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By D Pateman, F de Fredrick

The Bentley underground mine, which is located 60km north of Leonora, Western Australia, is owned and operated by Round Oak Minerals Pty Limited. A high-grade Zn-Cu Volcanogenic Massive Sulphide (VMS) orebody, Bentley was discovered in 2008 with production commencing in 2012. Long-hole open stoping is employed to mine the steeply dipping ore body, and in recent years the Avoca method has been adopted. This requires all development in a particular area of the mine to be completed prior to stoping commencing in a bottom up sequence. Voids are commonly backfilled with loose Run-of-Mine (ROM) waste loose rockfill (LRF); or alternatively cemented rockfill (CRF) can be used. Stopes in the 3860 AOS and 3900 AOS panels were located below previously extracted Avoca zones, with LRF situated immediately above them. These high-grade stopes were originally designed with rib and sill pillars to maintain control of the existing backfill during extraction. Due to changing factors over time, including mining economics, alternative options to achieve full extraction of the stopes were reviewed, including: • Mining small successive full height stopes which would involve drawing a blanket of LRF down with the extracted ore (stoping under waste); • Stabilisation of the existing LRF above the stopes and implementing a primary/secondary stoping sequence, with the primary stopes backfilled using a cement fill. An assessment of these options was undertaken which determined that the second full extraction method was the most beneficial to the operation, and could be achieved using a cement grout (Minova’s FB200 grout) to stabilise the LRF in conjunction with implementing a sequence where the primary stopes would be backfilled with cemented aggregate fill (CAF). Footwall drives were developed adjacent to the rockfilled stopes, allowing for the installation of horizontal grouting conduits, as well as providing access to the top of the planned 3860 and 3900 level stopes for the placement of CAF. An interval at the base of the previously rockfilled stopes was grouted at multiple horizons to achieve the required thickness, with a comprehensive quality assurance/quality control (QA/QC) process undertaken. Primary stopes were CAF backfilled via an arrangement of downhole winzes, linking the top of primary stopes to cross-cuts developed off the associated footwall drives. CAF was delivered underground through an open reticulation network that was extended to the specific levels. Overall the successful implementation of the revised mining method effectively increased ore recovery while maintaining control of overbreak and dilution, providing significant financial upside. This was achieved while maintaining effective controls in light of the changes to the risk profile. Stabilisation of the existing rockfill has allowed the extraction of stopes to full height, including the originally designed sill pillars, representing an average 23% increase in ore tonnes on the initial design, with dilution from the stope crowns averaging less than 1%. The use of CAF in association with primary/secondary stoping, eliminating the need for rib pillars, has yielded an average 47% increase in ore tonnes compared to the base case mine design.

Mar 15, 2021

By Propster M, Choudhry M

THIS note gives comments on the paper by Kitaev et al on p. 68 of this book and compares results with those obtained by ourselves. We wish to say that the authors are to be congratulated on their sophisticated approach to an important problem and that it complements our efforts on flow maldistribution.1-5 It is our view that Eqs. (1)-(5) on p. 69 are impressive, but unfortunately with present day computers and computational facilities, it would be quite impractical to contemplate the numerical solution of these. Eq. (8) in the authors' paper, on p. 70, does provide the logical starting point for tackling flow maldistribution problems and strictly speaking this equation is more accurate than Eq. (1) in our paper in this book. We note in passing that there is direct experimental evidence to support the contention that our Eq. (1) is at least a reasonable approximation and one may question in a practical sense whether the refinement afforded by Eq. (8) in the paper by Kitaev et a/ is justified. While one must readily accept the appropriateness of Eq. (8) of Kitaev et al as a starting point, the subsequent mathematical manipulation by the authors is open to serious criticism. In order to solve this complex, non-linear equation Kitaev et al postulated irrotational flow, which afforded considerable simplification. One can argue simply on physical grounds that the assumption of irrotational flow is inappropriate, a fact which should be readily apparent on inspection of the flow fields shown in Figs. 2 and 3 of Kitaev's paper. It follows that while the starting point through the use of Eq. (8) is correct the results derived from this starting point may be suspect because of the erroneous nature of the irrotational flow assumption.

