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By Hughes J. C

THE smelting plant consists of five large furnaces operating in the treatment of current flintered material, and one small furnace operating periodically in the treatment of copper dross and antimonial slag produced in the lead-refining process.he following table supplies the leading dimensions and details of the large furnaces:-(a) Crucible - Dimensions 17 ft. 2 in. long x 4 ft. wide x 2 ft. 3 in deep. Capacity - 30 tons lead. Class of lining - firebrick. No. firebricks required - 3000.(b) Crucible Tank - Dimensions 20 ft. 6in. long x 10 it. 6 in. Wide x 4 ft. 3 in. deep. Material - 1/2 in. mild steel.(0) Jackets - Dimensions 6 ft. long x 19 in. wide x 6in. thick. Material - Cast-iron. Average life - 2 years. Number per side - 11, with 13-in. bosh. Number per end - 3, with 9-in. bosh.

Jan 1, 1922

By C Zhang, I Canbulat, G Fan, D Zhang, C Wang

A clear understanding of the intensity of coal and rock burst is the basis for future research on burst mechanism and control. There has been a wide variety in the description of coal and rock burst damage at different countries using multi-methods, which makes the common understanding even more challenging. Therefore, this paper presents a broad review on the quantifications of intensity of coal and rock burst and seismic risk around the world, considering critical factors including seismic energy, magnitude, peak particle velocity and ejection velocity. It is found that the seismic energy of coal and rock burst can widely range from 0.002 MJ to 60000 MJ, with equivalent Richter magnitude from -1 to 4. The daily seismic energies can be used for seismic risk potential assessment, with energy levels from 0.1 KJ to 10 MJ, which is much lower than the burst sources. The magnitude of the seismic events can be also estimated based on the weight of damaged coal mass and human senses of vibration and sound. For the seismic intensity represented by peak particle velocity (ppv), it keeps constant within fault radius and attenuates with a speed of 1/r4 and 1/r in near and far field respectively, thus it is possible for a small seismic event to induce considerable ppv causing severe damage if the epicentral distance is small enough. There has not been a strong correlation between the ejection velocity and ppv, as seismic energy is only one of the energy sources that contribute to the kinetic energy of burst damage. CITATION:Wang, C, Zhang, C, Canbulat, I, Zhang, D and Fan, G, 2018. Intensity quantification of coal and rock burst risk – a review, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 223–233 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By T Trott, G Lumley

"The mining industry suffers from a shortage of professional and other workers. Research and analysis has demonstrated a close correlation between high performance in productivity, maintenance and safety. There is also a significant correlation between engagement and performance. It is the hypothesis of the authors that mines can use a strategy of establishing themselves as a high-performance mine to attract and retain high caliber professional people: step 1 is to become best practice in equipment performance (productivity, maintenance and safety) step 2 is to brand the mine as æbest practiceÆ by sharing what has been confidential performance and outcome information with the general industry.Previous research has shown that many professional people are attracted by the prospect of a high achieving site because of the learnings and the support for continually doing better. In addition, a link has been established in previous research between productivity and safety. Operators and drivers are attracted to sites which have fewer dangerous people operating or driving. Good management delivers exceptional performance and a work site which high caliber managers and operational personnel people want to work at. The strategy requires commitment and proper execution but it can work. The strategy needs a specific approach and this paper will discuss this. A case study is provided from a mine which over a nine month period increased dragline performance by 15 per cent and reduced stress on the boom by 30 per cent. This mine paid the employees (professional and operational) $25 000/a less than the major mines but the operators and professional people would not leave; in fact, people were happy to be paid less to work there.CITATION:Lumley, G and Trott, T, 2012. Using best practice operations as a strategy for attracting and retaining professional people, in Proceedings International Mine Management 2012, pp 35-52 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 20, 2012

