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The Coal Corporation of New Zealand Ltd (CoalCorp) is the largest coal producer in New Zealand, with extensive properties in both the North and South Islands. CoalCorp's North Island operations are kilcmetres to the south of Auckland. opencasts, are located in the catchment wildlife, historical and scenic values. in this catchment is the single most mining operations. centred on Huntly, a town some 80 Five coal mines, four of which are of Lake Waahi, a lake with significant The discharges of mine lodgement water important environmental constraint on Throughout New Zealand the use of water is controlled by a statute called the Water and Soil Conservation Act 1967. All industrial water users are required to hold Water Rights, which are in effect licences to take, use, dam, divert or discharge water. Water Rights are obtained through a legally defined process and any potentially affected party has the per to object to their granting. A special tribunal hears the evidence for and against an application, and issues its decision, which is reviewable in a higher court on Appeal. Rights, if granted, are issued subject to conditions and, in the case of mining discharges, limits would be set on flaw rate, suspended solids concentrations, turbidity, pH and the concentrations of any potential toxicants. This paper presents a case study of an integrated, catchment wide water management plan for Lake Waahi, that was prepared by the author, and others while the author was in the employ of CoalCorp, and its predecessor, State Coal Mines. The author is grateful to CoalCorp for their permission to submit this paper.

Jan 1, 1988

The Electricity Commission of New South Wales operates three power stations located on Lake Macquarie and Lake Munmorah. Coal for these power stations is supplied by three collieries operated by the Electricity Commission, three operated by the State Mines Control Authorityrand one privately owned. Most of the coal used in these power stations is won from the Great Northern seam which lies at depths of up to 220 ft at Awaba and at depths of the order of 600 ft at the remaining mines on the southern end of the field.

Jan 1, 1972

By Thomas W

Due to record low tin prices and an uncompetitive position in world markets, the Renison tin mine has undergone three major phases of restructuring in the last three years. This has involved substantial job losses, almost all of which have been through voluntary retrenchments. Retrenchments took place in 1988, 1990 and 1991.The last phase of restructuring was the most dramatic, as many aspects of the operation of the mine were changed. New pay structures were introduced, and the miners' contract system was scrapped. Drastic pay cuts occurred in many areas, although the opportunity was also taken to increase pay at some of the lower levels where inequities existed. Work practices were changed, as was the management structure.

Jan 1, 1992

By Shuguang L, Jing S

Computer controlled truck dispatching systems is a newly-developed technical system in surface mines with shovel-truck technology. The real time dispatching criteria, as the core of optimal truck dispatching software, are analysed and a new criterion, complex dispatching criterion, is put forward. Dispatching criteria previously proposed include: 1. `Earliest Loading' (EL) - to assign a truck to the shovel at which the truck can be loaded earliest. 2. `Max Truck' (MT) - to assign a truck to the shovel at which the truck will have the shortest waiting time. 3. `Max Shovel' (MS) - to assign a truck to the shovel which has been waiting for the longest time. 4. `Minimum Saturation Degree' (MSD) - to assign a truck to the shovel at the branch where the truck flow saturation degree is minimum. 5. `Minimum Saturation Degree with Truck Cycle time consideration' (MSDTC) - as the MSD principle, with the truck travel cycle also considered. 6. `Fixed Dispatching' (FIX) - to assign trucks to fixed shovels. A system simulation model has been set up for truck dispatching system analysis. A few surface coal mines have been selected for case studies. Equipment waiting times and shift production of the system are obtained as the main outputs of the model. Simulation results show that each dispatching criterion has its own applicable range, no one can absolutely dominate the others. For example, when under-trucked, EL and MT criterion can obtain higher production than the MS criterion; when over-trucked, it is vice versa; while for MSD criteria, better results can be obtained no matter how the truck numbers fluctuate. From the view point of shovel output balance, large fluctuations occur for EL and MT criteria, while a good balance can be obtained for other criteria. In the light of dynamic change of mining system conditions, a single dispatching criterion is not necessarily reasonable. A complex dispatching criterion has been put forward to seek the complex optimum effect. Taking the advantage of each dispatching criteria, the dispatching result of a complex dispatching criterion dominates over individual dispatching criterion and a comprehensive optimum effect can be reached.

