Search Documents

Nippon Telegraph and Telephone Corporation (NTT) developed a new construction method (the M-2 method) that could drive a long, curved small-diameter tunnel (4>1.2 m) without human labor. This method employs the cast-in-place lining system, using quick-hardening resin mortar, so that it can greatly increase the driving distance and execute both long distance driving (longer than 500 m) and curved driving with a radius of curvature of 200 m. Furthermore, the central control system with a mini-computer in a vertical shaft enables all work in a small-diameter tunnel, i.e., excavation, lining, and transportation of excavated soil and materials, without human labor. NTT conducted several field tests and a Practical Application Test (P.A.T.) under a public road bearing great traffic. Good results were obtained and the practicability of this method was demonstrated. Therefore, from now on, NTT will apply this ii-2 method to drive telecommunication cable tunnels in urban areas. This method will also be applicable to constructing public tunnel facilities, such as for water, sewage, electricity and gas.

Jan 1, 1987

By A Smith

Rock masses usually exhibit scale dependent mechanical properties primarily due to presence of discontinuities and their inhomogeneous nature. One of the essential preconditions for selection of appropriate strength and deformation parameters of a rock mass in relation to tunnel design is assessment of the scale of the joint network relative to the scale of excavation. In tunnel design practice, scale effects are estimated indirectly using small-scale unconfined compressive strength (UCS) tests and rock mass classification based empirical correlations. Large-scale UCS tests have the benefit of direct assessment of anisotropic and scale dependent properties of a rock mass.This paper presents results of a large-scale UCS test on a jointed siltstone. A 450 mm diameter sample with inclined bedding planes was cored and tested in uniaxial compression until failure with load and displacement measurements. The aim of the test is to determine strength and deformation parameters and correlate them with results of small-scale UCS tests of the same sample. The relationships between the small-scale and large-scale rock mass parameters were validated against published correlations from the literature.

Mar 8, 2011

By M Salu, G J. Kay

"As underground mines increasingly face the challenge of maximising production without losingfocus on safety excellence, the ability to predict the eff ectiveness of mine seals and stoppings andthe identifi cation of defects plays an increasingly important role in mine ventilation management.While technologies for sample testing installed seals provides signifi cant assurance, the difficulty of conducting tests in operational environments, combined with the production impact of destructive testing procedures, has led to the development of a new method for non-destructively testing ventilation control devices (VCDs). This paper addresses the challenges of in situ testing and reviews the approaches previously employed to verify the quality of VCD installations. It then describes a new testing methodology jointly developed by Whitfield Minerals PTY Ltd and Parsons Brinckerhoff (PB) and the range of tests that have been carried out in the laboratory, above ground, at trial underground sites and in active coal mine operations. Although this is a new approach to testing underground VCDs, the method employs recognised testing equipment in a new application. The aim of the new non-destructive technology is to not only verify the thicknessand therefore overpressure rating compliance, of new VCDs, but to allow mine operations t oidentify and locate defects in installed VCDs without causing damage to the material structure.Currently it is difficult, time-consuming and costly to carry out physical sampling and testing ofevery VCD. Therefore, a reliable and accurate means of non-destructively testing concrete andplaster seals in situ will provide substantial operational and safety benefi ts to the underground coal mining industry."

Jun 1, 2012

By Y S. Zhang

Natural phenomena and human engineering construction activities had great influence on the geosciences space. Natural disasters, particularly mine disaster and other geological disasters happened frequently, which brought great losses both in people’s lives and economics, therefore, to explore the essential causes and mechanisms of disaster by some useful approaches is the most important step in mine disaster prevention. In a variety of methods, building an aground-underground seamlessly integrated model, and then analysing the formation and development mechanism of mining disaster based on this model is a useful way. In this paper, we studied an aground-underground seamlessly Integrated modelling method, and correspondingly given an aground-underground seamlessly integrated 3D spatial model, CSG+CD-TIN+GTP-TTS, by which we can carry out analysis of surface subsidence and underground laneway distortion efficiently, finally preliminary applications verified the effectiveness of this method.

