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By McMahon DW, Schapper MA

Hard rock underground mining has been wedded to the drill-blast method of breaking rock. Current practice and technology have focused on greater efficiencies in the blasting and handling of ore, on the basis that thelower costs that come with larger scale operations compensate for the waste dilution associated with the bulk methods. However, it is suggested that new technology is available or is on the horizon that could completely change the shape of hard rock mining in the 21st century. Hard-rock continuous-mining machines, possibly assisted by high pressure water jets, coupled with automated sorting and materials handling systems, could re-orient the miner's focus to winning metal rather than mining tonnes of ore. More continuous mining processes could accelerate the penetration by high technology in the hard rock underground mine, with the potential of greater manpower productivities and lower costs per tonne of metal produced. This new technology will be important in maintaining a competitive supply of metals, given the falling headgrades of the orebodies remaining for development and the increasing market threat from manufactured substitutes.

Jan 1, 1985

Variety among deserts is nearly as great as among other climatic environments. Common to most deserts, and to areas downwind from them, is the dominance of aeolian transport of surface material, at least during some seasons of the year. The result is dilution of local surface materials with varying proportions of chemically uniform fine sand and silt, often imported by the wind from remote areas. Fortunately, desert pavement,.even though separated from bedrock by a meter or more of nearly pure loess, is simply a diluted reflection of nearby bedrock. Infiltration of loess through the surface debris and the rudimentary soil-forming processes in the desert usually preserve the integrity of the pavement. This pavement, or its "downstream" derivatives, provides a suitable sample for exploration geochemistry if proper care is taken to circumvent the aeolian dilution. The simplest and most commonly used method of circumventing the dilution is to use a coarse fraction of soils or stream sediments, discarding or retaining the finer fraction depending upon the magnitude of the dilution. Where the coarse surface debris is composed of rock chips representative of the bedrock sources, the method is successful. Under most circumstances the coarse fraction of the surface material will give a fair representation of gross lithology and will occasionally give an indication of mineral- ization. The major drawback to this approach is that selective weathering and erosion in the vicinity of mineral deposits often lead to the loss of ore minerals into the finer fraction, leaving a coarse residue enriched in feldspar and particularly in quartz; thus, the geochemical signature from a mineral deposit is effectively reduced or completely masked. The second most commonly used method to overcome aeolian dilution, and probably the most effective at present, is to use a heavy- mineral concentrate. This approach presupposes that the chemical signature sought resides in a heavy mineral. Fortunately, the arid weathering cycle is conducive to the formation of a wide variety of secondary ore

Jan 1, 1988

By C J. Moran

The Gladstone region, as one of the most industrially intense regions in Australia, uses significant quantities of fresh water. Awoonga Dam, situated on the Boyne River, is the only major source of water in the region. The current typical annual usage is 53 GL (Porteous, 2006) and approximately 80 per cent of the water is used by heavy industry (Gladstone Area Water Board, 2004). Until relatively recently, there has been ready and easy access to raw water for industrial use. The recent drought, which resulted in severe water restrictions in 2002 and 2003, emphasised the importance of water for a dominant industrial region like Gladstone. Although now in the process of changing, the typical contractual arrangements in the past have provided little financial incentive for efficient water use. From research undertaken on potential water reuse opportunities, several key questions have emerged related to water management in an industrial region such as Gladstone. This paper highlights these key questions, presents findings from recent regional strategies and assesses the potential for water reuse. Even though there is no clear-cut financial incentive for reusing water, there could be stronger regional and risk mitigation drivers for doing so. Initiatives to incorporate adaptive capacity through collaborative industrial synergies would allow for robustness and resilience in water security, leading to long-term sustainable water management across the Gladstone region.

Jan 1, 2006

By Riley S. J

The basic aim of mine planning is to design mine layouts and schedules that achieve optimisation of operations, minimum cost and maximum resource recovery. Successful accomplishment of this aim is facilitated by timely and comprehensive rehabilitation planning commencing at the pre-feasibility stage and continuing until the end of mining. Incorporation of a final landfomt design for waste rock dumps in a mine plan requires a prediction of surface stability, which may be achieved through erosion modelling. Erosion prediction models can be placed in two broad categories: soil loss prediction models eg USLE and CREAMS, and geomorphic models such as SIBERIA. A waste rock dump landform design based on selected slope form and grade and drainage systems should be developed as part of planning. A digital terrain model (DTM) of the landfonn should then be produced which can be modelled for long-term erosional stability using pre-determined parameter values. If acceptable standards of stability are not achieved, the landform should be redesigned and remodelled until the desired result is obtained. The planning process incorporating models requires knowledge of spoil or waste rock properties and model parameter values. This information is site specific and can be obtained from drill cores or costeans at the pre-mining stage and from spoil or waste rock during the mining stage. Realistic model parameter values are critical in post-mining landfonn design and can be obtained by several methods, including rainfall simulation, monitoring, geochemical analyses and grain size analysis.

