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By C E. Woolley, H Jebaliya, J Foster

The East wall of the Kalgoorlie Consolidated Gold Mines Fimiston Open Pit (KCGM Superpit) has a history of wall instabilities impacting mining operations; the most significant of which occurred in May 2018, when more than 1 Mt of rock dislodged over six, 30 m high bench stacks and impacted the pit floor. Since 2011 approximately 1.250 Mt of material has fallen from the East wall at Fimiston Pit across three failure events (2011, 2018 and 2020). Each failure has been associated with major structures intersecting the pit walls: the Fiji Fault, the Australia East Secondary Splay Fault and the EWD3 Fault. In each instance the trigger for failure has been transient pore pressure in the pit walls. Northern Star will mine a cut back behind the failure area over a vertical distance of 180 m. Cut back mining will include the extraction of a remaining in situ wedge, which is assessed as kinematically able to fail, and a subvertical failure backscarp in Stage 1. A substantial amount of rill material from the 2018 and 2020 failures will be extracted in Stage 2. This paper presents the methodology in use to mine Stage 1 of the cut back, safely, through this potentially high-risk area, detailing the specific mining methodology employed, the controls put in place and the monitoring required. Day-to-day monitoring will be undertaken using the already installed slope stability radar and will feed into a daily assessment of activities which may be undertaken in the cut back area. Initial activities will focus on eliminating the potentially unstable wedge and vertical backscarp with use of innovative drill and blast techniques/products and the extensive use of remote capable equipment to limit personnel exposure.

Jun 22, 2022

By M Johnson, M Horrigan

The scope of this report is to examine the aforementioned hypothesis by performing a detailed analytical comparison of a P&H electric rope shovel to an O&K diesel powered hydraulic excavator. In order to complement the integrity of the concluding results, two different size categories will be analysed in order to demonstrate that the findings can be extrapolated and applied to all the machinesÆ size classes. These two size classes are categorised by their bucket sizes and they are in the range of 43 - 58 cubic metres and 23 - 26 cubic metres. It should be noted that electric powered hydraulic excavators will not be considered in this report. In order to compare the electric and hydraulic types, the machine variants that will be analysed are commercial cost-effectiveness and operational flexibility. Although operational flexibility can be an ambiguous characteristic, a clear and thorough definition describing its exact meaning has been included. In order to simplify this study, all the data collected for this comparison have been for overburden removal, eliminating the variation that occurs with the movements of the shovel when selectively mining in the ore deposit. Thus, it ensures that all the data that is compared stems from a common origin for all the shovels. In other words the information will be compared when digging in the same material, loading into the same sized haul trucks, and when possible, with the same operators. Theoretical data received form the respective manufacturers, and actual data obtained from Mount Whaleback, was used for this comparison. This leads to the final comparison, where the operational flexibility and the cost-effectiveness are evaluated, with respect to their individual importance, ultimately influencing the final recommendation.

Jan 1, 2002

By A Grice

AMC has completed a number of backfill options studies, including several in recent years for large, three-dimensional orebodies involving total extraction by longhole open stoping with backfill. This has led to the development of a thorough review methodology that assists in the selection of the most appropriate backfill system and the most economic mixes to achieve the required performance. A recently developed design tool has simplified the calculation of backfill strengths for various exposure dimensions and automatically determines strengths incrementally over the height of a stope. Using a generic orebody with a plan dimension of 120 m wide by 360 m long, several different stoping layouts have been analysed to determine the effect of stope dimensions and sequencing on backfill strength requirements. This has been done for stope heights from 50 m to 300 m, in 50 m increments. The required strengths have been calculated in slices and summarised for each stope in four equal layers. The average strength requirement for each layout at each stope height has been compared graphically. For all stope heights, a panel stope layout that minimises the proportion of primary stopes results in a lower average strength requirement than grid layouts on a checkerboard pattern. However, for very high stopes, smaller plan dimensions become more economic. The increase in required strength with stope height is non-linear, making taller stopes potentially more attractive. The main cost factor in most backfills is the rate of binder addition, which is closely related to the strength required. By choosing a layout that minimises the backfill strength requirement, significant savings in binder addition rates and overall costs can be achieved. These must, of course, be weighed against other factors to determine the optimum stoping layout and backfill system.

