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The Lennard Shelf Operations owned by Western Metals Ltd evolved from the Cadjebut Zinc Lead Mine (BHP) in August 1994. Original production of 0.5 mtpa will rise to 2.0 mtpa at the end of 1998. Employees work a multiple of fly-in/fly-out (FIFO) rosters from the Kimberley region and the WA Capital. The three underground mines, treatment and services departments will employ approximately 300 people by the end of 1998. The expansion of the Lennard Shelf Operations as a remote mining location was based on a fresh look at management systems and employee rosters which were generated from many years of mining experience. This paper will endeavour to summarise these experiences and analyse some of their outcomes. Dealing with several mining methods, engineering difficulties, logistical problems and climate extremes, the Lennard Shelf Operations has managed social/employee issues with excellent results. Much time has been spent to get this correct for the Lennard ShelfÆs own set of circumstances. Employees and associated companies must expect continuing changes and improvement as Western Metals strives to continually improve its management systems and employee rosters.

Jan 1, 1998

By W A. van der Westhuizen, Beukes G. J, Vermaak J. J

Large parts of the arid northern Cape Province South Africa are blanketed by Quaternary cal- crete under which potential base-metal ore- deposits may occur. In an attempt to examine the nature of the distribution of such ore-re- lated elements in a calcrete environment, calcrete and soil samples from the copper-nic- kel prospect at Jacomynspan and the copper- zinc deposit at Copperton were examined. Both deposits form part of the Namaqua mobile belt. CALCRETE GENESIS In Southern Africa calcrete is restricted mainly to the western two-thirds of the sub-continent, south of the latitude 17¦ S. Various models have been put forward to explain calcrete genesis and Goudie (1973) and Netterberg (1969a) give detailed discussions on this topic. The most popular model for calcrete genesis is one of pedogenic origin. McPherson (1979), Watts (1980), Wright (1982), Arakel (1982), Netterberg (1969a), Goudie (1973) and Multer and Hoffmeister (1968), amongst others, support the hypothesis of calcrete formation by carbonate precipitation from downward percolating calcium carbonate rich soil waters. Calcium carbonate is usually initially precipitated as nodules or grains which can develop to form more compact layers.

Jan 1, 1988

By D von Horn

Mineral sand orebodies are typically mined for their TiO2 content. Increasingly over the past 30 years, the major mineral focus has shifted from natural rutile to ilmenite and an acceptance that the latter generally needs some form of upgrading for economic conversion into TiO2 pigment. This upgrading obviously has a cost, and in conjunction with diminishing mineable feed grades, results in higher cost TiO2 units for chloride route Pigment Plant feedstocks. The net cost of feedstock can be significantly influenced by the recovery and sale of accessory minerals and by-products from the processing chain to the extent that some producers have the potential to achieve a zero net cost. Whilst slagging plants typically reduce net cost from rutile, zircon and pig iron revenues, operations supporting Becher type synthetic rutile operations have been limited to revenues from rutile and zircon only. A range of alumino silicate minerals show industrial potential, as does activated carbon, iron oxide and gypsum, by-products of the synthetic rutile process. Tiwest is a good example of a company maximising revenue from the accessory minerals as well as from by-products of the synthetic rutile process.

Jan 1, 2001

The basic principles of mineral valuation were recognised and propounded at the beginning of this century and have remained virtually unchanged since then. Valuation is seen as a two part process commencing with a technical examination of the mineral property followed by a manipulation of the results of the technical examination in order to determine the monetary value of the project. A thorough and competent technical examination was seen then and remains now as the essential but not sufficient foundation for reliable valuation. All authors stressed the need to maintain the integrity of the data base and to ensure adequate coverage of all relevant aspects. The monetary valuation process through most of the first half of this century was mainly based on the Hoskold two rate method, derived from the formulae for valuing annuities but modified to provide explicitly for recovery of capital. Though the basic principles of valuation have not changed significantly, the means of implementing the components of the technical examination, the styles of deposits being evaluated and the mechanisms of monetary valuation have changed dramatically. Despite all the technological improvements, however, mineral

