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By P. Talonen

Since the last Iron Control in Hydrometallurgy Symposium in Montreal in 1996, the Kokkola zinc plant has increased its capacity from 175,000 t/y to 280,000 t/y by installing an atmospheric concentrate leaching process, which has also affected iron control in the leaching circuit. Major changes have been made at the jarosite residue pond; a subterranean plastic wall reinforced with bentonite and cement has been built around the pond. A new water collecting system that is used for groundwater level control in the pond area was installed. With these two investments in the pond area, it is now possible to prevent any seepage flow from the pond into the surrounding environment. Water pumped from the residue pond is treated in the water treatment plant. This paper describes the behavior of iron in Kokkola's current leaching processes. The treatment of the jarosite, the improvements to the residue pond and the water treatment process are also described.

Jan 1, 2006

By Paul E. Nilles

For every single BOF heat, the steelmaker must control the refining operation in order to satisfy at turndown the following conditions : - to reach the correct steel analysis (C, S, P, ...) in the shortest time possible, i.e. without reblow; - to maintain the temperature of the metal in a narrow range; - to produce the optimum steel weight. It is obvious that during refining limited time and scarce information are available and only very few corrective actions can be taken. For this reason, it is of the greatest importance to facilitate the control of the BOF process by taking adequate measures before and during charging of the converter. These are : - the availability of accurate and reliable equipments for the classical measurements, 5.e. weights, temperatures, flow-rates, analyses, etc... - the operation of an optimal charge calculation model which takes into account all information concerning the preceeding heats and the charged materials. '

Jan 1, 1972

By G. Y. Chin, M. T. Dolan, W. L. Mammel

We have obtained by computer methods the solutions of the Taylor analysis1 for axisymmetric flow in bcc metals. Four modes of slip have been treated in detail:2-4 (111), {112}(111), {123}( 111), and a mixture of all three. In addition to obtaining anisotropy of strength data for randomly oriented or textured polycrystalline material,4 we have also obtained the lattice rotation resulting from slip on the predicted systems. The patterns of lattice rotation are essential to an improved understanding of texture development during deformation. The present note shows the results of lattice rotation for 5 pct axisymmetric compression, for fifty-two axial orientations distributed at 5-deg intervals throughout the standard stereographic triangle. The data are presented in Figs. 1 to 4 for the four modes of slip. The lattice rotation is indicated by a vector, the ends of which correspond to the positions before and after the deformation. The different vectors emanated from a given orientation represent different combinations of five slip systems that satisfy Taylor&apos;s minimum shear criterion.&apos; Fig. 1 shows the results for {110}< 111> slip. They are similar to those obtained by Bishop5 for the case of (111 )(110) slip in axisymrnetric tension, since in axisymmetric flow the sense of lattice rotation for {111)( 110) in tension is the same as that for (110) (111) in compression. The pattern of lattice rotation may be divided into three regions: region A in which the rotation is toward [100]; region B, toward [lll]; and region C, toward either [ loo] or L lll]. Although some slip combinations in region C lead to [1101, the latter is not stable as continued activity of the same combinations will eventually move the axis toward [loo] or Llll]. It may also be noted that [loo] is itself not stable. However, close inspection of the vectors in region A shows that it is impossible for an axial orientation within A to rotate outside its boundary. Hence after heavy compression, all orientations from A and some from C are expected to form a diffuse band in the [100] vicinity. By far the largest region is B. Here all orientations rotate to [lll], which is a truly stable position. Thus the [111] texture component is expected to be rather sharp. For the case of (112 }( 111) slip, Fig. 2, region C is enlarged at the expense of A, with B about the same as for {110}( 111) slip. A significant difference, however, is that [loo], as well as [Ill], is now truly stable. Fig. 3 shows the results of slip on {123}( 111) systems. Region B is substantially enlarged at the expense of C, with A being intermediate in size between the {110}(111) and {112}(111) cases. Like the case of {110)( 111) slip, [100] is itself unstable. However, the lattice rotations here are confined to less than 5 deg; hence it may be considered "stable" for practical purposes. Finally, Fig. 4 shows the results of mixed slip. Here region B is the largest, and C the smallest, of all the cases considered. Both [loo] and [ill] are stable. The behavior of the three corner positions is, in fact, identical to the case of {112)( 111) slip, Fig. 2; it turns out that in these positions for the mixed slip case, all the active slip systems (based on Taylor&apos;s criterion) belong to pure {112}( 111) .4 In summing up the results for the four modes of

