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By A. Berckmans

The key variables in the financial analysis of a mining project include the metal price and the quantities of ore and metal. In general, if the metal price drops, the cutoff grade is increased so as to increase the average grade. This causes recovered tonnages of ore and metal to drop. Discussion is presented of the development of a new method to evaluate the relationship between the cutoff grade, z, the ore tonnage above cutoff, T, and the metal quantity above cutoff, Q. Detailed information is provided on the QTz curves for lognormal and inverse gaussian (Sichel's) distributions. Both these distributions are used as models for the grades in different types of ore bodies, and they are both T-symmetric. The geometry of the QTz curves is simplified, making it easier to work out the impact of minor variation in the parameter values for each distribution

Dec 1, 1996

By Mark R. Svinkin

Construction vibrations may adversely affect surrounding buildings and their effects range from human discomfort and disturbance of sensitive devices to visible structural damage. There is no unique conclusion regarding the effect of construction vibrations at every site. Measurement is usually made to monitor vibrations and control them with the vibration thresholds for disturbance of sensitive objects as well as damage to structures. To prevent potential litigation and mitigate the vibration effects on sensitive devices, people and structures, it is necessary to manage and minimize vibration problems before the beginning of construction activities or installation of vibrating machine foundations, and during construction. Pre-construction damage survey and engineering vibration investigations, including the prediction of anticipating vibrations, have to be made at most construction sites in advance of construction activities. Vibration monitoring and control have to be provided during construction. The instrumentation feedback of vibration prediction, monitoring and control provide the basis for choice of measures to prevent or mitigate vibration problems and settlement damage hazards.

Jan 1, 2002

By C. Melvin Lepper

The Bureau of Mines has developed an improved earth resistivity field system which employs a novel technique for obtaining null measurements. The instrument is designed to operate reliably in high-noise environments such as those found in the vicinity of operating mines. The system consists of a low-frequency transmitter, a sensitive receiver and an external battery pack, each in its own case to provide protection from the elements. The receiver and transmitter units have self-contained recharge-able batteries to supply power to the circuitry and separate built-in battery chargers that operate on standard 115 Vac power. The system is portable and simple to operate. Measurement accuracy, reliability, and dynamic range are superior to most commercially available equipment even though less time and effort is required to make null readings. Unlike some commercial systems, long integration times are not required to enhance signal-to-noise ratio in areas of high background noise.

Jan 1, 1974

By Peter Kowalczyk

Magnetic surveying and map production is well established in land based mineral exploration. Magnetic data are routinely used to map geology in covered terrains, to estimate the depth to basement in overburden covered areas, and to identify altered zones, mineralization, bedding attitudes, and fault networks both regionally in map view, and through interpretation to depth in 3D. Best practices for magnetic survey methods and magnetic interpretation exist in all areas of land based geophysical survey methodology - mineral exploration, hydrocarbon exploration, geological mapping, archeological mapping, and in military applications. At sea, and particularly under the sea, sophisticated magnetic surveys are being done, but it can be argued that these are primarily in niche applications, for example in naval mine-hunting and UXO applications. Magnetic data is not normally collected on AUVs and ROVs conducting mapping and hydrographic survey operations. OFG has developed physical and mathematical calibration routines so that magnetometers can be mounted directly onto AUV and ROV bodies where significant heading errors and magnetic gradients exist. This simplifies the routine deployment of magnetometers on AUVs and ROVs for mineral exploration and other magnetic survey applications without the need for towed bodies, ungainly mounting frames, or degaussing of the survey equipment. Our experience shows that magnetometers can be operated routinely on AUVs and ROVs and that with careful processing useful maps can be produced routinely at low cost.

Sep 1, 2014

By D. Brosnahan, J. Gathje

Newmont Metallurgical Services (NMS) recently acquired a Scanning Electron Microscope (SEM) with a JKMRC/FEI Mineral Liberation Analyzer (MLA). With the MLA software package, raw particle image and X-ray data can be converted into particle mineral maps and bulk and liberation data can then be calculated for minerals of interest. This type of quantitative mineralogical data can then be used for a wide variety of applications. Ore characterization with MLA can be carried out for existing or processing plants in development. MLA characterization of laboratory test products provides valuable liberation information that assists the research metallurgist in better planning and developing process treatment options for various ore types. This paper describes the use of MLA characterization in a copper flotation test program where the use of various testing options for arsenic depression was being evaluated.

