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By Shemek Oginski

The 5 km (16,194 lf) of 6.1m (20 ft) diameter TBM driven tunnel built by the J.F.Shea Co. will serve as sewage overflow storage. The TBM tunnel and four connecting tunnels excavated by drill and blast methods in hard granite will remain unlined. Based on the Geotechnical Baseline Report (GBR), the Contract documents provided a design with no required pattern of rock bolts, no probing, no pre-excavation or consolidation grouting, and lastly, no final lining of the tunnels was deemed necessary. This paper will provide a general overview of these topics with the emphasis on the actual ground conditions encountered versus the projected conditions provided in the GBR and how the GBR reflected the design of the project. Proposed modifications to the temporary and permanent ground support will be presented and the necessity of probing and pre-excavation grouting will be evaluated.

Jan 1, 2005

By B Mobilio, M Secheny, J Rachocki, G B. Sharrock, A Jäger, J L. Lett, I Brunton, G W. Capes

Establishment of the Cadia East Panel Cave Stage One (PC1S1) commenced with the firing of the first bell in early 2011. Production began with the completion of the undercut in May 2014. PC1S1 used a post-undercut composed of 114 drawbells covering a footprint area of 73 438 m². The extraction level is located at a depth of 1200 m below the surface and is based on a 32 × 20 m El Teniente layout. Cave establishment required the construction of multiple conveyor drifts, a large-capacity jaw-gyratory crusher and ancillary ventilation and pumping infrastructure. Preconditioning via hydraulic fracturing and blasting was implemented at various locations of the cave block height. This paper presents an overview of the key learnings from the commencement of undercutting to surface breakthrough, including rock mass classification and modelling, stress measurements, preconditioning, numerical modelling and cave monitoring.CITATION:Lett, J L, Brunton, I, Capes, G W, Jäger, A, Mobilio, B, Rachocki, J, Sharrock, G B and Secheny, M, 2016. Undercutting to surface breakthrough – Cadia East panel cave (stage 1), in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 65–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Thierry Bernard, Phillipe Cappello, Jean Marc Laboz

"The main reasons of the emergence of electronic detonators are linked to:-Local urban development close to mining operation sites-Environment regulations"

Jan 1, 1995

CrusherMapperTM - A New Tool for Crusher Condition Monitoring The efficiency of mineral processing plants is entirely dependent on the availability of the plant equipment critical path. This typically concerns comminution circuits consisting of primary crushers and primary grinding mills. Crusher and mill availability are determined by the frequency and duration of maintenance shutdowns, which are primarily driven by the need for replacement of sacrificial liners. The change of crusher and mill liner shape over respective life cycles also strongly affects plant efficiency. It is therefore highly desirable to accurately monitor the condition of mills and crushers in order to optimise plant efficiency through maximised availability and targeted liner shape. Traditional comminution liner and other production parameter condition monitoring has been attempted through ineffective methods which prevent satisfactory management of crusher and mill maintenance and reduce operational control. This situation has recently dramatically improved for grinding mills through the development and commercial deployment of MillMapperÖ, a technology based on three-dimensional laser scanning data and dedicated software (Franke, Lichti and Stewart, 2006; Franke and Lichti, 2007; 2008; Franke, 2008; Franke, Redman, Johnson and Michalek, 2009). At the time of writing in late 2009, MillMapperÖ is in successful use at a rate of approximately 170 surveys and associated reports per annum at processing plants in Australasia, South America, North America and Africa. This paper presents the introduction of CrusherMapperÖ, the MillMapperÖ equivalent for crushers. CrusherMapperÖ also utilises high density, high accuracy laser scanning data, and features dedicated algorithms for three-dimensional monitoring of wear on crusher concaves and mantles. This facilitates the detection of wear hot spots or zones or localised liner failures, and accurate forecasting of reline tonnages and dates. It also for the first time provides the means to establish optimised concave and mantle shapes in order to achieve production targets. In contrast to any other currently utilised condition monitoring method, CrusherMapperÖ data collection can occur remotely and does not require any shutdown or crusher isolation. This method therefore does not interrupt crusher production while at the same time eliminating any confined space risk normally associated with taking measurements inside the crusher cavity.

