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By C Reed

Titaniferous magnetite deposits are a significant source of vanadium for use in high strength steel alloying and other chemical applications. The mineralogy of the deposits varies markedly and the ore characteristics strongly influence the process route selected and the metallurgical outcomes. Characterisation of the ores reveals the presence of magnetite, ilmenite and other minerals such as spinel hematite and goethite with variable degrees of weathering along with weathered products of host rock. The standard processing route is to crush, grind and magnetically recover a concentrate for salt roasting to produce a soluble vanadate. Ore beneficiation is practised to generate an iron based mineral concentrate containing much of the vanadium with low silica levels of two per cent. Typical processing problems encountered are fine liberation size, over grinding of the magnetite and variable response to magnetic separation resulting from the weathering profile. Beneficiation options are restricted, and generally focused on producing a combined iron and titanium rich concentrate containing vanadium due to the fact that ilmenite and magnetite and their products of weathering are magnetic and have similar specific gravities making their separation difficult. The ilmenite usually contains low levels of vanadium making its separation highly desirable from the iron mineralisation containing higher levels of vanadium. Salt roasting of vanadium ores followed by water leaching has been the standard processing route for many years. The cost of suitable sodium salts, availability of capital and increasing energy costs and energy availability are critical factors in determining the viability of aspiring vanadium producers. To date, only Windimurra has acquired full capital funding, secured energy and sodium salt supplies at suitable cost that enable the construction of the project. Low overall recoveries of vanadium to concentrate roasting at up to 1200¦C are critical cost issues. In this paper, factors influencing the recovery of vanadium are reviewed and emerging processing trends explored. The important features of the processing of titaniferous magnetites have been condensed from the literature, published works, company websites, our own work and personal communication.

Jan 1, 2008

By Leggate J

In the past many coal mining projects commenced without any consideration being given to eventual site rehabilitation. Now that site rehabilitation is assuming greater importance with changing community expectations, and standards are becoming less negotiable, it cannot be ignored in either the development of mine working plans or economic models. The "unspecified" rehabilitation measures associated with many existing projects will be the subject of debate for some time to come yet. It would be wise to plan for the future. Once an agreeed standard of rehabilitation is accepted, good management involves considering practices which will facilitate eventual rehabilitation at least cost. Without planning for rehabilitation, many mines have adopted practices which are likely to result in very expensive rehabilitation measures and impact significantly on the overall profitability of the ventures. With adequate planning, procedures can be developed which achieve the same short term goals without significantly effecting cash flow but with very significant impacts on the final rehabilitation cost. This paper looks at the disposal of tailings and overburden in the coal mining process. The industry has in the past had an obvious preference for the "perceived" cheaper procedures for waste management such as wet disposal of tailings and high dumping of overburden. There are alternatives. The paper discusses the principles which should be incorporated into tailings and overburden disposal systems and identifies viable alternatives.

Jan 1, 1991

Australia had been enjoying a market boom led by the mining sector and West Australian mines were leading the way to satisfy the massive demand for our natural resources, especially from China. However, the Apache gas explosion on Varanus Island, 97 km off the west coast, has clearly demonstrated how the unexpected can suddenly impact on profitability and investor confidence for the mining industry. Risk management with contingency planning can provide the most cost-effective solution to help ensure mining projects are successful. For this discussion we will focus primarily on contingency planning, CP for mining projects à and how to plan for the unexpected. The Apache gas explosion will be our example æUnexpected EventÆ. Insurance may provide financial compensation but it will not protect your reputation as a reliable supplier or prevent damage to investor confidence and future mine projects. However, contingency planning can provide real protection for mining projects à to survive the unexpected.

