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This backgrounds the methods, and technical terminology, of digital image processing techniques used to write out remote sensing imagery.

Jan 1, 1983

The relationship between comminution testwork results and the milling circuit that is subsequently selected is not a direct one and frequently involves recourse to databases of past test results. This in itself reflects the lack of a systematic engineering approach in the design process. This paper reviews comminution tests for SAG mill design in an attempt to identify where the essential information comes from that will be used in mill selection. The conclusion is that results from traditional test methods, including obscure and little used procedures like the Mokken test, are more valuable from an engineering perspective than parameters for breakage rate based modelling. Suggestions are made on ways in which existing test procedures can be enhanced in order to generate parameters that can be directly related to characteristics of the milling circuit being designed.

Jan 1, 2002

By J E. Lynch

The Weda Bay nickel and cobalt laterite deposits on Halmahera Island, Republic of Indonesia were first drilled in May 1996 by Strand Minerals Pte Ltd (Strand). Subsequent exploration has delineated four large laterite provinces, parts of which have been diamond drilled to outline an indicated nickel resource of 59.9 Mt of 1.51 per cent Ni and 0.09 per cent Co within a total indicated and inferred resource of 117 Mt of 1.36 per cent Ni and 0.12 per cent Co. The project is held as a Seventh Generation Contract of Work (COW) by PT Weda Bay Nickel, which is jointly owned by Strand (90 per cent) and PT Aneka Tambang (ten per cent). Strand is a wholly owned subsidiary of Weda Bay Minerals Inc, a company listed on the Toronto and Alberta Stock Exchanges in Canada. Halmahera is located in the north-eastern part of the Indonesian archipelago at the convergent junction of three major plates and is a region of considerable tectonic and geological complexity. The western arms of Halmahera form a classic volcanic island arc while the central region and eastern arms contain ophiolite complexes and interlayered sediments. The extensive areas of laterite discovered at Weda Bay have developed over serpentinised harzburgites and dunites of pre-Cretaceous age. Weathering of these rocks has produced laterite profiles that are enriched in nickel and cobalt. There are three economically mineralised laterite types, namely limonites, ferruginous saprolites and saprolites and all are amenable to rapid pressure acid leaching with recoveries of 98 per cent nickel and 94 per cent cobalt in less than 20 minutes.

Jan 1, 1999

Bioremediation of Acid Mine Water Using Fly Ash and Desulfotomaculum nigrificans One of the major concerns for the mining industry especially after the mine closure is the generation of acid mine drainage (AMD), and its discharge into the environment surrounding the abandoned mines, leading to serious environmental pollution. AMD is usually characterized by high concentration of dissolved metal ions, sulfate and low pH. The efficacy of fly ash was assessed for the removal of metal ions such as iron, zinc and copper as well as sulfate from synthetic acid mine water. Complete removal of ferric and ferrous, 80 per cent of Zn, 83 per cent of Cu and 62 per cent sulfate removal could be achieved, with a concomitant increase in the pH value from 2.3 to 7 using fly ash as an adsorbent under appropriate conditions. The free energy of adsorption of the metal ions onto fly ash was found to be negative, while the adsorption process was endothermic and adhered to the Lagergren pseudo-first order rate equation. Bioremediation studies using a typical sulfate reducing bacterium namely Desulfotomaculum nigrificans, after pre-treatment of the synthetic acid mine water with fly ash, cumulatively resulted in about 94 per cent zinc, 100 per cent copper and 90 per cent sulfate removal. The possible mechanisms of metal ion removal and sulfate reduction from acid mine water utilising Desulfotomaculum nigrificans are discussed.

Sep 13, 2010

Good morning and thanks for the chance to talk to you. It's really pleasing to see so many industry representatives here I want to spend a few minutes talking about issues relating to your industry. At the end of today I would like to leave you with three strong messages from government. The first is that this government supports environmentally responsible mining and the endeavours of the mining industry. The second is that explorers and developers are wanted and welcomed in New Zealand. And the last is that it is up to the industry to keep the public properly informed about how your industry and to constantly work on improving your public image. The mining industry is a high-tech industry which fits snugly with our concept of a growing knowledge-based economy. It has particular value for regional development, the gold mining industry alone provides more than 4,000 jobs û mostly outside of the main cities. The industrial minerals industry is twice as large as that. As well as those people directly employed by the industry there are greater downstream effects for the community. One example from the broader extraction industry of this is of the local pie shop down the road from one of Taranaki's petroleum industry locations. The shop sells over $4,000 worth of pies a week to workers in the industry. That's just one example of the positive benefits the industry brings to its local community and is the sort of real positive benefit you need to be telling people about  