Sep 13, 2010

By William M. Camp

An extensive design phase testing program in which 10 piles and 2 drilled shafts were instrumented and statically load tested to failure, was undertaken to establish relevant foundation design parameters for two bridges in Charleston, South Carolina, USA. The bearing strata at both test sites was a calcareous, overconsolidated, firm to very stiff, slightly sandy, clayey silt (locally known as Cooper Marl). Confirmation dynamic and static loading tests on production piles indicated only 50 to 60% of anticipated pile capacities; including consideration of time effects. Supplemental subsurface explorations did not reveal any significant variations in marl properties. Ultimately, 22 static and 75 dynamic tests were performed on production piles for a 2 mile section of the project. Pore water pressures in the marl were also monitored during and after pile driving. A study of unit skin friction in the marl as a function of time revealed two distinct trends: piles driven in areas with a sand overlaying the marl gained more capacity significantly faster than those driven through a clay or silt. Although the insitu marl properties are apparently similar across the site, the material immediately above the marl evidently has a large effect on pile capacity. This effect of overburden on pile capacity was verified by testing piles over a period of two years.

Jan 1, 1993

By M. Zhang, M. Menabde, R. Middleton

Whilst mine planners almost universally assume deterministic forward commodity prices when undertaking valuations of mining projects, historical data well demonstrates that those prices are quite volatile. This paper seeks to understand and quantify how this forward price uncertainty will impact mining project valuation. This paper will also present a way of computing an upper bound on the expected Net Present Value (NPV) of a mining project given forward commodity price uncertainty.

Jan 1, 2007

By Kazimierz St. Sztaba

"Mineral processing – the first technological stage of utilization of mineral – has a very long history. In particular, it revealed and reveals the continuous development and perfection of technological operations and process organization, comprising not only new design solutions and exploitation procedures but also, for example, perfected systems of control and automation as well as methods of process description and result evaluation. During the recent decades the attitude to mineral raw materials was clearly changed, both to the primary ones, i.e. minerals, and to the secondary ones, such as side products and waste, formerly considered useless and at present more commonly used. This results both from the appearance and growth of demand for more and more numerous components of mineral raw materials and also from the necessity of protection of natural resources, constituting the integral part of the system of sustained development of society.These circumstances, and especially the requirements concerning gaining some components which cannot be separated by means of “classical” (used for many years) technological processing operations and aiming at increasing the technological procedures, evoked the necessity of using new technological solutions, applying other basic operations, also the ones characteristic so far for other processing technologies, i.e. chemical, biotechnological and others.These development tendencies, in general commonly perceived, allow us to formulate an opinion that the former state of tasks and processes of mineral processing is being transformed into a qualitatively new form. It can be assumed that this process was signaled by a situation in which, due to the growing role of technological operations based on physicochemical phenomena (flotation and others), magnetic and electrical ones, etc., one should have observed that the former term of “mechanical processing” became inadequate for the real content of the notion determining the discussed stage of mineral utilization, so the adjective “mechanical” disappeared in most languages."

Jan 1, 2003

These proceedings consist of an introduction and four descriptive papers. The first paper is an update on fire protection for large haulage vehicles, the second paper is concerned with improved visibility systems for large haul- age vehicles, the third paper is on improved ladders for large haulage vehicles, and the fourth paper is concerned with large haul-age vehicle operator training systems.

