Search Documents

The Coke Ovens Laboratory at Australian Iron & Steel, Port Kembla has been involved in the analysis of seam gases and mine airs for approximately twenty (20) years. This period has seen many developments and changes in the techniques used to the point when the current techniques are equal to other labora- tories involved in similar analyses. The laboratory has NATA registration for the analysis of mine airs and gases. Apart from routine testing of seam gases, ventilation airs and gases emmitted from coal bore cores a number of projects have been undertaken. These have served a twofold purpose, one to provide information to the customer, generally Collieries Research and Technology and secondly in developing the skills and capabilities of the Coke Ovens Laboratory. This paper discusses the development and services available at the Coke Ovens Laboratory for the analysis of gases and airs from collieries.

Jan 1, 1983

The use of coal as a fuel for heat and power generation has a long history. During the nineteenth century most of the present combus- tion technologies were pioneered, as shown in Table 1, This period was associated with the "golden age" of coal and its contribution of almost 80% of the world's energy demands in the early,1900s . The decline in the use of coal has been due to the transfer of the heavy transportation area to diesel power, the elimination of coal as a household fuel and the substitution of oil for coal in power plants. Coal remains the major fuel for the electric utility industry and the present paper will be concerned primarily with that application. Table 1 outlines the development of coal tech- nology with the parallel understanding of coal as a material and its behaviour during combus- tion. Clearly many developments in combustion technology have occurred in this century, although most of the processes had been invented in the nineteenth century. Also, the great expanse in coal research of the past few decades has led to a greater understanding of the coal combustion process.

Jan 1, 1987

By P Rourke

In this climate of increasing demand for commodities, it is becoming necessary to expand and optimise existing bulk material handling facilities in order to increase capacity to satisfy demand. Production capacity in these facilities is often adversely impacted during the expansion process. A successful and proven strategy to reduce this impact is to bring the additional capacity online in stages coinciding with routine maintenance or other short shutdowns. Compatibility of the automation systems with staged upgrades in capacity is the key to achieving a successful outcome. Since 1994, Hatch has been researching a generic, highly configurable product transport control system that can be reconfigured to cater for plant expansions or modifications without incurring significant risk to production capacity. In 2002, BHP Billiton Iron Ore (BHPB IO) recognised the need for such a generic Route Selection and Sequencing (RSS) system and engaged Hatch to build a generic RSS system as part of the $US351 million BHPB IO Products and Capacity Expansion (PACE) project. In 2004, Hatch successfully deployed such a generic configurable control system at BHPB IO Port Hedland Ore Handling Facility. This generic system is known as the Hatch Product Transport (HPT) System.

Jan 1, 2005

By A G. Thompson, E Villaescusa, D Howard

The Western Australian School of Mines (WASM) has developed a facility for the static testing of full-scale ground support elements (Morton et al, 2007). The test facility consists of several stiff steel frames used to support the sample and a screw feed jack is used to load the sample. A large-scale punch test method has been developed to load various shotcrete configurations. The shotcrete is sprayed on to a rock substrate containing a centrally located circular disc. The rock and shotcrete sample is placed on to the sample frame and restrained on all sides. The circular disc is displaced at a constant rate by the screw feed jack which in turn loads the sample. Instrumentation measures the displacement and the load being applied to the sample through the loading disc. The testing method is described in detail and the results from the testing program are presented. The results show that it is possible through laboratory testing to simulate some of the mechanisms of shotcrete support reactions better than conventional beam and panel tests.

Jan 1, 2008

XstrataÆs Mount Isa Copper Operations (MICO) is a world-class mining operation producing in excess of six million tonnes of copper ore per annum from its underground mining operations. The Mount Isa Copper Mines have been producing from the underground operations since 1952. Current copper reserves are 87 million tonnes at 2.8 per cent Cu, extending the mineÆs life beyond 2018. The underground orebodies in the copper mines are divided into nine distinct areas and are mined by sublevel open stoping techniques. One of the nine areas is the hanging wall lens, which consists of two sections; a northern lens (NHWL) and a southern lens (SHWL). The SHWL has a proven reserve of 2.2 million tonnes with an average grade of 2.9 per cent copper. Stopes in the SHWL have an average size of approximately 245 000 tonnes and will be extracted in a primary-secondary mining sequence, producing ore until 2009. This paper discusses various aspects of stope design applied in the southern hanging wall lens, including sequencing options and the rationale for the selected sequence. Design features are also discussed and how they have evolved as more is learnt about the SHWL orebody. These include mass firing techniques, focusing on minimising ground vibrations, using seed wave form analysis and prediction. Rock mechanics issues will also be discussed, in particular the reinforcement of stope hanging walls and the use of instrumentation to monitor behaviour within the hanging wall.