Jan 1, 1994

WaihiÆs Cornish Pumphouse is located on the edge of town in a dynamic and changeable area where history affects the future. As in any successful project, ingenuity and team work have been significant factors in the planning and implementation of the buildingÆs relocation.   Work around the Pumphouse site commenced circa 1900 with preparation to sink the No 5 shaft. Construction of the pumphouse and the steam driven C pump was completed by 1904 with hints of what was to come evident in 1905 as the No5 Shaft collar had sunk 350mm in four years. By 1907 surface cracking developed over the Milking Cow cave area and in 1913 200 mm was cut off the main pumping rod as the ground was sinking at a rate of 25 mm per year.   In 1913 ground around No 6 shaft had subsided 600 mm.It was also the end of an era as steam gave way to hydroelectricity and electric pumps replaced the C Pump. C Pump was maintained as a backup from 1913 to 1929 and then finally scrapped. 25 years of underground caving operations removed approximately 400 000 cubic metres of ore leaving a 7 ha collapse crater that eventually became known as the mine lake.   On the edge of town a tension zone over the Royal Lode began to develop 50 m diameter chimney collapses as large scale blocks relaxed into unfilled stopes in the old Martha underground mine. After the 1999 collapse part of the main street was closed and after the 2001 collapse Hazard Zones were declared, more streets closed and areas evacuated and retired from residential use.   By 1984 the Pumphouse has approximately one degree of tilt and in 2002 tilt on the Pumphouse accelerated briefly and then settled down. Tilt accelerated again late in 2004 and a scoping study was initiated to define protection options for the pumphouse. The Martha Mining Licence requires Newmont to 'Take whatever precautions are necessary to protect the old Cornish Pumphouse adjacent to No5 shaft' and viable solutions needed to found.   Any work on the Pumphouse comes standard with a wide range of stakeholders, governing agencies and legal framework to consider. Land Information New Zealand (LINZ) is owner and administrator of the pumphouse.

Jan 1, 2006

The New Zealand Mines Rescue Brigade was established as a result of the Dobson mine disaster on 3rd December 1926, when 9 men lost their lives. Prior to this, there had been four major disasters in New Zealand coalmines, with a total of 145 fatalities. Only large-scale events such as explosions or major fires were considered reportable. Until and including the Dobson disaster, no mine emergency response facilities or organisation was in place.   Unfortunately, over the next five decades the establishment of a Mines Rescue Service did not mean that disasters involving multiple fatalities ceased. The coal mining industry continued to suffer the consequences of poor mining practice, inadequate or inappropriate monitoring and management, and sometimes complete disregard for the regulatory requirements current at the time.   The role of Mines Rescue has been defined in statute, and regulated by Coal Mines (Mine Management and Safety) Regulations. Currently, the statutory obligations have been under the Mines Rescue Trust Act 1992.   The Mines Rescue Brigade historically, has primarily been a reactive service, with stations and facilities established to train brigadesmen in emergency response procedures, specifically to mobilise in the event of a call-out at any one of the many coalmines operating within each stationÆs area of jurisdiction.   Over the last ten years, this role has changed. The service has adopted a proactive approach to emergency response, and has established a close liaison with all mining and tunnelling operations throughout industry, both underground and surface. The objectives have become emergency prevention focussed, and the service has incorporated a range of theoretical and practical training, simulated exercises, more sophisticated equipment and techniques, and a desire to ensure that emergency response capabilities are not needed, whilst maintaining the traditional and statutory obligation to respond if they are needed.

