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Designing for early access to deep orebodies is an essential driver for improved project payback. Vertical shaft sinking techniques have been developed to allow concurrent mine level excavation while continuing to sink. Project cash flows can also be improved when simultaneously deepening existing shafts beneath operating hoisting systems. Further economic advantage has been realised through creative sinking sequencing in twin ventilation/service shaft projects. A fourth technique to reduce project schedules involves partial shaft barrel equipping allowing unrestricted access to construct stations and continue with level installations. This approach reduces interference with barrel sinking activities to insignificant proportions. This paper reviews how these approaches have added significant value to actual shaft sinking projects, as assessed from a contractorÆs perspective, and discusses some of the practical issues to be addressed when planning future projects. Designers need to take cognisance throughout all project engineering phases of the adage that you are only sinking when cleaning the face. Cleaning can only be sustained when there is sufficient hoisting capacity.

Jan 1, 2005

By Hinde J. S

The Fitzpatrick Orebody is a three and a half million tonne fault bounded portion of the early-middle Proterozoic Broken Hill Orebody.The Fitzpatrick Orebody was discovered in 1975 by diamond drilling from the 36 Level Exploratory Drive. This followed persistent geologically oriented exploration and a courageous decision by mine management to deepen No. 3 Shaft to provide exploratory development across the Globe Vauxhall Shear and allow effective drilling of the target area.The stratiforrn oebody consists of three lenses, the lead rich No. 2 and 3 Lenses and smaller zinc lode. They represent a down plunge extension and boudinaged, fault-bounded portion of the main Broken Hill ore lenses. The surrounding host rocks are extensively faulted and jointed due to complex history of movement on the bounding shears. This results in extremely poor ground conditions during mining. The ore was delineated for mining development using three dimensional fan drilling from exploratory and hanging wall drive drill sites.

Jan 1, 1990

Three separate and unconfined aquifers occur in the Hilton area, named relative to position in relation to ore horizons: Footwall Aquifer in the east; Ore-Zone Aquifer within the ore-bearing Urquhart Shales; and the Hangingwall Aquifer in the west.It is the on-going strategy it Hilton to drain the Ore-Zone Aquifer which occupies structurally- and sulphide-controlled leached zones in the steeply west dipping strata. The aquifer affects considerable ore reserves to 480 m below the surface. Dewatering began in 1976, and is essentially completed to 4 level (240 m below surface). Dewatering efforts are now based on 8 level (480 m below surface).

Jan 1, 1993

Mine planning typically involves designing an operation to uncover coal with the minimum initial costs with reclamation planning and earthworks being done as an "add on" task. The landform is too steep to remain stable, has no drainage and frequently has areas of excessive acidity or alkalinity. Extensive earthworks are required to reduce grades to an acceptable level and create a drainage system. The flexibility available to the mining engineer to alter the post mining landscape clearly depends on the mining methods. Straight dragline stripping provides virtually no flexibility. However most mining operations over the term of current ten year plans have a substantial pre-strip component. It is this pre-strip material which has the potential to reduce the final reshaping earthworks. The reshaping operation itself is subject to some flexibility with various options being available to re-grade and provide drainage. The full utilisation of this flexibility to minimise earthworks cost should be the aim of reclamation design. ACIRL's current thrust in reclamation is aimed at the integration of mine planning and reclamation earthworks. This involves gathering all environment and agricultural criteria and designing the earth works necessary to produce an acceptable final landform. A key component of our work is the use of computer aided design (CADD) for the design of spoil piles, pre-strip dumps and spoil re-shaping. This approach has been applied to a number of mine sites with earthworks operations covering hundreds of hectares and hundreds of millions of cubic metres volume. We are continuing to provide that consultancy service and at the same time are involved in the development of more sophisticated software tools to apply to reclamation design.