Jan 1, 2006

By Field R. V, Graieg O, George T. J

The design, construction and operation ofa laboratory scale rotary pot kiln are outlined. Charges ofup to 3 kg can be heated to temperatures up to 1200°C in a controlled atmosphere. Some examples of pyrometallurgical investigations carried out using the kiln are briefly described, including thermal reactivation ofcarbon using steam at 550-850°C, high temperature testing ofkiln liners for corrosion resistance to fluoride, and calcination oflimestone. Results obtained from these trials allow either direct scale-up to the Engineering Chemistry Laboratory's pilot-scale (50-100 kg/hr) rotary kiln or modifications to be made to commercial scale processes and/or equipment.

Jan 1, 1986

By H. J. Glass, A J. Cornah

Improving the quality of the variogram helps to improve subsequent estimation and simulation processes. Two strategies for conditioning data prior to construction of the variogram are investigated using data from the Luce iron ore deposit in Canada. One strategy is the classic approach in which the deposit is subdivided into a set of structural domains. The domains are analysed individually and datapairs are recombined to produce a variogram. The second strategy is reconstruction of the deposit at an earlier stage of its history through unfolding. This involves transformation of the Cartesian coordinates into stratigraphic coordinate system. Improvement in the variogram quality, expressed in a decreased weighted deviation from a fitted model, is observed for both types of data conditioning. This indicates that, for the Luce deposit, application of data conditioning could also help to inform the selection of sampling locations.

Jan 1, 2006

Suppression of the explosion of the world population and the surprising increase of waste and emissions are major targets confronting mankind in this century. Recycling and waste minimisation are key words for sustainable development in a highly industrial society. The argument is really whether or not recycling done well is the solution to the environment problem for the following generation. If energy is not necessary in the recycling, all materials have to be recycled. The greatest interest among the environmental issues is the regulation of CO2 gas emission. It must be recognised that it is not possible to completely renew expended energy. Some of the recycling systems currently used are thought to increase the load on the environment rather than to be beneficial. Although metal industries have consumed tremendous amount of energy and discharged a large quantity of CO2 and solid waste, the metals have supported a high quality of life. The metal production industries such as the iron and steel industry and the non-ferrous metals industry can work well recycling of not only metals but also other materials without consuming more energy. Waste plastics, for example, are use as a reductant in a blast furnace. The role of metallurgical industry in the recycling-based society is introduced in the present paper to recognise how the metal industries can contribute recycling and waste minimisation.

Jan 1, 2002

By Kajioka H, Nakamura Y

Na2CO3 is a powerful flux for both dephosphorization and desulphurization in oxidizing atmospheres. In order to study refining with Na2CO3 and the nature of the Na2CO3 slag itself, hot metal (4Kg) was melted in Al203 crucibles in a high frequency induction furnace and oxidised with oxygen under Na2CO3 slag. The behaviour of Na2CO3 at high temperature was observed by thermobalance. It was found that dephosphorization ceases in a few minutes and [,P] after refining is easily lowered to less than 0.010%. [%P] after refining is affected by [Si], [P] of hot metal, the refining temperature and the consumption of Na2CO3. Desulphurization also ceases in a few minutes but it shows curious behaviour, increase of [S], decrease of (S) and increase in sulphur lost, during the latter half of run. [%S] after refining is also affected by [P] of hot metal, the refining temperature and the consumption of Na2C03o

Jan 1, 1980

Copper entering a lead ,smelter in concentrate or from other sources is recoVered as matte and speiss which contain appreciable quantities of lead. The matte and speiss are usually sold to copper smelters to recover the copper content and also any gold and silver in these products, but the value of the lead is largely lost. Some copper plants pay for portion of the lead content, but regarded as a means of recovering lead it is more costly and less efficient than if the lead were recovered at the lead smelter.Because of the value of this lead loss, the metallurgy of copper recovery has assumed greater importance in recent years owing to the rise on the price of lead.Two processes are in use today to produce matte and speiss, namely the iron matte process and the soda matte process developed by the American Smelting and Refining Co. 1 in D.S.A. The latter process is characterised by a higher copper to lead ratio than the older iron matting process.The following analyses are typical of matte and speiss produced at Broken Hill Associated Smelters, by both processes, although the soda matte process is still in a developmental stage and experience indicates that matte and speiss of lower lead tenor can be produced under favourable conditions.