By I C. Carrasco, V G. Mirada, J F. D Domingo, F S. Leite

This paper investigates ore loss and dilution produced by rock movement in bench blasting. A total of four blasts, in which electronic detonators have been used, were monitored in Cobre Las Cruces Open Pit Mine (FQM Ltd) in Gerena (Sevilla, Spain). Rock motion has been obtained in 137 points of the free face and 6 points inside the block. Multiple liner regression has been applied to predict rock motion and estimate ore dilution as a function of hole coordinates, rock contacts, powder factor/hole, amount of explosive per blasthole, burden, spacing, hole length, stemming length, explosive energy, hole row, subdrilling, blast sequence, stiffness ratio, blasthole distance to free face, rock density and Young’s modulus. The model is statistically significant with a determination coefficient over 0.8. Rock motion measurements in 31 more points have been used to validate the model and to show a reduction in ore dilution.CITATION:Domingo, J F D, Leite, F S, Mirada, V G and Carrasco, I C, 2015. Dilution, ore grade and blast movement calculation model, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 71–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By G J. Halstead, R C. Steinhaus

The True Pipe® in-line sampler was developed in an attempt to address the need for a mechanically reliable and correctly designed sampler to suit one-dimensional pressurised slurry pipelines, often found in metallurgical process plants but for which no reliable and representative sampling solution as yet exists.The design, whose operation is based on the principle of symmetry, is described by Dominique François-Bongarçon (2005) with the synchronous opening and closing of relevant valves. It representatively isolates portions of the particulate material stream at predetermined intervals for effective extraction of primary increments for subsequent sample compositing.Theory of Sampling applicable solutions have proven elusive in flowing pressurised particulate material streams, with various attempts to date not having formulated a viable, mechanically reliable and acceptable design.Compliance to sampling theory is critical, and a number of tests were conducted where certain operating parameters were altered to determine their influence and sensitivity on sampling representativeness.The results of the initial series of tests performed on a carefully designed rig are presented, with additional work discussed for necessary investigation in the near future.Getting closer to a robust, economic and correct design for this challenging application in the minerals industry may now not be that far away. Plant management staff will see improved metallurgical mineral balances around their process plants and significantly reduced sampling discrepancies, particularly in tailings applications. Improved quality control is now possible where, due to plant head room constraints, classical cross stream sampling methods cannot be employed.CITATION:Steinhaus, R C and Halstead, G J, 2014. True pipe sampler – a correct design utilising the principle of symmetry in pressurised slurry particulate streams, in Proceedings Sampling 2014 , pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By Moeller T

The Bottle Creek mine, when opened next month, will consist of three open cuts, Emu, VB and Boags, feeding ore to a central mill. The open cuts cover a strike length of 4.5 kilometres which forms part of a linear structure, which can be traced geochemically for 26.0 kilometres. With the exception of a few small gossanous outcrops at Emu, the deposits are completely covered with insitu laterite and alluvial overburden. Since its discovery in 1984, the deposit has been subjected to three major reverse circulation (RC) drilling programmes which have successively closed up the drill spacing on the main mineralized zone to 25m horizontally and less than 25m vertically. All resource calculations have been based primarily on samples of RC drill cuttings from these programmes. Ore reserve calculations have been completed after each drilling phase. They began with a simple polygonal technique, progressed through two sectional half-distance calculations and are now being completed with a 3-D geostatistical technique. Because of the style of mineralization, Norgold personnel paid particular attention to assessing the variability of the mineralization by using repeat samples, repeat analysis and diamond drill vs RC comparisons. In addition, close attention has been paid to obtaining an accurate estimate of the global SG of the ore bodies. Particular care has been taken to obtain complete drill intersections of the orebody and to maximize wet sample recoveries. Extensive re-sampling and re-analysis of samples has confirmed that Bottle Creek is unusual for an oxidized gold deposit in that all the gold appears to be very fine grained, and evenly distributed within the mineralized zone.