Jan 1, 2009

Difficult ground conditions in the area planned for placement of vent rises to the surface at the Porgera Goldmine led engineers directing the project to chose blind shaft boring methods of shaft construction from the available alternatives. Zeni Drilling Pty Ltd was first contracted in 1988 to install a group of three closely-spaced, steel lined shafts. The success of these led to an order for a fourth hole in the same group followed by two more, less than a kilometre. away, under a separate contract in 1992. All of the shafts were completed on.schedule to within one day. The only significant difficulty arose during commencement of the last shaft when the strata collapsed trapping the drilling tools and jeopardising the stability of the surface collar pad. The situation was corrected by innovative lining techniques and the project went on to finish on schedule. This paper discusses the application of various technologies associated with the project including aspects of geotechnical input, drilling fluid chemistry, mining engineering and logistics.

Jan 1, 1993

By A G. L Pratt, G F. Dunstan, A Leonforte

The selection of the material sizing and mine dewatering systems are important elements in the development of a large-scale, high tonnage (greater than 4 Mt/a) underground hard rock mine. The sizing system will influence the size and type of the ore haulage system and therefore how the underground project is developed. With more underground developments considering or implementing caving methods of mining, the selection of the material sizing systems is also influenced by the caving fragmentation. Traditionally, crusher systems are used for material sizing in large hard rock mines, with the crusher installation and its ancillary equipment representing a substantial capital investment. Underground cave mining type operations generally express themselves with large surface subsidence areas, which can lead to large inflows of water from major rain events or purging underground aquifer systems. To minimise disruption to mine production, the dewatering system needs to be sized, with consideration to both storage and pumping capacities. The balance between storage and pumping capacity is assessed to provide the optimal economic solution with the appropriate risk measures. This paper outlines a process for the selection of material sizing and dewatering systems for large-scale caving operations. This process is illustrated with information drawn from NewcrestÆs Ridgeway Deeps Block Cave project. The Ridgeway Deeps Block Cave is located directly beneath the existing Ridgeway Sublevel Cave Mine.

Jan 1, 2008

By Shibata Y, Shimizu R, Fukushima A

Kobe is divided by the Rokko Mountains, runn- ing from east to west. The southern section of Kobe is highly developed in contrast with the northern section, but big, new residential pro- jects like the Hokusetsu New Town and Hokushin New Town are steadily being developed. To handle future traffic between the two sections of the city, the double-tracked Hokushin Line, now under construction, will connect the Shin Kobe Station of the Kobe Municipal Transit (Kobe's subway system) to the Tanigami Station of the Kobe Electric Railway. The locations of Kobe city and Hokushin Line are shown in Fig.-1 and Fig.-2 respectively.

Jan 1, 1987

By Frost M. T

Magnesium is the lightest metal used in structural applications but these are only a small part of magnesium usage, with the use in aluminium alloys consuming half the magnesium produced. Other applications include steel desulphurisation, nodular iron manufacture and metal reduction. Demand for magnesium is expected to increase towards the end of the decade because of a requirement to lighten the weight of automobiles. The current western world plant capacity and production rate is 250 000 tpa. The CIS and PRC also have production capacity but shipments from these countries have been limited in the last half of 1994. The price for magnesium has followed trends similar to aluminium with recent recovery from US$1500 per tonne in 1992 and 1993 to US$4000 per tonne in 1995. The major magnesium producers all use different production methods and the potential exists to establish a large-scale magnesium industry with operating and capital costs comparable to aluminium. The Australian Magnesium Research and Development Project has been established to develop a low cost method of production using the magnesite and infrastructure resources in Central Queensland.