Jan 1, 1980

By Dwight Newman

This paper discusses the author?s work identifying international law norms of consultation with indigenous communities and poses a potentially counterintuitive argument that corporate stakeholders? interactions with indigenous communities may have effects on the content of those norms. The claim is counterintuitive because the international law of pertinence is customary international law, which arises from consistent state practice and opinio juris (a belief by states that they are acting in a way they are legally bound to do so). Customary international law traditionally has no reference to corporate conduct per se. The paper first surveys several sources on developing international law on consultation obligations. Then it references the impact these norms can have on corporate stakeholders in industries like mining. Then, it poses an argument as to an economic ratcheting effect that can occur through various agreements between corporate stakeholders and indigenous communities that then feeds through into international law via several mechanisms. The consequences for mining companies are diverse and include the possibility that conduct by one company can have longer-term implications for the obligations of other companies and, indeed, of states. The effects will differ in the context of different competitive environments and may actually have effects on the economics of different competitive models.

Aug 1, 2013

A Seismic Hazard Scale (SHS) has been developed to provide a practical seismic hazard assessment tool applicable to mine site personnel. It has been applied to seismic data sets from numerous Western Australian mines. The SHS is applicable when quantifying seismic hazard on a mine wide scale, on a mining block scale, and on a local cluster-by-cluster scale. Spatial mapping of variations in seismic hazard is a particularly powerful application of the scale. The SHS is sensitive to temporal increases in seismic hazard. It has also been shown that the SHS can be applied to estimate seismic hazard when seismic monitoring data are not available. The SHS is a simple derivation of the Gutenberg-Richter relation. There are assumptions and limitations to the SHS that need to be considered when applying it to mine seismicity data.

Jan 1, 2004

By R. J. McLeod

"CONTROL STRATEGYThe Lake Dufault Division of Falconbridge Copper Limited has been concentrating a complex copper zinc ore since late 1964. An ARL X-ray on stream analyzer was installed in 1966 for process control. A Digital Equip-ment Corporation PDP8 was added in 1968 for more complete control. To improve the system the computer was exchanged for a Moded PDP-81 in 1971.The new computer is time sharing with 8K core memory and 32K disc storage. A new interface was installed to accommodate 14 X-ray streams and additional analog signals for process control. The system gave us additional capacity and flexibility to make changes in operating programs and control strategy while on line. As the computer is used for process control a modified focal language was chosen as the operating language for ease of operation. This language is more suitable for process control than for statistical work.The main components of the control system are(a) Computer(b) Interface(c) Production Control X-ray Quantometer(d) Teletype terminals(e)Reagent feeders(f) Sample SystemThe operation of the system consists in the computer selecting the various streams to be analyzed by a PCXQ Quantometer. When the flowing sample is presented to the X-ray the intensities of the various elements are read by the computer from analog to digital converter, the assays are then computed. From the tonnage and assays the computer is programmed to determine the amount of reagent added to various parts of the circuit. The computer drives the feeders via the interface for the required amount of reagent. After following a certain sequence the computer prints out the performance and control data on an ASR35 Teletype. The data is printed out approximately every seven minutes. Any des¬ired changes in the program or strategy can be made during operation via an ASR33 Teletype connected to the computer."

Jan 1, 1973

By F. Taylor Ostrander

Some countries are infinitely poorer than others in mineral resources-despite the perfect equality of their political leaders ambitions. Compare the mineral poverty of Kenya and Tanganyika with the riches of Katanga Province and Northern Rhodesia. Compare Paraguay with Chile, There never has been any equality in the distribution of nature's wealth. Minerals cannot play any role at all in economic development where they don't exist, and there are bound to be differential rates of economic development where there are basic differences in the wealth of mineral resources available. Africa is my principal area of interest and I know that there is an unfortunate but widespread misconception about Africa's "vast mineral resources, "its "untapped mineral wealth." Why is it untapped? Why is it undeveloped?

Jan 1, 1963

By E. F. Divers

This Bureau of Mines report describes the results of a program to develop small, rugged mechanical dust collectors (scrubbers) with high dust collection efficiency and low energy comsumption for controlling dust in coal mining operations. All of the scrubbers described are similar in configuration and are powered by 6-hp, 2,000-ft3/min vane axial fans. Air pressure differential is less than 6 inches water column. Height of the scrubbers? including fan is less than 14 inches, width is less than 16 inches, and length is less than 45 inches. The flooded fibrous-bed scrubber achieved respirable (less than approximatey 7 µm) dust collection efficiencies of 95 percent. The small-diameter-cyclone scrubbers showed about 92 percent efficiency and can be best where excess water is a problem. The wetted brush scrubber showed 88 percent efficiency at low cost, and the wetted fan scrubber showed a slightly lower efficiency (87 percent) but offered the smallest size and cost. A suitable water droplet eliminator is described.

