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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 "rusted" 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, '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 Steve Custer, Tim Kahl, Sue Parker

"The primary objective of the Barrick Goldstrike expert system is to achieve the desired liberation size for the autoclave circuit while maximizing throughput. In addition, when downstream limitations (autoclave circuit or others) restrict the milling circuit tonnage the expert system further improves grinding product size. Since its implementation, the expert system has provided expected throughput improvements while improving or maintaining circuit performance.Barrick Goldstrike and MinnovEX Technologies Inc. teamed up to install an expert system to control Line I and I1 of the autoclave grinding circuits. The dissimilar equipments of the two grinding circuits coupled to different production objectives, skepticism among operators, and the variability of the ore types processed in each line challenged the implementation.To ensure implementation success, Barrick Goldstrike dedicated four administrators full time to the project. The system administrators included two metallurgists, a process control engineer and a mill trainer. As usual, the control room operators were the experts who provided the operational logic for the foundation of the control system. The administrators and all eleven of the control room operators signed off on acceptance of the system. Current online utilization is 95%.INTRODUCTIONThe grinding circuit for Barrick Goldstrike’s autoclave process consists of two SAG Mill Ball Mill lines. Line 1 grinding circuit is comprised of a 22 by 8 foot, 2500 horsepower Allis Chalmers (AC) variable speed SAG mill, followed by a 12.5 by 14 foot, 1250 horsepower AC ball mill, and a 13.5 by 18 foot, 1800 horsepower Dominion ball mill in parallel. SAG mill recycle from the primary discharge screen (+5/16 inch) is processed through a 1352 Nordberg Omnicone crusher (4.5 foot). A secondary SAG discharge screen (+1/8 inch) closes the SAG circuit. The ball mill circuit is closed with 6 Krebs super D20 cyclones. Line 2 grinding circuit is comprised of a 24 by 12 foot 4000 horsepower Fuller variable speed SAG mill followed by a 16.5 by 30.5 foot 5000 horsepower Fuller ball mill. SAG mill recycle from the primary discharge screen (+5/16 inch) is processed through a 1560 Nordberg Omnicone crusher (5 foot). A secondary SAG discharge screen (+1/8 inch) closes the SAG circuit. The line 2 ball mill circuit is closed with 12 Krebs super D20 cyclones. The underground Meikle ore is typically fed through Line 1. Achieving the desired product size is critical for successful processing of Meikle ore. Open pit Betze ore is fed to Line 1 when Meikle ore is unavailable. Line 2 processes Betze ore exclusively. Throughput is maximized when processing Betze ore as the product size is less critical. The products of these two circuits are combined as feed to the autoclave circuit. The ore types and the autoclave circuit demands determine the required grinding circuit product size and maximum combined mill feed tonnage."

Jan 1, 2001

By J. Labuschagne

There are a number of factors that contribute to the profitability of a mine and its associated concentrator. Chief among these is the time taken from the first hoist of material from underground to the first batch of concentrate shipped. The main aim of this project was to integrate the mining model with a concentrator production schedule to minimize the time it would take to produce concentrate (without the concentrator having to stop because of a lack of feed material) in the most capital-effective manner. A secondary goal was to ensure detailed stockpiling requirements, as the concentrator is in an area where 'visual pollution' is to be avoided. To achieve these two goals a dynamic stockpile model was created by utilizing the mine production schedule and breaking it down to a daily production figure. Four different concentrator development models were then proposed. The difference between the mine production and concentrator consumption was integrated over the life of the mine to provide the accumulated stockpile tonnages for both Merensky and UG2 ore. To prevent a situation where the concentrator was operational without any feed, the stockpile levels were never allowed to fall below zero. When a development option was selected, the standard metallurgical performance calculations were used to derive a concentrate production schedule, which was used as a basis for commercial negotiations for the sale of concentrate.

Jan 1, 2013

By J. A. Holmes, EDWARD C. FRANKLIN, RALPH A. GOULD

The commission may be permitted to express its earnest hope that the litigation which comes to an end with the findings and recom- mendations herein set forth will be considered by both parties to the action as definitely and equitably decided. The commission trusts that its work will show the value of the commission form of settlement and that its work will serve as a prece- dent to be followed in disputes relative to technical subjects. If the work of the commission is productive of a tendency on the part of technical litigants to avoid the use of the courts for the settlement of disputes it will not have been done in vain. Such tendency will surely grow and ultimately such differences will be arbitrated by technically trained men without recourse to the courts of law. Appended to the report of the findings of the commission are to be found the detailed reports covering the several lines of inquiry and investigation carried on by the commission and upon which its findings are based, and also a detailed statement of the fiscal affairs of the commission. A word of explanation is necessary in regard to the fiscal statement. While each party to the litigation has agreed to bear one-half of the expense of the investigations of the commission, it will be noted that the Selby Smelting & Lead Co. is credited with $21,000, while Solano County is credited with but $6,000. In order that the investigations of the commission might go forward without interruption the Selby Smelting & Lead Co. has generously supplied funds at the times they were needed. This assistance has been

