Search Documents

By Garry Biles

The Eskay Creek Mine is a high-grade gold and silver underground mine in northwestern British Columbia. The mine started operations in late1994. For the first three years, ore was crushed to -50 mm(-2 in.), blended to satisfy smelter terms and shipped to smelters in Japan and Canada. Preliminary evaluations indicated that a complex metallurgical facility, requiring a large capital investment, would be required to recover the precious and other economic metals. So markets for raw ore were identified and underground mining and ore transportation operations began at a production rate of 300 t/d (330stpd).

Jan 1, 2000

By H. Meseck

Dynamic pile test methods to establish the bearing capacity of driven piles were developed in the USA more than 20 years ago. In the Federal Republic of Germany, the first dynamic pile tests were carried out at the end of the 70's. Today dynamic pile tests are successfully used to establish the integrity and bearing capacity of driven and bored piles. The Institute of Foundation Engineering and Soil Mechanics at the Technical University of Braunschweig has developed its own method of measuring and evaluation for the execution of dynamic pile tests. The principles of the dynamic pile tests, the measuring and evaluation plant as well as the experience gained with it in the examination of cast-in-place piles are presented in this contribution.

Jan 1, 2010

By A. S. Macfarlane

Mineral resource management (MRM) practice has developed in South Africa over the course of the last ten years, with the purpose of integrating previously isolated technical functions into a value chain aligned, process organization, responsible for mine planning and optimization. The implementation of MRM within various companies has met with varying degrees of success, often resulting in incremental improvements in the planning process and, conversely, often becoming the scapegoat for poor delivery on plans and projects. The reason for this has been, amongst others, a lack of a suitable metric to define the success rate of MRM in the business at hand, in terms of its contribution to the bottom line. This paper is the result of extensive research by the author into this subject, which has resulted in the conclusion that economic value added is an appropriate measure that will lead to real optimization and value creation in mining companies, if applied within a new, holistic model

Jan 1, 2006

By Paul J. O'brien, George N. Neary

"The base metal mine at Buchans, Newfoundland, has been producing since 1928. For many years, mill tailings were disposed of by dumping into a nearby natural watercourse via which they were transported to Red Indian Lake and deposited. In 1965, environmental concerns prompted the establishment of settling ponds near the mine site. Effluents fed to these ponds included slimes washed from mine backfill sand and waste water pumped from underground as well as mill tailings. Dusting around the perimeter of the ponds was first observed around 1970and within a couple ofyears reached serious proportions. A program to alleviate the condition by developing a vegetative cover over the tailings was commenced in 1974. The work was successfully carried out and demonstrated that the large area of waste could sustain a permanent cover of grasses.This paper outlines the experimental work done at Buchans as well as the procedures followed and the problems encountered in carrying out full-scale revegetation."

Jan 1, 1981

By John E. Newby

The Brightwater Conveyance System consists of four tunnel segments in three tunnel con-tracts, comprising over 21,760 m (71,400 ft) of pressurized face tunneling in complex glacial and non-glacial soft ground conditions with a large proportion 60 m (197 ft) or more below the ground surface with up to 7 bars groundwater head. This resulted in unique technical challenges for establishing geotechnical baseline values. The process used to develop these baseline values and specifications with regard to the level of risk that the owner, King County, was willing to accept is described in this paper.

Jan 1, 2008

By W Donovan

Concern exists about the potential release of metals from the proposed mining operation at Martha Hill to the Ohinemuri River. Speculation on possible impacts is fuelled by the dearth of published data on existing metal levels not only for this river system but for streams throughout the Coromandel. At first sight this lack of data is surprising given the apparent interest in this subject and the fact that future mining activity in this region has been a possibility since at least 1979. That such a situation has arisen is not altogether unexpected given the difficulties faced by various organisations, including the mining industry, in determining metal levels which are generally acknowledged to be low. This paper presents data for a number of stations in the vicinity of the proposed operation; it explains the analytical procedures which were adopted and the rationale for them and relates the information which has been obtained to water quality criteria.

Jan 1, 1986

By B. Jago

From the perspective of metallurgical processing, gold ores can be classified into freemilling and refractory ores. Their extractive metallurgy is largely driven by mineralogical factors such as gold particle size, association with other minerals, coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of refractory gold minerals, and invisible gold in sulphide and sulpharsenide minerals. Gold process mineralogy helps address issues and problems related to gold ore processing. It is widely used as a predictive and trouble-shooting tool in gold ore processing, and provides useful information on process selection, flowsheet development, recovery improvement, and reagent consumption optimization. By combining classic mineralogical techniques, modern instrumental analysis, and diagnostic metallurgy, the mineralogist is able to balance the various types of gold occurrence in an ore.

