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By Harry E. Holzschuh

The two Agrico Chemical Company self unloading Phosphate Rock barges put into service in 1976 operate at over their design carrying capacity. Each barge now carries 26,000 short ton instead of the planned 25,000 short ton at 32 foot of draft. They are in service between Agrico's Tampa, Florida Terminal and the Donaldsonville, Louisiana Fertilizer Complex, moving a total of 2,500,000 short tons each year. This was the first use of the Parascrew design for a marine application. The barges, with their 3,000 STPH unloading and matching loading rate is the vital link in this total transportation and handling system. Rock is moved from the Pierce, Florida Mines through the Tampa Big Bend Terminal, across the Gulf of Mexico, and up the Mississippi to the Agrico Faustina Phosphoric Acid Plant 30 miles below Bacon Rouge, Louisiana. The trip from the terminal to the plant is 600 miles and the turnaround time is just about six days. Seven years operating experience has proved that the system works. Fittingly, the two barges are named the "Faustina" and the "Pierce". They have a beam of 85-feet and are 495 feet long. folded depth is 43 feet, with a ballasted light draft of 19 feet and a typical loaded draft of 32 feet. There are four separated holds with the machinery room located forward of 101 hold. Each hold is 51 feet wide at the coamings with an 18 foot straight section on the side, and a 24 foot long, 600 slope sheet for a 23 foot clear reclaim width at the bottom. The Parascrew in each of the holds is 37 feet long between the bearings and is supported on a 14 inch diameter hollow shaft. The screw pitch varies and the diameter of the flights step up from l'-9" diameter to 2'-6" diameter on the discharge end. By sloping the centerline, a minimum four inch bottom clearance is maintained across the hold. Some bending of the tube does take place.

Jan 1, 1983

By S. H. Ash

NINE-TENTHS of the total anthracite deposits of North America are in Pennsylvania. Corrosion of pumping equipment by acid mine waters has been experienced at tremendous cost by mining companies in the anthracite region of Pennsylvania, for many years in many ways. The design and specifications of the large centrifugal pumps as provided in the proposed mine-drainage system (7-35, 45, 46, 48, 54, 64, 70, 71)° make it imperative that a metal or alloy be recommended that has the highest corrosion resistance and, at the same time, acceptable properties suitable for general workability (welding and machining). This report presents data on the corrosive and erosive effects of acid mine waters in the anthracite region on metals and alloys for pumping equipment and drainage facilities necessary to remove or control this water.

Jan 1, 1955

By P. Huang, D. W. Fuerstenau

Various factors that control the natural flotability of talc, including differences due to crystal face and edge effects, were delineated. For study of talc depression phenomena, dextrin was used as a model depressant. For the enhancement of talc flotation, dodecylammonium acetate (DDAA) was used as the collector. The interaction of DDAA with talc was assessed by flotation experiments and electrokinetic (zeta potential) measurements, from which the role of hydrophobic bonding can be demonstrated. The results presented in this paper provide useful information on how the crystal chemistry and surface chemistry control the electrical double layer, adsorption phenomena, wettability, and flotation behavior of talc in aqueous media.

Jan 1, 2003

By William A. Hustrulid

A technical and economic evaluation of the potential for improving mining productivity through the use of underreamers in blastholes, specifically in relation to Minnesota taconite, Arizona surface copper and in situ mining operations is presented. Included are (1) a review of the drilling and blasting practices presently being used, (2) a discussion of current underreamer technology. (3) the presentation of a general economic cost model for underreaming, (4) the application of the model to surface taconite, surface copper and in situ mining, and (5) a summary discussion including required performance specifications, potential overall benefits, and recommendations for further development.

Jan 1, 1977

By Robert L. Lagace

This final report documents the work done by Arthur D. Little, Inc. (ADL) on behalf of the U.S. Bureau of Mines, Pittsburgh Mining and Safety Research Center (PMSRC), on Contract R0122026 (which began in August of 1971). Under this contract ADI provided technical assistance to the Bureau on a task basis on virtually all aspects of the Bureau's programs related to present and planned emergency and operational communications and miner location systems for underground coal mines. The work consisted of independent investigations, analyses, experiments, breadboard and prototype hardware development, workshops and technology transfer seminars on mine communications, and on-going evaluations and guidance related to the Bureau's contracted programs on electromagnetic noise, mine communications systems, and trapped miner location. This final report documents the work in two volumes, Volume I, "Emergency and Operational Mine Communications," and Volume II, "Seismic Detection and Location of Isolated Miners." The Tables of Contents of both Volumes are included in each Volume. Phase I of the contract was devoted to performing an in-depth assessment of electromagnetic noise measurements taken by several contractors and other investigators, and then defining a new noise measurement program and instrumentation system tailored to obtain the necessary but missing noise data. These data are required for use in the design of new emergency and operational communication systems. This work, and the follow-on coordination and guidance activities of ADL on this noise measurement program in subsequent phases of the contract, are treated in Part One of Volume I.