Jan 1, 1915

By E. Rupprecht, J. Volkwein, K. Cashdollar, R. Gürtunca

The National Institute for Occupational Safety and Health (NIOSH) mining research program at the Pittsburgh Research Laboratory (PRL), includes the areas of coal mine dust control and monitoring, and explosion prevention. One very important project at PRL is development of a continuous recording person-wearable respirable dust monitor. This Personal Dust Monitor (PDM) is a respirable dust sampler and gravimetric -equivalent analysis instrument that is part of a belt-worn mine cap lamp battery unit. Prototypes were successfully tested in the laboratory and in four underground coal mines. The PDM testing demonstrated that it was convenient to wear and use, robust, and provided accurate and timely data. NOSH is also conducting research in the program area of coal mine explosion prevention, suppression, and mitigation. Aspects of this research program include: full scale explosion research, laboratory scale research, frictional ignition of methane, mine ventilation seal construction, prediction of coal mine methane emissions, mine monitoring systems, flame cutting and welding operations, spontaneous combustion, and emergency preparedness.

By A. Vorster

The objective with mine planning is to consistently deliver production conforming to quality and quantity requirements throughout the life of the mine. The complexity of the operational context of the modern mine extends far beyond the actual production actions and there is a need to find ways of analysing and managing this extended environment. A well-established approach to handling complex situations rely on the creation of representative models that use classification and visualization strategies. An example of the use of a classification scheme is the periodic table of the elements. All physical matter can be expressed as combinations of basic elements. Not only is the periodic table useful in classifying and identifying matter but it can also be used for the prediction of the properties of unknown matter and compositions of elements.

Jan 1, 2001

Gas-liquid contacting in the packed bed is a common operation in metallurgical reactors. Research has shown that, unlike wetting flow, non-wetting liquid flows in the form of discrete droplets or rivulets. Thus, modeling of the liquid phase as a continuum is in contradiction to the observations. Also, for the non-wetting case, continuum models have failed to describe liquid flow path when the liquid source is a point source. The aim of the current work is to put forward a combined Lagrangian-Eulerian approach to model the liquid and gas flow in the packed bed. Liquid is assumed discrete and modeled using a force balance approach. Gas is assumed to be interpenetrating continua and modeled using k-emodel for turbulent flow. Structured packing is assumed and x- ray imaging technique is used to visualize liquid flow lines in the bed. Simulation results for liquid flow path compared with the experiments.

Jan 1, 2006

By Rick Deschamps, Brian Barkauskas, Aled Hughes, Abigail Stein

In central Washington, six miles south of the small town of Vantage, the flow of the Columbia River is harnessed by the Wanapum Dam which is part of the Priest Rapids Hydroelectric Project owned and operated by Grant County Public Utility District (GCPUD). Extending more than 8,300-feet from bank to bank, the dam includes left and right earth embankments, left and right concrete gravity sections and a 10-unit powerhouse. Adjacent to the right embankment is a concrete gravity spillway featuring radial gates measuring 50-feet-wide and nearly 70-feet-high. In the early 1960’s when Wanapum Dam was built, these seven-story spillway gates were the highest in the world. In late February 2014, 50-years into its service life, during a routine maintenance inspection, observant workers noticed a slight misalignment in the roadway deck curbs and handrails located on top of the spillway. Further survey and inspection efforts uncovered a 65-foot-long by two- inch-wide crack that spanned the full length of Monolith 4. On discovering the extent of the damage, GCPUD initiated immediate drawdown of the reservoir to relieve pressure on the spillway monoliths. Wanapum Reservoir and the areas directly downstream of the dam were immediately closed, boat ramps and inlets were left completely dry, campsites were closed and boating activity was banned on the lake until further investigations and remedial procedures were in place and completed. An extensive root cause analysis ultimately led to the conclusion that errors in the initial design calculations and late changes to the final spillway design led to a condition that generated tensile stresses in the concrete at the upstream face, which over a period of 50-years resulted in the formation of a crack along a horizontal lift joint located about 85-feet below normal pool elevation. Further analysis showed that, although visible distress was found at Monolith 4, there was nothing preventing this issue from happening at other locations along the dam spillway. Although no visible cracking was found in the other monoliths, repair procedures for Monolith 4 would have to be replicated at the remaining monoliths.

