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By Bennett McLaughlin

AGNICO-EAGLE started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1,800 tonnes per day from a 2,240 metre deep shaft. Exploration success lead to the installation of a hoisting plant capable of extracting 4,500 tonnes of ore and 1,800 tonnes of waste per day from a depth of 2,210 metres. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

May 1, 2001

By R. Sprycha, J. Szczypa, W. Janusz, J. Neczaj-Hruzewicz

INTRODUCTION Because large aqueous suspensions of various fine solids originate during the beneficiation of ores, the Mining Industry constantly requires efficient and feasible dewatering methods. Among the techniques currently in use (1,2), filtration (vacuum, press) and centrifugation are fairly expensive and thus are limited to use with more valuable materials. Furthermore, installations of reasonable size produce only moderate outputs. Therefore, tailings from ore dressing plants are usually treated by sedimentation or settling techniques with a tailings dam as the ultimate sedimentation basin (3). Apart from growing environmental and economic questions, the solid product obtained from the tailings dam basin has in most cases, a rather high moisture content and a persistent semi-fluid consistency. Thus, it is difficult to transport and use further. On the other hand, the solids may be utilized as a filling material, fertilizer, etc. providing they are dry enough and properly granulated. Demands for an improved technique are met to a great extent, by the technique presented in this paper. AGGLOMERATION OF FLOCCIJLATED SLIMES Origin and Qualitative Description of the Process Phenomena of consolidation and pellet formation in flocculated fines were first observed by Yusa and Gaudin (4) while studying rheological properties of flocculated kaolinite. On this basis, methods of separating liquid from solids have been worked out (5-7) and many possibilities for application have been suggested (5,6). Yusa termed the technique "wet pelletization''.

Jan 1, 1980

By N J. Grigg

Gekko Systems has developed an underground pre-concentration plant (Python) to reduce mine operating costs. Many ores liberate favourably using either high pressure grinding rolls (HPGR) or vertical shaft impactors (VSI). Using these comminution circuits for mineral liberation; rather than for the final recovery process and by utilising a high mass pull, high recovery process route (gravity/flotation), a narrow, low head, compact processing plant was developed that can sensibly be operated underground. The Python underground processing plant can provide a number of advantages for narrow vein mines including lower haulage costs, improved mine call factor and lower operating costs. The focus on fine crushing reduces the power requirement of the plant to approximately 8 kWh/tonne. The Python underground processing plant has been designed to be towed down the decline or lowered down a shaft, and is capable of being installed in sloping, non-linear drives for placement close to the working face. The overall benefit to mining companies of this concept has been estimated to be a saving in mining costs and a significantly smaller environmental footprint.

Jan 1, 2008

By Cathy Aimone-Martin, Brent Meins

A comprehensive instrumentation program was implemented at the Howland Hook Marine Terminal on Staten Island, NY during proximate underwater rock blasting in 2014. Forty-two blasts took place over a 4-week period to deepen the 1200-ft (366 m) Berth 3 from -45 ft (-14 m) to -50 ft (-15 m) MLW to accommodate Post-Panamax vessels. Approximately 86,000 yd3 (65,752 m3) were blasted 120 to 9 ft (37 to 2.7 m) from the wharf to a total depth of -57 ft (-17.4 m). Pre-blast planning included developing and implementing a comprehensive monitoring plan and setting vibration and strain limits to protect the wharf. The plan outlined methods to measure vibrations on five corners of four concrete deck sections, on five concrete-filled pipe piles just below the pile cap near deck corners, and in bedrock adjacent to pile sockets. Water overpressures were measured near instrumented piles for 19 blasts closest to the wharf. A total of 19 geophones were secured to the wharf structure and buried 12 ft (3.7 m) in drilled holes.

