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By Takagi T, Seetharam R, Sie SH, Naito K

Tin-polymetallic vein type deposits are one of the major source of metal producers in the Circum Pacific Belt. This type of deposit is of great importance for the modem electronics and medical industries because of their high content of rare metals (especially indium and bismuth). We have studied two representatives, Tosham of India (Cu-In-Bi-Sn-W-Ag-Au), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), using proton and electron microprobes in order to delineate the distribution of medical/high-tech rare metals. The electron microprobe study showed that major indium carrier in such type of deposit are roquesite (CulnSZ), sphalerite, stannite and a Cu-Zn-Fe-In-Sn-S mineral; and that indium is incorporated in sulfides by coupled substitution like Cu + In = 2(Zn + Fe). The proton microprobe showed that indium at trace levels is also present in chalcopyrite and pyrite. In addition, zinc, copper, arsenic, antimony, selenium, tin, and bismuth are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are higher in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is genetically related to S-type magma, while the Mount Pleasant deposit is related to A-type granite. Tosham ore contains zinc-bearing biotites that coexist with chalcopyrite in ore bodies but Mount Pleasant ore lacks such biotite. We propose that the difference in elemental abundance between the two deposits are caused by the different character of source magma and different mineral associations of the ore body.

Jan 1, 1995

By J Hunt

A critical aspect of geometallurgy is quantifying mineralogical and textural relationships that affect mineral processing (eg, liberation and recovery). However, to date, this has been an expensive and time consuming venture and only minimal amounts of this type of data are typically available to be included in the mine planning process. Our research is focused on developing methods that will produce the required mineralogical and textural data rapidly and inexpensively. New methods of characterising liberation potential from image analysis of coarse particulate material and direct small-scale flotation measurement are compared with measurement of liberation at final grind size (ie conventional tests on MLA). The new tests are designed to rank the liberation potential of samples in order to classify an ore deposit into domains of low, medium and high liberation potential. This parameter can then be used to adjust the cutoff used to differentiate ore from waste. Results to date show that all tests provide the same ranking for the samples. The measurement based on coarse particulate material compares favourably to the results from MLA analyses on the same samples. Further work is being carried out to determine which of the tests will be the most effective in terms of time, effort and cost

Sep 5, 2011

By T Clemens, D Trumm

Adopting environmentally acceptable practices in New Zealand is a crucial requirement for mineral wealth development. Recent planned expansions in the coal and gold industry have increasingly placed mining in the media spotlight. A lack of appropriate standard environmental guidelines has resulted in inconsistent responses and assessments of current and proposed mines. These inconsistencies have lead to delays in decisions on developing economic mineral deposits that may have only minor short-term impacts, and have also allowed unacceptable environmental management practices to continue elsewhere. A research collaboration between CRL Energy, Landcare Research, University of Canterbury and University of Otago aims to provide regulator groups and the mining industry with a unified approach to the requirements of the Resource Management Act 1991,the legislation that largely drives the nationÆs environmental policies and guidelines. The tangible outcome of this research program will be water quality and impact management guidelines integrated into a decision-making framework. The result of this unification will assist in the development of viable mineral deposits and minimise environmental impacts. The framework will be derived from a synthesis of three objectives. Objective 1 identifies potential water quality impact. This objective is based on a targeted geochemical study of the lithology and waterways of the West Coast and Southland regions. Objective 2 categorises the degree of impacts on the ecology of receiving aquatic ecosystems and determines the processes that drive aquatic ecosystem recovery. Objective 3 identifies best strategies to sufficiently manage impacted ecosystems, and to prevent future unacceptable impacts. Wide consultation with representatives of the mining industry and regulator groups will occur frequently during the development stages of the framework. It is anticipated that this multidisciplinary approach will provide a robust and coherent, standardised system that will assist in achieving industry and environmental targets.

Jan 1, 2004

By Hawes GW

Until 1980 copper, lead and zinc sulphide slurries have been success- fully dewatered for rail and sea transport for many years at the Rose- bery site of North Broken Hill Holdings Ltd. utilizing conventional vacuum disc filtration systems. An upgrading and mill expansion program completed in 1981, which also permitted the introduction of ore streams changes, had resulted in difficulties dewatering copper and lead sulphide slurries to comply with transportable moisture limits. Following an extensive investigation which included both laboratory and pilot plant testing a program was commenced to replace the 2 vacuum disc filtration systems with 2 pressure filtration systems for use on copper and lead slurry dewatering and also to retain other existing vacuum disc filters as standby. An analysis of mill operations performance resulted in slurry storage tanks with a capacity equivalent to 20 hours of normal production being incorporated into the project. The pressure filters are mounted above the concentrate stock- piles. A sealed sloping floor incorporating launders is used to prevent any accidental contamination of the concentrate from pipe leakages, spillage, or from water hoses used for clean up purposes around the area. The project was completed in 1985 and operating performance has been better than that predicted from testwork. Equipment availability at 95076 together with the slurry storage capacity provided results in minimal requirement for the standby vacuum filtration system. Some typical operating results are given.