Jan 1, 2018

By A. Adu-Acheampong

The Mid-Tennessee Zinc (MTZ) mines, comprised of the Gordonsville, Elmwood, and Cumberland sites, last operated 4 years ago and are undergoing rehabilitation to begin production in 2008. The mines utilize a random room-and-pillar mining method that results in complex ventilation networks. Upon decommissioning, the mechanical ventilation units were removed and disposed of and several shafts sealed. In an effort to re-open the mines and operate in compliance with imminent Mine Safety Health and Administration (MSHA) diesel particulate matter (DPM) regulatory limits of 160TC µg/m3, a new ventilation system was required. The new ventilation system was developed primarily based on the diesel equipment required to meet production. Particular emphasis was placed on the DPM, diesel equipment utilization, main fan sizing, and fan locations to enable the mines to meet MSHA?s ventilation requirements in a cost efficient manner.

Jan 1, 2009

The roasting of sulphide ores and concentrates is often the first step in the production of metals or chemicals. In many processes, the production of sulphuric acid is viewed as a by-product, while in some plants production is an important economic factor. Regardless of the purpose, a pyrite roasting plant consists of mainly three plant sections: roasting, gas cleaning and sulphuric acid. With the addition of air, the pyrite concentrates are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600 - 1000° C. After cleaning and cooling, the sulphur dioxide in the roasting gas is further processed to sulphuric acid. Two types of reactors are used depending on the application: stationary or circulating fluid bed . For over 60 years, Outotec has progressively been developing the principle of fluidised bed technology in several different reactor types for a multitude of process applications. The versatility of the fluidised bed reactor system has manifested itself in the treatment of minerals, including solid fuels, and for metallurgical processes both in the ferrous and non-ferrous fields. Process applications have included roasting, calcining, combustion and charring of coals, as well as off-gas treatment. This paper provides a summary of the pyrite roasting technology currently used along with a simple cost comparison of pyrite roasting and sulphur burning processes.

Jan 1, 2009

By M. C. Villeneuve

A numerical modelling approach was developed to explicitly simulate geomechanical characteristics of intact rock: mineralogy, grain size and fabric. The approach involved creating a representative constitutive model for each of three common rock-forming minerals: mica, quartz and feldspar. The constitutive models developed are valid within the low confinement realm of excavation boundaries, where tensile fracture processes dominate. The mineral types were assigned to numerical elements, which were associated with each other through an algorithm created in a finite difference model, FLAC 2D (Itasca 2007a), to simulate real crystal geometries and orientations. The numerical models were used in a parametric investigation of the geomechanical characteristics and compared with published observations of the rock yielding process in laboratory testing. This approach has allowed the explicit grain-scale investigation of the impact of geomechanical characteristics on rock yielding at low confinement, leading to an improved mechanistic understanding of excavation-scale rock yielding processes at excavation boundaries.

May 1, 2009

By A. C. du Preez

The separation of nickel and cobalt from calcium, magnesium and manganese by solvent extraction using synergistic mixtures of carboxylic acids was studied. Addition of certain viable synergists to commercially available tertiary branched carboxylic acids, such as Versatic 10 (Shell) or Neodecanoic acid (Exxon), produced large synergistic shifts (?pH50) in the pH50values for nickel, and small antagonistic shifts (negative ?pH50values) in the extraction of calcium. Under the initial test conditions used (0.50 M each of Neodecanoic acid and the Mintek synergist, in xylene) a large separation (pH50Ca? pH50Ni= 3.09 pH units) between nickel and calcium in their extraction from 1.00 M sodium nitrate solutions was obtained, compared with only 1.11 pH units in the absence of the synergist. The selectivity series for the extraction of divalent base metals from 0.333 M sodium sulphate solutions by 0.50 M Neodecanoic acid and 0.25 M of the Mintek synergist in C12-C13aliphatic diluent was found to lie in the order (with pH50values in parentheses): Cu(3.42) > Ni (5.08) > Zn (5.58) > Co (5.73) > Mn (6.62) > Ca (7.48) >Mg (8.25). In batch counter current experiments, a simulated leach liquor containing (in gL-1): Ni 5, Mg 5, Mn 2, Co 0.5, Ca 0.5, Cu 0.1and Zn 0.1 was contacted with the mixed extractant in three stages at unit phase ratio and an equilibrium pH of 5.9. The recovery of nickel was 99.9 per cent and that of cobalt was 84.7 per cent, whilst the co-extractions of manganese, calcium and magnesium were 2.7,1.5 and 0.04 per cent, respectively. The recovery of cobalt can be enhanced by employing a slightly higher pH, although this will also increase the extraction of manganese, calcium and magnesium somewhat. Nearly quantitative stripping (99 per cent) of nickel from the loaded organic phase was achieved in a single contact at an organic-to-aqueous phase ratio of 4 using a simulated spent electrolyte containing 39 gL-1sulphuric acid and 33 gL-1nickel,thereby producing an ?advance electrolyte? containing 57 gL-1nickelat pH 3.5. Loading of acid into the organic phase was very slight, amounting to only 0.002 M H+in contact with the above-mentioned spent electrolyte. Keywords: solvent extraction; synergism; nickel; calcium; carboxylic acids.