Jan 1, 1975

By Fabjanczyk MW, Aziz NI, Hii J

The paper presents the results of a series of pull out tests performed on roof reinforcement systems currently being adopted in mines in Australia 7mm wire, dividag bar, 15.2mm strand cable, and birdcage cable. The study also investigated the load deformation chara- cteristics and the various design parameters controlling the effectiveness of a cable-grout system. Suggestions for continued work are Highlighted.

Jan 1, 1986

The basic flowsheet for the Kalgoorlie Nickel Smelter and Kwinana Nickel Refinery are discussed in relation to the mineral components of Kambalda produced nickel concentrates. Both processes handle violarite and pentlandite satisfactorily but the smelter has limitations where high copper recovery is required and in its ability to handle magnesia containing minerals. While the latter can be more economically handled at Kwinana the limitations of this tolerance are discussed together with problems arising from treating pyrrhotite, pyrite and precious metals by the Sherritt Gordon process.

Jan 1, 1973

The selection of an appropriate mining method should take into account the geometry of the deposit and its physical properties. Other factors which assist in the determination are the requirements for flexibility in the mining process, minimisation of risk factors and maximising the financial return. Several established mining methods exist which can encompass the requirements to deliver the optimum mining method, this can be in both an underground or open cut environment. The objective is to outline these methods and where they can be applied in a mining project.

Jan 1, 1997

The Iron Prince orebody occurs within the Lower Middleback Jaspilite Horizon of the Middleback Group and consists of hematite within host rocks of jaspilites and schists. The ore was probably the product of leaching of silica from jaspilites and replacement by iron, concentrations occurring in suitable structural traps. The narrowness and the presence of extensive dolerite amphibolite dykes within the orebody make it essential to operate a grade control programme in advance of the faces. Information from drilling is drawn up on bench plans, step plans and impurity overlays, and these serve both in day to day production planning and in long term planning. Mining is done selectively by open-pit methods and blending conducted by keeping at least three faces of different grades of ore open at any one time. No stock piles of ore are kept for blending, but contact ore, contaminated ore and enriched material are dumped for later beneficiation.

Jan 1, 1971

By Dennis B

The Hilton Mine, 20 km north of Mount Isa was discovered in 1947. The underground mine has been a significant producer from 1989. The long development history is the result of complex orebody geometry, difficult metallurgy, dewatering problems and competition for development funds from the then expanding Isa Mine at Mount Isa. At present it produces 1.4 million tonnes annually. Its 21 million tonnes of reserves are necessary to supplement Isa Mine production.Hilton Mine is located in the Urquhart Shale formation of the Mount Isa Group, within the Mid Proterozoic Mount Isa Inlier. The seven developed orebodies have suffered strong structural deformation. Each orebody has a unique mixture of mineralogy and texture which effects ore value and metallurgical performance. These characteristics have proven useful for correlation purposes.The faulting and folding have caused difficulties with orebody interpretation, geomechanical complexities and has influenced the choice of mining methods: Initial cut and fill and open scope designs have given way to bench mining methods in response to better understanding of the eedloav and economic constraints.

Jan 1, 1993

A mechanised sub-level overhead benching method is used at Cleveland, to produce 22,000 tons per month of ore assaying 0.92% Sn and 0.40% Cu. The ore occurs in a series of vertical lenses which can be mined by open stoping. Levels are developed at 60ft., vertical intervals by jumbos. The ore is silled out and the stope block formed between levels drilled out by long hole drilling. Each row of holes is fired and broken ore within safe reach from the stope brow is mucked out by Wagner ST-5A Scoop Trams. The remaining broken ore is recovered on extraction of the next lower level. Ore is hauled by road to the crusher station from the mine. As mining proceeds below the lowest surface portal a spiral decline will be used for ore haulage and mine servicing.

