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The Effect of Molecular Weight on the Adsorption and Efficacy of Polysaccharide Depressants

Sep 13, 2010

By William J. Rothschild

Ground water at construction sites can be controlled by properly placed wellpoint dewatering systems. Care must be taken in planning cofferdams to have adequate space for and access to pumps, headers and the points. A most important part of dewatering is protection of adjacent structures from movement. A checklist gives items to consider in bidding.

Jan 1, 1984

By A. B. Parsons

Jan 1, 1971

By O?Connor. D. F.

The ever increasing energy costs associated with mining at depth has become an important issue that needs to be addressed for future sustainable production. Vale Inco Limited?s Creighton Mine being the deepest has the highest energy cost per ton due to the ventilation system requirements. A review of the ventilation systems was undertaken with respect to current practices and identification of opportunities to the practical application of technology that would facilitate energy savings. Energy conservation initiatives such as time of day controls have been implemented; however there still remained some opportunity for further reduction. Based on previous studies that identified opportunities due to actual time spent in the workplace, our mining method and ventilation design, it was determined that Ventilation on Demand (VOD) could provide further additional energy reductions with respect to our auxiliary fans. A pilot project has recently been initiated to apply a Ventilation on Demand concept to two 112 kW auxiliary fans and their related workings located on the 2340m level of Creighton Mine. The project objective is to determine the practical methodology and application of this technology in the field. This project involves the installation of variable frequency drive (VFD) starters on the auxiliary fans to allow variable volume (through speed control) based on demand. The required flow is determined based on equipment and/or personnel via identification tags. The Fans adjust to the flow requirements as measured by flow sensors. Since the fans are sized for the final requirements the required flows can be achieved regardless of system length. Energy savings are realized by supplying only the volumes (power) as required and only when required. This paper discusses the rational and program being tested at the VALE Inco Limited, Creighton Mine.

Jan 1, 2009

By Whiten W. J

An investigation on the breakage characteristics of closely sized orc samples at different levels of input energy was carried out to determine an appearance function for possible use in ball mill modelling. A consistent pattern of breakage behaviour was observed and the resultant size distributions could be described by a one-parameter, ('t'), family of curves. For each particle size range tested, this parameter 't' has an exponential relationship with input energy below an upper energy limit. A tentative linear relationship between the input energy at a constant value of 't' and the work-index leads to reconstruction of 'I' - input-energy curves from the work-index values. To normalise the efrect of particle size and input energy, multidimensional cubic spline regression was performed on thc entire range of data. The results indicated that the parameter 't' can be determined, reasonably accurately, as a function of Ln (input energy, kWh/tonne) and Ln (particle size, mm) for input energies between 0.5 and 8.0 kWh/tonne.

Jan 1, 1983

In spite of the many contributions that have been made to our knowledge of the creep properties of polycrystalline lead, the precise influence of various factors on these properties is not yet fully understood. Indeed, the position is such that several important points in connection with the creep of lead are a matter of controversy. This has been brought about largely by the fact that, in the case of lead, the changes that are produced in the creep behaviour by slight variations of such factors as the purity, grain sizeand previous treatment are out of all proportion to the magnitude of these variations.In order to study the fundamental properties of lead as related to creep, and so gain a more enlightened perspective with which to consider the creep of lead in general, the work that is described in a series of papers, of which the present paper is the third part, has been carried out. It deals with lead in the form of single crystals.It has been shown (1) - (3) that the grain boundaries as well as the actual grains play a part in the creep of polycrystalline lead. The present work, by eliminating grain boundaries, enables the. contribution of the grains themselves to the process of creep, in other words, crystalline creep, to be studied effectively.This object was, possibly, the major one in this work.