Jan 1, 2004

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 scheme of rehabilitation of surface plant commenced in 1936, included the provision of improved and more hygienic changing and bathing facilities for the employees.At that time the Thompson's Shaft section of the British Mine was being prepared for a resumption of operations, and it was decided to repair and re-equip the existing building. Thus any new scheme adopted could be given a thorough trial, and the proved arrangement used as a basis for the contemplated new main changehouse on the North Section.Investigations were carried out to determine the most suitable arrangement for the Thompson's Shaft changehouse, to provide for a total of 120 men, with particular regard to the internal fittings and fixtures. Also, as the mining conditions were such that a large proportion of clothes worn underground by miners, etc., were wet by the end of the shift, the problem of drying these clothes in the availaole time from a man coming off shift to his commencing again some sixteen hours later was one of the most important to be dealt with.The changehouses in use on the North mine section of the lease were provided with racks around the walls for the men to hang their street clothes on, and a section was partitioned off to house the mine clothes and their drying facilities. The actual drying was carried out by means of hanging the wet clothes over racks between which ran pipe coils heated by means of hot water circulated from the hot water boiler supplying the showers.This method had proved to be far from satisfactory for several reasons, the main objections being:-

Jan 1, 1940

By Lumley G. I, Duffy W. J

The risk involved with incorporating new/unfamiliar technology into mines has, in the past, largely been evaluated by the supplier of the technology. The implications on safety and productivity has been accepted as part of the process of `getting up and running'.This has changed. As companies see the lost productivity and accidents actually costing significant dollars, risk assessment is becoming an important part of the implementation of new equipment. Regulatory authorities are also seeing the preventable incidents and in some cases are now requiring a risk assessment to be undertaken on new equipment at a Mine.

Jan 1, 1992

IN this paper the author's intention is to convey a brief resume of the lead flotation treatment and lead flotation machines, which have replaced the May jigs and Wilfley tables at the plant of the North Broken Hill Ltd., and converted this mill into an all-flotation plant.Attention is directed to the fact that this drastic change from semi-gravity to all-flotation treatment, has been successfully accomplished without resorting to finer grinding than that previously in vogue for Wilfley table concentration, viz.: 10% to 16% plus 40-mesh I.M.M. screen.From the figures now available it is manifest that the scheme of all-flotation concentration-new as regards its successful application to Broken Hill ores is resulting in considerably higher-grade lead concentrates, and is substantially decreasing charges for labour, stores, and maintenance.The new treatment is far-reaching in its simplification of plant, as evidenced by the idle jigs and tables, and the results being obtained by North Broken Hill Ltd. may possibly influence metallurgical practice generally in Broken Hill.The outstanding features of the treatment are:(1) The coarseness, and high grade of lead concentrates obtainable.(2) The low time factor required for flotation.(3) The plant capacity, and the simplicity of its operation.(4) The low horse-power consumption.(5) The small cost for reagents used (not exceeding 3d. per ton of ore).

Jan 1, 1930

By L Smith, R Beckie

Controls on environmental loading from acid rock drainage (ARD) are not well understood in waste rock material. In particular, relationships between subsurface flow and the timing, duration, and intensity of leaching of metals and acidity from waste rock dumps remain ill defined. This study investigates field-scale relationships between subsurface flow processes and geochemical processes in unsaturated waste rock. A 12-metre tall, unsaturated waste rock pile, constructed in 1994, was deconstructed and sampled at Key Lake, Saskatchewan, Canada, during the summer of 2000. A detailed sampling methodology was developed to characterise physical and chemical properties of waste rock material within the waste rock pile. Physical properties were characterised by measuring soil-water suction, volumetric water content, and grain-size distribution at 60 random locations within the pile and grain-size distribution at 20 grid locations within the pile. Attempts to develop a field-based soil water characteristic curve from physical field-data failed due to spatial variability and hysteresis of waste rock properties. As a result, grain-size distribution was used as a relative measure of subsurface flow. Paste pH, pore-water geochemistry, mineralogy, and water-soluble extraction results were used to characterise geochemical processes and sulfide oxidation at each of the 20 grid locations. Geochemical characterisation results demonstrated the preferential weathering of marcasite relative to pyrite and chalcopyrite. Dolomite was the main buffering carbonate mineral. Gyspum, jarosite and iron oxyhydroxides were the main secondary minerals. Pore-waters contained up to 800, 11.7, and 6 mMolar (78 000, 690, 1400 mg/L, respectively) of sulfate, nickel, and uranium, respectively, suggesting significant weathering has occurred. Measures of weathering indicators show no discernable correlation with grain-size distribution nor do they show any spatial relationship within the sampled grid. Reasons for this may include limited duration of waste rock exposure to weathering and development of fluid flow-paths, and limitations of characterisation methods used. Indeed, six years may not be long enough for weathering patterns to develop due to fluid flow-paths in this unsaturated waste rock pile.