Jan 1, 1974

By A. V. Nozhkina

"Transformation of diamond into graphite was investigated in the region of diamond metastability under the action of media chemically active relative to carbon in the temperature range from 770 K up to 2200 K and pressure range from 10-3 Pa up to 3 GPa/IV VIII group metals of periodic system and oxygen were used as media chemically active relative to diamond.Methods of electron diffraction, chemical analyses, emission spectroscopy and X-ray phase analyses were used for determination of the reaction products.It was found that in the region of diamond metastability the stage of catalytic phase transformation of diamond into graphite took place during the interaction between diamond and metal. Metal reduce activation energy for transition of diamond into graphite from 109,4 kcal/mole to 77,4 kcal/mole.Kinetic of phase transformation of diamond into graphite was investigated.Pressure does not considerably influence on the rate of phase transformation of diamond into graphite in the presence of transition metals."

Jan 1, 2003

By R. S. Simkus, J. R. Egan

"Changes have recently been applied to the Sullivan Concentrator lead and zinc circuits to treat fine-grained ores which make-up the majority of ore reserves in the mine. Pilot plant test work conducted in 1990-91 indicated that concentrate grades would be substantially improved by reducing the particle size (P,0) of the lead from 38 to 15 µm and the zinc from 45 to 24 µm.Circuit revisions involved installation of major new equipment including: two GUO kilowatt Vertimills for regrinding, a 4 metre diameter column flotation cell and a 4 metre diameter hyperbaric pressure filter for dewatering. Duties of the existing regrind mills were reassigned.IntroductionThe Sullivan ore body is a massive sulphide deposit consisting of fine grained mixtures of sulphides, sometimes inter-banded with country rock and varying widely in their content of lead, zinc, iron and silicates. Principal economic minerals are marmatite and galena. Iron is mainly present as pyrrhotite (85%), and to a lesser extent as pyrite (15%) .The orebody has been actively mined since 1923, with 1992 ore reserves estimated at 15,800,000 tonnes with an average grade of 4. 7% lead and 7. 9% zinc. Current plans call for treatment of 1,600,000 tonnes/year, (7,000 tonnes per operating day), with flotation feed grades of 5.9% lead, 10.1% zinc, and 22.0% iron."

Jan 1, 1994

By Christoph Mueller

Mining operations today are characterized by a high degree of mechanization and single machine automation. However, their potential for cost cuttings and increase of productivity in the future is quite limited. Enabled by newest IT and networking technology, the operation of underground mines more and more can be seen from a process related point of view: Standardized Ethernet and Wireless LAN are the basis for a seamless and unified communication backbones providing an integrated infrastructure for data, telephony and video. All the components are available as off-the-shelf devices leading to an excellent cost efficiency. Basing on this standardized infrastructure, the equipment is able to become part of the infrastructure. To enable machines to be integrated smoothly into IT networks, the machine also has to have enhanced networking capabilities. This results in a new system architecture for the on board machine electronics separating real time control from IT and networking level functionality which can be implemented by a Machine Server. This machine server communicates with all kinds of above ground systems using mainly standardized formats like html or the IREDES standard. This information is made available mainly in 3D mine visualization tools. The paper explains this technology and shows implementations by two working examples.

May 1, 2006

By Wilbur I. Duvall

In a review of so 40 papers on damage to residential structures resulting from blasting, only 3 were found that present data on the observed amplitude and frequency of the vibration levels produced by blasting together with an observed degree of damage to a residential structure. The data from these three reports have been analyzed statistically to determine if one of the quantities, displacement, velocity, or acceleration, is more reliable than the others for estimating the degree of damage to a residential structure. From this analysis the conclusion is drawn that a given degree of damage to a structure is most closely related to the magnitude of the particle velocity of the wave motion passing thru the earth at the structure location. On the average, only minor damage it observed for peak particle velocities of 5.4 inches per second, and major damage is observed for peak particle velocities of 7.6 inches per second. When the spread of the data is taken into consideration, the following statement can be made: Wave motions that have a peak particle velocity in excess of 2 inches per second have a fair probability of producing some damage to structures, whereas wave motions that have a peak velocity less than 2 inches per second have a very low probability of causing any damage. Therefore, the recommendation is made that vibration levels in the vicinity of residential structures should be maintained below a peat particle velocity of 2 inches per second. The above criterion for safe blasting is considered to hold over a wide variety of soil and rock conditions because the original data were obtained for a wide range of soil and rock conditions and on various types of residential structures. INTRODUCTION Ever since explosives were discovered and developed for mining purposes, there has existed the problem of what effects the air and ground vibrations resulting from blasting have on structures of various types. This problem is

