesota has tested, in its pilot plant facility, ores from 9 different deposits. Some of these deposits have as much difference within their own ore types as there is between the various deposits. Therefore, it is safe to say that over 20 different ore types have been tested and flowsheets developed for commercial applications. Of the 9 projects, 3 are in operation. These are Wabush Mines in Labrador, Canada, (1) Savage River Mines in Tasmania, (2) and The Griffith Mine in Red Lake, Ontario, Canada. (3) Pilot plant work has encompassed over 300 individual tests. These tests were carried out in mills that were 5-1/2, 8, and 12 ft. in diameter. Grinding power requirements for the primary autogenous milling has varied from 2 to 30 KWH/Lt of crude ore.

Jan 1, 1972

By Ken Wangerud

The benefits of historic mining to this country have been many, but have come at a cost to the environment that has only begun to be understood over the past twenty years. While estimates vary, it is generally recognized that there are over 200,000 inactive and abandoned hardrock mines, with most of them located in the western U.S. Only a fraction of them are believed to be sources of metal releases with significant adverse environmental effects to the watersheds and receiving streams. State water-quality and natural resource management agencies have noted that hundreds of miles of streams are metal-impacted, and the aggregate effects of these sites within watersheds and drainage basins is poorly understood. Resources for the environmental assessment of abandoned mine land (AML) sites and watersheds have been and continue to be limited. Few hardrock mining states receive substantial reclamation funds under the (coal) Surface Mining Control and Reclamation Act. EPA Region VIII (EPA8) has an estimated 90,000 abandoned mining, milling and smelter sites, mainly in Colorado, Montana, South Dakota, Utah and Wyoming. An estimated 13,000 of the sites may have metal releases causing Clean Water Act and CERCLA non-compliance. Results of inventories by states and federal land managing agencies, indicate it is plausible that only 3,000-4,000 of these sites may be causing significant environmental degradation.

Jan 1, 1999

By Mohammed Sakr

The use of helical piles as a deep foundation option has considerably increased in the recent years to support a variety of loads, from small loads for several applications such as residential housing, solar farms, utilities and retrofit projects, to large loads for many applications such as commercial, power transmission lines, oil facilities and industrial applications. Therefore, it is necessary to qualify and quantify their axial capacities and performance characteristics. This paper presents the first full-scale axial compression and tension (uplift) testing program executed on large capacity helical piles installed in cohesionless soils. A total of eleven pile load tests using either single or double-helix piles with shaft diameters that varied between 324 mm to 508 mm (12¾ in to 20 in) were carried out, including seven axial compression tests and four tension (uplift) tests. The results of the axial compressive and tensile pile load tests as well as field monitoring data of helical piles installed in dense sand are presented in this paper. Based on the results of this study it was found that helical piles have developed significant resistance to axial compressive loads up to about 2920 kN (656 kips) and tensile loads up to 2900 kN (652 kips).

Jan 1, 2011

By Donald F. Reed

In the Coastal Plain sedimentaries of northeastern Mississippi, high-alumina clays and kaolins, which are bauxitized locally to varying degrees, are found in many places along the contact between the Midway (Paleocene) and the Wilcox (Eocene) series. The trace of the contact extends from Tippah County, on the Tennessee border, south to Winston County, thence southeast to Lauderdale County, and into Alabama. Its length within Mississippi, disregarding sinuosities, is 185 miles (fig. 1). Commercial production of bauxite from the region has amounted to about 400 tons, shipped from one outcrop in Komper County. In December 1941 and January 1942, the Bureau of Mines and the Federal Geological Survey made a reconnaissance survey of the contact zone and selected the most promising areas for further study. In 1942, four areas in Benton, Union, and Pontotoc Counties were investigated by auger and rotary core drilling, and in 194, core drilling was done on five areas in Kemper, Noxubee, and Winston Counties. The present report records the work done by the. Bureau of Mines and the factual data obtained from the investigations of the nine areas in the two projects.

Jan 1, 1952

By C. H. J. Beaven, M. P. Jones

Since the various new techniques of automation and computing have enabled vast numbers of mineralogical observations of relatively small samples to be made cheaply and rapidly, the statistical assessment of these measurements has become of vital importance. Much of the theory and most of the procedures of sampling that are used in the mineral industry are based on Gaussian statistics, but modern measuring techniques show that many mineralogical parameters do not necessarily follow the Gaussian distribution function. Consequently, it has become necessary to examine the application of other, more suitable statistical methods in order to derive the maximum amount of useful information from the examination of mineralogical samples. Some of the errors that can be introduced by the use of incorrect distribution functions are discussed and the value of determining the function that is appropriate to the particular parameter that is being measured is shown. Examples are provided of non-Gaussian distribution functions in mineralogical materials that were encountered during prospecting and during mineral treatment operations: a Canadian uranium ore, a Thai tin ore, and gold ore tailings.