Jan 1, 1968

By Maidl B

A tunnel operations analyser is a new high technol- ogy instrument for use in underground work. By remotely sensing the acoustic emissions from operating machines and processes in a tunnel or shaft and by applying sophis- ticated computer processing to them individual process cycles and other detailed information about the operating processes can be collected. Detailed analyses and dissec- tions of the work in progress can be made and a variety of action oriented management reports produced. The pro- cess is fully automatic. Results of applying this device to two full scale tunnel projects are presented. The hardware and software that comprise the instrument are discussed in detail. Processes by which this device can be used to sub- stantially reduce tunnel costs are presented. It is concluded that this type of technology has great potential.

Jan 1, 1987

By K. Wu, L. Li, D. W. Zhou, J. W. Yu

The presence of a fractured water-conducting zone (FWCZ) is of significant importance for the safety of underground mining under water bodies. When a coal mining area is covered with a thick layer of alluvial soil, the height, width, and distribution pattern of the FWCZ in the area shows unique features. The internal mechanism by which thick alluvial soil affects the FWCZ is still unknown. Using the Huainan coal mining area (HCMA) in China as a case study, we investigated the impact of thick alluvial soil on the height, width, and distribution pattern of the FWCZ through numerical simulation using the distinct element method, theoretical derivation, and data validation. The results indicate that a thick layer of alluvial soil inhibits the FWCZ height and increases the FWCZ lateral width. When the soil-to-rock ratio is greater than a certain value (the numerical result in this study is 15:18), the FWCZ height and width are affected by the thick alluvium significantly, and the thick alluvial soil alters the shape of the FWCZ from tall and thin to short and wide. The load exerted by the alluvial soil transfers downward to influence the FWCZ; however, this process is obstructed by the hard strata in the bedrock. Therefore, the vertical and lateral change trends show a similar step pattern. Our results can provide a basis for accurate calculation of the FWCZ height in mining areas with thick alluvial soil, to mitigate mine water hazards and increase the safety of underground mining in coal mines covered with a thick alluvium layer. Moreover, reducing the FWCZ height can help extend the upper extraction limit in coal mines covered with a thick alluvium layer, which reduces the thickness of the impermeable coal pillar and increases coal production.

Jan 1, 2016

By B. M. Currell, M. J. Neate, P. W. Bowden

Historically the hydrogen fluoride laden fume emitted from the electrolytic cells in the aluminium reduction process is further treated in pulse jet dust collectors. These dust collectors act as dry scrubbers performing two duties: adsorbing the gaseous fluoride emitted from the cells onto alumina dust; and collecting the alumina dust minimising particulate and fluoride emissions to the environment.Patented StarBag (TM) technology has been used in aluminium smelters in Australia as a means of increasing the dust collection and fluoride scrubbing capacity of existing collectors. This technology provides an alternative to major capital equipment upgrade where increased capacity is required, and potentially lowers the production cost per tonne of aluminium where capacity limitations are being realised and production expansion is required. This paper presents the findings of on-site pilot scale, and full production scale comparative tests, highlighting the operational and variable differences observed utilising the Star-Bag(TM) technology at Boyne Smelters Ltd in Australia. The results illustrate how this technology can be utilised to increase the hydrogen fluoride scrubbing efficiency and dust collection capacity of existing capital equipment.