Jan 1, 1995

By M A. Etheridge

The evolution of economic precious metal and copper-gold deposits in high-level igneous terranes is dependent on very efficient fluid focussing. This is most readily achieved by contemporaneous deformation, igneous intrusion and hydrothermal activity. Mineralisation in these environments generally occurs in fault and fault-vein arrays developed in the cover sedimentary and volcanics sequences above older regional scale fault systems. Such reactivated fault systems are particularly prone to developing tile complex fracture arrays, extreme local dilation and dramatic increases in permeability that are necessary to efficiently focus hydrothermal fluid and produce large mineral deposits. The arc systems of tilePacific rim are typically structurally and tectonically complex. At any given period in the evolution of an arc system, it may be dominated by extensional, compressional or strike-slip deformation. Indeed, it is common for the tectonic environment to change repeatedly through the development of a single arc segment. As a result, structures formed in one tectonic environment are commonly complexly reactivated in quite different environments later in arc evolution. These complexly reactivated structures have greater potential to localise extreme fracturing, dilation and fluid flux than primary structures. Application of this knowledge to practical exploration requires an understanding of the primary geometry of the controlling fault systems, the fault movements during reactivation, intrusion and mineralisation, and the consequent location and geometry of dilational sites. Simple 2D lineament analysis and targeting on lineament intersections does not suffice. Chemical processes that results from structurally focussed fluid flow may also contribute to permeability enhancement and further enhance fluid flux. Two main types of chemical feedback are important. The first involves selective dissolution of minerals during alteration and tile consequent production of increased porosity and permeability. The second occurs where alteration changes the mechanical properties of tile rock mass, especially where it leads to a greater propensity for fracture (eg by silification). In near-surface environments (< ~1 km), geomorphic processes complement fault systems in focussing fluid flow to develop sub-horizontal bodies of mineralisation, such as the giant Ladolam gold deposit (>42 million ounces of gold).   Along with classification schemes which stress crustal level, host rocks and alteration assemblages, the styles of high level 'epithermal' and reated deposits must also be considered in respect of their controlling co-active fault structures. Such structural understanding, combined with understanding of tile chemical processes involved (eg host rock reactivity), provides a major tool for exploration particularly in terrains obscured by deep weathering. Geological interpretation based on integration of field mapping with magnetic, radiometric and other remotely sensed imagery provides a powerful complementary tool to the traditional geochemical and geophysical targeting techniques. Timely and effective geological input is capable of reducing exploration risk and providing a more cost-effective basis for drilling and development. Examples of deposits associated with fault reactivation in extensional, compressional and strike-slip settings within arc systems are discussed in this context.

Jan 1, 1995

By Melcher G

The challenge to the zinc industry is shifting from maximum metal recoveries to the environmentally safe processing of the ore concentrates. The main source of solid residues from hydrometallurgical zinc processing is the iron content of the concentrates. Unfortunately iron precipitates from leach liquors contain various compounds which cause them to be considered as environmentally unsafe, unless they have been cleaned in subsequent process steps. This calls for separating the iron from hydrometallurgical processing as early as possible. For this purpose a process has been designed to eliminate the iron directly after neutral leaching the calcine. This is being done by direct smelting the neutral leach residue with a cyclone/top blowing unit. The zinc is recovered from the neutral leach residue as a metal oxide to be recycled to the zinc process. The iron is converted to a slag, which is resistant to atmospheric attack. Key data of the integrated hydro-/pyrometallurgical process are presented as derived from pilot plant tests by cyclone smelting and top blowing the slag.

Jan 1, 1993

This paper discusses design concepts in planning a large modern bulk terminal. The need is emphasised for a studied master plan, in-built materials handling flexibility and staged development. An integrated approach is advocated, combining functional purpose designed foundations and structures to serve their mechanical, electrical and environmental functions. Dry bulk and slurry handling are also compared in perspective.

Jan 1, 1983

By Sen G

An amount of explosives, whether it be cylindrical, spherical, etc in configuration, with a hollow cavity in one face or end is known as a hollow or shaped charge. When this charge is initiated, a focussing of explosive energy will occur within this cavity. This focussing, or concentration of detonation products creates an intense localised force greater than just the simple detonation of a conventional explosive, (without a hollow cavity). If this hollow cavity explosive is directed against a target material this concentrated force is capable of creating a deeper penetration than the same amount of explosive without the hollow cavity. If a metallic liner material is used in the hollow cavity, upon detonation of the explosive this liner will form into a high velocity penetrating jet. Depending on the explosive type and the liner material's configuration the jet tip can travel up to 10 km/s. Linear shaped charges were developed using the abovementioned shaped charge concept but instead of being formed about an axis, they are elongated and constructed along the principal axis. Therefore instead of creating a narrow circular penetration jet, it forms a thicker planar cutting jet ideal for linear cutting purposes. Using Linear Shaped Charges (LSC) for pre-splitting is expected to result in more accurate directional fracture propagation, while minimising lateral micro fractures in the surrounding rock mass which is required to remain undamaged.