Jan 1, 2000

By D Nicoli, P Feltoe

The operation of grinding circuits are vital to the success of most mineral processing operations in the provision of effective size reduction whilst maximising throughput. However these same circuits, and especially semi-autogenous grinding (SAG) mills, are highly interactive with product re-circulations and long time delays. This makes the optimal control of these difficult by conventional controllers, such as PID, which generally places a heavy reliance upon operations for control. In order to account for the peculiarities (such as ore type changes) and the abnormal situations that continually beset these circuits, it is necessary to adapt linear control techniques to cater for these situations. The Honeywell Hi-Spec Solutions SmartGrindTM controller is a marriage of multivariable predictive control (MPC) with techniques that provide adaptation of the control to optimise the circuit under all conditions. Optimal control is achieved by incorporating pattern recognition techniques to detect and act on discrete events (eg ore type changes) and adaptation of the MPC to account for known process and equipment non-linearities. AlcoaÆs Wagerup Refinery is the first site worldwide to have this technology applied to the SAG milling circuits and this has resulted in throughput increases in excess of two per cent and significant improvements in circuit operations. This paper describes the implementation of the control to the refineryÆs Mill 3 bauxite grinding circuit and the capacity/operational improvements achieved thereof.

Jan 1, 2000

By T Haskell, Y Joe, S Dickie

A current trend amongst producers is the increase in dewatering of iron ore fines (<0.5 mm), due to an increase in wet beneficiation processes used to upgrade lower quality ore deposits, increased water content in orebodies located below the water table, and increasing focus on transportable moisture limits (TML). Vacuum filtration is commonly used for dewatering of iron ore fines, and as with all filtration processes performance decreases with particle size. Significant improvements are possible with the use of filter aids, usually anionic surfactants and flocculants. Anionic surfactants reduce the surface tension of the associated water, which is then removed more readily leading to improved filtercake moistures. Anionic flocculants used correctly can improve cake permeability, in turn, decreasing cake formation times and increasing filtration rates. In addition to increased throughput, savings and benefits for producers can include: moisture limit penalties, improved handleability, along with energy and water savings.The effect of filter aids on two iron ore fines samples from the Pilbara region were evaluated using a lab scale vacuum filtration unit. The first sample showed a reduction in the filtercake moisture content by 2.3 per cent weight/weight (w/w) with the use of BASF’s Drimax® 1234. For the second sample a reduction in the filtercake moisture of 3.4 per cent w/w along with an increase in filtration rate of 20 per cent was achieved by using a combination of Magnafloc® 5250 and Drimax® 1239 NF, as both filter throughput and cake moisture were considered important by site.CITATION:Haskell, T, Dickie, S and Joe, Y, 2017. The use of filter aids on iron ore fines, in Proceedings Iron Ore 2017, pp 183–186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The dissolution of the naturally occurring mineral zircon (ZrSiO4) is examined after ball milling it with magnesium oxide for up to 100 hours in a laboratory mill. There was little effect on the solubility for the initial two hours where size reduction of the zircon was considered to be the dominant effect. Beyond two hours the dissolution increased as a function of the square root of milling time. X-ray diffraction of the powders did not reveal the identity of the soluble phase. However, a nanocrystalline phase was present after milling and this is thought to be the soluble phase.

Jan 1, 2000

Natural Gas has been available in New Zealand for twenty years. During that time the gas share of the energy market has grown and now natural gas forms a significant part of New Zealand's energy scene, helping consumers to achieve a higher standard of living, and reducing dependence upon imported oil. Natural gas is now used for petrochemical manufacture and power generation in addition to direct supply to consumers. As concern for the environment continues to build, natural gas will have an increasingly important role to fill in these markets. This paper sets out the background to the development of natural gas in New Zealand and identifies the current markets. It then looks at those matters which are likely to influence the role of natural gas in the 1990s.

Jan 1, 1990

By Stitt P. H

In Australia, the term "heavy mineral deposits" is used to denote sands which contain variable but economic quantities of the minerals rutile, ilmenite and zircon, often with minor amounts of monazite and xenotime as co-products. Australia has been a significant producer of rutile, ilmenite and zircon from such sands for fifty years and has long been the leading producer of rutile and zircon. The industry had its beginnings with the mining of present day beaches in northern NSW in 1934. Early work was small scale and in some cases involved hand winning of naturally concen- trated mineral for direct export. During World War II and immediately after the industry became increasingly mechanised and by the 1970s on the east coast operated between Newcastle, NSW north to Fraser Island in Queensland. Deposits worked included present day beaches, fossil strand lines up to 5 km or more inland from the present coast and aeolian concentrations. In the mid 1950s, operations commenced on the west coast of WA, south of Perth. Western Australian mineral sands tend to be rich in ilmenite as compared to the east coast. However the WA ilmenites are lower in chrome oxide and make a better syn- thetic rutile feedstock.