Jan 1, 2006

By Bruce Jago, Joe Zhou, Chris Martin

"From the perspective of metallurgical processing, gold ores can be classified into free-milling and refractory ores. Their extractive metallurgy are largely driven by mineralogical factors such as: gold particle size, association with other minerals, coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of refractory gold minerals and locking of submicroscopic gold in sulfide mineral structure etc. Gold process mineralogy helps address issues and problems related to gold ore processing. It provides useful information on process selection, flowsheet development, recovery improvement and reagent consumption optimization. By combining classic mineralogical techniques, modern instrumental analysis and diagnostic metallurgy, the mineralogist is able to balance the various types of gold occurrence in an ore. This paper will provide a broad review of gold process mineralogy and the techniques available, and use case studies to describe how they can be used together, to provide the complete picture of gold process mineralogy in an ore. Examples will be used where applicable.INTRODUCTIONSince the early 1980’s, a great deal of work has been done in the characterization of gold ores, particularly refractory ores (Gasparrini, 1983; Wang, 1984; Hausen, 1985; Haines, 1986; Henley, 1989; Chryssoulis et al., 1990; Wang et al., 1992, 1994; Kojonen, 1999; Simon et al., 1999; Hong et al., 2000; Pals et al, 2003). Process mineralogy has come into its own as a respected inter-discipline in the fields of mineralogy and metallurgy – a subject that occupies an important place in both research and industry. As the free-milling gold ores are being depleted and more refractory ores are being discovered and processed, gold process mineralogy receives more and more attention from both the mineralogist and metallurgist as it helps to solve various problems encountered during gold ore processing. Steadily rising gold prices are also stimulating the need for gold process mineralogy due to the increasing demand for and production of the yellow metal. At SGS Lakefield Research, gold process mineralogy studies are conducted routinely on all types of gold ores and mill products to assist in a wide variety of metallurgical projects. This paper will briefly discuss the gold ore types and gold mineralogy, review the common mineralogical factors affecting gold extractive metallurgy and the techniques available to gold process mineralogy, introduce the procedure employed at SGS Lakefield Researc"

Jan 1, 2004

By Naoki Hosoya, Setsuo Maeda

This paper addresses establishment of an experimental system for measuring biodynamic response (BR) of hand-arm system at the NIIH in Japan. BR measurement system at the NIIH is nearly equivalent to NIOSH installed system. The feasibility of the system is examined through the apparent mass (AM) measurement of the empty handle and a set of calibration masses. Apparatus The grip force was measured by using the handle shown in Fig. 1. The handle has two force sensors (KISTLER, 9212) and one accelerometer (PCB, 356A12). A low-pass filter with 5 Hz cut-off frequency was used to the grip force from measured force signal. Figure 2 shows BR measurement system in this study. The push or pull force at the handle was measured by using the force plate (KISTLER, 9286AA). The grip force and the push / pull force were displayed on a monitor. The shaker (IMV, VE-100S) is used to vibrate the hand-arm system along the forearm axis (Zh direction) (ISO 10068, 1998; ISO 5349-1, 2001). In most situations force actions for operating tools are expressed by grip, push, pull and combined these actions. These actions can be simulated in the test system. AM was obtained by performing H1 estimator in the PULSETM system (B&K, 3109) and it is denoted at the one-third octave band center frequencies. [ ] Methods In order to investigate the reliability of the system, AM measurement of the handle was performed. It is assumed that the handle is rigid in the upper limit of adoptive frequency range in this study. This assumption is validated in AM measurement of the empty handle. A pseudo-random vibration in the frequency range of 10 to 1,250 Hz was used and its amplitude is 1.0 (m/s2)2/Hz with a flat power spectral density (PSD) in the experiment. Measured AM includes the mass effect of the measuring cap in a subject experiment. Compensated apparent mass AMc(?) is obtained by Eq. (1) 1-2.