Nov 22, 2011

By A McCallum, J Abols, G Patrick, G Johansen

The authors challenge the traditional thinking that whole ore cyanidation followed by Carbon in Pulp (CIP) or Carbon in Leach (CIL) should be applied as a standard process in the majority of gold processing flow sheets. The concept of whole ore leaching by using cyanide can result in unnecessary environmental and capital risk. Alternative, currently available technologies can be used to provide the desired level of gold recovery at a much lower installed cost and less impact on the environment. Gravity concentration, alone or in conjunction with flotation, can produce a gold bearing concentrate that can then be fed directly to a batch or continuous intensive cyanidation unit. The In-line Leach Reactor (ILR) is an intensive cyanidation unit developed by Gekko Systems of Australia. Advantages of this technology include significantly reduced capital outlays for greenfield plants or plant upgrades and increased investor returns. Reduction of onsite cyanide and carbon inventories improves plant safety, materials handling and site security. By using direct electrowinning to treat the gold bearing solutions produced by the ILR, the need for a conventional carbon stripping circuit is removed. Potential also exists to increase grind size û saving energy, further reducing capital and operating costs and decreasing the environmental impact of a mill. Detoxification of cyanide before the release of solution to the tailings dam can minimise tailings disposal and containment requirements. When used in the right application the proposed process will have little or no impact on gold recovery and may actually increase recovery for complex ores. Areas applicable to this type of treatment include: plants in environmentally sensitive regions, lower tonnage higher grade deposits, coarse gold deposits, and preg robbing ores û some of which may not currently be economically feasible using standard processes and flow sheets. We have provided two examples of such projects, where an alternative to whole ore leach and CIP or CIL has the potential to deliver these benefits.

Jan 1, 2004

By F Djukic, T Fisher, G Irving

Questionnaires were sent to 12 underground metalliferous mines in Queensland to enquire how these mines control diesel emissions from mobile diesel engines used underground. Where responses or controls were absent, discussion has been provided. A significant finding concerns secondary ventilation design rates. Some mines were designing ventilation rates to meet the superseded Mines Regulation Act of 1989 which required 0.04 m3/s/kW. The current Queensland Mining and Quarrying Safety and Health Regulation (2001) is risk based. In line with other jurisdictions, including New South Wales (NSW) and most Provinces in Canada, a minimum ventilation rate of 0.06 m3/s/kW is acceptable. However, this design ventilation rate will vary in practice depending on the diesel engines and controls. Dedicated ventilation engineers and technicians should be appointed to evaluate the effectiveness of the ventilation system. Personal exposure monitoring is required to confirm that exposure standards are not being exceeded. The primary control practice should be to reduce the emission at source. This can be ensured by purchasing low emission (Tier 2, Tier 3) equipment. In addition, the use of ultra low sulfur fuel (et al, 2002). Diesel fuel with a low aromatic content such as Eromanga diesel fuel will also mean employees are exposed to lower levels of poly-cyclic aromatic hydrocarbons. These controls should be carried out in parallel with good maintenance practices. Preventative maintenance should be programmed and emissions be routinely tested, including both gaseous and particulate pollutants and compared against defined criteria. According to McGinn, 2002, there are a number of fundamental tools necessary to carry out preventative maintenance. These are outlined in maintenance guidelines and best practices for diesel engines in underground mining produced for the Diesel Emissions Evaluation Program (DEEP). An effective diesel emission management system needs to be fully integrated within the Safety and Health Management System. These requirements are further discussed in this paper.

