Search Documents

By S Tavelli

This discussion will present a case study in developing solutions to a metropolitan quarryÆs public relations, legal, environmental, and productivity problems. It details an extensive and detailed project to address the blasting practice in a medium sized quarry that is surrounded by residential and industrial zones. The principle work was done over four months duration during the normal production season. It included detailed drilling and blasting audits for baseline information. In addition, geologic characterisation, seismic modeling, correction of deviations from best practices, and implementation and monitoring of precise electronic timing to provide dramatic solutions for the quarry. The quarry is in the near suburbs of a large metropolitan city. It is framed on two sides by residential municipalities and on two sides by industrial zones. At the start of the project, the quarry was in court as a result of the lawsuit by one of the neighboring towns that was suing to close the quarry. The lawsuit had progressed to the advanced stage where in the Judge had appointed an arbitrator to make the decision of continued operation. This arbitrator was to observe our progress and recommend to the Judge the disposition of the case.

Jan 1, 2004

The relevance of borehole and bore core evaluation to the design of underground coal mines is illustrated by considering the technical parameters of colliery design and the information from which they are constructed. The nature of this information is described, together with some methods for its storage, processing and presentation. Geophysical exploration techniques are compared as information sources. It is concluded that borehole and bore core evaluation is relevant and necessary for colliery design, but that optimum results will be obtained if drilling can be combined with geophysical techniques. Because of the inherent uncertainties in prediction of mining conditions the necessity of obtaining as much information as practicable from drilling evaluation is also stressed.

Jan 1, 1977

Mineral processing is at the hub of the exploration-mining-metals production system. Because of the large volumes of material processed, incremental technology investments can pay off better than for other parts of the system. However, much of mineral processing remains a 'black art', because we are behind in investing in modem technologies. Consequently, we have one of the best opportunities to improve efficiency and competitiveness through the application and transfer of technologies that have already been developed for other industries. The reluctance of minerals companies to place priority in our area is not because we lack new ideas; our senior management has not been convinced, based on our previous results, that such investments will pay off as well as other investment opportunities competing for the same resources. The key is the proper establishment of technology strategy and more effective transfer of technology. The presentation will identify the failure mechanisms of technology transfer and will present a model for improving the success rate, a prerequisite for raising the priority of mineral processing investment. Topics emphasised include strategy formulation, human resources planning, and total quality management principles applied to improving technology transfer.

Jan 1, 1993

The increasing introduction of high capacity mechanical equipment into the coal mines of New South Wales following. tforld War II brought with it problems of roof support. Rapidly advancing headings in difficult country could not be supported with heavy, close,timbering due to the time involved in installation and the reduction of available' space for the movement of machines. _ The installation of low cost, space saving, rapidly installed roof supports became a necessity if the new mechanical equipment wa-s to be allowed to operate at maximum efficiency. As, a result of experience in the United States of America, the system of roof support using steel reinforcing bolts began to find increasing, popularity in the mechanised mines in this State. From the somewhat'crude methods of in- stallation adopted in some of the, early trials, the practice of roof bolting has advanced into a-highly technical operation, requiring care and skill to ensure optimum results.

Jan 1, 1971

By Bowra N

Working capital is best described as money that must be supplied from a company's treasury to buy inventories for raw materials and finished products and to provide credit to customers who have not yet paid for delivered products. Working Capital requirements for resource projects are to a large extent, dependent on specific characteristics of the projects concerned. Important variables are the nature of the project and speed with which sales can be realised. The project's location is also important as this will influence inventory levels. Working capital requirements have a time profile, the present value of which can represent a significant portion of a projects overall capital needs. A significant component of a project's working capital is not readily recoverable or able to be reassigned should the project fail or be deferred.

Jan 1, 1986

By J E. Eberhardt

Ore sorting has long been used to raise the efficiency and thus lower the environmental impact of mineral processing operations. It was first instituted as hand sorting, according to a humanly perceived difference in the ore, but is now automated using large mechanical sorters in order to meet the high tonnage throughput required in most minerals processing applications. In the past, ore sorting was generally used as a niche processing route when other approaches failed, and in this context, consequential environmental benefits are often not the first consideration in adopting sorting. When applicable, ore sorting offers environmental benefits in reductions in fines waste, reagent usage and energy consumption in milling. Although there are significant opportunities for the use of ore sorting technology in many minerals processing operations, industry applications, to date, have been limited mainly to the processing of diamonds, magnesite, talc and uranium ores. This limitation has principally been due to a lack of suitable sensing technologies for a wide range of ore types. The authors report on a wide-ranging review of the automated sorting of mineral ores, and in particular, on methods for discrimination of ore characteristics prior to mechanical sorting.