Jan 1, 1970

Tectonic subsidence plots have been calculated for well, extrapolated-well and significant off-well (seismically-based) locations in the Vulcan Sub-basin and adjacent highs (western Timor Sea). The subsidence curves have been normalized to a common datum, the distinctive "near top Permian" marker, and corrected for sediment compaction, palaeobathymetry, eustatic sea-level change and loading effects.Four principal phases of post-Permian basin development are recognised and quantitatively described by integrating the results of the sub-sidence analysis into the regional (e.g. recent Ocean Drilling Program-derived) framework of the tectonic evolution of the North West Shelf. They are1. the Triassic-mid Jurassic Westralian Superbasin intracratonic phase,2. the late Jurassic-early Cretaceous North West Shelf rift phase,3. the mid Cretaceous-Palaeogene North West Shelf subsidence phase, and4. the Neogene-present Timor collision phase. Rapid Triassic tectonic subsidence occurred in an intracratonic setting, possibly subsequent to aborted late Palaeozoic rifting. Intracratonic sub-sidence mechanisms such as deep crustal metamorphism and/or intrustion and regional tectonic compression are invoked in addition to any post-rift thermal subsidence which may have occurred.

Jan 1, 1990

By Smith PE

The main components of face design are the power loader, face conveyor and powered support system and the interaction of these components determines the effectiveness of strata control. A major influence upon the interrelationship of this equipment is the geological environment, of which seam thickness appears to play an important role. Recent thick seam experience indicates a significantly different characteristic behaviour pattern from that observed in thin seams The structural integrity of the face wall is particularly influenced by seam discontinuities such as natural joint planes and mining-induced fractures in the yield zone ahead of the faceline. In addition, the presence of stone bands or dirt partings in the seam offers interfaces for uncontrolled release of blocky material. Some case study experience at British collieries provides a comparison with performance data at a specific location, that highlights the importance of coal face layout and design.

Jan 1, 1986

By Woodcock J. T, Millett R. N

It was shown that manganese dioxide could be used as an oxidant in acid thiourea leaching of a gold ore. Manganese dioxide could generate high redox potentials and was as effective as hydrogen peroxide in the leaching process. Results obtained under closely controlled leaching conditions confirmed that high redox potentials enabled faster dissolution of gold to be obtained but led to extremely high reagent consumptions (thiourea, acid, and manganese dioxide). Additions of sodium sulphite solution in an attempt to lower thiourea consumption by reducing formamidine disulphide back to thiourea were only marginally successful. Although thio- urea consumption was slightly decreased, the consumption of acid and manganese dioxide was substantially increased and there was no net benefit in using sulphite. Tests in which a single addition of mangan- ese dioxide was made before addition of thiourea minimized overall reagent consumption and gave only a slightly lower dissolution rate of gold. This is a promising technique for further Investigation.

Jan 1, 1987

By Raymond G. F

Geostatistics - a tool used by geologists and mine planning engineers to estimate grades and rapidly evaluate alternative mining strategies has reached an advanced stage of development for the silver-lead-zinc orebodies at Isa and Hilton Mines. Geostatistics has been used for over a decade in the massive copper orebodies but the stratiform lead-zinc orebodies are much more complex and provided a completely different set of challenges. Recent increases in computer processing speed and power provided by the Integrated Mine Planning System (IMPS) has aided the development of the geostatistics package. Also the formation of a project team and the subsequent in-house development which has drawn together the expertise of geologists, engineers and system analysts has contributed significantly to the success of the project.The most important feature of any approach to modelling the lead-zinc orebodies is that the kriging search must consider estimate and sample points according to their positions relative to bedding surfaces. By transforming co-ordinates as perpendicular offsets from a plane representing the local strike and dip, it is possible to elongate the ellipsoidal influence to parallel bedding. By interactively modelling surfaces using CAD facilities and then specifying these surfaces as 'hard' or 'soft' boundaries, the geologist has complete control over the kriging process.