Jan 1, 2007

By R Berry, J Lett, C L. Harraden

"In the past decade, increased processing capacity combined with precision robotics in high resolution spectrometers has resulted in a new generation of high-speed hyperspectral core logging systems. The application of these multisensor automated platforms provides a key advancement in the characterisation of metal resources. The development of this technology has allowed for comprehensive, drill core-based, mine-scale rock mass characterisation studies. Here we propose a new method for the extraction of parameters that seek to more accurately quantify ground conditions, including quantified rock mass rating (RMR) and the Rock Tunnelling Quality (Q) Index. Data inputs include rock quality designation (RQD), number of joint sets, joint roughness, joint alteration and joint spacing. Geologists and geotechnical engineers have historically collected these inputs by manually logging drill core. With automated core scanning technologies, these parameters can be estimated from the acquired image data and used to objectively calculate RMR and Q-index values for oriented core.Corescan is an automated hyperspectral core scanner that uses a 3D laser profiling system to measure the height of the surface of drill core. This technology allows for rapid core analysis to produce detailed fracture and rock condition data. Through an integrated geometallurgical approach, the proposed methodology will test the accuracy of joint measurement using the height profile Corescan data from oriented drill core. This will be combined with joint roughness and alteration mineralogy measured from the hyperspectral images to calculate the RMR and the Q-index continuously downhole. The values obtained can then be compared to the traditional, manual geotechnical log data. If the precision is sufficient, these techniques can then be applied site-wide to automate the collection and modelling of key ground condition classification indices across an entire deposit. Compared to the laborious manual geotechnical logging procedures that currently form the industry standard, utilisation of core laser profile data and high resolution red-green-blue (RGB) images provide an opportunity to collect large volumes of consistent geotechnical data, which can increase the efficiency and accuracy of deposit scale geotechnical models.CITATION:Harraden, C L, Berry, R and Lett, J, 2016. Proposed Methodology for Utilising Automated Core Logging Technology to Extract Geotechnical Index Parameters, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 119–124 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By A Purton, C Taylor, E Conroy

The spatial modelling of geometallurgical domains is an important step in the characterisation of an ore deposit allowing for the quantification of various rock types, their differing rock properties and the overall value of a project. The traditional approach to modelling such features is through the use of deterministic models, where a single estimate of the extents and structure of the ore deposit is mapped out by geologists based on available data and their interpretation of the geological processes. Any uncertainty in the layout of different domains is not accounted for and heterogeneities of chemical and physical properties of the orebody are likely underestimated. Spatial machine learning techniques can be used to derive geometallurgical categories, or classes, from multiscale, multiresolution and high dimensional measured rock properties. Subsequently, geostatistical simulations of these classes can be applied to obtain multiple equiprobable realisations that define the layout of the geometallurgical classes at unknown locations between boreholes, or domains. In-turn these realisations can be used quantify the uncertainties in the location of boundaries between different domains. The development of a workflow for defining geometallurgical domains and later geostatistically simulating them across the Orebody H; a complex stratabound Bedded Iron Ore deposit located in Western Australia’s Pilbara region is demonstrated. This could be used to identify zones of high uncertainty where collection of additional data might help mitigate or minimise risks and in turn improve forecast production performances.

Mar 22, 2022

By J Robinson, L D’Uva

"The Gold Fields group and Gekko Systems have successfully worked together on multiple projects, including at the St Ives, Agnew and Granny Smith operations in Western Australia, and the Damang operations in Ghana, with gravity recovery design, technology installation and optimisation the key driver on each occasion.In 2014, Gold Fields Australia identified an opportunity to challenge the historical thinking at Granny Smith and reassessed the benefit of upfront gravity gold recovery. The historical approach had been to employ gravity on the tailings stream of the carbon-in-pulp (CIP) circuit, recovering sulfide minerals into a concentrate from spiral concentrators for further liberation of gold via a regrind circuit.Gekko was engaged to assess the implementation of a gravity circuit within the grinding area, and to perform a comprehensive gravity recoverable gold test program. Test data was fed into the AMIRA P420 BCC Gravity Model to confirm the gravity recovery potential of the ore, and for process design basis generation. Height, space and capital limitations proved to be a design challenge. However, collaborative learnings throughout the project ensured the design and operation of a reliable and economic gravity gold circuit. Ultimately, the Granny Smith gravity circuit was a success, satisfying all the project objectives and yielding consistent, measurable benefits. On average, the gravity circuit recovers 33 per cent of total gold, resulting in an increase to overall gold recovery by 0.7 per cent.This paper highlights the key project drivers for Gold Fields, and the development of the Granny Smith free gold gravity circuit. It details application of test work and modelling, and the challenges and learnings encountered during the design, installation and commissioning stages. This paper seeks to demonstrate that continuous improvement in a long standing operation can be beneficial to overall circuit flexibility and increased ounce production.Citation:D'Uva, L, Robinson, J and Bell, T, 2016. Defying Gravity - Brownfield Continuous Improvement, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 135–144 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Allnutt S. L, Carswell J. T, Mutton A. J