Jan 1, 1995

In simple terms, heap leaching means the removal in solution of valuable elements from a heap of material, and their recovery from that solution. The heap of material can consist of essentially unprocessed ore, sub-ore, low grade gangue and country rock, tailings from other upgrading processes, or artificial materials such as slags or furnace and flue products. The solvents can be solutions of acids (commonly sulphuric acid because of cost) or of other chemicals such as cyanides. Because of cost factors the solutions are aqueous; because of this, leaching operations may be curtailed in cold-climate areas. The guiding principle must surely be `large volume / low cost'. Since solutions are generally easier to manage than gases, there is a strong incentive for replacing roasting of materials by leaching, eg arsenical gold ores. Where sulphides are present in the material to be leached, these may provide the necessary acid, with or without the aid of bacteria, to dissolve and extract the recoverable metals. The mineralogical aspects of the operation relate to the nature of the `ore' and gangue minerals present in the heap, their textural relationships, and their effect on the process itself.

Jan 1, 1994

Natural gas was introduced to the Melbourne reticulation system in April 1969 and since that date sales to industrial consumers in the Gas & Fuel Corporation of Victoria area of supply, have increased by over 50% This increase has occurred despite the fact that the areas in which the new fuel is available have been dependent on the progress of the conversion operation from manufactured gas. The half way mark for conversion was reached in May 1970. The reason for the adoption of natural gas by industrial users is usually the result of objective financial analysis leading to the conclusion that the new fuel will give the lowest overall production cost. Many factors are involved in such an analysis of which the price of the fuel is only one. Amongst other important elements in the cost calculation are:- -ò òò -(1) The effect of fuel on product quality (2) Maintenance and handling costs for alternative fuel. In addition to economic gains for the individual user, the use of natural gas should benefit the whole community through its effect on such things as, air pollution and overseas balance of payments.

Jan 1, 1970

My early experience with the coal industry was in the latter half of the 1970s, where attention to only ones own æaccidentsÆ and concentration on behaviour controls were impeding the introduction of effective engineering controls such as ROPS, FOPS, roof support and residual current devices. Lack of the broad picture of personal damage and of relevant veridical (true saying) knowledge and data had to be overcome to achieve progress in reducing fatalities. Thirty years on, it is again necessary to take stock. How good is our knowledge, our data, our information on which we make decisions. Despite Australian all industry 1992-93 data showing 80.5 per cent of costs came from occurrences which permanently altered peopleÆs lives, New South Wales is still the only state reporting permanent disabilities. In 1991 - 1992, the rate of permanent disability per 1000 wage and salary earners was two. In 2000 - 2001, it was over four û more than doubled. Also strongly motivating is the huge cost. Industry carried 25 per cent of the $34.3 billion costs for 2000 - 2001, up ten per cent of 82.8 billion if the costs of pain, suffering and early death are included.

Jan 1, 2005

Almost all industrial products, such as buildings, cars, plastics, railways, radio and television sets, computers, and others are made from materials extracted from the Earth. Earth is main resource of energy and up to now; the energy has been derived mainly from natural resources. Mining industry has significant influence to the nature, sometimes evokes a devastation of nature. On the other hand we have got a lot of nice examples that good preparation, sensitive mining practice and consistent reclamation can minimise the negative effects. All the mentioned problems calls for effective tools for mine design, mine operation and mine reclamation. Third millennium brings next challenge given by advances in information and communication technology. The development of very sophisticated software tools provides to technical systems some features of autonomous æthinkingÆ and intelligent behaviour. We can find large effort and a lot of scientific papers reflecting last advancement in science and technology and providing inspiration for new mining technology of third millennium called Intelligent Mine. Some aspects related to creation and utilisation of æIntelligent ModelsÆ as a background of æIntelligent MineÆ are presented and discussed in this paper.