Jan 1, 2016

By Jon Kellar, Samuel Kessinger, Prasoon Diwakar

Tantalum (Ta) and niobium (Nb) are extracted from many different ore types. The major economic orebody mined for tantalum and niobium consists of tantalite ((FeMn)Ta2O5) and columbite ((FeMnNb2O5)) in a solid-solution mineral commonly referred to as “coltan.” The largest supplying region, The Democratic Republic of the Congo (DRC), is unfortunately also the most ethically compromised source for this critical mineral. Officially, the U.S. government has deemed coltan ore from the DRC a “conflict mineral” [1]. The lack of pragmatic and effective local mining regulation in Central Africa, when coupled with high levels of violence and corruption, has spawned a widespread, illegal, unethical and, most importantly, unsafe economy. This illicit economy is centered around first, illegally mining these valuable conflict minerals and second, smuggling these minerals into the global supply chain. Handheld spectroscopy devices could provide further transparency to these opaque supply chains, giving miners, traders and refiners the ability to authenticate the provenance of the minerals they encounter, and allowing companies to prove compliance with the regulatory agencies attempting to curtail illicit mining.

Mar 1, 2025

By William J. Cavanaugh

In 1967, Lone Star Industries, Incorporated, established a program to carry out the necessary Research and Development work to bring the Snyder Process to commercial application. The purpose of this paper, is to present the detailed metallurgical results gathered in comparing the Snyder Process of Comminution to conventional grinding techniques for the milling and beneficiation of certain ores and other materials. The ore primarily dealt with in this paper is a fine-grained magnetite ore, containing approximately 23% acid-soluble iron, from the Lake St. Joseph ore body of Steep Rock Iron Mines, Ltd., (Canada). This particular example was selected for presentation in this paper because extensive comparative results with conventional methods of grinding were available. Also briefly described in the paper are the comminution of other ores and materials such as porphyry copper ore and alumina.

Jan 1, 1973

By J. O?Hanlon

The 4500 m3 blast furnace at the Redcar Works of ESC operates or, a burden of sinter and pellets, both materials being produced within the works. The early history of the furnace was given to the AIME Ironmaking Conference in 1981(1) when the burden was 65% superfluxed minter and 33% acid pellets. While ironmaking performance was adequate, it was felt that there were advantages to be gained by the use of fluxed pellets. For example, Kobe Steel had reported (2) that the rise of 30-50% dolomite fluxed pellets had enabled them to achieve better furnace permeability, higher gas utilisation, and enhanced ore/coke ratios. It appeared probable to BSC that the use of magnesia-bearing fluxed pellets would give a burden which had compatibility of softening and melting properties, i.e., fluxed sinter and dolomite pellets would result in a thinner cohesive zone because of closer matching of softening and melting temperatures, with consequential benefits on furnace stability and efficiency.

Jan 1, 1983

By Desiree Willis

One of New York City?s largest subway projects is under way 43 m (140 ft) beneath the surface of downtown Manhattan. The East Side Access project, more than 30 years in the making, was halted after a partial excavation in the 1970s due to a lack of funding. The project, once dubbed the ?Tunnel to Nowhere,? has been revitalized into a groundbreaking subway line that includes unique tunnel boring machines (TBM), construction methods and muck removal systems. Project overview The East Side Access project involves construction of a new 6.7-km (4.2-mile) subway line needed to relieve heavy traffic congestion between the boroughs of Queens and Manhattan. The line will serve approximately 160,000 commuters daily between Grand Central and Sunnyside rail stations. Manhattan and Queens will be connected under the East River by the 63rd Street tunnel, a submersed double-decker tube. The submersed tube consists of reinforced concrete sections barged in place on the riverbed. The tube contains operational subway lines on the top deck, while the bottom deck (the ?Tunnel to Nowhere?) will become operational when the East Side Access project is completed in 2013.

Jan 1, 2008

By S. Dessureault

Computer Integrated Mining (CIMG) is a process of using computer networks to transform islands of enabling technologies into a highly interconnected mining system. CIMG involves the integration of advanced technologies at various levels in the mine business to achieve higher flexibility, better quality of processes and control, and improved profitability. Justifying the benefits of CIMG are difficult as many of the advantages are derived from improved flexibility, quality, and control. Justification is based on the evaluation of the benefits to be gained, compared to the required capital investment. Management tools used in mining are currently inadequate in assessing the value of advanced technology whose benefits are primarily qualitative. A key aspect of successful implementation is management acceptance, which has to be won through the capability to justify the technology's financial costs and the true value of all of its benefits. The manufacturing industry faced similar justification difficulties when adopting advanced technology in factories. A significant amount of funding and research was invested into developing management strategies and approaches to justification. Many of the problems that faced the transformation of the manufacturing industry in the late eighties and early nineties are now facing mining. The solutions derived for manufacturing may help mining in its transition to an increased reliance on integration technology. Reviewing the industrial history of computer integrated manufacturing identifies several tools and strategic frameworks that can be adapted for mining. Keywords: Computer integrated mining, justification techniques, CIM, information technology.