Jan 1, 2003

Legislation up to the early 1950s prevented the mechanical extraction of pillars. The mines operating at that time had formed extensive areas of pillars. When permission for the mechanical extraction was gazetted, conventional equipment was employed for pillar extraction and generally using hand mining systems. The mid-fifty's saw the of continuous miners. These machines eliminated the disadvantages of conventional equipment and the necessity for multiple working places. Some new layouts for panels emerged; however, actual extraction methods of pillars still followed closely that of hand mining. During the early sixty's the extraction of standing or new formed pillars was undertaken by the "open-end lift" or a "split and lift" method.

Jan 1, 1974

By Seneviratne SP

The excessive displacement of the seam floor in headings (i.e. roadways) called 'floor-heave' is often experienced in the underground mines of the Southern Coalfield of New South Wales. Apart from interfering with the mining operations, the phenomenon could be detrimental to the stability of the pillars left for support leading to an unpredictable increase in the subsidence of the overlying strata. The latter could pose a serious problem, particularly in the design of partial extraction layouts of mining for areas where subsidence is to be controlled. The susceptibility of the floor of different rock materials and thicknesses in a given `panel and pillar' partial extraction geometry was examined by two- dimensional Finite Element Modelling of the displacements, stresses and failure zones around the excavations. The modelling, assuming elastic behaviour of the materials, indicated that the maximum vertical displacements of the floor increased substantially as the Young's Modulus of the material decreased to less than 7GPa and the thickness of the layer increased. The results also discount the possibility of a properly designed panel and pillar geometry in the Southern Coalfield of New South Wales being unable to adequately control surface subsidence through the pillar, or its core independently of the yielded ribs, penetrating the floor.

Jan 1, 1992

By Bogie I, White P. J

Active geothermal systems occur widely in Sumatra and in the Taupo Volcanic Zone (TVZ) of New Zealand. There are also many occurrences of epithermal gold mineralisation in Sumatra, some of which are economic. Minor sub-economic occurrences of gold have been reported in the TVZ but none have yet been mined. There are both similarities and differences in the nature of the active geothermal systems and mineral deposits in Sumatra and New Zealand, which can be systematically related to the tectonic setting. The thicker crust and consequent predominance of silicic volcanism in New Zealand leads to hydrothermal. systems which are little eroded and with limited lateral outflows. The systems in Sumatra are of mixed character, with some of the characteristics of those in andesitic island arcs such as Java or the Philippines, eg a higher proportion of systems with identifiable acid magmatic volatiles, a greater potential for deep erosion and lateral outflows than in New Zealand; but modified by the more oblique component of subduction and thickened crust so that some are localised in volcano-tectonic depressions and consequently have high piezometric levels of primary hydrothermal fluid. The unusual occurrence of calcic zeolites in veins associated with gold mineralisation in Sumatra is thought to be indicative of "satellite" boiling zones along de-gassed hydrothermal outflows.

Jan 1, 1995

By D Moy, T Carter

This paper outlines the feasibility assessment conducted to explore the possibility of constructing two submarine water supply pipelines beneath the Ma Wan Channel in Hong Kong using either horizontal directional drilling or tunnelling. The Ma Wan Channel is a major shipping channel in the Northwest New Territories, which separates Ma Wan Island from the mainland. The challenges faced by the projectÆs designers included space limitations on either side of the channel, marine department restrictions on construction activity within the channel and selection of a suitable crossing alignment and profile given the channelÆs depth, irregular sea floor topography and complex geology. The existing geological information indicated the proposed alignment would cross granitic and volcanic formations, which would likely be faulted. The primary concerns with horizontal directional drilling were:the length, diameter and depth of the crossing were at the limit of precedent experience in rock; the lack of available space at both the entry and exit sites; and whether the technique would be flexible enough to cope with the anticipated range of ground conditions. The primary concerns for tunnelling were: the possibility of encountering large inflows of high pressure groundwater; andthe possibility of encountering disturbed ground within the fault zones which could flow if not properly treated. As a means to evaluate and mitigate these technical risks for both construction options, a directionally drilled pilot hole was used to investigate the ground conditions along the proposed pipeline alignment. The pilot hole results indicated that either directional drilling or a closed face TBM drive were technically feasible crossing options at a crossing depth of 80 m. The results also indicated that either an open face TBM or a drill blast drive would need to be constructed at much greater depth because of the presence of highly permeable, disturbed ground in mid-channel at this crossing elevation.

Jan 1, 1999

By Morrison RD, Peberdy NJ

Simulator training provides a cost effective method of training operators in both the process and control aspects of a metallurgical plant. The components and requirements of a training simulator are described along with the benefits to be gained from simulator training. A table summarizing some applications of metallurgical training simulators is Given.