Jan 1, 2004

By S G. Keyte

Gravity methods of recovering alluvial gold are not very efficient at particle sizes below about 0.l mm. Whereas such gold may not have been economic to recover in the past, the same may not be true today. Centrifugal concentrators, like the Knudsen and Knelson bowls, are showing promise after an inauspicious start, at least in New Zealand. The large proportion of heavy mineral in many auriferous beach sands and the natural hydrophobicity of fine gold should make flotation an attractive contender for its recovery. The conventional mechanical flotation cell is effective, but roughing, scavenging and cleaning are necessary to achieve both high recovery and low mass Yield. More problematic is the difficulty of maintaining coarse and dense sands in suspension. The air sparged hydrocyclone is effective at recovering fine gold from a fine Colarado River sand, but is not effective for the coarse and dense beach sands of New Zealand. The flotation column shows much promise for these sands, when recoveries of over 80 per cent and mass yields of less than one per cent can be achieved in a single pass. The froth separator of the USSR and flash flotation could also be worthy contenders. It is felt that flotation could be limited to naturally and artificially de-slimed concentrates.

Jan 1, 1990

By French D

In presenting this paper may I preface my remarks by recognizing the presence here to-day of the many delegates from the overseas mining communities throughout the world. That is to say - those delegates not representative of Companies resident in Australia. This does not mean that my comments following are directed solely to the Australian exporter - far from it. The Company which I represent is internationally based. The experiences we have had in dealing and negotiating with our good friends the mineral cargo shippers vary very little in any operational area. However for the purposes of this exercise this address is based on some of our experiences within the Australian trade scene with the emphasis on the fact that we believe it has application to all trading areas.

Jan 1, 1989

By Pieter de Waal

The use of valuable minerals is a necessity to maintain a modern society. Not only the iron, aluminium, coal and oil that are used in large quantities, but also the uranium, copper, vanadium, tungsten, antimony and many others play an essential role in the bigger picture of our modern civilisation. Minerals occur in a form and in places determined by a long history starting at the dawn of creation. Over billions of years the elements have combined in wondrous combinations and structures. They have been broken up by massive explosions, movements in the earth's crust and erosion by wind and water. They have been restructured and recreated in even more configurations by the application of heat and pressure, leached by and exposed to new chemical compounds. The result is that most valuable minerals are found in impure form and mixed up with other, less useful waste material. 2. Mineral Beneficiation The processes used for the purification and enhancement of an ore, to satisfy the needs of downstream applications, are collectively referred to as mineral beneficiation. Mineral Beneficiation starts in the mine where only that portion of the ore, that can be economically processed, is selectively extracted. It may also include ore blending, to ensure a more consistent feed to the following stage of valuable mineral recovery. The next stage in mineral beneficiation is the liberation of the valuable minerals from the gangue. This is achieved by blasting, crushing, milling and grinding down to an adequately fine grain size to facilitate good separation. Separation can be achieved by a variety of different techniques. ?Screening coarse from fine particles is an easy method if the valuable mineral is dominant in a certain screen fraction. ?Magnetic separators can differentiate minerals on the basis of their difference in magnetic susceptibility. ? Electrostatic separators differentiate on the basis of electrical conductivity. ? The differences in density are exploited in spirals and jigs. ? Particular surface properties provide a separation technique in flotation. ?The selective sorption properties of a collector medium are another option.

Jan 1, 2007

By David Siskind

The authors studied small seismic exploration blasts for vibration characteristics and effects on structures in Mexico. Obtained were 267 three-component recordings of ground vibrations and structure responses from 62 test blasts at six single-story masonry structures. Charges were 4.55 kg (10 lb) of Vibrogel expolsive at depths of 20 and 30 meters. Initial blasts were 240 meters distant and proceeded towards the structures to as close as 5 meters. All blasts were in soil media in two basic types of terrain, low saturated areas and upland dry areas. Structural inspections were before, during, and after the test blasts.