Jan 1, 1962

The introduction and subsequent ascendancy of autogenous and semi-autogenous milling for comminution circuits has undoubtedly lead to many economic advantages. From a process viewpoint, however, at least one downside has been the sensitivity of these machines to process input variations. Foremost among these is ore competence, though feed size comes a close second. This sensitivity is due to the reliance of ag/sag mills on the feed ore for their grinding media competence and size. Autogenous (ag) mills are the most sensitive in this respect with semi-autogenous (sag) mills being increasingly less so as the ball charge is increased. Increasingly designers and operators are recognising the importance of feed size and the benefits of manipulating it to improve performance. This has been achieved by installing additional crushing/screening capacity ahead of the ag/sag, better operation of the primary crusher, better control of segregation cased by stockpiles and bins and by changing blast design/practices to modify the ROM size distribution. This paper describes the influence of feed size distribution on ag/sag mill performance with reference to a range of plant data. It particularly concentrates on how changing blasting practice to modify ag/sag feed size can have a considerable overall benefit.

Jan 1, 2003

By D Craw

The Rise and Shine Shear Zone is a mineralised low angle deformation zone traceable for at least 7 km through biotite zone schist of the Dunstan Range, central Otago. Rocks from the shear zone obtained from recent drillholes are unweathered and facilitate paragenetic studies. There is a progression of mineral deposition from semiductile foliation-parallel shearing, to subsequent folding, and brittle fracturing. Sheared rocks are dominated by microshears containing fine grained hydrothermal muscovite and rutile that has recrystallised from metamorphic muscovite and titanite respectively. Euhedral pyrite occurs within segregations in the schist and is locally brecciated by the shears.   Arsenopyrite occurs within microshears and is intergrown with hyrothermal muscovite. Fractures within relatively undeformed schist are filled with ankerite, siderite, chalcopyrite, sphalerite and galena and these veinlets also crosscut the microshears. Locally the schist is folded and zones of brecciation, silicification and vein deposition overprint the rock. Vein quartz and albite predominate and arsenopyrite and gold infill breccia matrix and crosscutting veinlets. Sulphide deposition began in the later stages of metamorphism with pyrite deposited in quartz-albite segregations. Subsequent shearing caused brecciation of some grains and accompanied deposition of arsenopyrite ¦ gold and rare sulphides along foliation-parallel microshears. Minor amounts of chalcopyrite, sphalerite and galena were then remobilised in ankerite veins that crosscut the shears. In areas of high strain, arsenopyrite was then deposited as euhedral grains in veins and breccias. Synmineralisation deformation caused the brecciation of some grains and gold was deposited infilling fractures in the arsenopyrite. The paragenetic sequence shows gold mineralisation occurred in two distinct sets of structures (semiductile and brittle) that formed at different times in the formation of the shear zone.

Jan 1, 2006

By M. T. Spyridopolous, S. J. Neethling

"There has been a significant research interest in the stability of single thin films, including prediction of their failure based on disjoining pressure and film thickness experiments and DLVO theory. It is, however, notoriously difficult to correlate information on the failure of a single thin film with measurements of foam stability. This is particularly true for the prediction of dynamic foam stability indicators, such as equilibrium froth height and surface bubble size.An alternative experimental approach to studying single thin film failure for predicting foam stability is to measure directly the coalescence probability between two approaching bubbles in a surfactant solution. These experiments can be performed under different chemical and physical conditions by using a micromanipulator that allows variation of bubble size, surfactant concentration, approach velocity and stationary position. The interface radius of curvature, the time to coalescence and the film area between the bubbles can be measured directly using image analysis.In a foam, the force exerted on the thin film separating two bubbles depends on the local radius of curvature of the Plateau borders and vertices, which depends in turn on the local liquid content. Results from different bubble sizes in the micromanipulator therefore translate into regions of different liquid content in the foam. Small bubbles, having a high radius of curvature correspond to the low-liquid content (Polyhederschaum) region higher in the foam, and large bubbles to the wetter (Kugelschaum) region closer to the liquid-foam interface. Experiments with different holding distances between the bubbles correspond to differences in bubble size in the foam, as the size of the film between the bubbles varies."