Jan 1, 2003

Major changes occurred in the management of loss prevention and risk management at operations in North and South America due to increased insurance premiums following the Olympic Dam fire in Australia in 2001. There are many different scenarios on how fires can develop and the estimated maximum losses (EML) those fires can incur. The EML is utilised by insurance companies to determine the cost of insurance premiums. The cost of insurance can be controlled at existing and newly designed solvent extraction (SX) plants by using risk reduction methods and design criteria to limit the fire exposure. A review of data collected during several loss prevention risk assessments can show how a budget can be protected from dramatically increased premiums and see which design of SX plant and fire protection standards best apply to your operations. The paper will investigate the pitfalls of existing materials of construction, capacity, geography, management practices, fire risk minimisation, and fire suppression systems. Intelligent engineering and managerial improvements implemented by the operations in the Americas in the past two years have further minimised the fire potential and benefited companies in insurance renewal negotiations.

Jan 1, 2003

A resource rent taxation scheme is based on the concept of taxing the rent or surplus profit generated from primary industry activity. Rent has been defined as profits that remain after deduction of company income which corresponds to the minimum return necessary to attract private investment to a new project.Rent taxation schemes on the mining industry within the Australasian region have been examined and widely discussed during the decades of the 1970s and 1980s. Forms of resource rent taxation schemes have been imposed on Papua New Guinea mining, some sectors of Australian petroleum, the Roxby Downs venture and are being discussed for the New South Wales coal industry. While no introduced applications have been pure rent taxation schemes, the concept has generally come to encompass arrangements which tax rent at a partial rate which may or may not vary with the level of profitability or return.An examination is made of a number of the more recent schemes. Aspects which should be considered in implementation of new forms of this taxation are discussed. It is concluded that there is an increased acceptance for this form of taxation on the Australian mining industry.

Jan 1, 1990

By S Ramsay, D Povey

This paper presents recent case study data collected by field portable x-ray fluorescence spectrum analysers (FPXRF) as part of grade control activities at three separate (nickel, copper and copper/gold) mining operations. FPXRF has been under utilised for grade control in recent years, largely because the success of early versions of FPXRF was limited to a few metals (eg tin). Efforts to utilise these early versions for other metals was largely unsuccessful and created a perception that FPXRF could not be utilised more broadly within the mining sector and specifically the area of grade control. The structural setting of the analytical function within mining operations has also contributed to the under utilisation of more recent FPXRF instrumentation. The concept of FPXRF as a grade control tool straddles the boundaries of the geology and laboratory departments. As such, this option is often not considered as part of an assessment of grade control procedures for new and existing mining operations. This paper assesses data collected by Australian and New Caledonian miners using FPXRF technology as part of the grade control function and concludes that FPXRF can provide operational and cost benefits to certain mining operations.

Jan 1, 2003

By G Huggins

Excavation in underground jointed rock masses creates cavities into which the surrounding rock mass deforms. Deformations, besides intact rock deformation, include mechanistic deformations such as slip and rotation. In this paper deformational moduli were measured for prototype and blocky (jointed) models using elastic analogue methods for stopes from MIM LimitedÆs Lead Mine. The blocks for the models were defined in terms of the prototypeÆs joint sets, their spatial separations, orientations and average friction characteristics. From dimensional analyses, a relationship between prototype and model deformations was used to predict stope mid-span deformations. The results of this physical modelling work, conducted in the 1970s, motivated an investigation into the electro-treatment of tailings backfill to achieve improved strength and stiffness characteristics. Tailings backfill containing fines and having a high clay content can be electrically dewatered, and at times grouted, cemented, ion exchanged or agglutinated, to achieve relatively high magnitudes of strength and stiffness. These treated tailings stiffnesses can reduce the deformation magnitudes within a rock mass and, in doing so, reduce problems encountered in mine pillar extraction. The application of these tailings modification techniques is examined in relation to the elastic analogue methods.