Jan 1, 1993

By Gole MJ

The Goodyear nickel prospect is located 45 km southeast of Kalgoorlie (31.04¦S, 121.80¦E) near the eastern boundary of Hampton Area - East Location 45 (Figure 1). Nickel mineralisation was discovered on the Goodyear prospect in March 1996 when a reverse circulation drillhole (GYC5), initially drilled in December 1995, was deepened to meet a minimum footwall penetration requirement of 20 in that had been set for the drill program. Approximately 3 in of sulphides averaging 4.9 per cent nickel was intersected from 296 metres down-hole, this being within 2 in of the first end-of-hole. Hole GYC5 was part of an eight hole drilling program undertaken by Titan Resources in late-1995. This program was designed to test whether nickel mineralisation in the Dunlop prospect, discovered by the Western Mining Corporation - BHP Camylia Joint Venture immediately east of the East Location 45 boundary, continued across the tenement boundary. The area targeted by the initial drill program had been explored by Western Mining Corporation in the mid-1980s using extensive surface sampling and a drilling program that included 17 RAB and percussion drillholes. None of these holes intersected nickel Mineralisation.\

Jan 1, 1996

By Palmer G, Dennis R, Clark A

The Ravenswood Mine in North Queensland is the first gold mine developed by Carpentaria Gold Pty Ltd, a wholly owned subsidiary of MIM Holdings Ltd. Carpentaria Exploration Pty Ltd began exploration at Ravenswood in 1978. However initial exploration of the main gold producing area (Buck Reef East) commenced in March 1987 when exploration rights to four key leases were secured. A rapid, co-ordinated exploration and development program produced gold from a heap leach operation nine months after the first costeans were dug at Buck Reef East. To treat higher grade ore found at depth in the Buck Reef East pit and the metallurgically more difficult Buck Reef West ore, a carbon in pulp plant was commissioned in May 1988. The mine is currently producing at a rate of approximately 40 000 ounces of gold per year. Ore at Ravenswood is hosted by hydrothermally altered diorites and tonalites of the Ravenswood Granodiorite complex. Alteration is controlled by planes of permeability formed by joints, shear zones and dilational breccias. The complex orebody geometry resulting from these controls required very detailed surface and drill exploration for adequate definition. Carpentaria's need for early cash flow meant that economic, mining and metallurgical considerations governed choices of exploration techniques, program timing, material and data collected. The initial reserve of 1.1 mt @ 2.87 g/t Au was defined by sectional polygonal methods. Grade control is based on geologic mapping and blast hole or channel sample assays. Ore is batched through the crusher and sampled to monitor grade control and mining performance. Minimal dilution has occurred. Gold content is greater than predicted by the reserve. Sprinkling of heaps commenced in November 1987. Changes have been made to the pad design and to the method of heap construction. Heap leach ore is treated at a rate of 400 000 tpa.