Jan 1, 1951

By Kitzinger F

The economic climate of the Canadian mining industry forced an increased interest in rapid, continuous excavation techniques for hard rock formations. The potential applications and advantages of continuous mining over the present drill- blast-muck labour intensive cyclical methods are considerable. Noranda investigated an electrical technique, Plasma Blasting showing considerable promise for mining hard rock. The background of the technology and the theory of blasting rock with electricity is described. The Plasma Blasting process is based on the fast discharge of stored electrical energy into a small amount of electrolyte, suitably located in the rock. The electrical energy converts the electrolyte into high pressure plasma, which expands very quickly, thereby, generating a shock wave. This shock wave produces a stress field inside the rock, resulting in a blast similar to that made by chemical explosives, but without the deleterious fumes. Noranda is currently blasting boulders of 4-5 tonnes and is at present constructing a mobile, autonomous secondary rock breaker for underground and open pit applications. Tests on in situ hard rock formations will lead to the development of a continuous mining machine. Production rates of 500 tonnes per man-shift could be obtained with such a machine.

Jan 1, 1990

By M J. Pascoe

The performance of 460 stope surfaces at WMC ResourcesÆ Olympic Dam Operation (ODO) has been used to investigate the confidence that can be placed in the Stability Graph Method for design of stope dimensions. A detailed database of stope performance and ground condition information was established for each stope. The database contains all the required stability graph information as well as other factors thought to influence stability, such as discrete major structures, poor shape and exposure time. The performance of each stope surface was quantified by calculating Equivalent Linear Overbreak/Slough (ELOS). The performance of stope walls and crowns was plotted on the supported and unsupported case history stability graphs. Based on this information an ODO design limit of HR = 3.3 x NÆ0.33 has been suggested for stope walls. Walls that plotted above this line were 80 per cent stable, 20 per cent unstable and zero per cent failed. Below the line 60 per cent were stable, 30 per cent unstable and ten per cent failed. Supported crowns that are flat or arched in shape and are not within the influence of major structures can be designed in the stability graphÆs æstable zoneÆ with a strong likelihood of stability. The Stability Graph Method did not reliably predict the performance of unsupported crowns at ODO.

Jan 1, 2005

By Olofsson O, Durance M-V, Villeneuve J

Modelling of the Sala Agitated Mill (SAM) using a simplified solution to the population balance approach has been carried out. The rate of breakage is modified by the mill power, providing predictions of the resulting product size distribution for different grinding conditions and mill sizes. The power of the mill is estimated by a physically derived function, using an assumption that the mill power consumption mainly arises from the ball to ball friction within the mill. The grinding efficiency, depending on the media ball size and pulp density is approximated in the model. Experimental work on grinding a complex sulphide ore using a pilot scale SAM 7.5 has been carried out. Good agreement has been found between the data from the test campaign and the simulated values. The model has also been validated with experimental data from a pilot grinding of calcium carbonate and from an industrial mill. The model is included in the USIM PAC simulation software.

Jan 1, 1995

Urban railway systems need high invest- ments, especially if their routes and stations have to be placed in the subsurface. In the FRG the construction and equipment cost of urban underground railway systems are in the range of 60 to 100 Mill DM per km tunnel. For this reason, track sections on the surface and on elevated structures are used as far as that is possible. Considering whole systems, the costs are in a range from to 45 Mill DM per km length for a metro system with about 80 % of its tracks and stations in tunnels and from 20 to 25 Mill DM per km for a light railway system with about 25 % subsurface infra= structure. The amount of route lengths in tunnels depends on the size of a city, the situation regarding above ground structure and free space on the surface, the level of service quality which has to be achieved with the railway system etc. Despite of the urgent needs to improve the transport conditions there very often arise doubts if an urban railway system is really necessary and can be justified in an economic sense. The experience from many cities around the world shows, that there arise a lot of benefits from urban railway systems, especially with larger sections placed under- ground. They are to be found in the interests of the operator (f.e. operating costs), the user (travel time, quality of service etc.) and regarding social aspects (environmental protection, accidents, consumption of energy Etc.).

Jan 1, 1987

By O&apos, Malley G. B

The properties of bearing metals are of considerable interest to mine engineers, since continuous running of mine and mill machinery is of vital importance. Of the several available types of bearing metal, the low melting point lead or tin base alloys are most generally used in mining plant because of the ease of replacement and the possibility of remelting scrap metal from old bearings. The most valuable property of these "white metals," however, is the plasticity which gives a self-aligning character to the bearings, enablingthem to adjust themselves to inequalities which may exist at the time of fitting, or which may develop during running. The object of the present paper is to explain in general terms the physical structures of white bearing metals, and to point out that constitution rather than composition determines the physical properties of these alloys. The same, indeed, is true of most engineering alloys. In steels, for example, a change in the structure may affect the properties to a far greater extent than a change of chemical composition.Structural changes in steels are produced chiefly by heat treatment. In the case of bearing metals no good purpose is served by heat treatment; the microstructure is determined by the conditions of casting, and striking differences in constitution (and therefore in properties) are encountered in an...