Jan 1, 2002

The beneficiation of heavy metal oxides, such as iron ore, is usually performed with heavy medium separation in cyclones, static baths and lately with Larcodems. Atomized ferrosilicon is most suitable as a heavy medium at densities above 3600 kg/m3 whereas a mixture of milled and atomized ferrosilicon is suitable at densities below 3600 kg/m3. When operating a beneficiation plant at densities higher than 3600 kg/m3 the quality of the ferrosilicon particles is an important factor that influences the control of the beneficiation process. Therefore, it is important to know how the rheology would be affected by the ferrosilicon quality as it also influences the control of the process at these elevated densities.

Jan 1, 2002

The Merrill-Crowe process for gold and silver recovery yields a low grade concentrate containing high levels of zinc and copper. External refining charges and high transport costs prompted the company to establish itsown enrichment facility.The route chosen was a wet chemicaltreatment which converts the gold, silver and other metals to their chloride. This is achieved with hydrochloric acid and sodium hypochlorite. Gold is recovered from the resulting filtrate by cementation with copper.The solid residue from the gold process is washed and treated with ammonia which dissolves the silver chloride. Metallic silver is recovered from this solution, againby cementation with copper.

Jan 1, 1985

The Kundana underground narrow vein gold mine had a recent history of large and damaging seismic events. Following a period of seismic events on 30 July 2001, in which nine miners were temporarily entrapped at depth due to falls of ground in several parts of the decline, the mine operation was required to develop a seismic management system to mitigate seismic risk to the operation. A micro seismic systems and boundary element modelling of mine sequence highlighted large-scale footwall faults and the mining of gold bearing shear veins to be focal structures for seismic energy release between depths of 300 m to the base of mining at 650 m. The integration of seismic data, identification of geological structures and mapping of zones of failed rockmass led to the successful generation of a non linear boundary element model and a seismic hazard strategy. This enabled mine sequences to be assessed daily, monthly and periodically for potential seismic hazards and therefore assigned both economic and personnel risks for the recovery of the ore reserve at the Kundana Underground Operation.

Jan 1, 2005

By Houchin MR, Jenkins DH

This paper examines the importance of processing to the properties and performance of high purity zirconia ceramics. Many of the principles discussed, however, apply to ceramic processing in general. For fabricated ceramic articles to display their wide range of high performance properties, they must be made fully dense. The precursor powder and postpowder processing requirements necessary to achieve full density in the fabricated body are discussed. Brittleness, the anathema of ceramics, can be overcome in zirconia by incorporation of toughening mechanisms. Transformation toughening and microcrack toughening and their origins in partially stabilized zirconia are reviewed.

Jan 1, 1989

By Pease JD

This paper reviews the changes in operating practices made in the heavy medium plant to meet the objectives of increased silver, lead and zinc production at lower operating cost. The effects of medium quality, screen- ing efficiency, medium consumption, equipment service life and plant availability on these objectives are described.

Jan 1, 1988

New Caledonia, Norfolk Island and northern- most New Zealand lie on a long, narrow, ridge system, the Norfolk Ridge System, which is sit- uated in the centre of a geologically complex region of ridges and basins between Pacific Basin oceanic crust and continental crust of Australia (see Eade, 1987).

Jan 1, 1987

Geomorphology is one of the most basic elements in geographic enviroments. Geomorphological mapping is significant in the spatial distribution of representing land form and understanding various features of geomorphology. Geomorphological mapping began very early in China, as the map, showing conekarst(karst pinnacles) of Juiyishan, Hunan province, it was drawn in 168B.C., which was excavated from Han tomb. Mawangdui, Changsha. Its original idea of map-making is rather similar to that of modern map and could undoutedly be the oldest map of tropical karst discovered in the world.Before liberation, landform mapping was done piecemeally and only a small number of maps were prepared by a few editor as insets.

Jan 1, 1990

By Burks WG, Hughes FE, Muceniekas E, Whitcher IG

The area containing the iron field, recognised by the writers, is part of an uplifted, portion of the 'Western Australian Plateau,' ranging in elevation from about 1,000 feet to about 3000 feet above sea level. The local rock succession is flat-lying or moderately-folded and belongs to the Nullagine Series of Upper (2). Precambrian age. This series forms the Hamersley Rangeland vast portions of the...

Jan 1, 1964

By Mousset-Jones P, McPherson M. J

This paper explains and discusses a computer program developed to deter- mine the optimum combination of fan pressures that will give a required distribution of airflows in a mine ven- tilation system. The program is based on an existing simulator, VNETPC and two experimentally developed relationships: (1) linearity between fan pressures and added regulator resistances and (2) a non- linear convex function relating the system air power and the fan operating Pressures.