Jan 1, 1988

By Forster G, Datta P. K

Many high temperature industrial processes involve gaseous halogen-bearing environments. Essentially, these fall into three subject areas: power generation, waste incineration and especially extractive metallurgy. Fundamental to any understanding of the process chemistry and efficiency in the process technology is an adequate knowledge of background thermodynamics relating to metal-chlorine reactions. In this context, existing free energy/temperature diagrams for metal chlorides do not include many elements, in particular the so called refractory elements from Group V and Group VI of the Periodic Table, namely niobium, tantalum and vanadium, and molybdenum. This paper reports estimation and calculations of the free energy values for these chlorides. The data is discussed in the context of high temperature chlorination processes.

Jan 1, 1991

Reconnaissance geochemical exploration in the vicinity of low angle detachment faults which bound the core of the Paparoa metamorphic core complex yielded Au up to 14 ppm, with 35% of greywacke, granitoid and quartz vein samples in the northern range exceeding the 0.01 ppm detection limit. Au is associated with Ag, As, Sb and Cu anomalies consistent with epithermal-type mineralisation. The Ag and Cu anomalies also distinguish this mineralisation from older, mesothermal Au deposits widespread in the Ordovician 'slate belt' greywackes, which comprise much of the upper plate of the core complex. Baryte, molybdenite, fluorite and stratiform U mineralisation in the northern Paparoa Range may also be related to hydrothermal activity along the detachment fault zones.

Jan 1, 1995

THOSE who have had occ.asion to sample a mine not infrequently find that it is impossible to take their sample cuts at regular distances apart, owing to the ground being close timbered, a stope having been taken out, or some other cause. When such is the case a tedious calculation becomes necessary in order to obtain an accurate result. A conscientious man will make the tedious calculation, but one who is inclined to be lazy, or who does not recognize the importance of accuracy, or has not the time, may be satisfied with either the arithmetical or weighted arithmetical mean result.There are two main systems of taking samples when the cuts are taken-(l) at equal distances, (2) at unequal distances. When the samples are out at equal distances apart there are three methods of computing the assay value :-1 (a) By Arithmetical Mean. The sum of the values and sum of the widths are each divided by the total number of samples, in order to obtain the value and width respectively, no allowance being made for the relative widths arid values. The result isabsolutely inaccurate, and should never be used under any circumstances.1 (b) By Geometrical Mean. The assay widths ie, feet %, feet oz, inch dwt, &c, are added together and the sum of these is divided by the sum of the widths.

Jan 1, 1911

An approximate rapid design system for tunnel liners and underground structures is presented which permits the effects of structure geometry and stiffness, rock quality in terms of its deformation modulus, and the applied system loading to be entered as data to produce direct designs conforming to stress limitations, optimum reinforcement requirements and restraints on section dimensions. An 'equivalent column' concept is introduced for modelling the rock mass in contact with the structure. Only the rock treatment is given in detail but the results of sensitivity analyses, with reference to rock quality, for a typical liner design are given and these results related to a number of empirical design approaches.

Jan 1, 1976

By W T. Pate, A V. Potapov, J K. Lichter

Even though flotation is one of the most important unit operations of mineral processing, accurate modelling of this process for plant performance prediction has remained elusive. In the last four to five years dramatic changes have occurred in our ability to make credible model based predictions. This paper briefly traces the history of flotation modelling from simple (lumped pulp-froth) æchemical kinetic analogueÆ models for single cells to more detailed multi-phase, multi-component population balance models for banks of cells. It then focuses on recent developments in physics-based modelling tools. This includes current efforts to model the forces of attachment and detachment at the individual event level as well as multi-event levels in individual cells and circuits. Two examples of these tools are presented. The first is DEM modelling of the mechanics of motion of bubbles in froths. The second is population balance modelling of the dynamics of flotation circuits describing how they are influenced by upstream processes (such as crushing and grinding) as well as internal process variables (such as aeration, agitation and reagent addition). Applications of each of these tools are discussed.