Jan 1, 1987

By M Olsson, U Nyberg, K Widenberg, P Svedensten, F Ouchterlony

During 2007 and 2008, the project Optimal Fragmentation in Blasting II was conducted at the Långåsen quarry of NCC Roads AB near Arlanda. The main goals were:an evaluation of the effect of using electronic delay detonators (EDDs) in quarry blastinga validation of the design curve concept introduced at the Vändle quarry.Five production blasts were monitored. After a first trial round, the remaining four rounds each had about 100 Ø89 mm holes in a 14–19 m high bench charged with site mixed emulsions. In rounds 1 and 2, a tighter pattern than normal was used in one half of the rounds, raising the specific charge there from 0.7 to 1.0 kg/m3. Non-electric initiation was used with two holes per 25 ms delay in-row and 67 ms between rows. In rounds 3 and 4, electronic delay detonators were used instead, with 10 and 5 ms in-row delays respectively.The monitoring encompassed drill hole collaring and alignment, in-hole deviations, the rock structure in the bench faces from 3D imaging, first row burdens, etc. Eleven 400 t samples were taken from the muck piles and sorted in the quarry and sieved in the laboratory (lab). The lab data made up a fines tail that was grafted onto the in-pit sorting data to form sieving curves for the test piles. These curves were then compensated for the absence of boulders to construct the sieving curves for the blasted muck pile.These have been used to derive fragmentation model formulas for the non-electric rounds, also called design formulas. They are based on blast geometry, charging data and the properties of the rock mass. The formulas may be used to estimate the effect of changing blasthole pattern, borehole diameter and stemming length for example.The use of EDDs gave several unexpected results. In comparison with non-electric initiated rounds with a somewhat lower specific charge the fragmentation was much coarser; x50 increased from 160 to 200 mm. The effect of raising the specific charge in the non-electric initiated rounds from 0.72 to 0.99 kg/m3 was a much finer fragmentation; x50 decreased from 160 to 120 mm.CITATION:Ouchterlony, F, Nyberg, U, Olsson, M, Widenberg, K and Svedensten, P, 2015. Effects of specific charge and electronic delay detonators on fragmentation in an aggregate quarry – building fragmentation model design curves, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 727–740 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Mineragraphy is a coined term to signify the field of microscopic investigation of ore minerals. The term is not euphonius and is sometimes regarded as superfluous because the subject is no more than an enlargement of the scope of petrology. In the past the practical field of petrology has been largely limited by the instruments which were designed for the study of rocks and' the microscopical properties of the transparent minerals. The addition of mineragraphy has been brought about by the use of the reflecting microscope and a totally different technique.The use of the petrological microscope, as it has been employed in the training oi geologists and mining engineers for nearly half a century, has been justified many times, not only in its application to general geological problems, but also in the more restricted field of the exploration and examination of ore deposits. It provides information of the gangue minerals and rocks associated with an ore body which is of great value in some mining fields. In cases where ore deposits occur selectively in certain favourable types of rock, the recognition and delineation of these rock types is a useful guide in prospecting. The Boulder Belt at Kalgoorlie forms one of the most striking examples in Australia where important significance is attached to different rock types, and the petrological microscope is essential to their elucidation.