Jan 1, 2003

By T. M. Tharp

Attempts to analyze the stability of slopes, foundations and underground openings in discontinuously jointed rock have generally assumed full joint continuity or ignored the role of stress concentration at the tips of discontinuous joints. The most common approach in rock slopes is to consider a failure plane consisting of coplanar, but discontinuous joints separated by intact rock. The intact rock is assumed to fail in shear as a MohrCoulomb material and to contribute a strength component proportional to the fraction of the failure plane that is intact rock (Jennings, 1970). An alternative approach by Stimpson (1978) applies Lajtai's (1969) theory for shear strength of discontinuously jointed rock masses to slopes. Lajtai allows tensile failure in the intact rock of a composite surface. This theory yields lower shear strength than that of Jennings (1970) except in the presence of high normal compression, however it also fails to account for the stress concentration at the tip of a discontinuous joint. For a given slope geometry, stresses increase with slope height, but in both of these models rock mass strength is independent of size. A fracture mechanics analysis shows that particularly for small slopes, rock mass strength decreases with size.A continuous stepped failure surface produced by propagation of preexisting joints may develop at lower shear stress than pre¬dicted by the Jennings (1970) or Lajtai (1969) models. This fracture mechanics model applied to slopes in competent rock is more realistic in its assumed failure mechanism, and for large slopes more conservative than the Jennings (1970) or Lajtai models (1969).

Jan 1, 1984

By A. U. Seybolt, R. E. Honnemon

THE purpose of this communication is to present activity data of nickel in the Ni-A1 binary system that was obtained for oxidation studies in this system. This data has been calculated from previous aluminum activity data at 1000°C1,2 by two types of Gibbs-Duhem integrations. These results should be of particular current interest to oxidation studies of aluminide coated nickel-base superalloys3 as well as other problems. The aluminum activity of Steiner and Komarek1 is plotted in Fig. 1 as a function of composition in Ni-A1 alloys at 1000°C. The dashed parts of the aluminum curves represent our approximate extrapolations from the directly measured regions. In the terminal solution regions (a and L phases) standard parabolic solution functions of the following form are assumed: where i is the component subscript, Ki is a constant at a fixed temperature, and xi is the atom fraction. The resultant nickel activity curve at 1000° C from the Gibbs-Duhem integration4 of the aluminum data is shown in Fig. 1. The solubility ranges of the phases present in the Ni-A1 binary at 1000°C are also denoted at the bottom of Fig. 1. Corresponding values of the nickel activity, aNi and yNi, are listed in Table I at useful compositional intervals. including phase boundary values. The aNi and yNi data listed in Table I are subject to the uncertainties present in the experimental aluminum activity data1 and to deviations from parabolic solution behavior in the terminal solutions. The errors introduced into aNi and yNi due to the parabolic solution assumption are expected to be relatively small (<20 pct of the values given) in all the phases except the liquid phase. Some deviation from parabolic solution behavior in the liquid phase is indicated

Jan 1, 1970

By V Ser, R Crosbie

To date, Anglo American Research Laboratories (AARL) has carried out several projects, based on the techniques developed in AMIRA International LimitedÆs (the mineral industries research association) AMIRA P9 project, to develop models for several Anglo Base Metals flotation plants. Further detailed analysis of the data which was generated has realised additional benefits: the various hydrodynamic measurements were useful in comparing cell operating parameters to literature sources, while the laboratory batch tests give an indication of plant recovery potential. A detailed cell by cell mass balance, which is a critical feature of the modelling process, is in its own right a valuable diagnostic tool. Several examples of how this can be used to highlight potential improvement areas in the plants are presented. The added understanding gained from sampling each cell is clear and this is shown to more than compensate for any necessary modifications needed to allow sampling to take place. The model fitting process generates an ore floatability distribution, which is used in the JK SimFloat simulation package to assess the effect of possible changes to each of the circuits. An example of an actual circuit change as a result of this approach is presented. The current limitations of and the potential improvements to the modelling process are also briefly discussed. Future models will be extended to include enhanced size and mineralogical information where the basic models suggest this has potential to improve understanding.