Jan 1, 2005

The Mary Kathleen uranium deposit occurs in 1740-1780 M yr-old calc-silicate melasedimentary and mela-igneous rocks of lhe Corella Formalion which have been tightly folded into lhe Mary Kathleen Syncline. The Corella Formation consists of malic and felsic tuffaceous(?) calc-silicates, quartzile, and minor marble, conglomerate and basic volcanics. Garnet-rich rocks form semi-concordant and transgressive masses in the middle and upper portion of the sequence. Granite, gabbro and acid porphyry dykes also occur in the syncline.Uranium-rare earth mineralisation is closely associated with certain malic rocks and occurs wilhin or close to garnet-rich masses. At Mary Kathleen, uraninite grains are enclosed mainly by allanite which is dislribuled through massive garnet as an irregular honeycomb of interconnected shoot and lenses. The mineralisation occurs along strike from dioritic rocks and conglomerate and lies close to the axis of the Mary Kathleen yncline and adjacent to a major faull zone. All other localities allanite-uraninile mineralisation is broadly stratiform.The mineralisation is interpreted to occur at or near centres of basic volcanism. Garnet formation and uranium-rare earth concentrations are believed to be caused by the volcanism, and to be contemporaneous with it. The former is seen as alteration of a hot, saturated pile of volcano-sedimentary material and the latter as intermittent hydrothermal exhalation.Deposition, volcanism, garnet formation, uranium and rare-earth mineralisation, granile and gabbro formation, and tectonism are seen as a continuum of interrelated processes which operated throughout the period of format ion of the rocks in the Mary Kathleen Syncline.

Jan 1, 1985

By T QUINLAN

A resource estimate uses data obtained by sampling an orebody. An example is described in which a random drilling pattern did not provide a representative set of assays, and the estimated resource was significantly less than the mine production. It is believed that a better estimate would have been made if the exploration holes had been drilled on a regular grid.

Jan 1, 1992

By KeBler H-W, Seeliger A

Vibration analysis for diagnosis of machines is a powerful instrument for condition monitoring. Especially for diagnosis of antifriction bearings various equipment and techniques have been developed and are available. The envelope analysis is the most reliable method for bearing diagnosis. Different bearing failures lead to different patterns of the envelope spectrum. Checking the amplitudes of characteristic bearing frequencies is mostly not sufficient for a reliable diagnosis. Therefore human experts compare the pattern of the spectrum with typical patterns of bearing defects. In this paper a diagnosis system is presented which imitates this action of human experts. Using a neural net the system not only distinguishes typical bearing defects but also detects unbalance, beating of disengaged machine parts and other kinds of machine failures.

Jan 1, 1995

By I Mason, A Bray, K Smith, T Sindle

Borehole radar is a proven geophysical technology that can be used to map an orebody ahead of mining. This paper will present a case study, where borehole radar is being used within the mining cycle to map out orebody blocks, both as a strategic and tactical tool. Refined equipment and procedures now enables a slimline borehole radar tool to be deployed on the end of drill rods, making it easier and faster to deploy in an underground mine with minimal impact on the mining process. Boreholes are drilled in advance of mining; cover holes to ensure the competence of the hanging wall and geology holes to determine the location and grade of ore are two such examples. All of these boreholes can be entered using a borehole radar tool to map geology and structure ahead. The radar data can provide images of the orebody as well as help detect potential water bearing structures that could impact on safety at a mining face.

Jan 1, 2009

By J O. Watson, V S. Vutukuri

This paper presents results of an investigation on acoustic emission characteristics of granite, sandstone and rock-like material in the unconfined compression and tensile tests. Both the acoustic emission signature and stress-stain curve are analysed in the experiments.The experimental results show that different acoustic emission characteristics are observed at different stress and deformation stages in unconfined compression and tensile testing. Extensive and unstable acoustic emission changes may be interpreted as indicating failure of the rock.

Jan 1, 1999

By M Ljunggren, M Lundh

Dissolved air flotation (DAF) in wastewater treatment as a separation process of submillimetre biological flocs is based on the generation of bubble/floc aggregates. DAF is a complex process but has got advantages, such as allowing a high hydraulic load, compared to sedimentation. A thorough knowledge of the physics of the DAF process is, however, still lacking. This paper will present results of experimental studies on three aspects of significance to the separation process û the flow structure in the flotation tank, rise velocities of aggregates, influence of floc size on the separation efficiency. Flow structure. Measurements were performed in a pilot plant mapping and visualising the velocity field. The dispersion water (bubbles) had a decisive influence on the flow structure due to the effect of the bubbles on the bulk water density. Stratified conditions with a less dense, bubble-containing upper layer and a clear water, denser bottom layer were important for a good separation. A simple model of the stratified flow structure was elaborated making it possible to interpret the function of the aggregate rise velocities. Bubble/floc aggregates. The dynamics of single flocs, bubbles, aggregates were visualised using a borescope + CCD video camera + digital recorder + image analysis. Sequences of video frames made it possible to determine the rise velocities of the single aggregates. These velocities were found to be in the range 1 - 9 mm/s with a tendency for large flocs to have higher rise velocities. Separation versus floc size. The floc size distribution was measured in the DAF process. Data from three different DAF cases showed, that large flocs (> about 100 ¦m) were entirely separated, whereas small flocs experienced a less good separation. It was, moreover, found, that a very significant separation of flocs took place in the very upstream end of the separation zone in a pilot plant case.