Jan 1, 2003

By J R. Lang, J K. Mortensen

The Canadian Cordillera contains numerous classic porphyry deposits and several unusual subtypes, including the alkaline suite of porphyry Cu-Au deposits and the Tombstone magmatic suite and associated Au¦W deposits. The alkaline suite formed in collisional settings in island arcs whereas the Tombstone suite was emplaced in an active fold and thrust belt in a continental arc. In addition to different regional settings, these suites differ in the type of underlying basement, metallogeny, and the styles of mineralization. Both magmatic suites were emplaced over short intervals, probably in response to specific tectonic events. In the case of the alkaline suite, the tectonic event promoted magmatic processes suitable for the formation of porphyry Cu-Au deposits. The tectonic environment is less well constrained for the Tombstone suite, but the result was the formation of distinctive porphyry and intrusion-related Au¦W deposits.

Jan 1, 1995

By S. J. Neethling

"Flotation is a complex process with many factors that influence the performance of a cell. This paper examines the impact of several key variables on the performance of flotation cells. The study makes use of a simulator for the froth phase of the flotation vessel, as the main purpose of this study is to separate the impact of different variables from one another.In experiments it is very difficult to separate the effect of variables from one another as a change in a singe input parameter, such as air rate, invariably also affects many of the other key variables, such as bubble size and bubble bursting rates. This interaction between variables makes it very hard to experimentally separate the impact of, for instance, the air rate from that of bubble size or bursting rate. In the simulator, though, it easy to make independent changes to these variables.In order to achieve this a base case simulation that is typical of many of the rougher cells found in sulphide flotation circuits was carried out. Four key variables, air rate, incoming bubble size, surface bubble size and the fraction of the bubbles flowing out of the cell unburst, were varied in order to obtain the system’s response.The most significant results were obtained when the bubble size was varied. An increase in the incoming bubble size has the effect of reducing the pulp zone recovery, but increases the froth zone recovery. If it were possible to vary the incoming bubble size without influencing the overflowing bubble size, the impact of the change would be unclear because of these two competing effects. The effect of a change in the overflowing bubble size has an opposite effect on the froth recovery, with larger bubbles resulting in lower froth recoveries."

Jan 1, 2003

By Kal Sastry, Anshuman Prasad

"Agglomeration of fine iron ore concentrates is carried out in two steps:Balling, which refers to the production of green pellets by tumbling moist fines powders in drums, discs, or cones, and Induration, which refers to the subsequent thermal treatment of the green pellets in straight grate or grate-kiln systems.This paper addresses computer simulation of balling or green pelletization step. The process of agglomeration from a mechanistic point of view can be described as the transformation of moist feed to well-formed species or pellets. The moist feed is composed of fines of infinitesimal size while well-formed species are of finite size and number. These well-formed species undergo changes in their size and number through different mechanisms of agglomerate formation and growth. Nucleation, coalescence and layering are the three main mechanisms that describe the formation and growth of granules during an agglomeration process. A population balance equation enables quantitative description of the evolution of agglomerate size distribution due to the occurrence of each of the mechanisms.A numerical solution for the population balance model is necessary and is obtained by the use of a sizediscretization approach. The numerical solutions provide a suitable basis for the analysis of the agglomeration process. Also a coalescence kernel has been introduced that is capable of describing the simultaneous occurrence of nucleation, coalescence and layering mechanisms. The effect of feed moisture has been described using a moisture factor with an exponential functional dependence on the moisture content. The effect of the feed to seed ratio is modelled by the introduction of a crowding factor. It was assumed that only the feed particles which are much more in number experience a crowding or restricted in space interactions effect. A computer simulation program has been developed with MATLAB as the simulation language."

Jan 1, 2003

By H. K. Shearer

Drilling for oil and gas in Arkansas in 1934 showed more activity than in any year since 1929; with a total of 96 completions, including 36 oil wells, 1 gas well and 59 dry holes. Of the producers, the lone gas well and 35 oil wells were in old fields, and one wildcat producer opened a new pool. Of the dry holes, 16 were in or near fields and 43 were wildcats. The total reported initial daily production of the oil wells was 9013 bbl., averaging 252 bbl. per well. Active drilling operations numbered 65 at the close of the year, compared with 26 at the beginning.