The Dugald River Zn-Pb-Ag deposit occurs within the complexly deformed and metamorphosed sediments of the Middle Proterozoic Cloncurry Terrane, Eastern Succession, Mount Isa Inlier. The sedimentary sequence comprises a thick package of variably carbonatic argillitic and siliciclastic sediments of the Corella Formation, Lady Clayre Dolomite and Knapdale Quartzite. A slate and calc-argillite unit locally referred to as the Dugald River Slates is the host to the economically significant deposit. The deformational history of the Dugald River area involved three phases of ductile deformation. The present geometry of the Dugald River Main Lode is recognised as a strike extensive steep westerly dipping tabular sheet, within which a steep north westerly plunging zone of pronounced thickening is evident. This zone is interpreted to have formed during folding via remobilisation of the sulphides into a shoot-like body, the geometry of which was controlled by stretching associated with the folding. Further modification of the shoot and sulphide re-distribution has resulted from late phase transgressive shears. The sulphide mineralisation is characterised by three distinctive sulphide types, laminated, banded and breccia, the distribution of which define two broad zones. The northern zone is a narrow I - 5 m thick stratabound unit comprising finely laminated and banded sulphide mineralisation within a well bedded fine grained argillite sequence. This is part of the Lady Clayre Dolomite sequence and is a predeformational precursor form of mineralisation. The southern zone comprises the thickest development of mineralisation (up to 30 m) characterised by slate-sulphide breccias and veins derived from complex polyphase remobilisation of the sulphide mineralisation. It is this zone which forms a stratabound locally transgressive body within the high strain Dugald River Slates and which contains the main body of economic mineralisation. Sulphide mineralogy comprises sphalerite, pyrite, pyrrhotite, galena and traces of chalcopyrite, pyrargyrite, tetrahedrite, marcasite and arsenopyrite. The present resource for the Dugald River deposit stands at 38 Mt grading 13.0 per cent Zn, 2.1 per cent Pb and 42 g/t AS. The Dugald River Zn-Pb-Ag deposit is regarded as an example of a syndiagenetic stratabound sulphide accumulation which, as the result of polyphase deformation and upper greenschist to middle amphibolite facies metamorphism, has undergone extensive remobilisation and Rccrystallisation.

Jan 1, 1993

By Morgan B. D

Since the mid 1950s, limonite deposits of a new type have been found in the northwest of Western Australia. The deposits consist of extensive fossil valley fillings up to several hundred feet in depth, of medium to high grade limonite, frequently containing limonitized fossil wood, and of Mesozoic or Tertiary age. The distribution of the deposits is closely linked with hilly outcrops of Archaean and Proterozoic jaspilite in the headwaters of the old valleys, from which the iron has been derived by leaching, and presumably re-precipitated by a process not unlike that which operates in forming bog iron deposits. Due to the relative resistance of tlie limonite to erosion, the rejuvenation of streams in the area in recent times has left limonitic remnants as mesas up to· several hundred feet above the levels of the present creeks, the courses of which generally are adjacent to or within a few miles of those of the old limonite filled valleys.The Robe River limonite deposits are the largest of this type known and can be traced for approximately 130 miles along the old stream, over 30 sq. miles of limonite remnants remaining at the present time.The present quantity of limonite in this system alone is probably in excess of 5,000,000,000 tons, and the original quantity must have exceeded four times this tonnage when allowance is made for erosion.Some thousands of millions of tons of this material contain in excess of 54 per cent Fe, with approximately 10 per cent combined water. The chief impurities are SiO2 and Al2O3, and minor elements are not present in objectionable amounts. A portion of these deposits was extensively tested by The Broken Hill Proprietary Company Limited (the B.H.P. Co. Ltd.) during 1962-1964. Most of the data presented in this paper are based on the work done on these deposits which are typical of those discussed. The overall problem of the origin of the limonite is discussed. It is apparent that the limonite originates from the jaspilitesof Archaean and Proterozoic age which form the highlands at the upstream ends of the deposits. The iron oxide has been chemically and/or mechanically derived from these jaspilites and deposited by one or more of the following mechanisms.A.-Chemical-sedimentary mainly by biological agenciesB.-Replacement of fluviatile sediments by iron-charged watersC.-Clastic sedimentary processesD.-Lateritization of fluviatile sediments.These various mechanisms are discussed; the authors favour machanismA.Manuscript received' at The Institute, 14th July, 1964.