Jan 1, 2005

Spatial continuity as described by a variogram is a reflection of the underlying mineralisation/geology. Modelling of the spatial continuity (variogram) must account for both the quantitative data (ie sample grades), on which the variogram calculations are based, and the qualitative information as provided by the geological interpretation. An understanding of the geology and the variogram interpretation tie together the sample values and allow us to go beyond the actual data (Journel, 1995). Variography makes geology transportable and allows the geological interpolations to be channelled downstream into mine planning, ultimately affecting the economic decisions surrounding a deposit. As such the process of variography and resource modelling is critical. Thus consistent expert decisions need to be made which force geologists to have a closer look at the available information and the geological interpretations. The aim of this paper is to provide an overview of the latest developments in visualising variography and to demonstrate their usefulness in decisions regarding the spatial continuity of mineralisation. New ideas concerning potential future developments in visualising and modelling spatial continuity through variography are introduced.

Jan 1, 1996

By Bronson B

The geotechnical and environmental aspects of heap leaching are very closely tied during design, operations and closure. Potential environmental impacts from heap leaching are mostly due to land disturbance and water quality issues, including both groundwater and surface water. Water quality issues are mostly related to containment design, which is primarily a function of proper sizing of the facilities and site specific liner design. Geotechnical analyses is the dominant discipline in providing cost efficient, operationally effective and environmentally sound heap leach facility designs. Much has been published on geotechnical aspects of heap leach design, for example Van Zyl, Hutchison and Kiel (1988) and Van Zyl (1987). This paper will emphasize a few specific aspects related to the geotechnical and environmental consideration for heap leach projects. These aspects are: ò site investigation; ò containment design; ò slope stability; ò heap flow dynamics; and ò closure design. Design of a heap leach project must consider not only the operating life but also closure and post-closure considerations. As a matter of standard practice, designing for closure is an extremely important concept. Not only is it important for environmental aspects, but experience also shows that projects designed for closure will be overall more economical for the total life cycle of the project. Closure considerations are also important during project feasibility evaluations to ensure that total life cycle costs are evaluated.

Jan 1, 1994

This paper considers three aspects of cemented fill practice and research in Mount Isa. Firstly, an account is given of the use of Portland cemented hydraulic fill both in MICAF sills and in recovery of major horizontal pillars in the 650 copper orebody, where, during mining, cemented fill has regularly been exposed on unsupported vertical faces up to 90 ft high. In the paper the main considerations are the role and specifications of the fill used but also included is a brief description of fill preparation and placement.Data resulting from a Portland cemented hydraulic fill sampling, curing and testing campaign covering about 18 months of operating practice are presented, analysed, and discussed. These yield information indicating the mode of operation of a fully-automated fill preparation station, as well as a means of comparing field and laboratory strength results. A technique with potential for use as a fill quality control without actual strength testing is also described. The data collected showed that the fill station can operate within tolerances set on product quality, that laboratory and field strength results are comparable, and that rapidly obtained fillsample properties such as moisture content and void ratio can be related to cement content and strength, and hence used for quality control.Results of a fill research programme conducted by the author in Mount Isa since early 1968 are presented involving Portland cemented hydraulic fill and alternative, cheaper additives for cementing hydraulic fill. The most significant alternative to Portland cement is quenched and ground copper reverberatory furnace slag, whIch behaves as a pozzolan, reacting strongly with any available lime to produce cementitious hydrated calcium silicates and allowing Portland cement reductions of at least 50 per cent without strength loss.

Jan 1, 1971

By Swift J. D

A key parameter affecting the performance of gravity thickeners in hydrometallurgical processing operations is the aggregation state of the feed after the addition of a flocculant. New procedures which measure the settling ratelsize relationship and the size distribution of aggregates in their process liquors have been used to quantify the aggregation state of the feedwell, overflow and underflow streams in a tailings thickener. The data obtained have been related to the thickener's operation and to a change in the flocculant dosage. A comparison is also made between the settling rate/size relationships determined with these new procedures and the mud-line settling rates from cylinder tests.

Jan 1, 1991

By Miyashita T, Yamamoto R, Kishimoto s

Following considerations of the effect of furnace size on pressure loss, pressure loss in front of tuyeres, gas flow in the lower parts of the furnace, the distribution of the burden and the gas flow in large blast furnaces is examined with particular reference to the burden distribution at the throat and the gas flow at high production rates. Improvement of gas flow is related to application of super-high top pressure and the use of moveable armour. A brief description of the NKK type moveable armour is given and its use in controlling the gas flow outlined. The operating results under controlled gas flow show an increase in production of Fukuyama No. 5 BF from 9,200 tpd to 11,000 tpd with a decrease in the fuel rate from 490 kg/thm to 460 kg/thm.

Jan 1, 1975