Jan 1, 2007

By Dick T. Atkinson

This report describes the Foster-Miller program that designed, developed, built and tested an automatic, remote control mine car coupler. This new coupler gives the motorman the capability to selectively couple and uncouple cars from the locomotive, to transmit braking intelligence to the coupled car s and to determine if the trip is intact. Hazards due to derailment and runaway cars will be reduced as the brakes are automatically applied in any uncoupled car. Laboratory tests described herein have been completed on the coupler set. Applications include, but are not limited to, the unit train system.

Jan 1, 1976

By U. Paschedag, H. Bussmann

"Bucyrus manufactures the most comprehensive product portfolio of mining equipment worldwide. Its mission is to have a positive, lasting effect on our world. Bucyrus makes sustainable development a fundamental way of doing business through economic, environmental and social initiatives that support, educate and benefit our employees, customers, shareholders and other stakeholders. Our participation in GRI (Global Reporting Initiative), a network-based organization that has pioneered the most popular sustainability reporting framework will be discussed as well as examples will be given on each major field of engagement. Two examples from surface machinery are most fuel efficient haul trucks as well as the Highwall mining system which allows access to coal reserves which are lost not making use of this kind of system. Two examples from underground machinery are Bucyrus’ automated plow systems for the mining of medium and thin coal seams with minimum rock and Bucyrus’ intelligent CST drive system for high-powered armored face conveyors (AFCs) for efficient use of energy."

Jan 1, 2011

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher production rates and a resultant reduction in production cost. The Mining Innovation, Rehabilitation and Applied Research Corporation (MIRARCO) funded by the Canadian Mining Industry Research Organization (CAMIRO) has developed a methodology for safe rapid drift development within the underground metalliferrous mining industry in Canada According to industry survey, about 36% of drift development cycle time is spent on support installation. MIRARCO has developed a methodology for safe rapid drift development based on minimizing time spent on support installation. The methodology includes a critical review of the rockmass classification systems, examination of current support practices in the mining industry and civil tunneling, review of rapid drift development practice in South Africa, introduction of risk hazard procedures to account for material property variability and the development of a WIZARD as a quick decision-making tool for the implementation of the procedures. A comprehensive field data collection procedure was put in place and data collected from various mines to verify and calibrate the support selection rationale. The findings of the research programme resulted in the development of an improved rockmass classification system and showed that construction effects have drastic influence on support levels but is often not accounted for in assessing support levels. Stress effects and structurally controlled failures are the other important factors to take into account in rapid drift development. Three support classes were established for safe rapid drift development as No Systematic Support, Light Support and Strong Support. The support levels took into account cost, rate of installation and safety based on compatibility with ground characteristics. This paper describes the methodology for safe rapid drifting within the underground metalliferrous mining industry in Canada and highlights the key issues and major drivers behind their continued development at the Geomechanics Research Centre within MIRARCO.

May 1, 2004

By Larry L. Wischhoefer

The Automated Breathing Metabolic Simulator (ABMS) is a versatile machine capable of performing almost any physiologically appropriate respiratory simulation. The first ABMS was delivered to the Bureau of Mines by IBM in 1973. Since then efforts have been made to refine the systems and components which make up the ABMS including the Breathing Simulator Module (BSM), Gas Analysis Module (GAM), and Supervisory Controller (SC)-each of which are also capable of stand-alone operation. Since September 1980, Reimers Consultants has been testing and modifying the ABMS and its components in order to improve the equipment and to develop simulation criteria and parameters. Changes have been made to the Phase I Design Plan and Performance Specifications; future improvements based on current experience are recommended; and test results of full scale testing conducted by Reimers Consultants in November 1983 on several types of breathing apparatus are reported and illustrated.