Jan 1, 1940

By E J. Hofmann, J E. Hofmann, A J. Hofmann-Fritz

"With its Head Quarters in Perth, global heavy engineering company Hofmann Engineering is one of the largest family owned engineering companies in Australia. The company has pioneered a number of new manufacturing processes and design improvements for components of large comminution equipment.Some of these innovations are: Innovative design improvements of high pressure grinding roll (HPGR) forged steel tyres. Hofmann Engineering has developed unique patented tungsten carbide stud and edge protection designs which improve wear life and introduce quick and cost effective replacement options to further extend the life of the tyre. Development of forged fabricated mill heads using rolled and welded high tensile steel plate as an alternative to cast conical mill heads. Establishment of Australian capability to manufacture and export up to 42 ft. (12.8 m) diameter SAG mill shells. Techniques for fast track, product improved replacements of cracked or damaged mill gears, including in situ profile & wear measurements of girth gears using portable coordinate measuring machine (CMM) technology, forged rim steel and induction hardening technology. Gear and pinion mechanical drive designs to 24 MW or higher for SAG mills of 38 ft. to 42 ft. (11.6 m - 12.8 m) diameter as reliable alternatives to gearless drives.The paper presents case studies from the Australian heavy manufacturing facilities of Hofmann Engineering on large, high powered equipment for both the domestic and export markets.CITATION:Hofmann, E J, Hofmann, J E and Hofmann-Fritz, A J, 2013. Australian innovations in high pressure grinding rolls and large grinding mill manufacture, in Proceedings MetPlant 2013, pp 141-151 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By C. -T. Mutale, A. S. Tuling

Titanium can exist in three different oxidation states. Its oxides are numerous and in presence of iron and oxygen, iron-titanium oxide compounds can also form. Some of the oxides are non-stoichiometric, making the determination of the thermodynamic properties of titanium and its oxides in molten steel and in slag difficult. Therefore, for the assessment of titanium activity in molten steel using the electrochemical measurements of oxygen partial pressure, the identification of oxides in equilibrium with titanium is important. This paper reports on an investigation of solid titanium oxide inclusions, which have been identified by combining different methods of analysis on quenched samples. These samples were taken from a Fe-Ti-melt at 1600°C, quenched in cold water then mounted and polished for optical microscopy. The oxide inclusions were analysed using transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS). Both single crystal and polycrystalline diffraction patterns were used to identify the oxides by comparing the d spacings with those in the ICDD X-Ray Diffraction (XRD) database. XRD was used to analyse the oxide particles on the top of slow cooled samples. It was found in the TEM study that the similarity of the diffraction patterns of the various phases meant that unique identification was difficult to achieve in some of the diffraction patterns. However, TiO, Ti2O3, Ti3O5, Ti4O7were identified in quenched samples, while TiO2, FeO.TiO2and iron oxides were seen in slow cooled samples. It was also confirmed that the type of oxides is related to titanium content of the samples. Keywords: Titanium, Titanium Oxides, Iron, TEM, XRD, thermodynamic.

Jan 1, 2004

By Wern-Ping Nick Chen

Durability risks for underground facilities can be underestimated during design phase as compared to well-known geological risks. However, unclear durability requirements can result in construction schedule delay and change orders. Unlike bridges or buildings, a unified underground durability code or standard does not exist. This paper will provide a durability approach for underground facilities, including degradation modes, mitigations, and compliance measures during construction. In addition, this paper will address how to clearly specify durability requirements in a contract document to reduce disputes during construction and discuss key durability tests that are time consuming and will impact construction schedule if not timely planned.

Jun 23, 2024

By T Harding, T Riggs, D Taylor

High-grade hematite ores in the Hamersley Province of Western Australia are associated with hydrothermal magnetite-apatite and magnetite-hematite-carbonate-apatite proto ores below the modern weathering surface. In addition, hydrothermal alteration of country rocks, once believed to be absent, is now recognised widely in shales and dolerites up to several hundreds of metres away from the ores. Both observations appear to exclude a simple supergene model for ugrading the host iron formations to high-grade hematite ore. Similar hydrothermal proto ores and country rock alteration are now being recognised in other high-grade hematite deposits worldwide, or have been recognised in the past.