Jan 1, 1978

By P. J. Bhonde, R. D. Angal, R. H. Tupkary

Manganese imparts numerous beneficial mechanical properties. Hence it finds extensive application in iron, steel and non-ferrous sector. Prevalently, it is incorporated in the form of master alloys i.e. 'ferromanganese'. In India, ferromanganese is mainly the inexpensive and paramount source of availability of manganese. Various conventional and non-conventional techniques of ferromanganese production have been adopted in past and present. However, these techniques have demerits viz. high refractory, energy consumption, losses of valuables in slag and fumes. Also geographical co-ordinates of the plant restricted the manufacturer to prefer an appropriate process. Accordingly, the industrially implemented methods had reliance on availability of infrastructure, energy, mineral resources, grade of raw material, outlay of labor, environmental compatibility of technique etc. In view of the liberalized economy and the gap scenario in the supply and demand of ferromanganese, the authors felt it indispensable to explicitly bridge up this vacuum by initially designing a simple energy conserving, eco-friendly, low capital investment technique for decarburization of ferromanganese. Measurement of the data involved studying the impact of rate governing parameters on the process kinetics. This laboratory scale investigation is expected to escalate the Mn/C quotient of high carbon ferromanganese. Key Words: ferromanganese, carbon, carbide, decarburization, rate, kinetic

Jan 1, 2007

By Hirokazu Narita

Keywords: solvent extraction, precious metals, thiodiglycolamide, rapid separation, hydrochloric acid The solvent extraction of some precious metals (Pd(II), Pt(IV), Rh(III) and Au(III)) and base metals (Fe(III), Cu(II) and Zn(II)) in a hydrochloric acid solution was carried out using N,N'-dimethyl-N,N'-dioctyl-thiodiglycolamide (MOTDA) dissolved in the mixed solution of 80 vol-% dodecane and 20 vol-% 2-ethylhexanol. The extraction percentages of Pd(II) and Au(III) in the 0.01 M MOTDA-1.0 M HCl solution system are 99.6% and 71.8%, respectively. In contrast, the other metal ions are hardly extracted under the studied conditions. The Au(III) and Pd(II) extracted in the organic phase are easily back-extracted with a 1.0 M thiourea/1.0 M HCl solution. A comparison with the conventional extractant for the Pd(II) separation, di-n-hexyl sulfide (DHS), revealed that the extraction rate of Pd(II) with MOTDA is much greater than that with DHS. The extraction percentage reached over 99% in less than a 2 min contact time. However, in the DHS-Pd(II) system, it takes about 240 min to achieve the extraction equilibrium. Furthermore, MOTDA can quantitatively extract Pd(II) up to half the molar amount of MOTDA. Therefore, MOTDA is a promising extractant for Pd(II) from the HCl solution after the removal of Au(III).

Jan 1, 2005

In spite of the many contributions that have been made to our knowledge of the creep properties of polycrystalline lead, the precise influence of various factors on these properties is not yet fully understood. Indeed, the position is such that several important points in connection with the creep of lead are a matter of controversy. This has been brought about largely by the fact that, in the case of lead, the changes that are produced in the creep behaviour by slight variations of such factors as the purity, grain sizeand previous treatment are out of all proportion to the magnitude of these variations.In order to study the fundamental properties of lead as related to creep, and so gain a more enlightened perspective with which to consider the creep of lead in general, the work that is described in a series of papers, of which the present paper is the third part, has been carried out. It deals with lead in the form of single crystals.It has been shown (1) - (3) that the grain boundaries as well as the actual grains play a part in the creep of polycrystalline lead. The present work, by eliminating grain boundaries, enables the. contribution of the grains themselves to the process of creep, in other words, crystalline creep, to be studied effectively.This object was, possibly, the major one in this work.