Jan 1, 1988

By G Q. Xie, J W. Mao, Y B Cheng

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The East China Mesozoic metallogenic province hosts the world’s largest resources of tungsten, tin, molybdenum, antimony and bismuth, with additional important gold, silver, mercury, lead, zinc, copper, uranium and iron deposits. These deposits form several giant metallogenic belts, including South China, Middle-Lower Yangtze River Valley, East Qinling-Dabie, eastern North China Craton and North-east China. Available data demonstrate that these metallogeneic belts are the products of episodic magmatic and related hydrothermal events between ~240 and ~80 Ma. Each magmatic-hydrothermal episode has produced distinct deposit assemblages that can be readily linked to the Mesozoic geodynamic evolution of East China, involving continental collision between the North China Craton and South China Block at 220–200 Ma, oblique subduction of the Izanagi plate under the Eurasian continent at ca 170–135 Ma and post-subduction extension and lithospheric delamination at 130–80 Ma. Metallogeny in north-eastern China is more complicated due to prolonged tectonic evolution related to southward subduction of the Mongolian–Okhotsk plate and westward oblique subduction of the Izanagi plate, and subsequent continental collision and post-collisional processes.CITATION:Mao, J W, Xie, G Q and Cheng, Y B, 2015. Mesozoic metallogeny in east China and their geodynamic processes , in Proceedings PACRIM 2015 Congress, pp 631–636 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Optical sensors have emerged during the telecom boom in the late 1900s, due to the availability to low-cost telecom-grade optical components. It's only after the telecom industry's fall in 2004 that optical sensors became sufficiently developed to be a viable technology for real-world applications. Geotechnical applications have long relied on electrical sensors such as thermocouples, strain, and the venerable vibrating wire to measure physical phenomena. Although these are well suited for a large variety of applications, electrical sensors cannot be used for all applications: these are vulnerable to noise, hazardous voltages and corrosion, limiting the environments in which they can be used. In addition, electrical wires can also become an issue when sensors require external excitation or are distant from the measurement system. Finally, changes in physical properties of electrical sensors and systems over time makes regular calibration a necessity - not easy to do when these are permanently mounted on structures. Optical sensing systems are non-conducting and use light to perform various measurements. There are several optical sensor technologies available, each with different strengths and weaknesses. In addition, there are different methods of interrogating optical sensors, each of which also present different strengths and weaknesses. To make matters worse, configuring the interrogation and scaling to physical units can also be challenging to the unprepared engineer. This paper will present a holistic view of optical sensing, presenting the different optical sensor technologies and interrogation techniques. Sample optical sensing systems will be revealed and top considerations for optical sensing will be presented.

Nov 25, 2010

By V L. Los, G J. Abramson

The paper examines three types of polar zoning of ore-forming and associated elements that can be detected from geochemical data. Polar zoning is mapped in the form of geochemical ore systems of various ranks. Various types of polar zoning can be found in some systems, which present a general geochemical model of the ore object. The genetic basis of zoning is examined from the perspective of the conception of geoelectrochemical redistribution of matter, including ore-forming elements. The volume of the geochemical ore system may be used in the prognosis of resources for every rank.

Jan 1, 1999

Improvement of Phosphate Ore Flotation Performance Through Sized Flotation

Sep 13, 2010

By G Sparrow

The Murray Basin is being heralded as the next major mineral sands province in Australia. Already exploration programs have delineated extensive commercial deposits and several companies are progressing with plans to produce zircon, rutile and ilmenite in the Basin. As these deposits are developed consideration will need to be given to several key issues of the Murray Darling Basin; the availability of fresh water and management of salinity in the area being two of them. In this paper ideas being developed in CSIRO that link the processing of mineral sands with the salinity problem in the Basin are presented. The proposal presented here is to process saline water to produce industrial minerals with large volume applications and to produce value-added products from the mineral sands in the Basin using reagents produced from the saline waters. Processes to produce titania pigment and zirconia consume chlorine, caustic soda, soda ash and hydrochloric acid, all derivatives of salt (sodium chloride). There may be a good economic incentive if these processing plants were located in the close vicinity of each other.

Jan 1, 2001

Disasters are often tragic outcomes of high-risk technologies such as mines. In Australia, more mines are being developed every day, and the risk of disasters is ever increasing. No matter how effective our conventional safety devices are, there is a form of accident that is inevitable. These relate to accidents that result from æinteracting failuresÆ in a way that could not be foreseen by the designers. In so-called ætightly coupled production systemsÆ (processes that happen very fast, such as on a high producing mine) the risk is even higher and our risk controls mostly introduce some sort of a technological fix. While we are at the one hand attempting to control the risk, we are also introducing another level of complexity. Are we really controlling the risk? This is one of the fundamental questions that will be addressed in this paper: Do we have the ability within the mining industry and other industries to effectively prevent these catastrophes, or are we, on the contrary, faced with an increasing risk as a result of increasing complexities of our technology, management systems and practices. This paper will contend that perceived improvement in risk control is an illusion of activity, and that the likelihood of mining catastrophes may be exponentially increasing. Although the paper focuses on the mining sector many aspects may be applicable across a range of industries. This paper will further contend that we are applying the right solutions to the wrong problems. Our focus is technological and procedural, while our problem is one of production cultures ripe for error and failure.