Jan 1, 2002

By Murray Pearson, Jack Murray

"The danger of autoclaves lies in the high temperatures and pressures that exist in autoclave vessels. The usage of autoclaves will continue to expand in the mining industry because of their efficiency and environmental friendliness. But increasing attention must be paid to ensuring their safety. Safety Instrumented Systems (SISs) play a critical role in autoclave plants by detecting potentially dangerous conditions, taking the plant to a safe state, informing the operator about the plant status and the cause of the trip and expediting safe plant restart. The SIS should ideally be fully integrated with but functionally independent of the Basic Process Control System (BPCS) and provide redundant logic solvers to increase safety and plant availability while reducing spurious trips.INTRODUCTIONWikipedia defines an autoclave as follows: “An autoclave is a pressurized device invented by Charles Chamberland in 1879 designed to heat aqueous solutions above their boiling point to process materials.” A typical autoclave system used in the metallurgical industry includes, besides the autoclave vessel, heat recovery (heater) vessels, high pressure positive displacement (HPPD) feed pumps, vessel lining systems, specialized internals and components, agitators, pressure letdown or flash vessels, isolation and control valves, over 2,000 I/O points and related instrumentation, and emergency relief systems."

Jan 1, 2009

By D Craw, J Pope, B Peake

Southland contains over 70 per cent of New ZealandÆs recoverable coal resources, and an investigation into the potential effects of coal mining on SouthlandÆs water resources is therefore of interest. This paper investigates pit-lake water quality in relation to current mining activities within the sub-bituminous coal and lignite deposits of Southland.   Water quality data was collected from pit-lakes in sub-bituminous and lignite deposits from October 2005 to March 2006. After periods of settled weather, turbidity increased with depth at the sub-bituminous pit-lake (10 - 21 NTUs from 5 - 30 m). In the stratified sub-bituminous pit-lake in March 2006, heavy rainfall caused higher turbidity in the epilimnion than the top of the hypolimnion (20 NTU vs 13 NTU) reflecting surface water runoff (up to 1993 NTUs) and epilimnion mixing. In contrast, turbidity at the lignite sites was variable due to the shallowness of the lakes, but noticeable increases following disturbance and adverse weather were recorded. High turbidity at the sub-bituminous deposits was attributed to the presence of clay minerals such as kaolinite whereas turbidity at the lignite sites was more likely short term and a result of heavier minerals such as quartz.   Trace element concentrations at both sites were low when compared to mine waters in other coal areas in New Zealand and no samples exceeded ANZECC water quality trigger values for 80 per cent species protection. Pit-lake water pH levels were lower and more variable in the lignite deposit (4.18 - 7.30 vs 7.24 - 8.98 in the sub-bituminous deposits). In the lignite pit-lakes, higher concentrations of trace elements (eg Dissolved As - 0.034 ppm and Dissolved Mn - 1.09 ppm) and lower pH (ÿ4) were observed at the bottom of active pits compared to inactive pits. It is possible that quartz pebble conglomerates containing sulphide minerals within the lignite seams are responsible for this.   Further investigation into the mine waters, waste rock and lake sediments will help get a better understanding of the results observed and long term processes that occur.

Jan 1, 2006

By Rony Yupanqui C

El presente trabajo señala el proyecto de remediación de los relaves mineros realizado en la relavera Ticapampa, ubicado en el Distrito de Ticapampa – Huaráz, región Ancash, con el objetivo de remediar los relaves de TICAPAMPA depositados por más de 30 años y que contaminan al río Santa, fuente principal de irrigación del Valle del Callejón de Huaylas. El proyecto comprende la extracción de contaminantes del pasivo ambiental de Ticapampa a través de la flotación de los sulfuros de fierro, y la obtención de un material inerte (con bajo contenido de sulfuros contaminantes) para la fabricación de productos cerámicos por medio de resinas recientemente desarrolladas.

