Search Documents

A good deal of criticism has been levelled at Mines Division over the slowness of processing mining privilege applications, some of which is justified and some which is not. There are many reasons for delays in the processing of applications and not the least of these delays are caused by the applicants themselves.

Jan 1, 1982

By Elber L, Whiten WJ, Cunningham KD, King GL, Bailey CW, Clay PA

The Savage River Mines concentrator treats magnetite ore at about 300 tonne/h, and produces feed for a pelletising plant. The plant incorporates two parallel grinding lines, each consisting of an autogenous mill, in closed circuit with a screen, a rougher mag- netic separator, a ball mill in closed circuit with parallel cyclones, and a finisher magnetic separator. Significant fluctuations in ore grade and grindability make it difficult to maintain pro- duct size in the narrow range desired, and to achieve maximum possible throughput at the same time, using the present largely manual control system. The present paper describes the develop- ment of a control system based on a mini- computer. It has been possible to implement a scheme of on-line estimation of product size which is sufficiently accurate for use in an automatic control system. The size estimation is essentially derived in terms of plant variables which control the ball mill cyclone cut size. Three control functions have so far been implemented and tested. These are control of the feed rate to the autogenous mill, control of water addition to the autogenous mill, and control of the ball mill sump level.

Jan 1, 1978

The limitations of the conventional practices, and their effects, in prospecting for and in the evaluation of alluvial gold deposits are briefly reviewed. Geophysical prospecting methods have demonstrated their complementary role in the delineation of deposits by reducing the number of boreholes which are primarily of a 'probing' type. Larger diameter boreholes, although more expensive on a linear basis, are much cheaper on a volume recovered basis. The need to have sufficient volume as well as number of samples is stressed. Classical statistical methods are not appropriate for such deposits as there is sufficient structure, or spatial correlation, to require the application of geostatistics. Quite reliable semi-variograms, but not in all cases, of the spherical scheme have been obtained. Subsequent kriging has, to date, been confined to unworked deposits: retrospective estimates to compare to production have not therefore been produced. However, the technique shows promise but indicates a considerably greater borehole density (of the conventional diameter) may be necessary to produce confident estimates. Used in conjunction with larger diameter boreholes, a lesser borehole density may be sufficient, through radical reductions of the sampling error.

Jan 1, 1977

By Wright S, Jorgensen F. R A

The reaction between lead sulphate and a number of base metal sulphides (galena, sphal- erite, chalcopyrite and synthetic pyrrhotite was studied as a means of desulphurizing lead sulphate containing fumes and residues to levels acceptable as ISF feed. The reactants were mixed with 50% zinc oxide to act as a "basket" to contain the molten products of the reaction and pressed into small briquettes 20 mm in diam. Factors such as temperature, time and the composition of the atmosphere were investigated. Using the PbS/PbS04 system as an example it was shown that the reaction became rapid above 800¦C and that both sulphur dioxide and oxygen in the atmosphere were detrimental to achieving low sulphur in the product. In an inert atmosphere all the sulphides when roasted for 1 h at 1000¦C gave results corresponding to the elimination of more than 95% of the sulphur in the reactants. Leach plant residues were considered for use as the "basket" material. It was shown that the residual sulphide and sulphate components of the residues underwent similar reactions to those experienced by the pure systems.

Jan 1, 1987

By Kuruppu M

Geotechnical design plays a key role in mine design. A proper geotechnical design provides a safe working environment and facilitates efficient mining operation. There are mainly three design approaches: (i) judgmental, based on observational and experiential facts, (ii) empirical, based on empirical design formulae; and (iii) analytical, incorporating numerical analysis. Most design applications are based on the design methods one and two as mentioned earlier. However, complexities arise in deep underground mining operations and deep open pit mines. These complexities and difficult geological environment introduce more uncertainties and simple empirical formulae would not be adequate as a design tool. These situations require numerical modelling and analysis of the design problems including interpretation of the results obtained from the analysis. There are several tools available for performing the numerical modelling and analysis. A brief review of the available tools is provided. The authors selected ANSYS (a general purpose finite element analysis tool) for use in mining geomechanics and geotechnical design. This paper includes several examples demonstrating the applicability of this software in designing mining structures. The authors hope that the design examples will demonstrate the use of the numerical modelling and analysis applications in excavation design.