Jan 1, 2006

By B E. De Gee, N Viviers, A Naidoo

In 2013 the Mopani Copper Mine Mufulira plant in Zambia embarked on a project that was aimed at improving concentrator recoveries. The project commenced with the automation of the milling and flotation circuits. This involved the installation of new instrumentation, namely measurement devices and actuators, and the connection of these to new programmable logic controllers (PLCs).The infrastructure changes were followed by the implementation of basic proportional-integral-derivative (PID) controllers on the PLCs. Supervisory control and data acquisition (SCADA) interfaces were also implemented to allow for switching between controller modes, inputting of setpoint variables and to provide a visual display for process monitoring. The final phase of the project involved the installation and commissioning of advanced process control (APC) solutions on the milling and flotation circuits. This work was carried out by Mintek over 21 on-site days. The APC solutions included the MillStar and FloatStar suites of advanced controllers.The MillStar control suite focused on stabilising the mill feed and mill discharge on the two primary mills as well as the flotation circuit feed. Mintek’s CyLas instruments, which provide a measurement of the hydrocyclone underflow angle, were also installed. The measurements were incorporated into the discharge stabilisation control on both milling circuits. The FloatStar level stabiliser controller provided flotation cell pulp level control on fourteen cells, including two columns.Performance tests showed that the Mintek APC system stabilised the mill feed and mill discharge while ensuring the process remained within operational constraints. The MillStar control system utilised the CyLas instrument to prevent roping on the hydrocyclone underflow. This was not always achieved under normal operation. Additionally, the flotation section was stabilised as a result of improved level control by the FloatStar control system.Performance comparisons showed that the Mintek control system improved the operation of the milling and flotation circuits resulting in a greater copper recovery.CITATION:Naidoo, A, De Gee, B E and Viviers, N, 2014. Implementation of an advanced milling and flotation control system at Mopani Mufulira copper mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 363–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By D Tuazon, M Powell, M Ziemski, G D. Corder

Although mining companies have made broad corporate-level commitments to adopt sustainability, there continue to be problems when attempts are made to adopt higher-level sustainability aspirations and translate them into appropriate targets and methods at the more-specific operational level. The integration of sustainability principles into minerals processing operational decision-making processes has unique challenges that are not addressed adequately by current tools and methodologies, yet impacts from operational decisions can have longer-term effects realised at closure and rehabilitation.This paper describes a proposed methodology to achieve the integration of sustainability at the operational level through a systematic and rigorous process of identifying and qualifying sustainability issues and opportunities in an operation. The methodology, starting from a sustainability point of view rather than an operational one, guides the identification of process issues and opportunities by examining the operation, unit-by-unit, similar to a Hazard and Operability (HAZOP) process. Each issue or opportunity is qualified according to its measurability, scopes of impact and consequences so that it may be understood fully and the correct engineering problems are formed. Through improved decision-making to account for broader sustainability factors, operations can better address environmental and social expectations and pressures (both corporate and community, as well as immediate and in the longer-term), whilst still delivering on operational and business goals.The methodology has been tested with two case studies at minerals processing operations. At one site, the methodology identified a dust issue which had considerable business risks (loss of valuable product) compared to conventional engineering analysis processes. The other site also benefited from using the methodology as an opportunity to improve the operation of the milling and flotation circuits was identified. The opportunity not only showed a potential to improve operational efficiency, but also potential improvements in water and energy efficiency and a resulting increased resilience against water and energy supply risks. It was important to utilise the holistic approach of the methodology in the identification of opportunities at this site; the goals of the operation showed a strong coupling between water and energy issues which would be difficult to overcome using the operationÆs current organisational model, which deals with such issues separately of each other.CITATION:Tuazon, D, Corder, G D, Powell, M and Ziemski, M, 2012. A practical and rigorous approach for integrating sustainability principles into decision-making processes at minerals processing operations, in Proceedings Life-of-Mine 2012 , pp 233-242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By David B. Brooks, Roger L. Williams