Jan 1, 1995

By S Vianna

Mineralogical information obtained from plant surveys is subject to errors, both due to sampling and experiment. To reduce these errors, and to ensure that information is consistent, a data reconciliation model has been developed for mineralogical data. Its capability includes mass balancing size data, total assays, assays within size-classes and liberation data. Unlike any other mass balance package, this package also allows reconciliation of the complex mineralogical information. For example, particles cannot simply be treated as binary, but consist of combinations of many minerals. Hence the distribution of mineralogical information is multidimensional and the mineralogical distributions are referred to as multiphase. In this paper, the different levels of mass balancing are explained, including how to mass balance liberation data. Furthermore a new technique based on probability theory can be used to infer distributions even when there is insufficient information to perform a mass balance, and this technique is also explained. Results for various stages are given.

Jan 1, 2002

Although the diesel engine is normally considered a tried and proven power source, many new and exciting diesel design concepts are being evaluated in engine development laboratories around the world. Three such programs currently underway at Cummins Engine Company are discussed. The turbocompound engine converts into power exhaust heat energy which is normally wasted. It does this by incorporating after the turbocharger a low pressure gas turbine which is gear driven to the crankshaft. The adiabatic engine has no conventional cooling system. It converts into useful power most of the heat energy normally rejected to the coolant. The series boost turbocharged engine uses seperate low and high pressure turbochargers to increase engine output and improve transient performance. These design concepts make possible increases in diesel engine thermal efficiency from the current 33 to 38 per cent range to the 50 percent range.

Jan 1, 1982

One of the most frequently asked questions at the feasibility study stage of a project is, æhow big can one go?Æ This important question effects costing and efficiency of metallurgical equipment, the real estate required and the operating plant strategy.The presentation covers both engineering and process considerations and explains the limits that exist today and explores future trends.The paper is specific about large slurry application usually found in gold applications; however, it could apply to silver and uranium or other dense media leach duties.Agitator drive sizes are examined as well as process risks associated with large tank agitation. New technology has increased the maximum tank size and designers are now experienced in tank volumes in excess of 5000 m3. Tanks of 6000 m3 have been agitated and 10 000 m3 tanks are within present engineering know-how and scale-up.Fabrication techniques for shaft and impeller designs exceed the existing standards and new specifications will be needed to cover large mixer design. The paper covers certain aspects of mechanical design and proposes alternative standards that are more appropriate. Process considerations such as fluid natural frequency as well as typical superficial velocities for efficient operations are examined. Scale-up techniques based on existing and new technology are also examined to ensure a successful installation.The presentation therefore covers the majority of large mixer design questions that are frequently asked.

Jan 1, 2006

By D Stow, R Goodridge, K J. Molloy

A range of explosives has been specifically developed for soft ground blasting. These explosives can be used in both wet and dry blasting conditions, range in density from 0.3 - 1.2 g/cc and range in VoD from 2 - 4.5 km/s. This range of explosives has the potential to be tailored to ground type and is predicted to be suitable for a variety of applications which include: blasting in soft to medium overburden, coal blasting, wall control, and low vibration blasting. Trials have been conducted in several applications with encouraging results. Several cast/throw blasts have been conducted with these products partially replacing either ANFO or Heavy ANFO. The results from the blast have been equivalent in cast (per cent) and at reduced cost per unit volume. These products have also been used in presplit blasting and have again achieved equivalent or better results when compared to conventional presplit blasting at a lower cost per unit volume. This product has also been used in a vibration sensitive area replacing traditional explosive products, and generating excellent fragmentation and digging whilst maintaining vibration limits. This new range of products, NOVALITE, has shown great potential in many applications either reducing cost per unit volume, improving wall quality or improving productivity in environmentally sensitive areas.

Jan 1, 2001

By W Farnworth, D Fergusson

Estimation of productivity is a key factor in the design of hydraulic mines and in assessing their economic feasibility. A published Russian formula for hydraulic mining monitor cutting rates overstated productivity by up to 2 tonnes per minute (251%) when applied to Solid EnergyÆs hydraulic mines. A new formula, taking into account additional productivity factors, was derived by Solid Energy and produced an acceptable correlation between predicted and actual cutting rates inNew Zealand and overseas hydraulic mines, with an average error of approximately 0.1 tonnes per minute.   Another key factor in hydraulic mine design is the transport of coal slurry via flumes. Solid Energy carried out a series of 80 full scale tests in a surface flume installation, varying the gradient and coal:water ratio. Both steel flumes and plastic-lined flumes were evaluated. A modification of the Chezy Open Channel Flow formula, including a factor for slurry density, gave a reasonable correlation between actual and predicted flows. It is believed that this Solid Energy formula is suitable for the design of flume installations for hydraulic mining.