Jan 1, 1995

Results from current NERDDC funded research into the geotechnology of highwall trench mining methods have clear implications for mine planners in the areas of blast design, trench shape, location of the surcharge spoil and remnant coal pillar design.Adoption of successful smooth wall blasting techniques not only removes safety hazards from the trench face, but limits development of bedding partings at the seam contacts that interrupt the smooth transition of stress across the coal seam.

Jan 1, 1992

The Joint' Venture Method is a procedure for assessing the value of exploration properties, particularly those for which resources have yet to be delineated. It aims to convert the terms of an actual or synthetic joint venture into the equivalence of an arms- lengths cash transaction between a willing seller and a willing buyer. This paper sets out one approach to achieving that conversion. It discusses both simple and complex cases and gives some examples from both public and private documents. It also includes some case studies in which the Joint Venture Method of valuation can be compared with values derived for the same project using other methodologies including actual cash deals. The Method has failings in both mathematics and logic. However because it does reflect or simulate an arms-length deal which takes into account past exploration effort and expenditure and an assessment of prospectivity at a particular point in time, it is felt that it can provide a reasonable approximation of trade value or asset value of a prospect, particularly if used in conjunction with other methods.

Jan 1, 1994

By Boyes B. A, Haydon D. J

The Paddington project is a gold mining and processing operation located 35 km north of Kalgoorlie in the Eastern Goldfields region of Western Australia (Figure 1). The project, which is operated by Pancontinental Goldmining Areas Pty Ltd, treats 1.25 Mtpa of oxidised gold ore, derived mainly from open cuts adjacent to the plant, with minor tonnages from other pits in the region treated on a custom-milling basis. Gold is recovered using a conventional CIL process. The process raw water supply of 3 500 kUd is derived from the local groundwater system. Average salinity of the raw water is around 90 000 - 100 000 mg/L total dissolved solids. A small portion of the raw water is passed through a vacuum distillation desalination plant to produce the project's 200 kUd requirement for high quality water for potable use and gold recovery.

Jan 1, 1988

By S R. Grano, J Duan, T A, D Fornasiero

We have determined the experimental rate constants for chalcopyrite particles floated from a complex sulfide ore and compared them with those calculated using a recently developed flotation model. The model incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using a surface spectroscopic approach. The calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell. We have extended this approach through the application of a property based model to an operating plant, with a satisfactory outcome.

Jan 1, 2005

By Komosa T, Muir D. M

Adequate levels of dissolved oxygen are essential for efficient gold dissolu- tion. The actual levels in plantpuips can be seriously reduced by the presence of oxygen consuming reactive minerals, and reduced oxygen solubility in saline water. The rate of gold dissolution is then limited by oxygen availability rather than cyanide. Ion selective electrode dissolved oxygen meters can give an effective indication of the relative oxygen saturation, but they are not able to give meaningful values of dissolved oxygen in saline water, without custom calibration curves. When the dissolved oxygen concentration is rate limiting, the addition of oxygen or peroxide can improve gold leaching kinetics as well as reduce cyanide consumption.