Jan 1, 1995

Since 1975 two electric hydraulic drills, a Robbins 11ND and an Atlas Copco C0P1038, have been part of the production drilling fleet at Mount Isa Mines Limited's Isa Mine. As might be expected with innovative and technically more complex machines, breakdowns and mainten- ance problems have been greater than those experienced with pneumatic drifters. This has been especially so with the COP1038 but in co-operation with Atlas Copco, many modific- ations have been made to alleviate operating problems. The training and quality of the maintenance workforce is of great importance. The use of coloured pictorial diagrams for hydraulic trouble-shooting will aid in minimising maintenance downtime. Both machines have achieved good operator acceptance. This is the result of many factors, the major ones being the more acceptable environmental conditions, the relatively low amount of physical effort and the high degree of mechanisation. The drilling area is one in which there is great potential for cost savings and product- ivity gains. Because both machines are capable of a high drilling output, Isa Mine is confident of achieving these aims.

Jan 1, 1978

By Sturgul J. R

ZC Mines investigated a proposal to replace the present underground train haulage system with rear dump trucks. The number of rear dump trucks required to achieve target output and the required mix of trains and trucks during the changeover was of importance to the designers, and a GPSS computer simulation model of the operation was constructed using GPSS/PC, a recent form of the language for the personal computer. Three models were 'constructed to simulate initial and final configurations of underground haulage systems to transport ore from ore passes to the crusher and then to the skip for transport to the surface. The initial model simulated train operation on two levels and rear dump truck operation on a third level. The second model simulated rear dump truck operation on two levels with ore being loaded through the crusher to the skip as in the previous case. The third model replaced the rear dump trucks on the lower level with a train to establish the relative merits of the two methods of transport. The simulations identified equipment numbers, required operating hours and critical points in the operation which can then be addressed by the mine designers.

Jan 1, 1988

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 planning and operating mining projects, managers must take into account economic conditions in foreign markets in addition to Australian conditions. As the manager has little influence over the price or the demand for the product, it is particularly important that close attention is paid to the control of costs to ensure that the mining operation remains competitive with foreign producers. This is not necessarily true for some sectors of the domestic manufacturing industry where foreign competition is restricted and costs can be passed on to consumers because of the protection afforded by tariffs. The effects of protection on the cost structure of Australian industry are more pervasive than is commonly understood. The issue of protection is particularly important to the Australian mining industry management because the cost burdens imposed by local protection must be absorbed within profit margins. Furthermore, because protected industries are effectively subsidised to use scarce resources such as skilled labour, the development of more efficient industries such as mining is inhibited. The mining industry has much to gain from any relaxation in protection policy, and hence the issue is of considerable importance to all managers in the mining industry concerned with costs.

Jan 1, 1980

By West Coast Staff

Attention to the design of facilities for drainage, of both surface water and seepage, made it possible to attain, for a qam impounding residues from a concentrating mill, a more stable sand wall which can eventually be carried to a greater height.EXPERIENCE WITH No. 1 DAMResidue from the lead zinc concentrating mill, which treats the ore from the Rosebery and Hercules Mines, was pumped 3,600 ft. through a 5-in. diameter woodstave pipeline to the site of the dam. It was formerly delivered through a 4-in. steel pipeline.State laws prevent the residue being discharged to waste into the Stitt River. Furthermore, as a pyritic residue it is a potential source of sulphur.Between 1936 and 1956 more than 1,000,000 tons. of residue was paddocked. The run-of-mill product was roughly classified at the dam in a 6-ft. diameter cone classifier and the sand fraction was pumped by a 3-in. pump to the front wall of the dam across a shallow valley. The overflow gravitated to the rear of the dam (Fig. 1). Typical sizings were:

Jan 1, 1958

The application of single liquid cement for fracture grouting in base rock may have history more than 120 years. The disadvantage of it is difficult to increase the grouting efficiency, because the jelling time of it is very long and hard to control. The double liquid grout, such as chemical grouts and cement water glass grout was developed at the end of 1960.'s Although the jelling time of this kind of grout can be controlled, it mast adopt double liquid grouting technology, use complicated equipment and is not easy to control component's ratio of the grout. Another disadvantage for chemical grout is high price, and have pollution to environment. OCE series single liquid grout is the effective grout material developed recently by making large efforts in Ohina. Main feature of it is that the jelling time is easy to control, materials from cement and clay are very cheap and without pollution to environment, and the grout can be injected by single liquid technology. The effect of QCE series grout has been proven by its application in China. It can be believed that QCE grout has great economic efficiency and will give a push to develop grout material.

Jan 1, 1988

By C Gypton

This paper gives some insights into what to look for when reviewing feasibility studies. The review by a third party is an important element of the risk management process and may be the last remaining opportunity to uncover errors, or identify and reduce project risks on paper before they are converted to financial disappointments, steel and concrete monuments to process failures or cost overruns. The mining industry has had a spotty record in the area of estimating initial capital costs and operational performance, even though the standard of feasibility studies is generally acknowledged to have improved in the last decades. Third party reviews rarely have the luxury of enough time and unlimited funds, so where should the reviewers focus their efforts to be most effective? Assuming that the project already apparently meets investment criteria, the authors suggest where and how to look among fundamental project parameters for signs that serious flaws exist that have the potential to become project killers. We also give advice on how to review cost estimates without becoming lost in the details. The paper is supported with numerous actual examples.

Jan 1, 2003

By D S. Terekhov, N Victor, M F. OÆMeara

The current extraction method of the Platinum Group of Metals (PGM) from an ore concentrate and the subsequent separation of one PGM metal from another is a timeconsuming complicated multi-step process. The use of the Chemical Vapour Metal Refining (CVMR) process for the extraction and separation of PGMs is a simple and economical alternative. The paper covers the CVMR process, which is based on the formation of volatile metal compounds, followed by extraction and thermal decomposition into the pure metals and reagent gases. In the case of PGMs, CVMR does not use CO, and hence, the process is quite different from the carbonyl process previously attempted by a number of organisations and test facilities. CVMR extracts PGMs via synthesis of trifluorophosphine complexes at low pressures and low temperatures (80 to 100¦C). These two facts alone make the process highly economical, compared to other methods available. This paper presents a comparison between the process of extraction of PGMÆs and CVMR proprietary carbonyl process for the extraction of nickel and cobalt. In the carbonyl process, CVMR also uses very low pressures and temperatures, compared to those other processes currently use.

Jan 1, 2002

The introduction of legal certification of mine managers is a matter of history. It was introduced as part of legislation for mine safety. It has been said that such legislat- ion was written in blood. Like all legislation this legislation is divided into three sections; commands, obligations and sanctions. While legislation in all States on this subject is similar, the differences are great enough to have prompted the preparation of a Uniform Code by the Annual Conference of Chief Inspectors of Mines. This Uniform Code has not been adopted fully by any State to date. Legal certification of mine managers has made managers more aware of the requirements of the legislation covering their industry, legislation that reads as a summary on past accidents and methods of preventing them. While budding managers spend considerable' time in their early years in the preparation for certification, history has shown that the industry has benefited from their efforts. A better knowledge of the safety acts by the managers has produced safer operations, and a higher standard of management has raised the technical standards of mining operations to a stage where Australia can be proud.

Jan 1, 1980

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

By P Trotta

The paper provides a structured methodology to investigate metallurgical problems within the operating concentrators. The strategy uses classical metallurgical data analysis as well as pulp, solution and surface analysis to determine the reasons for particular behaviours. The approach applies equally to all mineral-processing operations. To demonstrate its effectiveness a case study, based on work conducted at Pasminco Rosebery Mine, is described. In this work, the classical metallurgical analysis indicated that a significant amount of sphalerite reporting to the lead concentrate occurred as liberated particles. A combination of pulp, solution and surface analysis supported the hypothesis that the liberated sphalerite was recovered by inadvertent activation by lead ions. Laboratory studies have indicated that the use of sodium carbonate, by itself and in combination with zinc sulphate and sodium cyanide, when added to the lead regrinding mill can depress sphalerite flotation, resulting in an improvement in the lead grade/recovery curve. When this approach was tested in the plant other more dominant issues masked any positive effect the addition of sodium carbonate may have had. The plant trial highlighted the real need for additional regrinding capacity.