Jan 1, 1932

By D David

Amongst those whose task it is to design tumbling mills and other comminution machines there is an almost religious divide between devotees of the Bond method and devotees of other methods developed in more recent times. For a decade or so the issue was between the Bond power-based methods and the JKMRC (JK) simulation based approach. The newest method to challenge the status quo is power-based and was developed by Steve Morrell. As the title suggests, this paper will take some liberty at concluding that Fred Bond and Steve Morrell may be separated by history, but not by their approaches to their individual contributions to the science of comminution. Another driver for the paper is that although it is good to have diversity of thought, the existing divisions are problematic for those of us signing public disclosure documents. If alternative design methods produce materially different outcomes for the mill duty, then at least one of them is wrong or being used incorrectly. At some point the unsustainable argument may need to be put in a court of law that we metallurgists have two or more materially different design methods, each of which is correct! Therefore, perhaps a resolution is needed before this occurs?The works of both Fred Bond and Steve Morrell are each directly related to their contemporary grinding mill design and operational environments. Both their approaches are empirical, borne of observing and measuring real world situations. Both worked with theories that preceded them, gathered their own data and then each saw shortfalls in the status quo.Fred Bond was an escapee from revolution, a victim of The Great Depression, and had several near death experiences during his early site-based career. Perhaps he was fortuitously rescued from himself when asked by Allis Chalmers (A-C) to set up its rock testing laboratory in Milwaukie in 1930. Fred’s testing led him to conclude that neither the Kick nor the Von Rittinger theories explained his measurements. His writings on the failings of these old theories caused a divide between devotees of the old and new methods at that time. After many years, and much thought and plotting of data (the old way!), he came up with his now-famous equations (and his Third Theory) which have stood the test of time, certainly in the world of Bond-era machines.Coming from England via several African diamond mines, Steve Morrell immersed himself into the comminution world of the JK in Brisbane about a decade after Fred passed on. The JK had developed its semi-autogenous grinding (SAG) simulation framework using its own pendulum breakage tester, itself a derivative of the twin pendulum impact device invented by Bond decades earlier. At the JK Steve developed his authoritative Tumbling Mill Power equations and was involved in real world analysis of comminution problems on the global stage. Steve’s JK experience coincided with the demise of the rod mill, the rise of autogenous grinding (AG) and SAG milling and a rapid expansion in concentrator capacity.Morrell left the JK to pursue his own interests, which included ongoing consulting work, now demanded by the comminution world. He then turned to investigating a growing list of discrepancies between the opinions of designers and theoreticians, and the factual outcomes. The Morrell Method of design arose from this re-examination of ore testing, real world operating data and these glaring and expensive discrepancies between design and outcome. The elements necessary for a relook at the world of rock breakage were in place!CITATION:David, D, 2017. Steve and Fred would have been mates – a comminution design evolution story, in Proceedings MetPlant 2017, pp 2–11 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By P Ring, B Cooper, C Carr, G Laing

The Nova Ni-Cu-Co Operation, located in the Fraser Range of Western Australia, commenced commercial production in July 2017 only five years after discovery. Owned by Independence Group NL (IGO), the operation has successfully ramped up over an accelerated schedule and currently deploying leading technologies. This paper begins with a description of the Nova Operation, and its journey to achieve full production in such a short time frame. It includes discussions on development and production design, selection of fixed plant infrastructure, and the features challenges of running a low-pressure primary ventilation circuit. The paper also discusses key technologies that have improved overall safety for the underground workforce, and improved operational efficiencies. Investigations continue into the implementation of further technological applications for safety and productivity enhancements. This paper also discusses the findings from a study into transitioning from a diesel to an all-electric underground mining fleet, based on a review of Nova if it were to be developed today with the current EV offerings. The study indicates compelling savings will be available to future mines when considering development design, project schedule, capital outlay and operational savings, and the ‘next Nova’ is expected to be all electric.

Mar 15, 2021

By D Brown, Z Tabor

Projects must be flexible to account for the rapid development of new technologies and changing stakeholder expectations. Coupled with calls for bleeding-edge solutions, customers, shareholders, and regulators demand robust, safe products and systems-of-systems. Developing and integrating these solutions is becoming increasingly complex and maintaining the flexibility required to ‘pivot’ to effective solutions can be a serious challenge. The necessary flexibility is fundamental to the Agile ethos, and this family of methodologies therefore offers a potential solution to this challenge (Beedle et al, 2001). These have traditionally been delivered with systems engineering applied through a Waterfall methodology. Agile Systems Engineering combines both approaches and presents a means to achieve these goals without compromising flexibility, quality or safety. A robust methodology for the application of Agile Systems Engineering is required to enhance practical outcomes and reduce risk for real-world mining projects.