Jan 1, 1999

Enhancement of Energy Efficiency in Fine Grinding of Copper Sulfide Minerals Using a Pilot-Scale Stirred Media Mill - IsaMill The mineral liberation size of run of mine ores has dramatically reduced over recent years. As a result, the demand for fine grinding which is the most energy-intensive form of grinding has markedly increased in the minerals industry. Furthermore, the fine grinding costs increase exponentially with decreasing product particle size. As a result of the increased energy requirement for fine grinding, it is desirable to optimise fine grinding processes such as stirred media milling (ie IsaMill) to enhance energy efficiency, throughput and the product fineness. In the present study, the influence of slurry rheology, grinding media type and grinding media-to-feed size ratio on energy efficiency in a pilot-scale IsaMill was investigated under certain industrially relevant pulp processing conditions. It was shown that a critical rheological state existed, below which the energy required to achieve an 80 per cent passing (ie P80) 20 ¦m product size was unaffected by shear rheology (ie apparent viscosity and shear yield stress) whilst above which the grinding energy required increased dramatically with increasing shear rheology. Colorado River sand (3.35 mm) showed higher energy efficiency than MT1 ceramic media (2.5 mm) for a target P80 of 20 ¦m in the solids concentration range of 38 to 55 per cent by weight, but the former experienced more than four times the wear rate of the later. The high wear rate of the Colorado River sand may be due to its much lower hardness. For feeds with an 80 per cent passing (ie F80) 70 to 110 ¦m, 2.0 or 2.5 mm MT1 media appeared to be more energy efficient than 3.5 mm MT1 media whilst a media-to-feed size ratio of 41 to 53 is applicable for ~50 ¦m (ie F80) feeds for efficient grinding.

Sep 13, 2010

Efficacy of Enhanced Gravity Separator in Processing Indian Iron Ore Slime The slime sample was subjected to concentration using Falcon concentrator for their enrichment. The effects of three important variables, eg bowl rotation frequency, back water flow rate and per cent solid were studied on the process performance. Increasing the rotation of the Falcon bowl, enable more material to the underflow by increasing the yield, whereas, the iron content decreases steadily with increasing the rotation of the bowl. The increase in the back water flow effectively removes the clay materials from the underflow at the expense of the yield. Similarly, increasing the per cent solid concentration in the feed produces a better product both in terms of yield and Fe content. Results show that EGS/Falcon can be used for processing Indian iron ore slime and producing pellet grade concentrate.

Sep 13, 2010

By E N. Isaev, L E. Levin

New data on the geology of the Late Jurassic to Holocene sediments cover of the World and associated mineral resources (oil, gas, ferromanganese nodules, ores of massive sulphides and other metals) have been compilled in the Atlas at scale 1:25,000,000 and 1:10,000,000. The work was performed by scientists from four Institutes of Russia (VNIIzarubezhgeologia, VNIIoceangeologia, Vernadsky Institute of Geochemistry and Analytical Chemistry of theRussian Academy of Sciences and Geological Institute of the Russian Academy of Sciences). The Atlas shows variation of thickness and formational composition of the large complexes (Upper Jurassic-Early Cretaceous, Upper Cretaceous Eocene, Oligocene-Neogene, Pliocene-Pleistocene), distribution of oil/gas and ore deposits in each complex, data of deepsea drilling (leg 1-130),  thermo-pressure condition in the sedimentary basins within Circum-Pacific Rim.

Jan 1, 1995

By W J. Rankin

Metals are well suited to sustainable development goals. They are not biodegradable and have virtually an unlimited lifespan and the potential for unlimited recyclability. Thus metals can be considered as renewable materials. However mineral resources, the source of primary metals, are ænon-renewableÆ as their supply is finite, but this does not necessarily mean scarcity. In this paper the results from a series of Life Cycle Assessments of primary metal production processes for copper, nickel, lead, zinc, aluminium and steel have been used to examine how metals may contribute to societyÆs transition to sustainable development. Particular issues considered include:current metal reserves and how these may change in the future; some of the environmental impacts (Total Energy, Global Warming Potential and Acidification Potential) associated with primary metal production and how they will be exacerbated by declining ore grades; new processing technologies with lower energy consumptions and improved metal extraction efficiencies that will reduce reserve depletion and environmental impacts; increasing the utilisation of æmetals in useÆ by recycling, with particular reference to aluminium; and the potential impact of a carbon tax on metal prices and how this may influence the ways in which metals are used in the future.

Jan 1, 2002