Jan 1, 1964

By K Watanabe

A relational database in which its complex contents can be navigated through a map interface (ie spatially enabling) is relatively a new concept yet attractive for geoscience fields. This concept is made possible using the new breed of geographic information system (GIS) that utilises component object model and relational database management system. Such sophisticated yet open and highly interoperable platform makes possible the integration of data management, analysis, and modeling processes into single workflow. Taking benefit of this technology trend, several initiatives emerge in geoscience to establish digital data models, such as the petroleum industry, the North America digital geologic map data model, and the ESRI geology data model. The mining industry unfortunately has not followed same paths due to the lack of data model and standards in its history. This paper presents an effort on establishing a digital data model for mining-related geoscience databases. The aim is to promote several standards by proposing a preliminary data model and demonstrating that the model is working for the mining business datasets. The case study is the island of Java, the western part of the Sunda island arc of Indonesia. Many types of datasets, such as geologic maps, topography, mineral deposits, structures, geochemical and geophysical data were dealt with and were transformed relational geologic databases of Java using the new Geodatabase geographic data model. Intelligent GIS tools were investigated for geologic applications, ranging from generic to specific purposes. Subtypes and domain were used to set up constraints, while topology rules and relationship classes were used to create links among data layers. The linear referencing system was used to model drillhole data. The current results show that the generic GIS and relational database can handle typical tasks related with mining business datasets. A preliminary data model is finally suggested.

Jan 1, 2004

By Cowie WJ, Utting BS

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850's has been an estimated 480 tonnes (15 million ounces) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 tonne of gold for 1989.Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

By J P. Burr

The Waterview Connection will complete a strategic Auckland motorway route linking the south, west and north. The project will include 2.1 km of ‘undrained’ driven tunnels, 500 m of drained cut-and-cover tunnel and tunnel portals.The project is aligned beneath a stream valley of Oakley Creek, which is incised through alluvium and in places overlain by landfill, between Mt Albert volcano and a ridge formed in alternating sandstones and siltstones. The resulting topography, geology and hydrogeology of the tunnel alignment are complex.The Assessment of Effects required estimation of the likely settlements resulting from the tunnel construction and assessment of their effects on the buildings, services and other features. A conservative approach was taken when estimating settlements in order to provide an upper bound estimate of the consequent effects. There are three sources of these settlements: mechanical settlement from the tunnel excavation, mechanical settlement from the displacement of retaining walls and consolidation settlement from the groundwater drawdowns during construction and, in some cases, in the long-term.The settlements from these sources were calculated independently and then combined to identify the most critical effects. These combined settlements were used to assess the potential damage to the buildings, services and other features above and around the tunnels. The combined settlement results generally followed the anticipated trough shape centred on the underlying tunnel but with some noticeable effects relating to the underlying geology and hydrogeology.The effects on buildings were typically assessed as negligible with some areas of very slight to moderate damage predicted. Effects on services are anticipated to be minor but some large and older pipes will require specific monitoring during construction. A monitoring programme is proposed to allow the actual settlement and effects to be compared to those estimated with appropriate responses should those effects significantly differ.This paper describes the methods used to calculate and combine the settlements and assess their effects.