Jan 1, 2000

By U König, N Norberg

To cope with varying raw material qualities and increasing prices for energy, a more frequent and accurate monitoring of the processing of iron ore became the focus in sinter plant operations. Traditionally, quality control in iron producing industries has relied on time-consuming wet chemistry or the analysis of the elemental composition. The mineralogy of a sinter that defines the properties and behaviour in the blast furnace is often not frequently monitored. One fast method to analyse the mineralogical composition of iron sinter, raw mixtures and iron ores is X-ray diffraction (XRD). Recently statistical methods such as similarity analysis or partial least square regression (PLSR) in combination with XRD raw data has become more and more popular in handling large amounts of data and correlating process-relevant parameters directly with an XRD measurement. PLSR can be used to correlate process parameters directly from the XRD pattern without investigating the mineral content. Hidden information that is present in the measurement but not determined with traditional methods can be used to improve the characterisation of the analysed materials.CITATION:König, U and Norberg, N, 2017. Iron sinter process control using X-ray diffraction – part : monitoring of low temperature degradation, in Proceedings Iron Ore 2017, pp 75–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Predicting the future is a task that should always be delegated. If that is not possible, then stating your views confidently, but retrospectively, is preferable. Hindsight encourages clarity of thought and sharpens perception. When all else fails one can look back into history and see the trends, evaluate the current situation and project it a little way into the future - in this case 10 years. In exploration the rate of change has been increasing over the past 20 years. With expected developments in technology, legislation, and their sociological impacts, we will see such rapid change over the next decade as to make us uncomfortable, unless we are prepared for it.   The social obligations of our industry also have changed enormously over the past 20 years and are still changing. This will lead to further changes in the way we conduct our business if we wish to stay in business. As exploration technology improves, a further dimension is added by the expectations of the communities in which we operate. This extra dimension needs to be quantified so that we not only keep up with current developments but also get ahead of the game. This paper is based on the New Zealand experience, some of which will be familiar to mineral explorers in other countries.

Jan 1, 1997

The material presented in this paper describes experimental work to determine the effect of variations in suction nozzle design upon inlet flow conditions. Four entrance profile shapes were examined under controlled conditions of slurry flow and it was found that the straight ended nozzles had consistently higher entrance losses than the straight taper or the ellipse, and that the circular arc profile nozzles were the most efficient. Subordinate considerations were the measurement of the quantities and the forces involved.As the work progressed, three distinct phases in the pattern of flow were apparent and the static pressures in each were carefully examined. An inlet zone was found to be unstable in changing boundary conditions, a transition zone was largely independent of slurry density and in a zone of stability the pressures were found to be directly related to the characteristics of the flowing pulp. In this zone pressure measurements were reproducible within ± 2 per cent regardless of changing boundary conditions.The effect of varying the "1" parameter of nozzles with a part circular entrance profile was examined and it was found that flow conditions approaching the ideal were obtained when the radius of curvature was between 0·40 and 0·550.

Jan 1, 1966

By D David

Clearly a plant designed only to treat average ore at the nameplate rate will fail to achieve nameplate in any typical year. To insert the necessary capability to achieve nameplate it is common process engineering design practice that plant must be able to treat an ore with 80th percentile value (hardness or competence values for example) at the nameplate rate. In the authorÆs experience, apart from a couple of notable cases, this has been applied reasonably well as a principal, and with widespread success. However, in a number of recent instances it became clear that the use of the 80th percentile number would have resulted in significant under design of the plant. This paper makes the case that the 80th percentile, as a principal, has can have serious flaws and its use needs to be assessed on a case by case basis. The discussion in this paper is the first step in developing a new design principal, and the associated methodology for selection of a design value, that will ensure plants are designed to achieve their nameplate capacities.CITATION:David, D, 2013. Is an 80th percentile design point logical?, in Proceedings MetPlant 2013 , pp 6-12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

North Flinders Mines Limited (N.F.M.) is an Australian-owned mineral exploration and mining company based in South Australia. In the 1970's it researched the prospectiveness of the Tanami (central western region of the N.T.) for the identification of possible economic gold deposits. Having outlined the potential for such a deposit at The Granites (550 km. N.W. of Alice Springs), it marked out and in 1975 applied for the grant of eleven gold mining leases (G.M.L.'s) under the provisions of the then Mining Ordinance. This application was deferred by the Commonwealth Government during the time of the Aboriginal Land Rights Commission (Woodward), subsequent enactment of legislation and land claims. In 1980, the Walpiri and Kartangarurra-Kurintji land claim encompassing the G.M.L.'s, became Aboriginal land. It therefore became necessary for N.F.M. to negotiate a mining agreement with the Central Land Council (C.L.C.) represent- ing the Traditional Owners, before the G.M.L.'s could be granted. In August 1983, the C.L.C. and N.F.M. concluded an agreement to enable the grant of mining interests necessary for the devel- opment of The Granites Gold Project. In several ways this agreement is unique in That:

Jan 1, 1984

Projects to be undertaken in remote locations require special attention with regard to constructability from the very first stages of design. This is to ensure not only that the project is compatible with the environment in which it' is proposed to be built, but that it does not require facilities or special construction equipment and expertise that is not available in the proposed location. This paper draws on experiences gained on projects in Alaska, Northern Canada, South East Asia, outback Australia, and more recently Bougainville, in Papua New Guinea, where over the past 5 years Minenco has undertaken in excess of A$120 million of work on a number of different projects for Bougainville Copper Limited Although many of these projects have been close to large populous cities, which have been served by regular shipping and airline services, the locations have not had the availability of construction facilities which exist in major cities of Australia and thus can only be considered as remote locations by current day standards. As a result, every nut bolt and washer has had to be brought to the job site by the construction company. No hardware or electrical warehouses existed for those forgotten half dozen high tensile bolts, spring

Jan 1, 1986

Both innovation and excellence are desirable attributes of education, as they are also markers in the progression of the human race, but how attainable are they? The interaction of minerals and humanity provides a special insight into the development of both criteria, from the discovery that chert cuts, through the Bronze Age and the first use of metal alloys for implements, to using coal, oil and uranium as sources of fuel. However, there have been many hiccups along the way, where excellence in one respect has meant disaster in another. Examples are in the exploitation of asbestos, and in traditionally poor work practices in mining, both contributing to the widespread public belief that minerals and mining are ecologically undesirable. Yet is this perception based on the unrealistic expectation of innovation and excellence being simultaneous qualities of any given process? Common sense born of experience indicates that the journey from one, to the other, is usually a long and often tedious process, with much trial and error before excellence is attained. In our time, the partnership between academia and industry is the usual pathway to achieve it. Even so, we should take care that innovation does not become overwhelmed by the pursuit of excellence: as history clearly demonstrates, humanity depends upon both.

Jan 1, 2004

By Bowmaker MD

Zinc and lead sulphide flotation con centrates containing from 0.02 to 0.20% Cd are roasted on an updraught sinter machine at the Cockle Creek Works of Sulphide Corp- oration Pty. Limited to provide sinter for simultaneous smelting of zinc and lead in an Imperial Smelting Furnace (I.S.F.). The major portion (about 85%) of cad- mium in concentrate feed to the Sinter Plant is eliminated with sinter fume and is rec- overed by weak acid leaching in the Cadmium Plant'followed by counter-current decantat- ion, ion exchange concentration, precipitat- ion of cadmium sponge and partial refining to caustic refined cadmium metal. Cadmium not eliminated during sintering is volatilised in the I.S.F. and subsequently recovered as zinc alloy by distillation in the zinc ref- ining columns of the Zinc Refluxer. The partially refined cadmium metal and cadmium- zinc alloy are blended as feed to the cadm- ium refining column where separation and recovery of cadmium is effected. Condensate from the column is further refined under caustic soda flux and cast into anode shapes. Production is 200 t.p.a. at 85% recovery of cadmium in concentrates. Emphasis is placed on changes from the practice described by Baker and Munro (1965) and upon operation

Jan 1, 1972

By R P. Langford, T A. Moore

Over the last 15 years Indonesia has experienced a surge in coalexploration, which has led to the development of a major export industry. This coal exploration has improved the understanding of the geology of the Indonesian coal deposits. The main economic coal deposits are of Eocene and Miocene to Pliocene age, which mainly occur in Kalimantan and Sumatra and were formed from peat deposits in an equatorial paleoclimate similar to that prevailing today. Some of these peats were domed peats, which grew above the normal water tables, under a climate of year-round rainfall; these peats grew above the level at which waterborne mineral matter can enter the system, resulting in low ash and sulphur, and locally very thick coal. It is believed that such peats have formed the unusually thick, low ash, and low sulphur Miocene coals of Indonesia. Coal deposits of Eocene age are typically characterised by thinner seams, with relatively higher contents of ash and sulphur. The Miocene coals and Eocene coals both appear to have formed in lacustrine, coastal plain or deltaic depositional environments, similar to the modern peat-forming environments of eastern Sumatra and parts of Kalimantan. The Eocene coals formed mainly in extensional tectonic settings. Miocene - Pliocene coal deposits formed in a range of tectonic settings.