Jan 1, 1935

By K. S. Kalenchuk

Massive landslides display complex deformation processes. For instance, slope movements of the Downie Slide, monitored using borehole inclinometers, extensometers, and survey monuments, show considerable spatial and temporal inconsistencies in the displacement rates. This study assesses the influence that inferred shear surface geometry, as a key factor contributing to variable slope movements, has on resolving spatially discriminated slope deformations in three-dimensions. Borehole data defines the shear surface location at discrete points within the slide and therefore, the shear surface geometry for the extent of the slide must be largely inferred. A series of three-dimensional numerical simulations have been run to assess the effect of different interpretations of the shear surface geometry. This investigation illustrates the importance of rigorous geospatial definition of slip surface geometry and the value of three dimensional modelling.

May 1, 2009

By L Bartsch, M Kelahan, E Wingate, J-S David

The use of column flotation cells for recovery of phosphate is becoming more common practice in certain parts of the world (Brazil, Russia) where igneous phosphate ores are processed. Igneous phosphates are generally finer grained (< 200µm) than some of the traditional sedimentary phosphates (<400µm). Australian phosphate from the Georgina basin is sedimentary, but has a much finer grain size (typically < 106µm) than similar deposits in North Africa and the USA.In 2013, Arianne Phosphate completed a bankable feasibility study for the development of their igneous phosphate deposit at the Lac a Paul site in Quebec. Initially, lab test work and bench scale piloting indicated that using traditional mechanical flotation would be able to produce adequate concentrate grade and an economic level of recovery, but would necessitate the installation of a complex and operationally challenging flotation circuit. Later pilot plant testing using column cells resulted in a significant reduction in process complexity and facilitated the processing of the -20µm ore fraction which resulted in a 10% increase in P2O5 recovery and a 5% increase in concentrate grade %P2O5.Flotation column testing achieved a concentrate grade of 38.6% P2O5 at a P2O5 recovery of 90%. Using a mechanical flotation cell circuit, the concentrate grade was 36.4% P2O5 with a P2O5 recovery of only 78.8%. A noticeable feature of the testing was the simplicity of the column flotation circuit configuration (Rougher + 2 stages of cleaning + Cleaner Scavenger) compared to the mechanical flotation cell circuit (Rougher + Scavenger + 3 stages of cleaning).The financial benefit for this case study was estimated using a sales price of US$ 195/t FOB for a 38.6% P2O5 product, and an assumed cost of production of US$ 95/t, the netback price is calculated at US$100/t. For a daily milling rate of 55,000t/d, the improved flotation performance provides additional concentrate production of 1,203t/d. Using the netback price calculated above, this calculates to additional gross profit of US$ 120,260/d.Annualised, this equals US$ 40.7 million in additional revenue for a similar or reduced CAPEX.The use of column flotation on fine grained phosphate ore types often requires fine grinding and desliming to liberate the phosphate value, such as the Australian sedimentary phosphate ores. This may enable the development of deposits previously regarded as uneconomic.This paper discusses the potential benefits available to operators, and developers of new projects, for the use of column flotation cells in their metallurgical circuits as assessed by an engineering company.CITATION:Wingate, E, Kelahan, M, David, J-S and Bartsch, L, 2015. Does it make cent$ to use flotation columns for phosphate beneficiation?, in Proceedings MetPlant 2015, pp 353–365 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Jack Curran

KANSAS CITY, MO - Performing one of the most impressive urban building-implosion projects in recent memory, Tulsa, Oklahoma-based Dykon Explosive Demolition Corp. and Omaha, Nebraska-based Anderson Excavating recently felled the landmark Columbia Bank Building in downtown Kansas City, Missouri, USA. Although every structural blasting project presents special challenges, this undertaking was most notable for its unusually unique structural design, tight clearances, and high risk to adjacent structures.

Jan 1, 2003

By M. C. Irani

This survey was conducted to determine the magnitude of the methane emission and control problem in U.S. bituminous coal mines. The resultant data indicate that the emission rate for any given coalbed depends primarily on the coal production rate and on mine depth, as well as on the nature of the coalbed and the surrounding strata. An excellent correlation was found between (1) the methane emission rate and (2) the product of coal production rate and mine depth for the mines in the Pittsburgh, Pocahontas Nos. 3 and 4, and the Illinois Nos. 5 and 6 coalbeds. The highest total emission rates found in U.S. bituminous coal mines were as follows, in million cubic feet per day: Monongalia County, W. Va., 39; Marion County, W. Va., 30.4; McDowell County, W. Va., 13.1; Washington County, Pa., 11.9; Greene County, Pa., 11.4; Buchanan County, Va., 21.6; Jefferson County, Ala., 10.3; and Franklin County, Ill., 6.6.

Jan 1, 1972