Jan 1, 1998

By H R. Watli, K L. Davies, J A. Johnson

Novel microbial isolates that readily oxidise iron and sulfur were recovered from samples collected from a spent chalcopyrite/pyrite test heap. Methods were developed to enrich and isolate microbes that thrive in low pH environments and utilise iron and/or sulfur as sources of energy. Screening of these isolates revealed diverse substrate utilization (sulfur, ferrous ion, chalcopyrite, pyrite, glucose) as well as growth at temperatures between 30 - 50¦C. When native isolates were employed, shake flask leaching tests of chalcopyrite concentrate resulted in higher copper yields in comparison to laboratory reference strains Acidithiobacillus ferrooxidans (DSM 583) and Sulfobacillus thermosulfidooxidans (DSM 9293). After 700 hours several native isolates had leached between 20 - 30 per cent more copper than laboratory reference strains during experiments conducted at 45¦C. This research has established a unique culture collection of mining microbes that readily adapt to Australian conditions. Exploitation of these microbes may result in improved leaching kinetics and copper recovery from Australian chalcopyrite ores as demonstrated from shake flask leaching tests. Whilst this research provides a capability for Australian mineral sulfide ores, this technology can be easily adapted to suit ores of any origin resulting in more effective and efficient microbial leaching.

Jan 1, 2004

A real Dorothy Dix title has been selec- ted for this paper. It has the advantage, however, of being capable of being interpreted in many different ways and hence I can select my own approach. You probably are thinking that this topic would be more appropriately handled by an Accountant. I wish to make it clear at the outset that I am not skilled in the sometimes mysterious ways of Accountants - likewise that profession frequently has difficulty in pinning down economists. We have our own strange ideas about profits, marginal efficiencies, cost/benefit analysis etc. What follows is in the main a mixture of two disciplines, probably in a form that few of the purists from either side would accept. Nor do I expect the reader to accept my own prejudices. The paper is designed to stimulate thought and discussion'on the subject. Emotive words such as "profit" and "loss" make for wide differences of opinion. At the time of writing there is a surprising degree of acceptance of the viewpoint that profits in Australia are too low and one is tempted to make this point of near agreement a starting Point.

Jan 1, 1975

By O Ostrovski

Direct iron smelting reduction has been examined using a modified 50 kg induction furnace. The furnace was equipped with continuous raw material feeding, a top oxygen lance, argon bottom bubbling, and sensors for measurement of gas and bath temperatures, gas composition and other parameters. In the base case, iron ore was charged at the rate of 1.5 kg/h, coke flowrate was adjusted to maintain a char fraction in the slag at 30 wt per cent, the oxygen flowrate was 100 Nl/min and the post-combustion ratio (PCR) was 60 per cent. The PCR was varied from 45 to 75 per cent by changing the lance height relative to the bath surface. Smelting reduction of Whaleback iron ore was investigated at different post-combustion ratios and iron ore feedrates using coke and coals with different volatile matter. The rate of iron oxide reduction increased with increasing iron oxide concentration in the slag, with a slight deviation from a linear function. The post-combustion ratio affected iron ore reduction and partitioning of elements between phases in the smelting reduction furnace. The high volatile coal investigated was found to be unsuitable for iron smelting reduction in the laboratory furnace.

Jan 1, 2000

In six deep hard coal mines situated in the coal district of the Saar and Lorraine, Saarbergwerke AG produce annually 9 to 10 million tons of coal. The coal is either coked or fired in power plants. Comprehensive planning work is done for the producing coal faces, 15 stone drifts and 60 seam headings. The computer can assist in drawing up the short- and medium-term planning by taking over, on the one hand, work done so far by hand and by supplying, on the other, additional information. The computer can draw up time schedules, can do quantitative calculations, can draw up plans for the em- ployment of manpower, machines and other equipment, and can calculate cost and earnings. It is ensured that all part plans are always adjusted to each other. Because of the volume of work involved, planning in this form and extent becomes possible only by the computer. Especially with the periodical continuation of planning, the new system facilitates the work to be done. The ideas of the planning engineer are and remain the basis of all planning work and the computer gives him an aid to assist him with calculations, report writing and feasibility studies.