Mar 8, 2011

By D Xu

BHP Billiton Iron Ore is one of the world’s premier suppliers of iron ore. It currently has operations in Western Australia and Brazil and also has some iron ore interests in West Africa.BHP Billiton’s Optimisation R&D team has developed a proprietary mine planning optimisation tool that uses a mixed integer linear programming (MILP). This tool is called Blasor and it is used to rapidly evaluate the resource development potential (RDP) scenarios for the company’s business development strategy. In addition it generates life of asset (LOA) mine plans for the company’s operations and growth projects. The Blasor optimiser maximises the discounted operating cash fl ow (DCF) as the objective function, subject to mining, processing and transportation capacity constraints and blended product quality constraints. The paper will outline how Blasor has been applied to the resource development potential (RDP) strategy scenario studies, growth project evaluations and LOA mine planning within BHP Billiton Iron Ore.The practical application of Blasor to resource planning optimisation within BHP Billiton Iron Ore has demonstrated the value of such a tool for optimising strategic directions through the evaluation of a number of carefully proposed scenarios and maximisation of operational decisions, such as cut-off grade, open pit development sequence, etc. Particularly for the company’s business development direction studies, Blasor plays the role of a fair valuation tool in that it discovers the most valuable resource development scenario, thus establishing a sound basis for comparing the economic merits of each scenario.

Jul 11, 2011

By Kagl J, Publlier M, Nekitel S, Arumba J, Rangin C, Mosusu N

Since the advent of plate tectonic modelling, the Ramu-Markham valley has been thought the site of a classical island-arc/conti- nent collision zone. In this interpretation the units south of the Markham Valley are held to be island are / micrcontinental mate- rial accreted to Australia and those north of the valley are thought to represent a separate Finisterre island-arc terrane. Recent remapping by the Geological Survey of Papua New Guinea shows: (1) there is no terrane boundary along the Ramu-Markham valley (2) the Finisterre Volcanics are probably part of either a fore-arc sequence or oceanic plateau obducted onto a microcontinent/ volcanic-arc composite terrane, accreted to the continental Australian plate. A new tectonic model is proposed for northern PNG and involves: (I) Eocene to Late Oligocene subduction below a microcontinent remote from Australia to produce the Sepik are and related intrusives, the Finisterre Volcanics (fore-arc or possible oce- anic plateau), together with the Alife blueschist. (2) obduction of the Sepik arc in Late Oligocene-Early Miocene times over the advancing Australian plate. This resulted in crustal melting, some of the products of which are the Mid- dle to Late Miocene Akuna and Bismarck intrusive complexes of the Maramuni arc. (3) obduction of the Finisterre Volcanics began in Early Pliocene times and continues today. (4) post-Middle Miocene mineralisation is the result of melting after obduction of the Sepik microcontinent.

Jan 1, 1997

By D Brereton, C J. Moran

Intensive resource extraction, in the form of multiple mining operations, presents significant assessment and management challenges for resource developers, governments, community and the environment. Cumulative impacts, ie the successive, incremental and combined impacts (both positive and negative) of an activity on society, the economy and the environment, can place significant pressure on social, economic and environmental capital and render conventional mine-by-mine approaches to management ineffective. Cumulative impacts can be what are most important to environments, communities and economies surrounded by multiple mining operations because cumulative impacts are what they experience. There is much to gain from increased consideration of cumulative impacts. Unmitigated impacts have the potential to delay or even prevent expansion of mining in existing and prospective areas. On the other hand proactive management of cumulative impacts can benefit regional environments and communities and contribute to the industryÆs social license to operate. Resources are often not the limiting factor to better cumulative impact management. More effective coordination of existing resources may go a long way toward mitigation and enhancement, and better planning and assessment may help avoid impacts and exploit opportunities for efficiency gains through reduced duplication. In this paper we draw from working examples to present five practical assessment and management strategies applicable to resource companies to enhance positive, and avoid and mitigate negative, cumulative impacts. The strategies are presented based on their capacity for achieving outcomes, ease of implementation and cost effectiveness and are drawn from a multi-year study on the assessment and management of cumulative impacts in the Hunter Valley, New South Wales and a follow-up study to improve cumulative impact assessment and management practice in the Australian coal mining industry, both reported elsewhere.  