Jan 1, 2005

By D. Harker, M. J. Murphy

The mechanism by which age-hardening takes .place is still not completely understood. The principal theories range from the extreme of "precipitaiion-hardening" to that of "order-hardening," with many intermediate gradations. In the hope of obtaining new data on which to base a choice among the many theories, the authors have made electron micrographs of formvar replicas taken from metallic specimens at various stages of age-hardening. The results so obtained on an alloy of 2 per cent beryllium in copper and one of 20 per cent molybdenum in iron will be described in the following pages, as well as the technique used in preparing the replicas. Preparation of Formvae. Replicas of Metallic Specimens This section is concerned with the techniques that have roved successful in preparing formvar replicas for studying the microstructure of metals with the electron microscope. Because of its simplicity and accuracy, the formvar replica1 method developed in the General Electric Research Laboratory has been used exclusively, since it is much simpler than the silica replica method of Heidenreich and Peck2 and produces as good results. The formvar method to be described requires a technique acquired only by practice, and no foolproof set of rules can be given. it is a rapid method and a replica can be obtained in less than five minutes under favorable conditions. This does not mean that perfect replicas can be produced every five minutes, but rather that one can well afford to take several strippings* in order to produce a replica of high quality. The metallographic technique required for replica work—very fine polishing and etching with very dilute solutions—is described here. It can be said, in general, that almost any surface that has been carefully prepared for a photomicrograph at 1000 or more diameters can be used to obtain a replica for the electron microscope. Preparation of Metallographic Specimens The preparation of the metallographic specimens is somewhat more exacting than that usually given to samples to be used for inspection under the light microscope. After much experimentation, it was concluded that the best method consists in polishing the metal through to the coarse cloth, then etching and repolishing on final cloth until the layer of distorted metal is removed. After this procedure has been completed, a dilute etch—to approximately the depth necessary for a micrograph at 1000 diameters—usually produces a sur-

Jan 1, 1945

By Uusna S, Canning R. G, Goodheart B. A

The development of a process for removal of iron oxides from ilmenite is outlined whereby the Ti02 content of Western Australian ilmenites can be upgraded from 55 to approximately 90 per cent. In the first stage, the iron oxides are reduced with solid carbon (coal) to metallic iron. Experimental reductions were carried out in crucibles, a fluidized bed, and a small pilot plant rotary kiln. The reduced ilmenite was then agitated in aerated water, in the presenceof catalysts, so that the iron &quot;rusted&quot; away from the ilmenite grains and the precipitated iron oxide was easily separable by decantation.The influence of variables on the rates of reduction and oxidation are discussed. The oxidation rate was examined for both the physical oxygen transfer characteristics and electrochemically by reference to Pourbaix diagrams, in which redox potential is plotted against solution pH.The upgraded ilmenite is expected to be an attractive material for pigment manufacture, and the iron oxide has prospects of being a marketable by-product. The process may possibly be applied to other ores.INTRODUCTIONThere are extensive deposits of ilmenitic beach sands, Le. iron titanium oxides of the general formula FeTi03, &apos;occurring in the lower south-west portion of Western Australia, and although there has been considerable commercial development, local producers face keen competition on a freight-cost basis. Thus the removal of the unwanted iron oxide constituent would have the double advantage of reducing the freight differential and presenting a more attractivematerial to pigment manufacturers.

Jan 1, 1965

By Stephen C. Tadolini, Dennis R. Dolinar

The risk of injury caused by minor roof falls continues to increase in underground mining. Most ground control injuries result from small rock falls that occur in a supported area, but do not involve the failure of the support system. In the roof, these are the "skin failures" that occur between previously installed primary or secondary bolting systems. To minimize skin failures and the associated accidents, several devices were designed and tested in the laboratory to maximize stiffness, minimize material thickness and weight, and ease material storage and handling on roof bolting machines. The goal of this project was to design and evaluate devices that can be installed with traditional primary or secondary roof supports, and that are easy to handle/install under temporary or previously supported roof.