Control of the environment is as old as mining. Engineers have always had to consider how best to deal with the surface, and the character of the surface environment always affects mining method in some way. However, if the relationship of the mine to the environment is old, today&apos;s approach is new. For one thing, land, air and water formerly could be viewed simply as obstacles to be overcome or resources to be utilized to win ore at the lowest possible cost. Now we have come to realize that these nonmineral components of the environment also are highly valuable. For another thing, environ- mental protection has become a public policy issue. Again, a special public interest in land and land use is old. From the firs(, the crown claimed extra rights in valuable minerals, and to this day a multitude of laws and regulations control-and tax-land use in every country. What is new is the detailed public attention bring given to waste management practices, whether these wastes be in the form of solids, liquids or gases, and regardless of where in the environment they appear. (It is convenient to lump all mining environmental problems, including hank fires and subsidence, together under the term "waste management," for in effect that is what they are.) As a result of these changes, the mining engineer must consider that lie is dealing with two productive resources the minerals and the remainder of the environment-and he must expect that lie will be judged not only on his efficiency in recovering the one but also on his effectiveness in protecting the other. Further, in seeking to protect the environment, the modern mining-environmental engineer has a dual role. First, there is the obvious task of finding better ways for industry to cope with waste-management problems in actual operations. Second, there is the less obvious but equally important task of helping formulate appropriate public policy objectives for the environment. Throughout; the section it is assumed that mining is an acceptable land use for the tracts under consideration. The question of whether mining will be permitted at all on these tracts is a further public-policy issue, ultimately to be resolved politically and thus, since it is beyond the scope of engineering, is not a subject that can be usefully discussed in a mining handbook. Finally, none of the statements in the section are predicated on the assumption that required waste-management measures will be privately profitable in the conventional sense. Indeed, the reverse is more likely to be the case-at least if accounts are kept so as to include all appreciable costs and a normal rate of return on investment in waste-disposal and reclamation equipment.&apos;,&apos;,&apos; However, it is clear that improved waste management will be required of mining firms and that, to a considerable although undetermined degree, this expenditure is in the best long-run interest of both public and industry. The several studies that have attempted to quantify the impact of mining on the environment are admittedly rough but still provide enough information to indicate that there is a big job to be done. For example, something approaching 7,000 mi of stream in Appalachia alone are continuously or significantly affected

Jan 1, 1973

By James Hance

INTRODUCTION SEVERAL years ago the writer was connected with the Mint and Assay Service of the Federal Government as Assistant Assayer at the-Salt Lake Assay Office. At that time cyanide bars formed approximately half of the bullion purchased by that office. Disagreement in valuation between the producer and the office was not infrequent and to a lesser extent between the Assay Office and the Mint, this latter issue being soon obviated, however, by adopting uniform methods of sampling the bars. A nice problem seemed to offer itself for research and the writer began a series of experiments which were soon terminated, however, by his going into other work, and which he regrets have not since been completed. The results attained may suggest lines of approach to this problem and are, therefore, offered in this article. Frederick P. Dewey, Assayer of the Mint Service, U. S. Treasury, has had abundant opportunity to study this phase of metallurgy, and has published several articles relative thereto.1 In the last article cited Dewey quotes analyses of cyanide bullion similar in content to that with which the writer worked, and which show some of the variations met with. In the discussion of these papers,2 comparison has been made in terms of copper bullion, but to the writer this seems of questionable value. Copper bullion may resemble silver bullion, but its similarity to, gold bullion with little or no silver content is another thing. The freezing-point diagram of Roozeboom, reproduced on page 881 of the discussion cited, is for the gold-silver series as stated. The original problem under discussion, however, is not this alloy but gold with base metals other than copper. As for the statement that the corners are the worst places or

Jan 2, 1916

By P Hawke, J Hurst, B KrapeP

Hancock Prospecting Pty Ltd (HPPL) drilled two deep diamond stratigraphic holes (ECD0001 and RHD0296) within the eastern Fortescue Valley in the Pilbara of Western Australia. Located south of the Roy Hill Iron Ore project, the holes aimed to define the stratigraphy of the Marra Mamba Iron Formation (MMIF) of the Chichester Range and its south-dipping extensions below recent cover. Previous attempts to define the MMIF of the Chichester Range have resulted in differing interpretations due to the data available at the time.The unweathered MMIF beneath the Fortescue Valley in the HPPL drill holes is characterised by dolomitic carbonate interbedded with stilpnomelane-rich shales, chert and banded iron formation (BIF) with hematite staining. This intersection equates to ~75 m of carbonate-facies iron formation, as opposed to the ~230 m thick oxide-facies BIF and shale sequence encountered south of the Fortescue Valley.Various detailed geological core analyses and interpretations from ECD0001 and RHD0296 were integrated with regional diamond and reverse circulation (RC) holes from across the Fortescue Valley. Interpretation of the data indicates that the eastern Fortescue Valley MMIF represents a thinned thickness sequence of the whole formation. The MMIF of the Chichester Range and Fortescue Valley has gamma logs that correlate strongly in parts to the type section used for MMIF south of the Fortescue Valley. Therefore, the outcropping MMIF in the Chichester Range represents an eroded equivalent of the æreducedÆ thickness MMIF observed in ECD0001 and RHD0296.Data from deep diamond drill holes across the valley, from the Hamersley Basin to the Carawine Basin, were correlated. The correlation shows that the depositional site of the MMIF in the HPPL diamond drill holes is consistent with a proximal ramp setting, in which iron-rich shales wedge up-palaeoslope and shelf-derived carbonate turbidites wedge down-palaeoslope. Not only is it the occurrence of these shales that define the MMIF, but they also determine the northward potential to develop orebodies, as they are the source of iron from which iron-rich oxides and carbonates of metamorphic or diagenetic origin form.CITATION:Hurst, J, KrapeP, B and Hawke, P, 2013. Stratigraphy of the Marra Mamba iron formation within the Chichester Range and its implications for iron ore genesis at Roy Hill - evidence from deep diamond drill holes within the East Fortescue Valley, in Proceedings Iron Ore 2013 , pp 91-106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By W. Dingley, G. R. Hoey