Jan 1, 1940

By Donald R. Johnson

Apparatus providing simultaneous differential thermal analysis, thermo-gravimetry, and evolved gas analysis, has been developed by the Bureau of Mines specifically for thermal study of oil shale and other solid, natural fuels. The apparatus is described in detail, and simultaneous analyses on a single sample of an oil shale mineral, nahcolite, and a thermal analysis demonstration compound, calcium oxalate monohydrate, are presented to demonstrate the instrument's capabilities.

Jan 1, 1970

By M. Yavuz

Multiple Criteria Decision Making (MCDM) is one of the most considerable branches of Operation Research. MCDM refers to making decisions in the presence of multiple, usually conflicting, criteria. The problems in MCDM are classified into two categories: Multiple Attribute Decision Making (MADM) and Multiple Objective Decision Making (MODM). However, very often the terms MADM and MCDM are used to mean the same class of models and mostly confused in practice. Usually, MADM is used when the model cannot state in mathematical equations and otherwise MODM is used (Hwang and Yoon, 1980). Decision-making (DM) is extremely important stage in Mining Engineering like other engineering branches. Every mining engineer makes several decisions in daily mining applications. Most of the decisions made by mining engineers are completely instinctive according to their past experiences and there is not any DM method applied in DM process. Analytic Hierarchy Process (AHP) is one of the well-known techniques solving the decision problems. The AHP is very simple, and understandable method especially non-numerical data considered in DM process. Equipment selection is one of the prominent problems of mining engineering. Mining engineers have to make difficult decisions when equipment selection stage. As the decisions in the equipment selection have radically influenced the economic life of any mining scenario, these are considered as complex MADM problem. So, the decision maker can evaluate the subjective criteria in the problem of equipment selection. The decision maker wants to maximize more than one objective criterion for equipment selection stage. Among the number of alternatives, the most suitable equipment must be selected according to objectives and alternatives. MADM applications can help the decision maker to reach the optimal solution for the equipment selection. In the mining industry, MADM methods can be applied for the equipment selection because it is a process that includes subjective and objective criteria affecting the selection of equipment among the alternatives.

Jan 1, 2007

The OptiPit® software program is developed based on expertise gained at the Colorado School of Mines (CSM) using Mixed Integer Linear Programming (MILP) techniques. This program has been developed to satisfy the need in the mining industry for a multi-time period schedule and cutoff grade optimization tool that handles large scale open pit and underground mining operations involving many dumps, stockpiles, complex processing options and blending requirements. The current software (or earlier development versions) has been beta tested and used on various large scale projects within Placer Dome Inc., Newmont Mining Corporation, and Phelps Dodge Corporation since 2003. Through the use of this software, these companies experienced additional value creation by optimizing mine sequences, cutoff grades, material process flows and stockpiles under complex operational and processing constraints. This paper will present simple case study results to demonstrate the power of OptiPit® when used as a cutoff grade optimization tool. Furthermore, the paper will show, by example, how significant the difference in the Net Present Value (NPV) of a given project can be, depending on whether results are obtained by way of cutoff grade optimization using OptiPit®, or by using traditional breakeven cutoff grade approach.

Jan 1, 2007

As mining operations in the United States (US) have become more productive, controlling the dust exposure of mine workers has become more challenging. In response, US mining operations are applying basic controls at elevated levels and are looking to emerging control tech­nologies in an effort to better control airborne respirable dust levels. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) conducts research to develop and/or improve control technologies that reduce the respirable dust exposure of workers in underground coal mines. The goals of this research involve optimizing the use of water sprays and ventilating air, as well as, evaluating emerging control tech­nologies. An overview of dust controls typically utilized in underground US coal mines will be provided. An update on ongoing PRL research efforts that are evaluating new control technologies will also be presented.

Jan 1, 2008