Jan 1, 1932

By C F. Prins, C LantuTjoul

Mineralisation in alluvial diamond or vein gold deposits is often hosted in trapping mechanisms. For instance, diamonds are nested in bedrock depressions such as gullies and potholes which were carved out by the sea long before the diamond deposition took place. Similarly, gold mineralisation can precipitate in the necks of a boudinage structure. In such deposits, the spatial distribution of the mineralisation is governed by the mutual arrangement of the trapsites and by the grade variations within each trapsite. Reliable estimates can be obtained only if they rest on a proper knowledge of both degrees of variability. This creates a challenging sampling problem, as during the exploration phase it is important to have a good global mean estimate to enable decision making towards the future. A similar problem occurs for local estimates at a later stage of development. To understand and manage the sampling for global means, specific sampling procedures are required based on an appropriate choice of sample support size and spacing. Estimates from such sampling campaigns should be unbiased, and the less variability they display, the better the sampling parameters. The performance and impact of sampling parameters are tested and compared on different simulated deposits.

Jan 1, 2005

By Eri G

Ok ledi Mining Limited underwent a major transition from radio based truck dispatching to computerized dispatching for its equip- ment fleet in October, 1996. Modular Mining's Computerized Dispatch System was selected based on reputation and superior customer support. Modular's dispatch system is a fleet management system that uses computer, data communication and global positioning sys- tem technology to produce automatic, optimized haul truck as- signments. Optimization is achieved by equally distributing trucks to shovels so that truck queuing and shovel idling times are mini- mized. Computer illiterate mine operations personnel had to overcome a rather steep learning curve to use the high technology equipment. fortunately the system was able to be configured to use bitmap

Jan 1, 1997

By P Walton, L W. Armstrong, D P. Blair

Sydney is the capital city of NSW and has a population of approximately four million people. Eighty per cent of the cityÆs water is supplied by Warragamba Dam, which is situated some 75 kilometres south west of the city centre. A risk assessment was carried out on the dam and future predictions of water flows into the catchment area showed that there was a risk of a one in 700-year flood not being contained by the dam. The predicted loss of life and property damage warranted the construction of an auxiliary spillway on the eastern side of the existing dam to cater for any uncontrollable influx of water. A test blasting program was instigated and the blasting parameters were established that would lead to routine production blasting of the sandstone rock making it more cost effective to excavate. Blast induced vibrations were a concern to the owners and the dam wall and ancillary infrastructure was instrumented with sensitive vibration monitoring equipment during the test blasting phase of the operation. Once the blasting parameters were established from the testing program production blasting was carried out on a daily basis to maintain æstockpileÆ of fragmented ground for the excavation equipment. Blast vibration models were developed to predict vibration levels for more sensitive areas of the dam to give the operators more confidence in their operations. The blast induced vibration levels recorded did not cause any structural damage to the dam wall and the waveform frequencies of the blasting operation were much higher than that experienced during a recent earthquake. The integrity of the SCAÆs assets were at no time jeopardised.

Jan 1, 2001

By P D. Franzmann, D J. Readett, J Peterse

A better connection between laboratory- and pilot-scale test results, and heap bioleaching performance can be achieved by generating reliable information on the fundamental microbial, chemical and physical processes that occur in heaps and incorporating this information into a comprehensive and robust model. More efficient heap bioleaching, particularly of chalcopyrite, has the potential to add value to the mining industry as well as deliver attractive environmental and social benefits to the communities within which those companies operate.The results of fundamental chemical and microbiological studies of the leaching mechanism, the temperature dependence of chalcopyrite bioleaching, and the optimisation of leaching conditions are described with examples from full-scale heaps. The development and application of a number of novel techniques and tools has assisted our understanding of heap subprocesses mineralogy, hydrology, chemistry and microbiology. The heap bioleaching model HeapSim, which embodies a large number of effects not previously accounted for in other models, continues to be refined and has been applied successfully to the study of several heap bioleach systems.

Jan 1, 2004

By M Hudyma

Open stope mining is the most common mining method employed in underground, hard rock mines in Canada. It is characterised by relatively small, single lift stopes (20 000 to 100 000 tonnes), and fast stope turnaround times. Host wall rock mass conditions, which are typically poor to fair, are the controlling parameter in stope dimensioning. Rock mass stability is maintained by designing all stope surfaces at a stable dimension, and through extensive use of cablebolting for stope backs and frequently stope hanging walls. Dilution control is a high priority. The typically small, high-grade, deep and irregularly shaped orebodies are incrementally developed, usually in a bottom to top direction. In many cases, high stress is encountered due to the depth of the orebodies. Overstressing of pillars and hanging pillars are avoided through the use of pillarless or early pillar recovery mine sequencing strategies. Stopes are invariably filled, and in higher grade and wider orebodies, cemented fill is commonly used. This paper generalises many of the similarities found in Canadian open stope mines.

Jan 1, 2000