"Thirteen Canadian sulphide ore mines were surveyed for corrosion control. The mines visited were a small, yet representative, proportion of this segment of the Canadian mining and metallurgical industry. Information on metallic corrosion and methods used to control it in underground workings and mills was gathered (a) by discussing corrosion problems with company personnel, (b) by examining equipment and structures during under-ground and mill tours, (c) by photographing corrosion sites, and (d) by collecting and analyzing mine water samples.The corrosion survey, which is summarized in the re-port, leads to the following general conclusions. Mine environments are corrosive, particularly when the mine w1a-ter is acidic. Because of a lack of good corrosion control measures, excessive deterioration of equipment due to corrosion occurs in mines. Mill environments are also corrosive, but in some cases good preventive measures are being taken to effectively control corrosion losses.Ways to reduce corrosion losses in sulphide ore mines and mills are discussed. The main areas for more corrosion research and development are selection of materials of construction, protective coatings, cathodic protection, inhibitors, equipment design, and mining and milling practices."

Jan 1, 1971

By Marvin E. Lane

Viburnum, located in the foothills of the Ozarks in south-east Missouri, is the site of a modern lead mining and milling operation. Two mines are currently producing a total of 5,000 tons per day and a third mine is in the final development stage, with full production scheduled for late this year (1964). These mines will supply the tonnage required to keep the Viburnum mill operating at a full capacity of 7,000 tons per day for many years. The efficient underground mining operation is completely trackless. Drill jumbos are used to break the ore in a room and pillar method of mining. Transloaders, or St. Joe shovels, and trucks do the loading and hauling. The Viburnum mill has a world-wide reputation as a most efficient operation. This is due to the extensive use of automatic process controls, and labour saving materials handling facilities. Introduction THE St. Joseph Lead Co., has operated lead mines in southeast Missouri for 100 years. These operations have been confined largely to the area called the

Jan 1, 1964

The cost of power is an important matter to mining companies generally and this thought that the members of the Australasian Institute of Mining Engineers, as well as the engineering and mining professions generally would be interested in any proposal for the reduction of that cost-has led to the presentation of this paper.The writer trusts that the description will be found clear and increase the interest in this exceedingly interesting subject. In the working up of the electrical arrangements touched on in this paper, the author has had the able assistance of hisfriend Mr. F. J. Mars, to whom he offers his hearty thanks. The selection of the best class of power plant for a mine is a very difficult and large problem and it is quite out of place to dogmatise that anyone of the many systems that offer isbetter than another, eg that the all electrical is better than the partly direct steam-driven and partly electrical, or that a gas plant is better than a steam plant.Such a selection is one that calls for very careful and close consideration, in each particular case, of a large number of regulating factors before it is possible to arrive at a proper decision.