Jan 1, 1991

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber. With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

In seeking to improve the economic performance of mines, the management or human aspects are usually seen to be quite seperate from, and more significant than, the technical aspects. There are obvious aspects of industrial relations, man-management, skills training and supervision that are currently the focus of efforts to improve the productivity and quality of the mining process. However technology also has a lot to offer. Analysis of the costs involved suggests that innovations leading to improvement in the productivity of the excavation and transport of overburden and the recovery of coal (both in the mine and preperation plant) can lead to improvements in the economic performance of a mine that may outstrip the obvious non-technical or management opportunities for improvement. While there are some innovations currently being investigated within the industry that relate to the design of mining equipment, the type of machinery being used in open cut mines has not changed dramatically over the last twenty five years. It is also likely that mining equipment will remain essentially of the same form in the forseeable future. If significant improvements to mining performance are to be achieved other than by futher increases in the scale of machinery, then we need to seek ways to operate these same types of machines in a more productive and controlled manner. This paper discusses the identification of mining processes the improvement of which is likely to have a significant effect on mining costs and performance. Some areas of current research are discussed and potentially fruitful areas for future development are identified.

Jan 1, 1991

By Kirkhouse C. B

Soon after the Broken Hill Limited started operations at their Iron and Steel Works at Newcastle, NSW, it was found necessary to install a mill for rolling small merchant bars, rounds, etc.An arrangement of the first mill laid down is shown on Plate 1., Fig. 1. This mill commenced operations on the 18th July, 1917.The feed for this mill was rolled in the existing 18-in. mill and sheared to the lengths required before being delivered to the billet storage yard. The billet storage yard is 90 ft. span, and is served by one 10-ton electric overhead travelling crane. Billets were placed on the billet bed preparatory to being charged into the heating furnace.The heating furnace was of the continuous recuperative with end discharge and had a hearth 40 ft. long by 10 ft. wide. The billets were pushed through the furnace by means of two hydraulic rams, which could either act together and push one row of billets, or act singly and push two rows of billets. This furnace was fired by producer gas from the producers shown on Plate I., Fig. l.The gas was conveyed to the furnace by means of a brick underground flue.

Jan 1, 1935

A comprehensive analysisof rock structures in non-oriented (axially oriented) drillcore is now available (Laing, in press). The system embodies new concepts which better equip the geologist and engineer to deal from the outset with optimising the acquisition of structural information in drillcore, logging, interpreting, and graphically presenting the results. The few existing techniques for determining orientations of structures are augmented by a wide range of new techniques, and all are brought together into two solution types by considering the underlying Euclidean geometries. Analysis of these solution types in terms of what data are required to implement each solution and what assumptions need to be made, leads to strategies which facilitate intelligent design of different drilling programs for blind and outcropping situations. Drillcorc is variably structurally fertile, depending on the number of different structures present. This concept fosters the selective logging only of the more fertile core. Drillholes are also variably fertile, depending on their orientational relationship to the structures in the host rocks. Structural parameters are either vectorial or non-vectorial. Vectorial structures parameters comprise normal structural orientations plus polar vectors like vergence, younging, shear sense and so on. They can be determined by one of two solution types: external solutions, which use an external reference structure to fix the drillcore and thus permit orientation of all structures within that core, and internal solutions, which use orientational data from a selected structure at three or more different drillhole orientation to determine the unique orientation of that structure, without reference to any external structure.

Jan 1, 1990

Four data sets are required to put constraints on the tectonic evolution of the southern rim of the Pacific Ocean basinI . data bearing on the dispersal of the major Gondwanaland continental fragments and the birth of the Southern Ocean,2. data bearing on the interaction of the Pacific Ocean basin lithosphere with the South American, Antarctic, and Australasian continental masses,3. data bearing on.the evolution of the Scotia Sea floor, and 4. data bearing on the evolution of the various continents, microcontinents. and volcanic arcs.

Jan 1, 1990

By Shu DM, Moxon P

Subsidence profiles over longwalls at West Cliff Colliery (WCC) are predicted by three methods, NCB Emperical Method, Salustowicz's Profile Functions and Superposition of Two Critical Profiles. A method of deriving maximum subsidence using local data is also presented. For the first four longwalls, the results are compared with those from the subsidence surveys conducted during and after the extraction of each longwall. Longwall V has not yet been extracted, so the results are for the predicted subsidence profile. Superposition of two critical profiles is carried out in an attempt to check the principle of superposition. In addition, strata movement above the extracted longwalls is discussed.