Jan 1, 1991

The investment worth of a mineral deposit can only be realistically evaluated in relation to specific engineering design criteria, which fully details the proposed method of exploitation. These criteria have not in general been taken into serious consideration when leaseholders have reported reserves in the past. In fact, many "reserve" figures quoted are probably more correctly classified as geological resources. The industry now recognises that it is necessary to take into consideration not only grade and mill recovery factors, but also likely mining and processing costs as well as the current market price for the commodity. Once having estimated those costs which are applicable to the resource under study, they can be deducted from the gross inherent worth of the orebody to result in an estimate of the potential net revenue. Through a process of interactive trial mine designs and evaluation, reserves can be quantified to provide an estimate of the available recoverable economic reserves given a set of assumed cost and operational parameters. It follows then, that the available economic reserve recoverable from a given resource will vary from time-to-time as cost and price factors vary in response to changing technology and economic factors. A methodology is described which may be used to derive economic recoverable reserves based on a computerised model of the geological resource data and appropriate economic and operational cost algorithms. Examples are provided from both coal and gold studies to illustrate the impact of economic criteria on the magnitude of the reserve figure reported for each project.

Jan 1, 1987

By K Ellis, K Quast, R Newell

The use of ammonia as a leaching agent in the recovery of copper from ores and concentrates has a number of potential benefits. These include the ability to treat ores with an acid consuming gangue, non-corrosivity, the insolubility of iron in the solution and increased selectivity. This paper reviews the previous and current use of ammonia based leaching systems for copper recovery and presents the results of a laboratory investigation that involved leaching of a copper concentrate and a low-grade ore. The effects of the operating variables (particle size, oxygen addition, agitation and temperature) are discussed. Of these, the particle size had the greatest effect, with decreasing size giving improved leaching rates and recoveries. The possibility of using ammonium salts in heap leaching is also discussed, and the results of some small-scale column leach tests presented. Possible methods for recovering the copper from the leach solution are outlined, and the types of ores and concentrates for which ammonia leaching may prove to be a viable alternative processing route are discussed.

Jan 1, 2000

By K Osman, P Bennett

The mining of an underground orebody requires development both in waste and ore before stoping commences. Regardless of what metal is being extracted, the waste development is minimised to reduce the cost per unit of metal mined. At the Western Metals Zinc Kapok mine site, reducing the cost per tonne of lead and zinc mined is paramount. Decline waste development costs can be minimised by methods such as increased gradient or reduced drive size. Ore development will also involve some mining of waste. The degree to which waste mining can be minimised will depend on the thickness and dip of the orebody. The drive geometry will also determine the percentage of waste within the face. It is by mining methods such as resue mining that selective mining may be used to maximise the amount of metal mined and reduce waste dilution. Resue mining can be used around a set of selection criteria established by the mine site. These selection criteria will determine how resue mining can be applied to the mine site. Selection criteria include firing times, number of headings available, acceptance criteria for percentage lost metal, dilution and most importantly operator acceptance. The single pass or two pass resue mining method should be chosen depending on the site acceptance criteria and selection criteria. The Western Metals Zinc Kapok mine site has established a set of parameters which accept the two pass resue mining method for the mining of the ore drives. The blasting results from a single pass resue method were reviewed during more recent trials in a single heading. Through a comparison of results, the parameters allowed the decision to determine the applicability of resue mining and its current form to Kapok. This paper outlines the parameters set by the Kapok mine site, reviews these in relation to the two forms of resue mining and examines the criteria which make this mining method applicable for Western Metals Zinc.

Jan 1, 2002

By Tapp B. A

To date, few studies have been made regarding the energy requirements of the Australian mining and mineral processing industries. This paper indicates that these industries use a substantial proportion of the total Australian energy input (32.7% in 1971-72 and 36.10% in 1974-75). With the growth orientation of these industries, this input is likely to increase. Data shows that mining energy requirementE varied from 4.22% (of total Australian energy requirements) in 1971-72 to 4.16% in 1974-75. Energy requirements for the total mineral processing industries increased from 28.49% to 31.93% for the same period. The total estimated primary energy input varied from 22.56% to 25.2%, whilst indirect energy use, in the form of electricity increased from 10.16% to 10.66%; in the same period. Analysis of primary energy input data within the processing industries (1973/4) showed that the Iron and Steel Industry consumed 15.03% of the Australian total consumption, Non-Ferrous metals, 5.43%, Cement, 1.64%, and Refractories, 1.59%. In toto this represented 24.57% of the total

Jan 1, 1979