Jan 1, 1984

By Badiozamani Khosrow

Introduction The mining industry has been using computers since the late 1950s. Despite this early start, the use of mine planning software is not a common practice in many operations. But the trend might be changing because of the availability of relatively inexpensive personal computers (PC). The introduction of these machines has generated unprecedented interest by mine managers to computerize their planning operations. However, some managers have become disappointed with the PC's lack of adequate software and the inability to handle the massive amounts of information required for modeling. This paper is an attempt to shed some light on the future of computers in the mining industry. It will examine: • historical progress in the computer industry, • future advances in the computer industry, • historical usage of computers in mining, and • future alternatives available to mining. Historical Progress The computer industry has come a long way since the first full-fledged electronic digital computer Electronic Numerical Integrator And Calculator (ENIAC) was built in 1946. This machine weighed more than 27 t (30 st). It contained 19,000 vacuum tubes, occupied 139 m2 (1500 sq ft), and could perform 5000 additions per second. By contrast, today's fastest, commercially available computer is the CRAY-X. It weighs less than 5 t (6 st), has no vacuum tubes, occupies less than 9 m2 (100 sq ft), and performs over 100 million operations per second. This is an incredible advancement in less than 40 years. One person commented on the rate of advancement in the computer industry. He suggested that if the auto industry had advanced at the same rate as the electronics industry, we could buy a Rolls Royce for $2.75 and it would run

Jan 9, 1984

By J. D. Findlay

The demands on development in London in recent years has led to the increasing use of top down construction methods in which there is a requirement to place steel columns to high tolerances into large diameter bored piles with deep cut-offs. A number of different proposals for the sequence of construction are being suggested. The tolerances requires for the steel columns are becoming increasingly stringent. This review examines a number of basic construction proposals and comments on the problems and solutions used by foundation contractors to provide the required foundations.

Jan 1, 1989

By Andrew K. hg` Officer, A. L. Griffiths, J. Andrew Hindmarch, Gert Wittneben

Durban Harbour in South Africa is one of the continent’s busiest ports however the harbor entrance is currently too small for the new generation of container ships. There-fore it is to be deepened and widened by the National Ports Authority in the near future. An existing immersed tube tunnel carrying major sewer, water and other utilities under the harbor first needs to be removed and replaced by a deeper 4.4 m ID ser-vices tunnel. Construction of the deeper tunnel saw the first use of a slurry machine in South Africa and was required to negotiate grades up to 20%.

Jan 1, 2007

The first principle one usually Learns about blasting is that cunpetence in this field is best gained by experience in making blasts rather than by reading a book or by listening to a lecture. The reason for this is that there are a large number of variables affecting blasting results and not all of these can be accounted for by a few rules or a few sets of equations. Even an experienced blaster when operating in a new area, may have to make one or two shots just to acclimate himself to the new conditions with which he is faced.

Jan 1, 1989

By Mohammad Irshad, Klaus Mussger, Harald Wagner

Despite the fact that the New Austrian Tunneling Method; NATM, has been used in the United States for the past 23 years or so, still considerable misconceptions exist in the industry about the nature of the method and its implementation. In the authors’ view its implications are usually not well understood. The paper provides an overview of the highlights of NATM usage over the past two decades to illustrate the point that NATM is now a well-established tunneling method in the U.S.A. Accordingly the thrust of this paper is on the more pragmatic aspects of the NATM technology usage as it concerns the Owners, Designers and the Contractors. Prior to examining the implications of NATM usage from the viewpoints of various stakeholders, it should be helpful to first briefly provide an overview of the history of the method as it was introduced and implemented on several key tunneling projects in the US, over the last 2 plus decades.

Jan 1, 2005

By Andy Cole

Barrick Gold recently implemented an oxygen roasting process to treat carbonaceous ore from its Goldstrike property in Nevada. One of the key project challenges was the design of the roaster gas cleaning system, which was driven by the requirements of a strict air permit and the need to achieve very high reliability. The roaster gas systems include multiple stages of wet particulate collection, a dual-alkali SO2 scrubber, mercury scrubbing, CO oxidation and NOx reduction. This paper describes the gas system, the influence of regulations on project implementation, and performance of the system.