Jan 1, 1999

By P Gardner

The Kanowna Belle gold mine in Western Australia has reached a depth of 1000 m on the way to 1300 m. A feasibility study undertaken in 2006 identified the mining of E-Block as both technically and commercially feasible. One of the major risks identified in the study was the ventilation capacity, as the existing primary ventilation system would not support the production schedule for mining and a major system upgrade would be required. Failure to provide the necessary airflow would put the project at risk. A review of the airflow requirements and infrastructure options detailed in the feasibility study was undertaken to ensure that the assumptions and design were optimised. This review recommended a minimum airflow of 206 m3/s, but by acknowledging the necessary constraints imposed by mining at depth and re-engineering the mine layout to optimise the primary ventilation circuit, this requirement was reduced to 160 m3/s. This represents a 22 per cent reduction in airflow and a reduction in capital cost that will see mining at depth become economically feasible at Kanowna Belle. This paper discusses the processes that led to a redesign of the mining layout and highlights the importance of including the ventilation network in the optimisation process.

Jan 1, 2008

By R G. Barker, N Mortimer

In New Zealand, platinum group metals (PGM) occur in three main geological environments of economic interest: layered mafic igneous complexes, the Dun Mountain Ophiolite Belt, and in association with placer gold deposits. Most of the layered mafic complexes with PGM potential occur in the Median Batholith. These include the Longwood (Permian), Bluff (Permian), Riwaka (Devonian) and Rotoroa (Jurassic) igneous complexes. Exploration of the Longwood Complex discovered PGM associated with gabbroic rocks. Best assays to date include a 1 m drill intersection of 1 g/t Pt + Pd and float rock with 3.0 ppm Pt and 3.3 ppm Pd. The Greenhills complex at Bluff consists of basal dunite overlain by wehrlite and gabbro. PGM occur with chrome spinel in the basal dunite and Pt geochemical anomalies have been identified associated with the wehrlite-gabbro contact zone. The Greenhills complex has some similarities to Alaskan-Ural type complexes.Reconnaissance exploration in the Dun Mountain Ophiolite Belt has identified PGM geochemical anomalies, but no follow-up work has been carried out. During the late 1800s and early 1900s, PGM were recovered as a byproduct of placer gold mining in Southland. Placer gold prospects with PGM potential include the Waiau River, deposits flanking the Longwood Complex and some Southland beaches.

Jan 1, 2002

Natural leaching of minerals has been recorded for some two millenia but surprisingly only in recent years has enough been known of the process for any serious design to be made. Copper has been recovered from natural mine waters since about the 17th century but again little progress was made in de- sign procedures until recently. Natural or dump leaching was started as a recovery process late in the 19th century and in the years up to the classic study of Taylor and Whelan in 1943 a series of impirical optimis- ations made it a valuable process for treating low grade or waste material. The biological nature of Sulphide leaching was proven by Colmer and Hinkle in 1947 and since then a large mass of data has accumulated on the microbiology, biochemistry, and response of ores to this form of attack. In spite of this knowledge and the vast amount of pract- ical experience available there are few recorded attempts to present methods of calculation or design procedures that can be used for setting up a leaching process. A framework is given here on which such procedures can be based and indications given of the inherent advantages and limitations of the process,

Jan 1, 1969

The process of refurbishment is not a precisely defined one. It is under- stood to mean an upgrading of a plant which is normally performed only once. The application of refurbishment in the field of materials hand- ling equipment poses particular problems because complex plants con- sist of individual components having quite different remaining service lives. For this reason, a systematic, proven procedure is proposed for the refurbishment of large materials handling equipment, designed to ensure economic implementation in accordance with the company goals. Rheinbraun2 has been using materials handling equipment since 1900, the largest units today being bucket-wheel excavators with a daily capacity of 240,000 bank cubic metres of overburden and a service weight of up to 13,500 t (metric tons). Since 1975, more than 50 large-scale refurbish- ment projects have been carried out in the company. In the process, refur- bishment has turned out to be the proven alternative to replacement of large materials handling equipment. Rheinbraun Engineering,3 a Rhein- braun subsidiary, carries out planning, consulting, and supervising work in the implementation of refurbishment projects in Germany and abroad. The most recent example is the refurbishment of Dredger 11 of the State Electricity Commission of Victoria in cooperation with Krupp-Australia, Melbourne.