Jan 1, 2009

The progress between 1983 and 1989 towards Management Guidelines for R16 was extremely slow and painful because protection of the mining heritage was a new function and administrative activity not referred to in any Queensland mining law. Also, until 2 December 1989 the Queensland political climate was anti-preservation. Therefore an understanding had to be achieved between John Hay, the Mines Department and the National Parks and Wildlife Service, to ensure preservation of the mining machinery in situ rather than being removed to a town site such as in Ravenswood.

Jan 1, 1990

By J Vann

The philosophical context of many activities in mine geology can be an important lever in adding value to operations. For mine geologists (including resource and grade control geologists) we argue that the tasks of problem formulation, observation and data collection, interpretation and modelling invoke various philosophical considerations whether the practitioner is aware of them or not.Constructing testable models to explain reality is the definitive aspect of any activity claiming to be ‘scientific’. A primary goal of mining geology is to build models that accurately predict reality to an acceptable degree and these include litho-structural, stratigraphic, grade control, resource or reconciliation models. What’s more, in mine geology we are often able collect additional drill samples or access new underground openings, for example, that can provide relatively rapid feedback on how predictive, and therefore useful, our models are. In this paper, we describe the key philosophical frameworks proposed for conducting scientific investigations, including falsification, the method of multiple working hypotheses and structural concepts of scientific theory. The strengths and weaknesses of these approaches are discussed and an attempt is made to relate them to activities undertaken by mine geologists. Common perceptions of what constitutes the scientific method have been dominated by how scientists do experimental physics and chemistry in particular. There are very important differences in the types of problem confronted in these experimental sciences compared to the ‘historical sciences’, such as geology, where the processes studied are unique and only evidential traces of past events are available. The philosophical implications of attempting to validate numerical geological models, such as resource estimates are also briefly considered.Some practical conclusions are drawn about how mine geology activities can be better implemented if practitioners are cognisant of the importance of philosophical considerations when attempting to gain new knowledge through a scientific investigation. We believe that the implications for creating additional value to a project or operation can be very significant when geology is applied by a practitioner with an understanding of the philosophical basis of the activities we think of as constituting a scientific investigation.Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful? (Box and Draper, 1987, 74 p).The demand that theories be highly falsifiable has the attractive consequence that theories should be clearly stated and precise. If a theory is so vaguely stated that it is not exactly clear what it is claiming, then when tested by observation or experiment it can always be interpreted so as to be consistent with the results of the test. (Chalmers, 1999, 67 p).

Aug 22, 2011

By C A. Brannon, C A. Dipas, H A. Vega, D Villa

The development and construction of the Grasberg block cave mine (GBC) is in progress, currently targeting initiation of caving in late 2018. Current production planning anticipates ramping up to full production of 130 000 to 160 000 t/d by 2027. As GBC approaches the production phase, there is a high priority on increasing the accuracy and level of detail in the production plan. The advance of the cave front directly controls the drawbell opening rate that is achievable. Therefore, an essential component of this plan is to produce an undercutting and drawbell sequence that honours the caving parameters that have been set for the mining blocks by the GBC production planning team.The PT Freeport Indonesia (PTFI) mine planning team and the Geovia caving business unit have developed a computational tool (Undercut Tool) capable of generating an undercutting sequence that follows a set of caving rules, such as advance rate per tunnel, maximum blasted area per period, control of lead-lag and shape of the undercut face. This tool also produces a drawbell sequence that honours the undercutting advance sequence, which is ultimately used to generate a life-of-mine production plan. This paper describes the inputs and outputs of the Undercut Tool that have been used to compute the long-term production plan for the GBC mine. It will further describe how the Undercut Tool takes into account operational constraints and geotechnical considerations that must be considered when developing a defendable production plan. Included is a discussion of the initial results of the planning outcomes from the tool; it will demonstrate how this work will support specific aspects of the plan such as the detailed undercut production drill and blast plans for the drill ring sequence, as well as how that plan will drive the drawpoint opening plan.CITATION:Villa, D, Brannon, C A, Dipas, C A and Vega, H A, 2017. Integrated drawbell and undercut scheduling using a computational tool at the Grasberg block cave mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 271–276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017