Jan 1, 1988

In the sixteenth century the Spanish Captain da Alvaro Soavedaro, on a search for the explorer Ferdinand Magellan, came across the main island of New Guinea which he named Isla del Oro (Island of Gold). Since that time exploration for, and mining of, gold has been pursued by many, culminating in . the development of major world-class projects in the latter part of the 20th century. Though various prospectors have panned for gold and small gold mining projects were undertaken through the seventeenth and eighteenth centuries, it was not until the 1880's when mining became a more concerted economic venture. Misima and Woodlark Islands in Milne Bay, Gura-Ackera and Yoada in Oro, and Lakekamu in Gulf Province and Keveri in Central Province were all gold producers by late nineteenth century. It was in the 1920's that corporations began mining in PNG and with the commencement of production at Panguna in Bougainville in 1972 a new era of mega-project mining began.' Today there are two large mining projects producing mainly gold and copper. The first, already mentioned, is Panguna on Bougainville Island. This project has provided Government with $US 475 million in taxes. ok Tedi is the second large mine development located in Western Province. It began production in 1984 with the extraction of the deposit's "gold Cap".

Jan 1, 1987

Obvious differences in mineral deposit types occurring in Outer Melanesia and Northern Chile can be related to the sub- marine-dominated nature of volcanism in the' former area and the subaerial-dominated nature in the latter area. Subtle variations in subvolcanic epithermal-porphyry ore systems between the two areas probably result from differing ore fluid compositions. Hydrother- mal convection cells in Outer Melanesia will be seawater-dominated, consequently rela- tively high salinities and chlorine contents will characterise the ore solutions. Trans- portation of metals as chloride complexes is likely and the ease of seawater sulphate reduction to sulphide in the ore systems will lead to widespread, sparse dissemination of sulphide minerals. Relatively low grade por- phyry copper deposits will typify these ore systems. In Northern Chile hydrothermal convection cells will usually be dominated by meteoric waters. Consequently ore fluid salinities are likely to be lower and chlorine will be less abundant. Under these circum- stances transport of ore metals as bisulphide complexes could be important. Boiling and loss of H2S gas from these fluids would lead to rapid precipitation of metals and higher grade deposits. Erosion rate is a very important factor in the preservation of ore deposits and this may be the major control on the richness of a metallogenic province. The abundance of mineral deposits in the El Salvador region of Northern Chile compared to Fiji is probably a function of the much lower rates of erosion in the former area.

Jan 1, 1987

The thick coal seams of the South Maitland field are the only ones in New South Wales which have been worked extensively to heights beyond 3.8 m (nominal "thin" seam height). Under shallow cover only minor difficulties were experienced in developing first workings but later the widespread occurrence of incidents of spontaneous combustion and the growth of "creeps" extending over large areas gave the field its own peculiar problems. As the mines have driven under deeper cover extreme difficulties in forming development roadways have been experi- enced. Various methods have been adopted in an attempt to overcome the problems of the field.

Jan 1, 1976

The paper outlines the development and objectives of the slim core (50 mm dia.) testing procedures employed at the Company's Central Research Laboratories with particular reference to washability studies required for coalfield evaluation. It shows that when the routine test procedures, that have been developed for cores recovered form the Sydney Coal Basin, were applied to Bowen Basin Coals some of the washing data obtained appeared to be suspect. Though yield indications appeared to be of the right order, product ash, required separating gravity and percentage of near gravity material were found to be at variance with bulk washability data. The results of a correlation study made on an underground seam from the Bowen Basin comparing slim core, hulk sample, and pilot plant washing data are given. The results of a series of studies including washability studies made on slim cores, strip samples, large diameter cores and bulk samples, pilot washing trials and computer simulations of washery circuits treating Lilyvale seam coal from the Bowen Basin are shown.

Jan 1, 1977

By Morrison R. D, Davis J. J, Fraser B, Kojovic T

1991 saw the completion of a three-year $1.1 million research and development program in mineral sands beneficiation, funded in two associated projects by the Australian mineral sands industry through AMIRA, and carried out by the Julius Kruttschnitt Mineral Research Centre. It is believed to be the largest R&D project in mineral sands ever conducted by a university research group. It covered dry plant operation, and delivered several products to the industrial sponsors, including: ò A detailed characterisation of the radiation properties, mineralogy and size distribution of inhaleable dust arising in dry plants. ò New process models of magnetic and electrostatic separators. ò New on-line instruments for elemental assay (in association with AMDEL) and bulk conductivity measurements of dry process streams. ò Demonstration and evaluation of the Magstream magnetohydrostatic separation technology.

Jan 1, 1992