Jan 1, 2004

By A Maurer, N Pereira

Low-density explosives have been developed with trials being conducted for over 20 years and yet have still only gained limited market acceptance despite producing some very promising results. The biggest concern with industry acceptance has been disbelief that a product with lower density than the ANFO benchmark could fragment anything but the weakest of strata. Trials have been carried out with products such as diluted ANFO, low-density ammonium nitrate (AN) and various other mixes, although it has been only recently that low-density explosives have been accepted as a serious alternative to traditional products such as ANFO and heavy ANFO. The recent uptake of low-density products has been the result of several key factors: the current resources boom forcing AN supply issues, the development of new handling techniques, and a far better understanding of the utilisation of such products. This paper highlights the benefits of low-density products available in the market and focuses on the situations where low-density explosives can provide the end user with benefits that would otherwise be achieved through more time consuming methods. Through correct implementation, low-density explosives can provide the blast designer with another option when looking at the optimum method of breaking the rock. This while still controlling the other limiting factors such as cost, environmental impacts (noise, vibration, dust and fumes), coal damage and safety (stable walls).

Jan 1, 2005

By V Sahajwalla, S Shin

Research activities to classify the quality of iron oxides have a long history but most of such activities are for the existing processes such as blast furnace or DR plant. Therefore the newly developed process, such as the COREX process, needs new standardisation although some basic functions of the new process have similarity to the existing processes. Many researchers (Hauk, 1990; Cho et al, 1998) in the field of COREX process have conducted investigations since the early stages of the process development and activities are underway for further plant optimisation. As Agrawal and Oshnock (1995) pointed out, because coke is not included in the COREX reduction shaft the strength requirement of the feed materials in COREX process will be more demanding than that in the blast furnace. This condition is similar to Midrex DR plant but the main reduction gas of COREX plant is carbon monoxide generated from coal combustion while that of Midrex DR plant is hydrogen from natural gas.

Jan 1, 2000

The commercial outcomes from new mining projects or brownfields expansions often fall short of feasibility study forecasts because of technical under-performance. This paper: reviews past feasibility study performance; identifies the key drivers of underperformance; and proposes actions that can be taken to manage the risk of underperformance. There have been a number of published reviews of feasibility study performance since the 1970s. The results of these studies are summarised together with recent unpublished data. Key drivers of underperformance include inadequate metallurgical testing, simultaneously pushing a number of project parameters beyond comfortable limits and a failure to recognise the linkage between mining rate and head grade. Actions can be taken during the data acquisition phase and during the feasibility study to manage project technical risks. These generally require a more flexible approach to study management than can be achieved under a ælump sumÆ contract.

Jan 1, 2003

By Royston D

Victoria has an extensive brown coal resource, 202,000 Mt, of which 43,300 Mt is regarded as readily recoverable. This brown coal is located principally in the Latrobe Valley as thick seams and is being extracted at low cost primarily to support base-load electrical power generation. The high moisture content of the coal is partially off-set in many applications by the high reactivity of the coal and the generally low levels of potential pollutants such as ash, sulphur and nitrogen in the coal. Large scale development of this brown coal resource began in the 1920's. In addition to electricity generation, it is used for briquette production, carbonisation of briquettes to char and was gasified for town gas supply to Melbourne (1956 - 1969). The BCLV coal to oil pilot plant at Morwell is a major new initiative in the use of Victorian brown coal. Many other new developments are in place and emerging in the utilization of low rank coals. Examples of these developments are, the large-scale gasification of lignites in the USA, and value-added products such as bulk chars, solid fuels, activated carbons and coal-water mixtures. The Government of Victoria has created the Coal Corporation of Victoria to promote current sales of briquettes and to encourage further new industrial developments based on the State's brown coal resources, in particular the Loy Yang coalfield. The Coal Corporation also has a vigorous product and process oriented research and development Programme.