Sep 12, 2011

By T Grenne, R. B. Larsen

Paper presented at the conference on Economic geology in Europe and beyond II, models for mineral deposits in sedimentary basins, held in Keyworth, UK, 13-14 April 1994. Paper originally entitled: Processes in a newly discovered sulphide-PGE mineralisation in Norway. The Stormyrplutten mineralisation is hosted by a minor tholeiitic metagabbro of low-Ti composition intruded at a high level in the volcanic lithology. It is thought to be the subvolcanic counterpart of submarine basalts generated during an extensional episode of ensimatic arc evolution. The sulphide-PGE mineralisation occurs as stratabound pyrite, pyrrhotite and chalcopyrite disseminations with average grades of 376 ppb Pd, 313 ppb Pt, 40 ppb Au, 0.5% Cu and 0.08% Ni in a deposit 15-25 m thick. Locally the PGE content peaks at 2 ppm over 1 m. Microprobe analysis isolated 14 different platinum-group minerals, dominated by sperrylite, temagamite and borovskite and occurring as 1-20 micron compounds embedded in the main sulphide minerals or along the sulphide/silicate grain boundaries. Mantle-normalised plots reveal strong depletion in Os, Ir and Ru and enrichment in Pt, Pd, Cu and Au. The general decrease in Pd and Pt and increase in S up through the stratigraphy is similar to PGE distribution in the Darwendale subchamber of the Great Dyke in Zimbabwe, and may reflect strong fractionation of Pd and Pt in favour of the first droplets of sulphide melt; two reversals of the trend at the 4 and 12 metre levels represent replenishment with fresh magma and repetition of the cycle. In contrast to the Darwendale system, Cu and Ni also show peak concentrations in the first-formed liquids and Pt appears to have fractionated more strongly into the sulphide melt than Pd

Aug 1, 1995

By P W. Wypych

The iron ore industry faces significant challenges in the control of dust to meet emissions regulations and goals, as well as ensuring sustainable operations. This paper describes some of the different techniques and innovative technologies that are being developed and implemented to improve the suppression of airborne dust, specifically through the use of high energy micromist sprays. The utilisation of computational fluid dynamics (CFD) modelling and simulation is identified and described as a key enabling technology for an improvement in dust suppression solutions both from a level of understanding the source and flow of dust emissions, and for the development of new systems that can be used in the iron ore industry. CFD modelling is shown to be effective for modelling both spray dispersion and cross-wind effects, allowing designers to develop high-efficiency dust suppression systems with a greatly improved level of confidence when compared to traditional techniques. New high energy micromist technology is also outlined as a key element in developing high-efficiency dust suppression systems. Experimental results and industry applications are presented to demonstrate the significant improvements that can be achieved in suppressing or reducing airborne dust emissions.CITATION:Roberts, J M and Wypych, P W, 2017. Research into improving the efficiency of water spraying airborne dust control techniques in the iron ore industry, in Proceedings Iron Ore 2017, pp 359–364 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Yao Zhou

Under the United Nations Convention on the Law of the Sea (UNCLOS), the international seabed area (Area) and its resources are the common heritage of humanity (CHH). Patent rights can be incompatible with the CHH doctrine and its underlying principles because patent holders might charge unjustifiably high prices to license patented technology for exploring and exploiting the Area’s resources (creating a "patent holdup" situation), might choose not to license, or might license exclusively when doing so would contravene CHH principles. However, a reasonable patent licensing regime can contribute to sharing the benefits derived from the Area and promote environmental sustainability. Provisions of the UNCLOS that stipulated compulsory technology and financial transfers were removed in the 1994 Agreement relating to the Implementation of Part XI of the UNCLOS but to promote equity and sustainability I propose a voluntary licensing regime modeled on the concept of reasonable and non-discriminatory patent licensing that has been used in other contexts. The International Seabed Authority or another entity will need to coordinate and promote this licensing regime through governance of intellectual property derived from the Area. This proposed approach can better effectuate the CHH doctrine and its underlying principles.

Sep 1, 2014

By D. Hoffmann, S. Plumb

IRUP is an iron-rich ultramafic pegmatite rock that formed due to hot ironrich fluids and gases replacing local stratigraphic zones of the Bushveld Complex. This study focuses on the estimation of the probability of IRUP occurrence on the Merensky Reef at the Marikana Karee Mine. A 2.15 million centare IRUP-rich domain at the Karee Mine was initially defined from the interpretation of a surface aeromagnetic anomaly, and exposures in the mine workings. Surface boreholes (spaced 250-500 m apart) within this IRUP domain contain approximately equal numbers of IRUP-replaced and IRUP-free intersections. Owing to the uncertainty in the continuity of the IRUP alteration (a result of the wide borehole spacing), the risk associated with the development of mining infrastructure within this domain is unquantifiable. Semi-quantitative data comprising visual estimates of IRUP replacement from reef development mapping data and surface borehole reef intersections was interpolated into blocks using indicator kriging estimation. Comparative analyses of the estimate of IRUP occurrences were made by changing the block size and declustering the data systematically. Reconciliations of the probability of IRUP predicted from the block models derived from the different data-sets and sequential indicator simulation models were analysed for four mining study blocks. A quantitative approach to modelling the occurrence of IRUP can be an additional tool for refining the estimate of the geological losses that inform the mine plan in such high-risk zones.