By Ronald L. Pariani

To date, significant advances have been made regarding the development and commercial implementation of full deposit stripping in the copper industry such as practiced at Copper Refineries, LTD in Townsville, Australia. The paper describes the history and current practice of Electrowinning (EW) plants which may be coupled with solvent extraction. The modular nature and degree of automation are described in relation to the various sizes of operations. Reference is made to the expansion capability of commercial equipment plus associated economics of the mechanical processes for producing full cathode deposits. It is recognized that the technology described may be adaptable to other nonferrous refining areas where feasible. The paper highlights the state of the art in mechanized stripping equipment as applied to current and planned SX-EW plants.

Jan 1, 1987

By D. W. Wu, M. T. Haque

A novel impedance probe has been commissioned specifically for capturing fast dynamic information about filtration processes. It provides an attractive alternative to more complex measurement techniques in situations where the slurry system is primarily one-dimensional. The probe can monitor mud-line, slurry densification and drainage. Dynamic variations in cake permeability are obtained by combining dynamic mud-line information obtained with the probe and filtrate rate data derived from a leaf test apparatus. The measurements are re-viewed in relation to micro structural measurements obtained on iron ore filter cakes. The practical significance of these measurements for optimization of the filtration process is discussed.

Jan 1, 2000

By W. T. Thom

RegaRding the elements necessarily involved .in working out a scientific scheme of classification, Stansfield and Sutherland, (94)† quoting Grout, (34) make the following statement: All bases (for a scientific classification) should be capable of quantitative determination, or be exactly related to some property capable of such a test, so that, if no natural groups are found, arbitrary lines may be drawn to limit the classes. The best basis for classification should involve inherent and fundamental qualities of the materials considered. Allied to this is the requirement that advantage should be taken of any natural grouping. As a further help in selection, the bases or tests should be easily applied, widely known, and have a wide range of values in the material classified. In order that we may apply the philosophy thus expressed, it is necessary for us to have clearly in mind both the reasons why coals differ and the specific purposes to be served by the classification to be devised. Coals differ because, as modern science has shown, coal beds are actually neither more nor less than buried and altered peat deposits, formed in remote geologic time. And as is generally known, such peat beds consisted of masses of partly macerated and decayed trees, shrubs, plants, mosses and/or algae, deposited under swamp or semiswamp conditions. It is therefore to be expected that coals will vary: 1. Because of differences in the parent vegetation, due either to evolutionary plant changes, as from the fernlike types of the Paleozoic to the coniferous and hardwood types of the late Mesozoic and Tertiary; or due to the differences in floral assemblages (growing at the same time) induced by differences in local environmental conditions. For example, moss, sedge, woody and other peats are today accumulating simultaneously in different bogs in North America. 2. Because of differences in the stage to which bacterial decay proceeded in the peat bed. Peats laid down in stagnant waters suffer

Jan 1, 1932

By Craig Haase

A. Introduction

Jan 1, 2003

THE slide-rule, as a quick and convenient instrument for performing approximate calculations, is steadily growing more and more into favour with the engineer, and results obtained by it are considered close enough to enable him to satisfactorily dealwith a considerable portion of his work. To the surveyor, however, whose ordinary computations must be as precise as his measurements, the present makes of rule are insufficient, except for a very narrow margin of the scales and for rough work. Few will carry the rule when they can clearly see that it is unreliable for general routine, and the careful surveyor is inclined to look askance at those who do use it, recognizing the temptation there undtmbtedly must be to push it into work that the log book should be called upon to treat. From the fact that a surveyor&apos;s duties take him on the surface in all weathers, and underground in many wet and uncomfortable places, where the manipulation of a book of mathematical tables becomes both awkward and patience-trying, an efficient slide-rule must offer the mbst transparent advantages. Again, a surveyor being specially trained to read divided scales quickly and accurately, the slide-rule must commend itself as an apt addition to his outfit.

Jan 1, 1912