Jan 1, 1987

By Eren H

For a hydrocyclone of fIXed geometry, DC, Di, DO and ? are constants, the variable parameters affecting the performance are Qi, Fi, Du and H. (See Appendix 2 for definition of symbols).The relationship between d50c, Qi, Fi, Du and H gives models which can effectively be used for performance predictions. Such models have already been established by Lynch et al and by Plitt.These models have been tried in a limited manner under continuous operating conditions for on-line cowol. For on-line control effective and accurate instrumentation is required for which a new set up is proposed. Using this set up, a new model was established. A feature in this model is that deviations from the norm of operational parameters affecting d50c were considered. It is shown that these deviations generated by the disturbance of one or more of variations in the parameters, can be monitored by a computer and suitable signals generated to control servo mechanisms for restoring the required d50c value.The logic followed in developing the computer software is described and the application of the model is indicated.

Jan 1, 1990

The Australian mining industry can expect to be working internationally competitive high quality coal mines during the twenty-first century. Cost efficient mining methods such as high productivity longwall units with heavy reliance on remote control will be standard and worked by well paid and intensively trained operators. Major changes in mine ventilation engineering can be expected in the use of computers and mine telemetry, the understanding of the mine environment and the frequency of mine disasters, the utilization of mine air contaminants for profitable purposes and the provision of a pleasant and comfortable work environment. New approaches to mine ventilation such as air recirculation will have been considered. There will be an increased need for highly trained ventilation engineers. With the present pace of technological change, quite revolutionary new approaches to mining and ventilation can be expected by the end of the twenty-first century.

Jan 1, 1988

By S J. Henderson

Over much of Australia, rainfall is highly seasonal and storm-driven. Consequently, operational mines often need extensive earthworks – drains, dams and levees – for protection during the occasional large floods and for water storage against the dry times; however, it has not been appreciated that many of these earthworks will need to function after mining has finished, sometimes, beyond a normal design life for engineered structures.While a mine is operating, standards for design and maintenance are dictated by regulation and risk assessment. For dams and levees – regulated structures – the standards imposed mainly relate to life-of-mine. The levels of risk and maintenance accepted by the mine operator may not be acceptable to another landholder in perpetuity. However, the Environmental Authority cannot be surrendered unless the landholder has accepted responsibility for any unrehabilitated regulated structures (Department of Environment and Heritage Protection (DEHP), 2016).In order for a future landholder to be willing to take responsibility for a dam or levee, the structure should be of value to the business of the property. In addition, its management needs must be consistent with that business; for example, it should be maintainable using skills, equipment and materials normally available to the business.CITATION:Henderson, S J, 2016. Earthworks or landforms? Designing for lease surrender, in Proceedings Life-of-Mine 2016 Conference , pp 151–153 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Better quality at lower cost is today's formula for remaining competitive in a world market. For an integrated steel company, high quality low cost steel production must originate before the blast furnace. In 1979, when U.S. Steel initiated a Quality Management Program throughout its steelmaking operations, efforts began at the coal, ore and flux mines. The objective was to improve the quality and reduce the variability of the critical parameters for steelmaking raw materials, to get the blast furnaces, and subsequently the melt shops, under optimum control. The general details of U.S. Steel's Quality Management Program are discussed and how it was used to promote the desired improvements in steelmaking raw materials. Some of the outstanding results obtained by the cooperative efforts between the mines and the steel plants are reported. The lessons learned by U.S. Steel were through upgrading existing operations and facilities. These principles should now be applied to new projects and the benefits of good quality management should commence from the time new projects are Commissioned.

Jan 1, 1986

This paper provides an overview of current and future mine developments in the major island nations Indonesia, Papua New Guinea (PNG), New Zealand, and Fiji, and the French territory of New Caledonia. Many of the other 11 small island nations in the region, such as Vanuatu, Pulau and the Solomons have been the subject of considerable exploration orientated towards gold in the past few years but without any deposit found with confirmed economic viability.

Jan 1, 1990

A case is made for broader commercial education of executive and operational managers in Australian mining companies. The competitive advantages and disadvantages of Australian miners are examined. Areas of opportunity are identified which could be exploited by broader applications of proven techniques to commercial management of mining companies.

Jan 1, 1985

Most mining dredges are adapted from canal/harbour dredges. Their automation and control systems are generally not designed for integrated mining operations. Consequently they have a number of limitations. This paper describes a new dredge control concept which paves the way for improved efficiency and increased production.

Jan 1, 2001