Jan 1, 2015

By N F. Fraser

Seafield ResourcesÆ offshore placer gold project covers c.10 000 km2 of the Westland continental shelf between Karamea and Jacksons Head, from the low-water mark out to the 120 m isobath (Figure 1). De Beers Marine (DBM), the marine diamond subsidiary of the De Beers Group, will carry out the project with geological input from Placer Solutions (PSL). DBM bring a wealth of expertise and advanced technology to the project, developed during their 20 years of exploration and mining of diamond placers on the Atlantic shelf of southern Africa, where they have also maintained a strong environmental record.   Glaciers and high-energy rivers emanating from the Southern Alps have transported substantial quantities of gold bearing sediment onto the Westland continental shelf during Pleistocene glacial periods, when fluvial gradients are steeper, sea level is c.120 m lower and most of the shelf is exposed. These deposits have been extensively reworked by the advancing shoreline and marine processes during interglacial marine transgressions, and most are now buried beneath a variable thickness of post-glacial marine sand, silt and mud. DBM will use side-scan sonar, swath bathymetry, Chirp sub-bottom profiling and a magnetometer to map the sea floor and sediments beneath it, guided by PSLÆs predictive geological model for gold distribution on the shelf. Cactus grab and vibro-core samples will be used to ground-truth the geophysics and provide stratigraphic, sedimentological and gold distribution data for incorporation into the geological model. Areas of interest identified by the geophysical and sampling data will be investigated in more detail, with closer-spaced geophysics and Mega-drill sampling to a maximum sediment depth of 20 m beneath the sea floor. These samples will be raised to the ship with air-lift suction technology, processed onboard for mineralogical and grade information, then returned to the sea floor. Environmental baseline data will be gathered from Van Veen grab samples of seabed sediment taken throughout the area during the prospecting programme.

Jan 1, 2005

By P. Foster, A. Burton

Over the past decade there has been a great deal of research into the use of virtual reality (VR) and computer graphics in the mining industry. Much of this has led to developed applications including training simulators and accident re-construction. One other area where there is considerable potential for virtual reality is that of mining ergonomics. This paper identifies those common ergonomic limitations associated with mining equipment that can be effectively modelled using VR techniques. From this, two simple models have been developed namely (i)remote control continuous miner operation and (ii) free steered vehicle sightlines, which demonstrate the practical use of VR in this area.

Jan 1, 2003

By G. J. van Tonder

The use of Molecular Recognition Technology (MRT), a highly selective separation technology using specifically designed ligands (such as macrocycles), has been demonstrated to be an effective treatment process for removal of several ions that are commonly found in many hydrometallurgical circuits as well as in environ-mental treatment operations. Ions removed by MRT include base, heavy and transition metals, precious metals, halides, and alkali/alkaline earths. A MRT pilot plant run was conducted at Zincor to demonstrate the cobalt/nickel purification of zinc electrolyte, and to recover saleable pure cobalt/nickel sulphate solution. The MRT process holds various advantages, which include the elimination of a catalyst such as arsenic trioxide, conventionally used in cobalt and nickel cementation. SuperLig® 138 can be used to remove cobalt and nickel from120?170 g/l Zn-solutions at pH 1?2. The Zincor MRT application demonstrated its capability of concentrating large volumes o copper barren impure solution at low cobalt and nickel concentration levels in the feed, to small solution volumes at high cobalt and nickel concentrations. Around 99.5% of the cobalt was removed from solution with cobalt impurity levels in feed varying between 10 mg/l and 26 mg/l.

Jan 1, 2002