Jan 1, 1911

By Peter Cunningham

Teck Facts and Figures ? Employ more than 14,000 around the world, includes: ? Over 8,600 in Canada (close to 7,800 in British Columbia) ? Close to 2,000 in Chile ? Over 2,700 in Peru ? Approximately 600 in U.S. ? Hundreds more in exploration around the world ? Total capital expenditures ? $1.8 billion for 2012

Aug 1, 2013

By W. H. Gross

To pollute means to make impure or unclean. We tend to forget that man defecates, urinates, sweats, expectorates and exhales and in himself is a beastly little pollutor-but then so is Mother Nature! The object of this paper is to try to put what man and nature do into perspective. The facts indicate that although man may sweat a little, Ms. Nature is by for the greatest pollutor of all.

Jan 1, 1979

By Jarvensivu M, Ylinen R, Jamsa-Jounela S-L

The paper presents a new integrated system for control of concentration processes. The system is based on cluster-based modelling taking the ore quality into account and a new on-line particle size analyser capable also for reliable measuring of particle size distribution of concentrate. A metallurgical precontrol audit was performed at the Hitura concentrator in order to design the control strategy of the integrated grinding and flotation control. A new analyser PSI-200, was used to the measurement and control of the distribution of nickel in the total particle size range. An expert control system using the cluster model together with a new control strategy for decision of necessary control actions is outlined. The method has been tested to real data from mineral processes. The results are in good correspondence with empirical process knowledge. KEYWORDS: Cluster analysis, expert control, flotation control, mineral processes, modelling, particle size.

Jan 1, 1993

By Longworth C. R

Competing requirements for land usage sometimes make the correct all- ocation difficult. The decision can be complicated by many factors such as local resident pressure, previous government decisions, economic pres- sures and the duration or permanency of the competing land usages. This problem often confronts the extractive industries with consequent delays in granting leases and some- times considerable local dissension. A proposal to extend the high grade silica sand quarry of the Wamberal Sand Company Pty. Limited is a microcosm of these competing requirements. The sand quarry is located on the New South Wales central coast. It is an open pit operation on a near beach deposit of silica sand suitable for flint glass manufacture.

Jan 1, 1976

Esso-BHP have installed a Production Supervisory Control System that is presently controlling the offshore oil and gas facilities on the Barracouta and Marlin platforms from an onshore master station. This control is achieved with a computerized master station onshore which uses a UHF radio system for telemetry and control. The system is designed to control, monitor, and gather data from a large number of oil and gas production platforms and has flexability to handle future variations in operating conditions. Thn -etom ..ill kn nvt,,ndnd to thn I-lalihn+ rJ,+f, rr , Into +hie -- -A +n the lei...,fieh .,lo+fnrmc A.,;- 1071

Jan 1, 1970

By John H. Bassarear, A. A. Dor

INTRODUCTION Primary grinding mills as defined in this paper, are autogenous or semi-autogenous rotating, tumbling mills having a coarse feed with a top size usually varying from 150 to 300 mm (6 to 12 inches). Most frequently, the feed to these mills is the product of primary crushing plants but in some cases run of mine ore is used as feed such as at Benguet, McDermitt, L-Bar Sohio, Bear Creek and others. The size of the largest lumps in the mill feed is principally determined by limits set by the mill feed trunnion diameter and by the type and size of conveying equipment used for handling and of bins and stockpiles used for storage. The use of primary mills in mineral processing plants has expanded very significantly in the last twenty years, and they have been successfully applied to the treatment of a wide variety of ores in both wet and dry grinding applications. In the present state of technological development for primary grinding mills, there is a wide choice of acceptable options with respect to type and size, grinding flowsheet and grinding media. The choice of the optimum combination which would result in the most satisfactory condition of operation, from the standpoint of both metallurgical results and costs, depends on the nature of the ore, the required characteristics of the grinding products and on various geographic and economic circumstances. The effects of such factors and considerations on the choice and sizing of primary grinding mills and flowsheets are reviewed and discussed in the following pages. PRIMARY MILLS SELECTION Inherent Characteristics of Primary Grinding Primary grinding is complex because it involves several comminution mechanisms which occur simultaneously and to some degree interfere with one another. These mechanisms of impact, attrition and abrasion have been described earlier. The relative importance of these three main grinding actions and their mutual balance resulting in a continuous uniform operation of the mill depend to a very large extent on the nature of the ore and its physical properties. Homogenous, single mineral ores will behave quite differently from heterogenous ores consisting of different minerals bound together along defined

Jan 1, 1982