Jan 1, 1991

By L C. P J Fonteneau, B Godel, E R. Ramanaidou

The Hamersley Province in Western Australia hosts large iron ore deposits. Each deposit displays various iron ore types that were defined on their metallurgical properties, especially in terms of porosity and mineralogy. Conventional porosity and mineralogy information on iron ore types are provided on 2D thin sections using automated image analysis with scanning electron microscopy (SEM)-based techniques combined with chemical analyses. However these techniques cannot accurately quantify the 3D porosity. High-resolution X-ray computed tomography (HRXCT) is a non-destructive technique providing a 3D image of the sample with a resolution close to 0.5 - 0.7 ¦m for samples size of up to few centimetres in length. 3D image analysis using customised algorithms now provide accurate quantitative porosity and mineralogy of iron ore types.CITATION:Fonteneau, L C P J, Godel, B and Ramanaidou, E R, 2013. Application of high-resolution x-ray computed tomography to iron ore characterisation, in Proceedings Iron Ore 2013 , pp 243-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By C Glassock, P Tilyard, T Sandeman

Computer simulation is a well accepted tool for modelling the behaviour of large and complex operating systems. It is a particularly useful technique in complex operations where there are multiple interactions between the inputs and outputs of various unit operations. It can be utilised during the early stages of a project as part of the business case definition phase or the early engineering phases, or alternatively to help understand the various options available in an upgrade or expansion. With the design of a new processing plant to handle a different ore type at Lihir Gold Limited (Lihir), there was concern that the existing conveying system could separately handle the increased tonnages. A simulation model was constructed which allowed Lihir to examine the impact on the conveying system of the new process plant, as well as investigate the effect of different trucking options. As is often the case, once the simulation model was built, further understanding of the downstream bottlenecks was able to be investigated, including the sizing of critical equipment.

Jan 1, 2006

Gold is actively precipitating at grades up to 80 g/tonne at and near the surface of the Waiotapu geothermal system, located in the Taupo Volcanic Zone of New Zealand. Many characteristics of this active system makes it analogous to the environment deduced for epithermal precious metal mineralisation in the circum Pacific region.The near surface area of the geothermal system is approximately 17 km2, caused to an extent by the upflow of deep, neutral pH fluids being deflected into a lateral flow of several km. This fluid has pervasively altered the rhyolite pyroclastic and ash deposits to an assemblage generally characterised by the term propylitic; major vein mineralisation is not observed. The temperatures at the 1100 m limit of drilling are 300¦C, and decrease to the surface along a boiling point curve.Condensation of steam and H S (subsequently oxidised) at the surface (derived 2from deep boiling) results in the formation of heated acid sulphate waters. These have caused a shallow (50 m) cap of advanced argillic alteration. Mixing of this oxidised condensate with the deep neutral pH fluid appears to be the principle cause of gold deposition from thiosulphide complexes. The major focus of gold mineralisation is in Champagne Pool, a hot spring which fills one of several 900 year old hydrothermal eruption craters.

Jan 1, 1984

By J Q. Cooper

The New Zealand rail authority, Kiwi Rail and Auckland Regional Transport Authority (ARTA), are jointly planning a new mainline rail link between Auckland’s downtown Britomart Station and the existing Western Line at Mt Eden. In 2009, APB&B, a consortia of Aecom, Beca, Parsons Brinkerhoff and Hassell Architects where commissioned to develop the conceptual design, Assessment of Environmental Effects (AEE) and business case for the new 3 km rail line towards preparing a Notice of Requirement to protect the route through Auckland’s central business district.This paper describes the engineering challenges in the development of the conceptual design for the three proposed underground stations, the running tunnels and connections to the existing network. Feasible alignment and station location options were developed and evaluated using multi-criteria analysis based on key client functional requirements, constraint mapping and environmental impacts. The resulting preferred scheme was then developed to a conceptual design suffi cient for assessment of environmental effects, risks, and the development of a robust construction methodology to allow high level capital cost estimates.The paper describes some of the major challenges overcome to develop the concept, including steep gradients, narrow street envelopes with existing buildings and structures, the need for large platform spaces with low ECBF rock cover and complex connections at Britomart and the main line near Mt Eden.The development of the conceptual design of the underground stations in particular demonstrates the need for a holistic value engineering approach to satisfying the architectural and functional requirements, in a highly constrained dense urban environment and at lowest practical cost. The construction methodology was a key input to the conceptual design development throughout.The conceptual design will be used as the fundamental basis for the development of the AEE and business case for the project in the future.

Mar 8, 2011