Jan 1, 1977

Geologists employed by Metals Exploration Pty. Ltd. discovered nickel enrichment at Greenvale, 180 kilometres West of Townsville, in 1967. Subsequent drilling proved an ore body containing 45 million dry tonnes of ore containing an average of 1.5% nickel and 0.11% cobalt. The Freeport Minerals Company, who had experience in treating lateritic nickel ore, were invited to participate in development of the ore body. This resulted in the formation of the operating company Queensland Nickel Pty. Ltd., jointly owned by Freeport Queensland Nickel Inc. and Metals Exploration Queensland Pty. Ltd. With the completion of successful pilot plant testing of Greenvale ore at the Freeport research facilities at Belle Chasse, Louisiana, a treatment plant was constructed at Yabulu, 24 kilometres North West of Townsville. A 225 kilometre railway line was built connecting the Greenvale Mine and Yabulu Treatment Plant. The ore reduction and ammonia/ammonium carbonate leaching flowsheet is similar to that constructed and operated by the Freeport Minerals Company during World War II at Nicaro, Cuba. Modifications to the Nicaro flowsheet implemented at Yabulu include facilities to recover cobalt in a mixed nickel/cobalt sulphide product and the reduction of nickel

Jan 1, 1978

By S C. Goel

The Obuasi Mine in Ghana, West Africa is the largest producing gold mine in Africa, outside South Africa. The mine has changed from a mine producing from narrow vein, high grade quartz orebodies to a mine producing from wide, lower grade sulphide rebodies. Traditionally mining methods were cut and fill and sublevel caving. Now the preferred stoping methodologyis long hole open stoping. Transverse or longitudinal methods are both used, dependent on the orebody characteristics. The change has been technically, socially, economically and politicallychallenging and at times has tested the abilities of those responsible for the operation of the mine. However, the benefits have been many. Safety has improved significantly, ounces from underground have doubled. Productivityhas doubled and underground unit costs have reduced bya third. These achievements have allowed the Obuasi mine to staycompetiti ve in this time of falling gold price. During 1999 and 2000 a full review of the mining and processing operations was undertaken, and as a result, the mine is now in a phase of restructure. Efforts are being made across the mine to improve efficiencies and to reduce costs. The future for the Obuasi Mine is an exciting one.

Jan 1, 2000

Carbonate replacement tin deposits in the areas studiedhere are genetically related to biotite granites. Biotite in the granites is distinguished by distinctive compositional features. High MgO content is found in biotite in the Renison Bell granite; high MnO and A1203 contents in the Gejiu granite; and high FeO content in the Xinlu granite. The compositional features of biotite in the granites are reflected in skarn minerals formed around the granites.Granites associated with these tin deposits are characterized by different accessory minerals. Magnetite-bearing granite in the Xinlu deposit is related to the andraditic garnet (andradite 40-45 mole%)-hedenbergite skarn, with tin mineralization occurring in the contact skarn only. The sphene-bearing granite in the Gejiu deposit is related to the grossular garnet (grossular 50-60 mole%, almandine 20-30 mole%) -salite skarn, with tin mineralization occurring in the contact skarn, as well as stratabound replacement orebodies in the distal skarn. The ilmenite-bearing granite in the Dachang deposit and the Renison Bell deposit is related to the grossular-diopside skam, with tin mineralization occurring 500-1500 metres vertically and 1.5-3 km horizontally away from the granite contact.

Jan 1, 1990

By Luck D

Current methods of mucking out small development tunnels are a major limitation to improved efficiency and high rates of advance. This is particularly true in the deep metalliferous mines of South Africa, where the harsh environment, remoteness of operations and the hard abrasive rock conditions mitigate against the use of the tunnel borer type of equipment. The Loader Distributor Train was designed to overcome the special problems of hard rock tunnelling. It combines advanced innovative technology with proven simple methods of operation and maintenance. The system aims at taking advantage of new, efficient and cost effective power sources in South African mines based on replacing compressed air with electro hydraulics and the new concept of hydropower. It also introduces electronics and computer technology, for both automatic control and fault finding, into the production environment. The system is designed to permit sophisticated equipment to be operated and maintained by a semi skilled labour force. Although still undergoing trials it is believed that the Loader Distributor Train will prove highly effective, and that the new concepts offer considerable potential in areas other than flat tunnels, in particular the cleaning of inclined shafts.

Jan 1, 1986