Jan 6, 2006

By D. J. de Beer

South Africa had a late start with rapid prototyping (RP), with the first system being available in 1991. Up to 1994 only three systems were available in SA. Through active research participation from the CSIR and a number of universities, supported by technology transfer programmes and industry awareness workshops, adoption of RP technologies started to grow. Internationally, RP grew to the extent that several country-based member organizations were formed, and an initiation meeting of the Global Alliance of RP Associations (GARPA) took place during the SME Rapid Conference in Dearborn, USA in 1998. South Africa (SA) was invited under the auspices of the Time Compression Technologies Centre (TCTC) launched by the CSIR, and received an invitation to become a member of GARPA through the launch of a national, inclusive organization. The latter gave rise to a RAPDASA planning/launch meeting held at the University of Stellenbosch, which culminated in the first RAPDASA international conference held in November 2000 at the CSIR, and the election of a first RAPDASA management committee, also at the 1st AGM held during the conference. RAPDASA has been a pillar of strength since then, with an annual international conference being presented. As South Africa?s RP awareness grew through the RAPDASA and independent activities, so did the availability of RP platforms in SA.SA also became a benchmark for other countries/late adopters to follow, as slowly a position of following became a position of leading through innovative applications. The paper highlights SA?s development approach and history, together with the discussion of case studies in various fields. Contribution to the light metals industry will also be discussed. Keywords Rapid prototyping, additive manufacturing, product design, rapid tooling, rapid manufacturing, medical product development.

Jan 1, 2011

By Hebert Arias, Christian Mendoza, Mervin Tapia

El Complejo Pasco —ubicado en la Cordillera Oriental de los Andes de la sierra central del Perú, en el distrito de San Francisco de Asís, provincia y departamento de Pasco— está constituido por las unidades subterráneas de Atacocha y Porvenir, la operación a tajo abierto Glory Hole y tres proyectos brownfield ubicados en la periferia de la concesión. Tanto Atacocha como Porvenir son depósitos tipo skarn, con mineralización distal de Zn y Pb(+/-Au) y proximal de Zn+/-Cu, asociados a cuerpos hipoabisales de composición cuarzoandesítica y andesítica. Estudios y exploraciones recientes muestran otros tipos de sistemas mineralizados, como brechas tectónicas con reactivación hidrotermal tardía, un sistema epitermal de sulfuración intermedia en vetas, cuerpos irregulares, entre otros, y un sistema tipo pórfido. La Falla Milpo-Atacocha, de rumbo N-S, juega un rol importante, ya que los intrusivos (Stock Milpo y Santa Bárbara) que generan la mineralización del tipo skarn están controlados por esta falla. Existe otro tipo de mineralización, asociado al sistema NW-SE (Falla 13): un sistema epitermal de sulfuración intermedia. Este trabajo pretende mostrar los últimos avances en las interpretaciones metalogenéticas, producto de un intenso programa de exploración (aproximadamente 80,000 m. DDH / 2018) y de un programa de recategorización de recursos (a través de 60,000 m. DDH), que permitirá hacer posible una operación sostenible de 12 años.

May 22, 2019

By David S. Yantek

Miners in underground coal mines experience prolonged exposure to high noise levels, often with A-weighted sound levels in excess of 90 dB. Field tests have shown that the continuous miner conveyor is a dominant noise source. This paper will identify the most significant noise-radiating surfaces on the continuous miner tail section using vibration levels and surface areas to estimate the sound power levels of each surface. In addition, using five test cases, this study will examine the effects of three engineering noise controls on the surface-averaged vibration levels and average sound levels measured with four microphones located two meters from the tail section. The noise-radiating surfaces of the conveyor’s tail section include the top and bottom decks, the sideboards, and the flex plates. Emphasis is placed on the changes in the estimated sound power levels in the 500 – 2500 Hz 1/3-octave bands since this frequency range accounts for 80-85% of the sound energy near the tail section. The results show that the bottom deck is the most significant noise radiator for the untreated miner. Installing a coated bottom deck reduces the estimated sound power level radiated from the bottom deck by 11 dB and the average sound level by 2 dB. Using a coated tail roller results in reductions of the estimated sound power levels for individual components from 1 to 4 dBand reduces the average sound level by 2 dB. Coating the slide plate has little effect on both the estimated radiated sound power levels and the average sound level. The test results indicate that modifications that reduce flex plate vibration and reduce energy transfer from the tail roller into the tail section will be effective in reducing noise when combined with a coated tail roller and coated return deck.