Dec 1, 1971

1. Book reviews Phosphate rock, a bibliography of world resources. London, Mining Journal Books Limited, 1984. £10 (surface mail), £12.25 (airmail). Reviewer: P.Le. Grubb Ok Tedi, by William S. Pintz. London, Mining Journal Books Limited, 1984. 206 pp. £19 (surface mail), £22.25 (airmail). Reviewer: R.P. Plewman 2. Publications of the Canadian Mineral Policy Sector Lime by D.H. Stonehouse. 5 pp. Phosphates by G.S. Barry. 9 pp. Statistical summary of the mineral industry in Canada. 77 tables. Talc by M. Prud'homme. 6 pp. Zirconium by M.A. Boucher. 6 pp. Cement by D.H. Stonehouse. 13 pp. Gypsum and anhydrite by D.H. Stonehouse. 7 pp. Regional review by T.M. Buch. 12pp. SaltbyG.S. Barry. 7pp. Silicon, ferrosilicon and silicon carbide by D.G. Law-West. 6pp. SulphurbyB.W. Boyd. 9pp. Mineral Report 31. Canadian Minerals Yearbook 1981. Available from the above address at $40.75 per copy. 3. Mintek reports Report M18D The recovery of pyrite and gold from acid-leach residues from the Merriespruit Gold Mine. (First issued Feb. 1982; reissued Mar. 1984). Report M2OD The separation of ore from Cooke into high- and lowgrade fractions. (First issued Feb. 1982; reissued Mar. 1984). Report M33D Explanatory tests on the reduction of the sulphur content of sponge iron. (First issued Apr. 1982; reissued Mar. 1984). Report M43D Beneficiation tests on andalusite-bearing shales from a farm near Thabazimbi. (First issued Aug. 1982; reissuedMar. 1984). Report M129 The determination of tin, niobium, and tantalum in pegmatite by X-ray-fluorescence spectrometry. ReportM131 The determination of copper and nickel in iron- and chromium-bearing materials by a pressed-powder technique and X-ray-fluorescence spectrometry. Report M135 The installation of a 100 kV A plasma furnace at Mintek. The selection and installation of a 100 kV A a.c. plasma Report M136 The determination of gold in activated charcoal by use of a loose-powder technique and X-ray-fluorescence spectrometry. Report M140 The effect of physical and chemical factors on the corrosivity of a synthetic mine water.

Jan 1, 1984

By P. R. Segopolo

"The purpose of the project is to convert current shuttle car utilization on an underground coal mine to best practice by focusing on change-out points and tramming routes, which have a major influence on shuttle car away times. Time studies were an integral part of the project as these enabled the determination of shuttle car away times. An indirect proportional relationship between shuttle car away times and productivity is established. Through the time studies, it is deduced that a third shuttle car will make an insignificant contribution to production when there is only one split open. During this time, maintenance on the third car can be optimized. In order to satisfy the mine’s key performance indicator of keeping shuttle car away times less than 75 seconds, a belt extension must be scheduled after the third split is open. It is established that at any given time, a minimum of two shuttle cars should be used. When cutting on the left-hand-side of the belt road with only two shuttle cars available, the centre and left (left of the feeder breaker) shuttle cars should be used for coal hauling. When cutting on the right-hand-side, the centre and the right-hand-side cars should be used. If only one shuttle car is available, the centre car is the most efficient to use. Alternative anchoring configurations can be employed so as to enable cars (left or right, especially) to reach the opposite extremities of the panel and hence minimize cable length restrictions. Paper written on project work carried out in partial fulfilment of BSc. Eng. (MiningEngineering)"

Jan 1, 2015

By Maurice Deul

For the first half of the 21st century, the United States will rely on the same mix of fuels it has for the past 50 years. Petroleum for the United States will cost more and availability will decline as developing nations modernize. Increased use of natural gas for electric power generation will result in stress on the gas supply. Coal will be the fuel of last resort. More than half the petroleum used is imported, about the same amount as used for transportation. Only coal can provide relief by fueling railroads through electrification while encouraging “piggy-back” trailer haulage, co-generation for manufacturing and expanded passenger service.