May 1, 2002

By Masaki Kitazume

"Abstract The wet type and dry type of deep mixing methods have been developed and widely applied for on-land and marine constructions in Japan. The quality assurance (QA) of the methods has been usually carried out by unconfined compression test on field stabilized soil sampled by core boring in Japan. In some other countries, stabilized soil excavated by the wet grab sampling instead of core sampling is often subjected to unconfined compression test for quality assurance. There are several merits and demerits in each method, but few studies have been carried out to compare the stabilized soil strength of these two types of specimens to discuss their applicability to practical construction. The author has conducted a series of field and laboratory tests to compare the stabilized soil strength and discuss the applicability of wet grab sampling to QA for wet and dry types of deep mixing method.In this study, the wet grab sampling was carried out at two road embankment construction sites where the wet type and dry type of deep mixing were applied. The cement stabilized soil was excavated at the three depths by a wet grab sampler soon after the DM column construction. The test result is compared with the other test data in the previous study to discuss the applicability of the web grab sampling method for QA of cement stabilized soil.IntroductionThe Deep Mixing Method (DMM), an in-situ soil stabilization technique using cement and/or lime as a binder, is often employed to improve soft soils (Kitazume and Terashi, 2013). A variety of factors and their interactions affect the eventual strength of a deep-mixed column, while some of which are controllable (e.g. binder type and dose) by engineers while the others are not (e.g. soil types, ground temperature, etc.; Babasaki et al., 1997). In addition to laboratory mix tests, which in essence are a parametric study to estimate the influence of these factors on a particular soil’s strength, the quality assurance (QA) practice in Japan usually involves unconfined compression test on sampling cores from the stabilized columns after a given curing period. It has been recognized, however, that the ‘field strength’, or the strength of the retrieved core, quf is on average lower than the ‘laboratory strength’, qul, evaluated by laboratory mix test. Also allowing for the inevitable variability, existing guidelines (for example, PWRC, 2004 and CDIT, 2008) recommend the design quf /qul values of, for example, 0.5-1.0 for the CDM (Cement Deep Mixing; a wet-type technique, in which binder is added as slurry) and 0.2-0.33 for the DJM (Dry Jet Mixing; a dry-type technique, in which binder is added as powder)."

Jan 1, 2014

By Peter Zhang

Shield recovery in a longwall move is normally conducted from tailgate to headgate. However, if the face is wide and the immediate roof is weak, difficult conditions with considerable roof sag, excessive shield load, and local roof falls could occur as the shield recovery proceeds to the middle of the face, causing delays in shield recovery. The situation could be aggravated when a pre-driven longwall recovery room is employed. Alternatively, a bi-directional approach for shield recovery, i.e. shield recovery starting from the middle of the face towards both tailgate and headgate, can alleviate the roof sag significantly by quickly withdrawing the shields towards the lower abutment pressure zones at the headgate and tailgate sides. In this case, the bi-directional shield recovery approach was used in a longwall move for a 1450 ft wide face under weak roof conditions. Shields were successfully withdrawn within five days without experiencing significant roof sag. The time-dependent roof-to-floor convergence, shield pressure, and roof conditions were monitored during shield recovery. 3-D finite element modeling was conducted prior to longwall move to evaluate the difference between a uni-directional and a bi-directional shield recovery during a longwall face move. Vertical stress, yield zone in and around the recovery room, load on the shields, and convergence at the center of the shield canopy were obtained from computer modeling, and compared with the data from field monitoring. Finally, the advantages of the bi-directional shield recovery are discussed.

Jan 1, 2007

By C. Sawmliana, P. Pal Roy

Near-field blast vibration response of restrained pipelines either buried or exposed was studied during rock excavations at sensitive locations for Stage-II (4x500 MW) commissioning work in a super thermal powerplant of the National Thermal Power Corporation Ltd. (NTPC) of India. The existing running plant of capacity 1000 MW has many important installations including pipelines of varying diameters. These pipelines were very close to the blasting locations (mostly within 12m). Blast optimization and consequent monitoring of vibrations were carried out simultaneously for more than 250 experimental blasts conducted by the authors. This paper emphasized, particularly, on the safety of pipelines and their responses due to repeated blasting impacts. A few guidelines supported by theoretical derivations are provided for futuristic research.

Jan 1, 2001

By D. L. Murr, J. R. Jensen

Testing was conducted on a Minnesota Iron Ore concentrate with Cook Clay as a binder using compressive sheer mixing to enhance the performance of the agglomeration mechanism. The testing was conducted on a bench scale at the Midland Research Center the summer of 2004. Results of the test program will be presented that shows the impact of compressive sheer mixing had on the strength achieve in a green ball.

Jan 1, 2006

By A Giblett, R Dunne, D Appelhans

There are a number of hurdles that must be negotiated in order to design an effective gold ore treatment facility such that the expectations forming the basis of project economics are valid and can be achieved in practice. Selecting samples based on geometallurgical context, performing and interpreting testwork relevant to the selected process flowsheet are essential considerations towards achieving this aim. This paper discusses recent experiences in process development for free milling gold ores giving consideration to frequently encountered challenges of this nature.CITATION:Giblett, A, Appelhans, D and Dunne, R, 2013. Considerations for effective gold process development, in Proceedings MetPlant 2013 , pp 445-454 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013