Jan 1, 1986

Firedamp drainage has become an essential part of many mine environmental systems, and new applications are arising. Installations are evolving further to satisfy ever changing basic requirements, standards, and iniilny needs. In this paper, water seal, vacuum based installations are considered, as well as moni- toring, protective and control systems which have been developed for continuous, manless, and trouble free operation. Some factors affecting plant capacity and extractor per- formance are identified and assessed. INTRODUCTION Firedamp drainage applications are incr- easing world wide as mining engineers strive for improved safety and security, and further concentration of coal output. Fewer and fewer mines are able nowadays to satisfy coal prod- uction and firedamp control requirements solely by air dilution or by air dilution and underground firedamp extraction plants. As a result, dependence on surface extraction plants is increasing. This paper deals with som requirements and applications of such installations. I. DEVELOPMENT AND PRACTICE Firedamp drainage has existed for over 250 years following the early work of Carlisle Spedding at Whitehaven (1730). Some fundamentals of current firedamp drainage systems can be recognised in the

Jan 1, 1982

By Hargraves AJ

Pre-drainage experiments have been conduct- ed at Appin, Cook, John Darling, Leichhardt, Macquarie, Metropolitan and Moura No. 2 Collieries. Appin (550 m deep) experiences particular gas problems in development drivages, and the almost pure CH4 seam gas makes difficult tiro compliance with statutory maxima in intakes and returns. Patterns of 43 mm diameter drain- a,.;e holes drilled ahead and laterally into virgin coal have improved gas conditions in working places and have allowed tolerable advance rates. Cook, Leichhardt, Metropolitan and Moura No,. 2 Collieries have experienced gas and stress phenomena ranging from conical bursts less than one tonne to full scale instantan- -us outbursts of hundreds of tonnes with tens ,f thousands of cubic metres of seam gas. Gas ~Irainage experiments with patterns of holes up a,, 200 mm diameter have been undertaken with ;,;siness monitors on the coal to establish .lative effectiveness. Incremental flows into mg 43 mm diameter boreholes have investigated drainage patterns relative to length, and at comparative incremental flows have nlicated lowered permeability zones at stress ,.,utments. In some CO2 seam gas areas where iammability problems are reduced to perhaps ii, but where outbursts proneness is increased,

Jan 1, 1982

The Bureau of Mineral Resources has been engaged in regional geological and geophysical field work in the Alligator River and Cobourg Peninsula area since 1971, following the discovery of major uranium deposits. Geophysical work commenced with a regional airborne magnetic and radiometric survey which was followed up by some helicopter and ground work in August 1973. The interpretation of the earlier radiometric work is presented in conjunction with the results obtained from the follow-up work. Analyses of 100 outcrop and drill core samples collected have provided basic information on the physical properties and concentrations of uranium and thorium in various rock types. The uranium determinations were made by X-ray fluorescence and delayed neutron analysis, good agreement being obtained between the two methods. X-ray fluorescence was the main analytical technique used because of its ability to produce both uranium and thorium determinations.

Jan 1, 1975

The cost of power is an important matter to mining companies generally and this thought that the members of the Australasian Institute of Mining Engineers, as well as the engineering and mining professions generally would be interested in any proposal for the reduction of that cost-has led to the presentation of this paper.The writer trusts that the description will be found clear and increase the interest in this exceedingly interesting subject. In the working up of the electrical arrangements touched on in this paper, the author has had the able assistance of hisfriend Mr. F. J. Mars, to whom he offers his hearty thanks. The selection of the best class of power plant for a mine is a very difficult and large problem and it is quite out of place to dogmatise that anyone of the many systems that offer isbetter than another, eg that the all electrical is better than the partly direct steam-driven and partly electrical, or that a gas plant is better than a steam plant.Such a selection is one that calls for very careful and close consideration, in each particular case, of a large number of regulating factors before it is possible to arrive at a proper decision.

Jan 1, 1911

In this paper a quantitative deterministic risk modelling approach (Quadrim) is introduced. The mathematical framework and equations for quantifying uncertainty within and aggregating across value chain nodes from error propagation techniques is proposed and discussed. A case study and worked examples, based on a hypothetical mine are then presented. This illustrates how uncertainty from the mining and economic value chains can be handled in a typical net cash flow calculation, and how this can be translated to a risk model. It is then illustrated that current valuation techniques do not just result in an information gap for decision makers. Traditional approaches such as discounted cash flow (DCF) analysis and truck and shovel productivity analysis, which do not take into account uncertainty in input values, can result in potential bias in estimates such as net present value (NPV) or equipment hours

Sep 26, 2011

By A Litwinowicz, M Laxman, A Fourie, A L. Li

This paper presents a design approach and analytical methods that were used for assessing the potential of static liquefaction and developing the mitigation measures for a tailings dams. The rigour of the design and analysis approach represented leading practise in the industry to address static liquefaction, which contributed to a robust design with high confidence and certainty. The salient features of our approach to static liquefaction included geotechnical investigation and tailings characterisation, static liquefaction screening assessment, static liquefaction triggering analysis, limit equilibrium analyses and numerical modelling of static liquefaction using the NorSand model, which was amongst the first tailings dam projects involving numerical modelling of static liquefaction using these methods.