Jan 1, 2002

By Luis Maldonado

El presente trabajo señala el desarrollo y aporte de la geotecnia en la minería subterránea, particularmente de la mina Ares, así como define algunos conceptos importantes empleados para determinar los diferentes tipos de refuerzo y/ o sostenimiento utilizados.También evalúa la estabilidad de las labores subterráneas y la elección de un sostenimiento apropiado por zonas delimitadas en los planos geotécnicos. En ese sentido, para la sistematización, cuantificación y calificación de las características geomecánicas de los macizos rocosos, se evalúa las propiedades del macizo como la combinación entre las características de las rocas y sus discontinuidades. De forma que se pueda determinar una cuantificación geomecánica que dilucide el sostenimiento y el método de excavación en base a la más adecuada clasificación requerida.

Sep 13, 2001

By D Connelly

Magnetite orebodies generally means mining lower grade iron ores, crushing and grinding with significant energy costs in processing and the capital costs being significantly higher than for direct shipping ores (DSO). Overseas, the mining and processing of magnetite ores has a long history of production due to the lack of DSO deposits. This raises the question as to why the new magnetite projects have been so problematic and also whether there is a future for the long list of potential magnetite projects in Australia.The quality of the magnetite concentrate product is superior to most DSO products and the magnetite contains energy benefits when converted to hematite in sintering or pelletising. The industry’s hopes for new projects have been dashed and questions are being raised as to the financial viability of such projects.A comparison of Grange Resources Savage River, Arrium’s Project Magnet, the Sino Iron Project and Gindalbie’s Karara Iron Project is used to understand the differences between the projects and why some are more successful than others.CITATION:Connelly, D, 2015. What is the future for magnetite projects in Australia and why have some of the new projects been so problematic?, in Proceedings Iron Ore 2015, pp 107–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By C. Frenzel

Tunnel boring machines (TBM) utilize disc cutters as the primary means for excavating hard rock. Depending on rock excavatability and rock abrasivity disc cutters can exhibit significant wear. A detailed analysis has been carried out to characterize failure modes and wear patterns of disc cutters. The relationship between rock properties, op-eration of the TBM, and failure modes of cutting tools is clearly high-lighted. On that basis a prediction tool for disc cutter consumption has been developed that allows to estimate not only gross cutter life, but accounts for cutterhead design, premature cutter changes, and disc cutter repair costs.

Jan 1, 2011

By Launa G. Mallett, Charles Vaught, Dana C. Reinke, Lisa J. Steiner, Lynn L. Rethi, Kathleen M. Kowalski-Trakofler, Jr. Brnich, William J. Wiehagen

Safety and health professionals recognize that training is a critical element of any effective safety and health program. An extensive literature survey has led the authors to conclude that we are at the beginning of a revolution in training due to changes in the demographics of the workforce, the rapid growth of technology, and the universal ascendance of the information age. Of present major concern in the mining industry is how to provide appropriate training for an aging workforce and concurrently develop training for the expected influx of new and less experienced miners as older workers retire. This report explores the key issues in the changing safety and health training area as identified by the multidisciplinary team of NIOSH researchers who conducted the literature survey. Issues include generational differences between newer mine workers and the present workforce with respect to their physical, psychological, social, and cultural characteristics; their learning styles and work expectations; and the impact of technology. Some preliminary conclusions are offered for future training needs.

Jul 1, 2004

By Christopher R. Lattanzi

"Discounted cash flow analysis provides a means of relating the magnitude of expected future cash profits to the magnitude of the initial cash investment required to purchase an asset or to develop it for commercial production. The objectives of discounted cash flow analysis are to determine:.. The net present value of a stream of expected future cash revenues and expenditures... The rate of return which the expected future cash flows will yield on a given level of initial cash investment.In the case of mineral properties, discounted cash flow analysis is generally accepted as the preferred method of valuation, whenever sufficient data are available to permit its reasoned application. Sufficient data are required to support estimation of all of the individual elements of cash revenue and cash expenditure which will be associated with the development and operation of the property, up to the end of its estimated life. It is the accuracy of these input estimates which determines the validity of the resulting determinations of profitability and rate of return on invested capital.In undertaking any discounted cash flow analysis, it is important to recognize certain fundamental attributes of the mining industty:.. The basis of any mineral development is the existence of an ore reserve... Costs are determined by the number of tonnes mined and processed, while revenues are determined by the number of pounds or ounces of metal produced. The two are related by the recovered grade of the ore... Profit is typically more sensitive to changes in revenue than it is to changes in cost... Commodity price is a principal determinant of revenue, but it is also the factor with which is associated the greatest level of financial risk.In the end, of all of the factors which must be considered in the discounted cash flow valuation of a mineral property, the most significant are the reliability of the reserve estimate, particularly with respect to recovered grade, the price at which the product is to be sold, and the risk of not maintaining the projected level of price."

Jan 1, 2003