By Beardsmore G. R

Geothermal gradients in the Gippsland Basin commonly exceed 35¦ C/km. Consequently models of thermal maturation may indicate exploration targets with an anomalous age/depth distribution. However regional geothermal models are constrained primarily by observations of surface heat flow. High geothermal gradients may simply reflect the presence of low conductivity coal beds within the basin. Heat flow data are not readily available for the Gippsland Basin. Normally special purpose drill holes are required to provide direct determinations of surface heat flow. These provide core samples for thermal conductivity and allow measurements of a stable geothermal gradient at least one year after drilling. Different indirect procedures are now required to provide estimates for the Gippsland Basin. Bottom hole temperatures can be used with suitable corrections to provide an indication of the regional geothermal gradient. However the corresponding thermal conductivities are more difficult to determine. Geophysical logs can be used to detect the major lithologies but detailed statistical analysis is required for numerical estimates. Complex mixing models are now suggested for geothermal surveys linking physical properties to variations in the mineralogy of each well. Allowing for low conductivity coal measures the data in the Gippsland Basin suggest values for heat flow consistent with regional trends in Australia. Interpretation is complicated by overprinting of transient thermal events with different time scales. Apart from the tectonics of basin evolution geothermal signatures may be complicated by regional ground water migration, the 'hot spot' trace associated with southward younging of Cainozoic volcanism, diagenesis, and basin refraction.

Jan 1, 1992

Estimating Breakage of Fine Ore Particles by Media in a Small Ball Mill Using DEM

Sep 13, 2010

By C. Musingwini, A. S. Nhleko

"Since the Global Financial Crisis (GFC) in mid-2008, capital has been more difficult to access. Mining projects must contend with projects from other industries for scarce capital. A decision to invest available capital in mineral projects requires that valuation be conducted to assess the expected return on the projects. The discounted cash flow (DCF) analysis is generally applied for the valuation of mining projects, whereby future cash flows are discounted to present value using an appropriate discount rate. The discount rate significantly affects the outcome of a valuation. Economic and finance theory provides tools to calculate discount rates. The discount rate must account for factors such as the risk and stage of development of the mineral project; hence the appropriate discount rate to utilize in a project is often a subject of debate.The discount rate is the weighted sum of the cost of debt and equity. There are several methods for determining the cost of equity. This study considers the commonly applied Capital Asset Pricing Model (CAPM) and Gordon’s Wealth Growth Model because of their simplicity and availability of parameters required to estimate the cost of equity. This study explores how differences in the cost of equity obtained by these two methods can be explained for a mining environment. Data for empirical analysis were collected from the I-Net Bridge, McGregor BFA, and Bloomberg databases. It was found that Gordon’s Wealth Growth Model provides better estimates of the cost of equity compared to the CAPM under depressed market conditions. Therefore, this research recommends that Gordon’s Wealth Growth Model be used to estimate the discount rates for mining projects during periods of depressed market conditions."

Jan 1, 2016

By C. J. Roos

Ground engaging tools are used to prevent damage to the main components of earth-moving equipment. These tools consist of everything from shovel teeth to replaceable drill bits to dozer wear plates. The costs of these ?consumable? items are increasing with the costs of raw materials. This project developed a tool to be used by Newmont Mining Corporation to predict the consumption of excavator teeth. This paper presents the results of a Montana Tech research project in which an equation was developed to predict excavator teeth consumption based on production rates and rock properties.

Jan 1, 2009

The projection of operating costs for mining, processing, and other site operating costs is an exercise which can be fraught with considerable peril. Not only are the physical characteristics of each mineral property unique, but a range of other factors will influence the consultant's approach to compiling cash flow estimates. This paper details some of the techniques used in estimating operating costs for use in order-of-magnitude cost studies and feasibility studies, and describes how to avoid common areas of difficulty. A series of examples relating to open pit gold mining and processing cost estimates illustrate these problems, and various corrective methods are described. The mining and treatment processes, and their associated cost elements, are followed in sequence of operation from on-going ore delineation through to disposal of the product. In addition the problem of assigning management, administration and overhead costs along with taxation allowances is addressed. Of critical importance is the application or possible misapplication of accrual procedures to the cost elements. In many cases such misapplication can introduce more pronounced errors with projects of short duration, such as the typical open pit/C.I.P. gold operation commenced in the last decade. The importance of providing verification of estimates depending upon the standard of the cost study is also investigated, and opinion is provided upon the minimum levels of verification necessary at various stages. Finally, the amalgamation of the various individual cost elements into a coherent whole is reviewed.