Jul 1, 2021

After a short theoretical comparison of various typical large bell tops with the bell-less top for segregation and other ,ffects on the material flowing through the equipment proper, a comparative analysis between classical and the new burdening in the furnace is given, showing the theoretical effects of distribution and segregation on the horizontal pressure variations, temperature values and gas composition in the stack. Then some typical theoretical charging patterns of the bell-less top for wall and centre temperature adjusting, pressure drop corrections, dissymmetric local action for blow-in and scaffolding are described. Finally the available practical results on furnaces equipped with the bell-less top are compared with the theoretical statements made before and conclusions indicate that the new approach to burdening blast furnaces is a real improvement.

Jan 1, 1975

The McArthur lead-zinc-silver deposit is of the stratiform type. It consists essentially of a mineralized bituminous shale sequence that incorporates tuffites, numerous graded beds, and isolated but massive slump breccia horizons.The principal sulphides are' pyrite, sphalerite, and galena. These occur mostly in the shales. The accompanying turbidites contain only minor mineralization.The geochemistry of the deposit has been investigated in relation to the stratigraphic column and mineralogy of the sediments.A sedimentary origin is proposed for the deposit. Volcanism, thermal spring activity, salinity, regional faulting, and climate are examined as possible factors that may have contributed to sulphide formation and which could be used as criteria for mineral exploration.The metallurgy 'of the McArthur deposit is discussed in terms of its geological history.

Jan 1, 1972

By Taylor GP

Mt Kasi in Fiji is a high sulphidation style of gold deposit exposed at a high crustal level. Individual alteration centres are localised at the intersection of cross structures within a through-going structural corridor, the Mt Kasi Fault System. A two stage alteration/ mineralisation model suggests that much of the high sulphidation alteration is derived from the initial rapidly moving gas-rich portion of the hydrothermal fluid. The gradual cooling and neut-ralisation of hot acid fluids by mixing with oxygenated ground waters forms the characteristic zoned alteration assem-blages which grade from cores of residual silica through silica-alunite to peripheral clays. The liquid-dominated phase of the hydrothermal fluid brecciates the competent, altered rocks and deposits sulphide mineralise-ation within the breccia matrix. High gold grades occur in the matrix-rich breccias and decline from the hydro-thermal fluid upflow to outflow zones.CSAMT (controlled-source audio magneto-tellurics) geophysics has been used to define the geometry of the alteration centres while strike slip movement on the major structures accounts for the dilational structural environment in which the ore hosting breccias form.

Jan 1, 1994

By J G. Webster-Brown

The Tui Mine is located near Te Aroha at the base of the Coromandel Peninsula. It was a lead-zinc mine, which closed in 1973 due to declining concentrate prices, high overheads, and high mercury levels in the ore. The site was abandoned, leaving behind an acid rock drainage generating system, including a sulfide-rich tailings dam which has since caused pollution of Tui Stream, as well as open adits and waste piles which drain predominantly into the neighbouring Tunakohoia Stream. At the AusIMM conference in 2003, Harvey and Webster-Brown presented water quality results from the Tui mine site and lower stream catchments in 2002. In April 2006, Environment Waikato undertook remediation works to stabilise the dam and reduce acid drainage entering Tui Stream. In this study, water quality results from the Tui mine site and lower stream catchments are again being determined, in order to compare with the pre-remediation results. Preliminary data collected for summer indicate a minor but consistent improvement in water quality in the lower stream catchments, although lower Tui Stream continues to exceed ANZECC (2000) aquatic life guidelines for Cd, Cu, Pb and Zn. This slight improvement may be due to a decrease in the flow of ARD into Tui Stream, as there does not appear to have been an improvement in quality of the contributing ARD waters.

Jan 1, 2007