Jan 1, 2002

By Roy Lindsay, Paul O'Hara, Gary Halverson

"The New Britannia Minesite is located in Snow Lake, Manitoba, 420 miles north of Winnipeg (figure 1). The mine previously operated from 1949 to 1958 extracting some 5.39 million tons of ore at a 0.150 opt gold grade. From 1959 to 1986 the property was held by Nor-Acme and Hudson Bay Exploration and Development and in 1987 High River Resources Ltd. Optioned the property, dewatered the mine and conducted a diamond drill program between the 1 780 and 2400 levels. In 1988 two companies, Nor-Acme Mines Ltd. and High River Gold Mines Ltd., negotiated an option agreement with INCO Gold whereby !NCO assumed management control of all site exploration work. During this period, a bulk sample of 10,000 tons was extracted from the 1780 level with no further exploration recorded after its removal. Both Hudson Bay Exploration and Development and INCO Gold conducted feasibility studies on reactivating the property but at a calculated capital cost of Cdn $70 to $80 million found the rate of return on their investment unacceptable.In 1991 !NCO Gold merged its interest with the assets of TVX Gold Inc. and in February 1994 TVX Gold Inc. and High River Gold Mines Ltd. entered into a joint venture partnership to develop the Snow Lake property, naming TVX Gold Inc. the operator. Upon completion of a feasibility study in April 1994 by Bharti Engineering Associates Inc., a decision was made to reopen the Britannia Mine at an established project cost of US $33 million.Project construction commenced in July 1994 with the hoist house excavation. The first concrete for the hoist house level footings was poured on August 4, 1994 and the project was completed on October 1, 1995 at a cost of US $36 million. The first gold pour took place November 4, 1995.This paper not only presents the metallurgical aspects of the operation but also describes the novel approach used to complete the design and construction of the site facilities."

Jan 1, 1996

To George Orwell the year of 1984 was the inspiration for a book. To most New Zealanders it was the year that the fourth Labour Government was elected to power. It was also the year that the review of mining legislation commenced. While Orwell's book and the election of Labour are clearly events of some historic note, one could be excused for classifying the review of minerals legislation somewhat differently in terms of its present achievements! Since the review began it has led a tortuous path through a rapidly evolving policy environment to a point three years hence where no major policies have been determined.

Jan 1, 1987

By Joel Moskowitz

A new office complex is being constructed within 25m of the Hudson River in New Jersey. The project, about 140 m by 100 m, will include 4 basements under the entire footprint. The perimeter was to be secured by a 0.8 m thick diaphragm wall, laterally supported by high capacity tieback anchors to rock. Columns were to be supported on footings or piers to rock at a nominal bearing pressure of 3.8 MPa at depths up to 17m. Although some variation in rock quality was observed in borings, a substantial vertical seam of weathered and/or decomposed rock, 1 to 2 meters wide by as much as 8 meters deep, was encountered during construction necessitating field redesign. In some locations the seam dipped below more competent rock. Footings were redesigned for support on drilled caissons, or soft rock was excavated and replaced with concrete necessitating a reduction in bearing pressure of the footings by one half.

Jan 1, 2002

By Ivan Simon, R. K. McConnell

Anticipating the availability of tiltmeters suitable for use in boreholes, this article proposes a method of using one or more of these meters to determine in situ stress distribution before and after mining operations. Several ways of using relief techniques to measure in situ stresses in rocks have been developed. These techniques, summarized by Merrill,1 involve measuring deformations which take place when a specimen of rock is wholly or partially isolated from the stress field in the surrounding rock. Measurements of rock deformation caused by stress relief from mining operations can, in principle, also be used to estimate in situ stress distributions. Müller2 has mentioned experiments being carried on in Austria with a "deformation indicator" to determine the tilting of holes drilled before a mine opening is made. Similar work using borehole extensometers has been reported by Potts? and Duvall4 has called attention to the possible use of tiltmeters in making these measurements. Considerable attention is now being paid to the use of tiltmeters in detecting rock deformation associated with fault movements, earthquakes, earth tides, etc. The instruments used for these measurements have usually been of the mercury tube, water tube, or quartz fiber type, but because of their large size, and/or fragile nature, such instruments would not be suitable for use in mining stress measurements. Recent instrumentation developments, however, give promise that rugged, sensitive tiltmeters small enough for use in boreholes may soon be available.' In anticipation of these developments, this article presents a number of calculations of the possibility of using one or more tiltmeters emplaced in a drill hole prior to mining operations to determine the in situ stress distribution both before and after a mining operation. Consider point p (x, z) near a tunnel of radius a

Jan 1, 1969