Jan 1, 2002

Mt. Whaleback, the property of the Mt. Newman Joint Venturers, contains more than one thousand million long tons of high grade hema- tite averaging 64% Fe, ranging from 70%, the grade of absolutely pure hematite, to 54%. The ore occurs in the Dales Gorge and Joffre Members of the Brockman Iron Formation. The interbedded shale bands common in other orebodies occurring in these horizons are seldom more than a few inches thick and are commonly partially enriched to about-35% Fe. In the generally hard, massive hematite orebody, the gangue minerals tend to break preferentially to the fines, or -6 mm product, and for this reason it is of a somewhat lower grade than the lumpy product. The control of the chemical qualities is concentrated on the fines product for it has been found that maintaining the iron and alumina levels in this product ensures that all chemical specifications are met in both the lump and fines products. Physical qualities are monitored to ensure that the physical quali- ties of decrepitation and degradation of the lumpy product are maintained at levels accept able to the buyers.

Jan 1, 1973

Gold mineralization belt of eastern China in the adjacent part of the northwestern Pacific rim is orientated NE to NNE and as-sociated with Mesozoic faults and igneous intrusives and Mesozoic to Cenozoic volcanism and subvolcanism extending more than 3000 km in length and 300 to 800 kni in width affected by the movement from the Pacific Plate subducted against the Asian Plate.The relative movement between the Pacific and the Asian plates give rise to two types of fracture zones, the tensional ones providing the space for the formation of fissure-filling type of auriferous quartz veins and the shear zones providing the space for the formation of hydrothermal replacement type of gold de-posits in Shandong Peninsula. The fissure filling type of quartz vein, is represented by Linglong gold deposit which is hosted in Mesozoic Linglong Granite and consists of hundreds of quartz veins filling fractures trending NE to NNE and the hydrothermal replacement type is represented by Sanshandao gold deposit which is hosted in crushed and hydrothermally altered Mesozoic Linglong Granite in contact with Archaean metamorphic complex of Jiaodong Group along a Mesozoic upthust fault zone trending NE.

Jan 1, 1990

By R Dunne, D Yan

In flotation where a bulk flotation concentrate is produced or a gangue sulfide such as pyrite contaminates a concentrate, residual collector has to be removed from the sulfide surfaces to allow selective separation in a subsequent flotation step. Depending on the sulfide mineral, the main species that needs to be removed when using a xanthate collector is either a metal xanthate or dixanthogen. For the identification of surface species, specific solvents may be used to remove each species û metal xanthates are known to be soluble in acetone whilst dixanthogens are known to be soluble in non-polar solvents such as diethyl ether. Xanthates break down with time, temperature and pH into various decomposition products. The major decomposition product is dixanthogen which can aid flotation but other products such as perxanthate and carbon disulfide can have an adverse effect on flotation. Various analytical techniques can be employed to monitor the formation of decomposition products on the surface of the mineral and in solution. The best of these is ultraviolet spectroscopy as it has diagnostic peaks for decomposition product determination. In this work two approaches were taken to understand the relationship between the flotation of a chalcopyrite and pyrite from an ore containing these two minerals. One approach was to remove the xanthate species with an organic solvent and then use ultraviolet spectroscopy to determine the concentration of dissolved species. The second method involved measuring xanthate decomposition in solution by measuring the residual xanthate concentration using ultraviolet spectroscopy. These experiments confirmed the species adsorb at the surface of the mineral and how these species affect the recovery and grade of the valuable mineral. In both cases pH and temperature were varied and two xanthate collectors (SEX and PAX) were used to study these relationships. These relationships could be applied to industrial flotation systems and allow for more accurate determination of optimal xanthate dosage and hence save on reagent costs.

Jan 1, 2005