Sep 1, 2024

By P Jones

Fosterville Gold Mine is an underground operation located approximately 20 km northeast of Bendigo and 170 km north of Melbourne. Fosterville is the most productive gold mine in Victoria, producing over 100 000 ounces of gold annually. Access to the underground is via two portals cut into previously mined open pits. Fosterville is 100 per cent owned and operated by Northgate Minerals, a gold and copper producer with mining operations, development projects and exploration properties in Canada and Australia. (Northgate Minerals Corporation, 2010).Underground operations commenced in 2006 with ore production focused on three orebodies – Phoenix, Ellesmere and Falcon. Primary ventilation to the existing operation is provided by wall mounted exhaust fans located underground. This system provides approximately 220 m3/s of primary ventilation to the operations with intake achieved through the portals. Exploration drilling during recent times has uncovered another lode, the Harrier orebody, located 2.2 km to the south of the existing workings. Due to the location of the new Harrier orebody, vent analysis revealed the requirement for a separate source of primary ventilation to service Harrier. Figure 1 shows a current underground long section and the location of Harrier in relation to the existing workings. A number of options were considered, including a parallel decline from one of the existing two portals, however, a 4 m diameter, 350 m deep surface ventilation shaft was selected as the most suitable and feasible option for the mine.In December 2009, geotechnical drilling commenced to determine the most suitable location for the shaft. Site locations were constrained by a number of factors including interaction with current and planned surface infrastructure as well as proximity to nearby community members at the southern end of the mining lease. Results from the geotechnical drilling indicated that the majority of the proposed shaft would be suitable for a 4 m raise bored shaft. However, the top 40 m of the proposed shaft were deemed unsuitable for raiseboring due to zones of weakness that would likely influence the stability of a 4 m diameter shaft (Robinson, 2010). Following independent geotechnical advice and input from experienced raiseboring contractors, it was decided to construct a 40 m presink prior to raiseboring activities.A crane mounted auger was chosen as the preferred method to construct the presink. This method differs substantially from traditional blind sinking methods which are highly labour intensive. The auger, or drill, is designed and built to be attached to a crane base using engineered pivoting cradles. The auger is suspended from the crane jib by pennant ropes attached to hydraulic rams. The auger applies rotation and axial loads to the drilling tools via a telescopic steel bar (Kelly Bar). Drill tools are attached to the bottom of the Kelly Bar and comprise an assortment of drilling buckets and reaming barrels. Drilling buckets cut in situ material and collect the spoil for removal and are used for the excavation of the ‘pilot hole’. Reaming barrels are used to expand the diameter of the excavation by directing cuttings into the pilot hole which are then removed by the drilling bucket. In June 2010, the presink was constructed utilising a crane mounted auger with support to the shaft walls applied via a remote fibrecrete unit. The excavation method involved cutting a series of smaller diameter holes (2.4 m wide) before reaming out to the final diameter (4.7 m wide) in 4 - 5 m vertical increments. Fibrecreting activities were carried out on the backshifts, to ensure the stability of the excavation and minimise interaction between the two units. The presink was completed on time and offered many advantages compared to traditional blind sinking methods, including safety, costs and timing. This paper will examine the benefits of this method as well as lessons learnt and future applications in the mining industry.

Mar 21, 2011

Bolivia, due to its turbulent past with a history of constant military coups, has given an image of complete instability to the foreign investor. The effects of this have been several fold, the major one resulting in a complete lack of exploration in modern terms since their revolution in 1952. What was overlooked by the foreign investor was the fact that revolution produced Agrarian Reform which is the foundation of the stability which Bolivia enjoys today. Another factor that is overlooked is the fact that its past history is one of vast mining fortunes having being made. Their political problems resulted in economic chaos in 1985 with an annual inflation rate of 26,000 percent. This resulted in the collapse of the government but the democratic process continued. Then came the so-called"South American Miracle" in 1986 when the government of Dr. Paz Estenssoro enacted an extremely harsh austerity program which consisted of the abolition of wage and price controls, the abolition of monopolies, the right to hire and fire, the weekly auctions of dollars and the free convertibility of currency which yielded a stable government with 8 percent inflation. This was followed by massive personnel reductions in the various mines and other industries.