Jan 1, 1989

By Steinbrucker G

Improvements in mining by the application of electronics necessitates analy-sis of the objectives and problems. A detailed analysis has shown that increased tunel-ling performance is one of the most important objectives. In mining, the environmental conditions for machines, their handling and servicing are very hard. Therefore a health monitoring system for tunnelling machines in hazardous areas has been developed. This system measures operational parameters, such as-flow, pressure, temperature, etc., de-rives forecasts of possible failures from these values, and assists maintenance person-nel. Important data are transmitted to a surface computer via telephone cables. Health monitoring is based on the cognition that slow deterioration of characteristic parame-ters, e.g. fluid loss, are symptoms of wear. Sudden changes of machine parameters indi-cate sudden destruction. Computer technology is very advanced, but transducer technolo-gy has not,been able to keep pace. Filling the yawning gap in the mining industry is a challenge to technology and requires special techniques. Machine monitoring and automa-tion in underground mining is still in its infancy. A lqt of development and research work is still necessary. The risks are great-The expected benefit due to increased min-ing performance (up to 5 %) justifies the risks in development.

Jan 1, 1985

By Rienks, Wyborn D

The Ravenswood Batholith in the Charters Towers -Ravenswood area of north Queensland, was formed by three main episodes of granitoid emplacement between the Early Ordovician and the Early Permian. Granite to granodiorite plutons of the first phase of intrusions in the Early to Middle Ordovician, probably formed by partial melting of a thin continental crust as a result of the emplacement of mafic material derived from the mantle. Some of this mafic material subsequently intruded the Ordovician granitoids as gabbro to diorite complexes. The early granitoids were deformed and metamorphosed prior to emplacement of second phase granodiorite to tonalite plutons in the Late Silurian to Early Devonian. These later plutons have generally not been deformed or recrystallised. Geochemical and isotopic data suggest the Siluro-Devonian plutonism may have been generated by a partial melting of the tholeiitic material emplaced in the lower crust during the Ordovician. A third intrusive phase consists principally off Late Carboniferous to Early Permian gabbro-granite complexes, high level granite to granodiorite complexes, and rhyolitic plugs and diatremes near the batholith margin. Gold mineralisation in the batholith is associated with two major events: mesothermal vein formation in the Early Devonian and porphyry types in the Late Carboniferous to Early Permian.

Jan 1, 1990

Drill and blast excavation in underground mining and. civil engineering projects has grad- ually given ground to mechanical boring of tun- nels, shafts and raises during the past twenty years. The use of.boring equipment must today be considered significant and wide spread al- though comprising only a very small percent of total underground excavation. The encroachment of mechanical boring into the domain of blast- ing has been by slow incremental advances. There have been few, if any major breakthroughs in this development, and none can be foreseen in the next decade. After 1990 it is possible that scientific. development will provide some form of breakthrough in rock breaking, but this is so uncertain that it should have little relevance to planners in the 1980's. A more near term view of the future, con- centrating on the next five to ten years, has lead to the conclusion that significant im- provements will be seen in tunnel borers for poor ground conditions. A universal machine will be developed that converts from a dry hard rock machine to a closed slurry type machine for passing through fault zones with unstable crushed rock and water. Two other machines have been described as alternate designs for tunnelling in squeez- ing ground conditions.

Jan 1, 1981

To obtain the best economic results in treating the comparatively high-grade ore of the Kalgurli Mine a good roast is essential, and the effort of this paper will be to briefly describe the plant and the conditions prevailing in roasting, which, on an output of about 360 tons daily, subsequently enable an average extraction of slightly over 94% of the gold to be maintained.The percentage of sulphur in the ore varies between 2'5 and 3'5, the lower figure existing when treating oxidized ore. The average gold value is 13 dwt; this occurs chiefly as sylvanite, containing .a lower percentage of silver than is usually present in that mineral. One ore body in the mine contains hessite (Ag2Te) in considerable quantity, associated with gold telluride, and when ore from this stope is being treated the silver contents rise to as high as 20 dwt, but the usual amount is about 9 dwt. per ton, of which only a small proportion is extracted. Other metallic minerals, in addition to pyrite, occurring more or less commonly, are arsenopyrite, magnetite, chalcopyrite, and the tellurides calaverite (AuTez)and coloradoite HgzTe3). A small proportion only of the value occurs as free gold.

Jan 1, 1911