Jan 1, 1989

By Johnson G. D

The typical management systems used to address the issue of operating risk centre around technologies that identify, analyse and evaluate the risk factors. These logical systems such as HAZOPs, Fault Tree Analyses, etc rely heavily on technical considerations and process flow analysis. However, several research projects, across industries and countries have clearly shown that up to 80 per cent `operating risk' is determined by the actions of workers, supervisors and managers. Yet, most of the focus of risk management is on technical and procedural issues. This suggests that a significant imbalance exists in our management systems and that industries are unlikely to show significant improvement on current levels of safety performance. Effective risk management must include the intangible element of the organisation psychology towards risk. A practical and theoretically sound approach had been researched and developed in and for the mining industry. This paper describes the approach and methodologies applied at the Cosmo Howley Gold Mine in the Northern Territory, where an inclusive approach to managing financial and operating risk was followed. The Cosmo Howley Mine showed a dramatic reduction in lost time injuries and improvements in financial indices - providing conclusive evidence of the link between management effectiveness, safety and productivity. This `triangle' has often been the subject of speculation and theory. It is demonstrated in this paper how the management team of Cosmo Howley focused their practices and systems on the improvement of organisational dynamics, ensured tangible and clear focus on parameters of costs and safety and how the improvement process was managed. It is concluded that the improvement process did not require a `major re-engineering' of the organisation. The organisation culture changes that occurred were incremental, planned and effective. It entailed the implementation of sound risk management methodologies, and ensured that a significant emphasis was placed on an aspect that is defined as `organisational dynamics'.

Jan 1, 1994

With the progress of modern mining engineering, one of the features of which is the mining from greater depths and the hoisting of greatly increased loads, it becomes a matter of increasing importance that the engineer should be able to determinewith some degree of precision the character of the strains on the hauling rope. But a wire rope is a complex structure; it is made up of spirally-twisted strands, which in turn are composed of spirally-twisted wires, and it is not particularly easy to say exactly what happens when this "doubly-twisted structure is wound round a drum or over a pulley.. The difficulty has been generally evaded in ordinary practice by the simple device of adopting a large factor of safety for the rope-usually from 8 to 10-a factor which experience has shown is sufficiently large to cover the bending strains set "up when the rope is passed over pulleys of the sizes commonly considered appropriate.When, however, we add the stress due to the bending of the rope to the stress produced by" the direct pull, we find that the actual factor of safety is usually more nearly 4 than 10, and frequently the bending stresses in the rope are so large compared with the simple tensile stresses that their neglect may easily lead to disastrous results when dealing with problems a little out of the common run. Common Empirical Rules.-It is always "recognized that the bending of a wire rope round too small a pulley is likely to do the rope serious injury, but as it is desirable in ordinary winding operations to reduce the inertia of the moving parts to a minimum...

Jan 1, 1907

By Dunbavan M, Mallett C. W

The sequence of development and back analysis of the failure of a spoil pile in the 1B pit of the Moura Mine are given. The mode of failure was a two-wedge mechanism with a basal slip plane passing through a clay band about 2 m below the pit floor. Remedial actions for improving spoil pile stability are discussed.

Jan 1, 1981

By Gray N. B, Grimsey E. J

A steady state heat and mass balance simulation of the Western Mining Kalgoorlie Nickel Smelter (KNS) flowsheet was developed within the framework of the commercial software METSIM. The KNS simulation can achieve all plant setpoints through the adjustment of controlled process inputs, and provides a useful tool for the evaluation of the current flowsheet and potential flowsheet developments The simulation model and a number of applications are discussed in this paper.

Jan 1, 1991

A major tool in the search for petroleum is reflection seismic mapping. The period which has seen most of the exploration in Victoria is also one which has seen major advances in this technology, from 1963 try present day. Seismic mapping can be divided into three interlinked areas - acquisition, processing, and interpretation. In acquisition the major changes have been from an explosive energy source in 1963 to gas exploders in 1968 and airguns in 1970. The number of recording channels has increased from 24 to 192, with digital recording introduced in 1966, and floating point recording in 1976.

Jan 1, 1982

Drag pick roadheaders and continuous miners have been applied in the coal mining industry for several decades, having replaced drill-blast methods as the primary means of excavating coal and coal-measures strata. The generally harder rock types associated with metalliferous mining have precluded the use of such machines in the past, however, developments in machine technology and increasing labour costs and environmental constraints suggest that there are now likely to be applications suited to the method. Metalliferous mining engineers are generally unfamiliar with the machines themselves and with the fundamental criteria controlling rock cuttability. This paper gives an introduction to the machines and the controlling factors.

Jan 1, 1987