Jan 1, 1991

By G Kirk

Definition and delineation of in-pit ore and waste material are the most significant tasks for an open pit production geologist; adding or destroying value in the mining value chain. Anglo American’s Mogalakwena Platinum mine, an open pit operation in South Africa moving 100 Mt/a, has recognised the value of improved material definition and is in the process of changing from blasthole to reverse circulation (RC) sampling for in-pit grade control. This is aimed at obtaining more representative samples, which are required to maximise ore recovery, minimise waste dilution and to increase the accuracy and confidence of production forecasts. Early in the project, it was realised that the key risks for implementing RC grade control were related to change management processes, rather than failure of technology. Recognising the importance of this issue, Mogalakwena chose an integrated implementation approach that incorporates all stakeholders of the mining cycle in order to develop a process that delivers maximum value and is sustainable within an active mining environment. The following core goals were addressed over five phases of project implementation: extensive definition and design of integrated project implementation, comprising: project buy-in and ownership from all key stakeholders, including survey, geology, mine planning, drill and blast, load and haul, maintenance, supply chain and finance; and detailed analysis of all potential issues and possible solutions, allocated to stakeholders as part of the scoping process; optimising hole patterns and drilling procedures, focusing on delivering maximum value for minimum cost using multiple scenario analysis from borehole data and operational sequencing requirements; and evaluation of lessons learnt during project implementation in order to optimise the technical solution and operational efficiencies. Although this project is not yet finalised, Mogalakwena Platinum Mine is already providing a blueprint for the effective development, implementation and optimisation of sustainable in-pit grade control RC drilling for other open pit mines within Anglo American plc.

Aug 22, 2011

By M K. Singh

Mining is nothing but an art - besides being a science - of extracting valuable minerals from the womb of the mother earth. In this gigantic task, a large number of machinery and equipment are employed judiciously. Wire ropes play a vital role in lifting or hoisting men and materials under hostile/adverse working conditions and constitute a major item of investment on machinery/equipment. The economy of using a wire rope is a concern for engineers, users and the planners. The economic use of wire ropes for mining purposes largely depends on the following factors;Mechanical design considerations - which include tensile strength of wires, elasticity, resistance to abrasion and crushing, fatigue values, static and dynamic loads on wire ropes, factor of safety, fleet angle, etc. Metallurgical consideration - Composition and heat treatment of wire materials, defects like inclusions and voids, surface quality factor, lubrications, micro structural parameters. Operational consideration - Seizing and cutting of rope, storage, care and maintenance, cutting back, etc. Environmental consideration - Temperature and humidity, pit condition, dust, corrosive atmosphere, etc. In the present paper, an attempt will be made to suggest steps for achieving optimum economy while using the wire ropes for extraction of precious minerals and coal keeping in view the points noted earlier. Once technical viability is established, economy is the ultimate consideration for an industry for safe hoisting of men and material.

Jan 1, 2000

The Resource Management Act has been in force now for approximately ten months. This Act, and the Crown Minerals Act which accompanied it, have substantially changed the manner by which mining operations and other resource uses obtain access to resources and are subject to controls of their environmental effects. This paper briefly summarises the key elements of the regulatory provisions of the Resource Management Act. It identifies the types of resource consents required, and discusses these and procedural matters in relation to mining in Otago. It addresses the transitional provisions and highlights inconsistencies and difficulties in the implementation of these provisions. This paper identifies potential future developments in the planning and regulatory environment relating to mining in Otago.

Jan 1, 1992

By Green A. D M

The establishment of the Imperial Smelting Furnace at Sulphide Coporation Pty. Limited for the smelting of zinc and lead made it necessary to design and install sintering capacity to produce approximately 500 t.p.d. of zinc-lead sinter. The updraught sintering process installed is a recent development and the plant was designed with adequate flexibility and equipment to enable operating staff to investigate the process and achieve maximum production under optimum operating conditions.Sulphur dioxide gases from the sinter machine are passed to a contact acid plant for the manufacture of sulphuric acid.

Jan 1, 1964

By M Foster

The new environmental legislation of 1986 was left incomplete and to date remains so. The 'missing' process by which environmental consideration should be applied was never embodied in law and has predisposition to a wide interpretation. The Resource Statutes which govern land use and development place demands on the environmental process without that definition. The Resource Statutes are themselves under review by Government. There is a new Government Department of Conservation. It is still in its early days and facing a challenge to compose its role as a steward over large tracts of land holding significant marketable resources, animal, vegetable, mineral, and abstract. It has also taken over numerous consent and advocacy roles in legislation beyond its own empowering Act. Enter the mining company, anxious if not able to get an easy passage for consents to prospect and mine, then at least to have a clear path to tread to get there, within a fixed time period. Whichever options appear available to process environmental approvals, public participation is that being favoured most by the regulatory bodies. Where a public notification of consent applications is mandatory, public participation should lead to the fastest track available.

Jan 1, 1988

By M J. Nimmo

extremely powerful tools for building predictive and generative models. ML can be used for building highly accurate regression and classification models. But without careful data science and statistical analysis, a regression or classification model could be highly biased and completely wrong – and we may not even realise. An example rock density estimation task will be used to illustrate the potential gains and possible pitfalls in using ML and AI in Mineral Resource estimation. What could possibly go wrong? Nothing! For most simple regression or classification problems, very little. For density estimation, using the global mean may be all that is possible, but the resource classification would need to reflect the uncertainty in global estimation of tonnage. Everything! From data collection and measurement, from selecting ML and AI techniques and designing the analysis workflow to our own cognitive bias. The things that could go wrong are vast and may include but not limited to asking the wrong question, not asking questions, data bias, measurement errors, insufficient data coverage, not collecting the right variables, not collecting enough observations, collecting clustered samples, unbalanced data, filtering out data without reason (outliers), clipping data (outliers), relying on automatic feature selection, including irrelevant variables, excluding relevant variables, geological interpretation, changing context, blindly following best practice, splitting small data sets, subsetting large data sets, using the wrong tool for the task, insufficient budget to complete the analysis, not allowing enough time for testing and experimentation (the science), focusing too much on building the model (the engineering), not learning from the data, our assumptions, our preconceptions, and our skill. This paper will explore the question of how training regression models to predict rock density are affected by gaps in the data (missing observations and missing variables). What could possibly go wrong?

May 24, 2023

By A Weston

Northparkes Mines is a joint venture between Rio Tinto and the Sumitomo group and is operated by Rio Tinto to produce copper concentrate from ore sourced from open cut and underground. Underground ore is mined with an owner operator workforce using the block cave method from the E26 deposit, with the first lift of the cave now completed. Development of the Lift 2 block cave commenced in March 2001 using a contract workforce. The Lift 2 Project required the mining of 14 700 m of decline and lateral development to establish a new mining horizon at the 9450 level and to develop two new conveyor declines. Also included in the scope was the excavation of a Crusher chamber to house the jaw-gyratory crusher. This paper describes the excavation of the hydroset chamber and orepass that sit immediately underneath the Lift 2 Crusher chamber. It includes risk assessment, planning, development of method statements and standard operating procedures, through to the excavation of the orepass and the installation of ground support in seismically active ground. There was a major ground failure in the backs of the conveyor feeder chamber during its excavation, which affected the excavation of the orepass due to its proximity to the breakthrough site.

Jan 1, 2005