Jan 1, 1990

By T. Celik, B. Genc, C. Musingwini

"Mine planning software continues to be an important factor when it comes to the development of the South African mining industry. To contribute to this development, a new methodology to define and measure mine planning software utilization in the South African coal mining sector within an evolving data-set framework was developed. An initial data-set showing the mine planning software providers, their corresponding software solutions, as well as the software capabilities and information on the number of licences was collected and compiled in 2012 in an online database for software utilized in the South African mining industry. Details of the database development and implementation were published in the Journal of the Southern African Institute of Mining and Metallurgy in 2013. In 2014 the data-set was updated with additional and new information.In this paper, using the 2012 and 2014 time-stamps, a methodology for estimating the software utilization is developed. In this methodology, three variables: commodity, functionality, and time factor are used to define and measure the software utilization in order to ultimately inform decision making strategies for software utilization. Utilization in the coal sector was measured according to six different functionalities, namely Geological Data Management, Geological Modelling and Resource Estimation, Design and Layout, Scheduling, Financial Valuation and Optimization. The methodology is useful for stakeholders reviewing existing software combinations or intending to purchase new software in the near future and wanting to estimate the comparative attractiveness of a certain software package. These stakeholders include mining companies, consulting companies, educational institutions, and software providers. The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand."

Jan 1, 2016

By T. Celik, B. Genc, C. Musingwini

"This paper discusses a new methodology for defining and measuring mine planning software utilization in the South African gold mining sector within an evolving data-set framework. An initial data-set showing the mine planning software providers, their corresponding software solutions, as well as the software capabilities and information on the number of licences was collected and compiled in 2012 in an online database for software utilized in the South African mining industry. Details of the database development and implementation were published in the Journal of the Southern African Institute of Mining and Metallurgyin 2013. In 2014 the data-set was updated with additional and new information. Using the 2012 and 2014 timestamps, a methodology for estimating the software utilization was developed. In this methodology, the three variables of commodity, functionality, and time factor were used to define and measure the software utilization in order to ultimately inform decision-making strategies for optimal software utilization. Using six different functionalities, namely Geological Data Management, Geological Modelling and Resource Estimation, Design and Layout, Scheduling, Financial Valuation, and Optimization, utilization in the gold sector was measured. This paper presents the methodology employed for measuring the mine planning software utilization. The methodology is useful for stakeholders reviewing existing software combinations or intending to purchase new software in the near future and who want to estimate the comparative attractiveness of a certain software package. These stakeholders include mining companies, consulting companies, educational institutions, and software providers. The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand."

Jan 1, 2015

By Yukihiro Ishihara, Nanase Ogawa, Ming Lei

"Abstract In the Press-in Method, a static jacking force is used to install a prefabricated pile, while a reaction force is gained from previously installed piles. This piling technique has solved problems in urban piling construction such as noise and vibration associated with the piling work, restricted construction conditions due to the existing structures, and so on, since its emergence in 1975. Its applicability to hard ground conditions has been improved, with the development of press-in machines that involve augering or rotation. Besides, information such as time, penetration depth, jacking force and rotational (or augering) torque in piling work are automatically obtained. The concept of PPT, Pile Penetration Test, has been developed by the authors, to apply the obtained information to the processes of construction planning or foundation design. This paper highlights the technique to estimate SPT N value from data acquired in standard press-in (press-in without any auxiliary methods), press-in with augering and rotary press-in. The technique will be helpful in assuring the adequate embedment depth, re-selecting the adequate press-in machine or auxiliary method, and re-pricing the project objectively, particularly when a contractor encounters unexpected ground conditions.INTRODUCTIONThe Press-in Method is one of the piling techniques that use a static jacking load to install piles. It mitigates environmental problems of noise and vibration that have been associated with other conventional piling techniques.It is also featured by its spatial efficiency; since a ‘press-in’ piling machine gains a reaction force from the previously installed piles, there is no need of bulky weights that will occupy a large space. This feature is emphasized in the piling system in Figure 1, where a press-in machine and its related devices are all positioned and ‘walk’ on top of the pile wall.Its applicability to hard grounds has significantly been improved, with some newly developed piling machines that involve augering or that install tubular piles with teeth on the base by applying axial load and rotational torque at the same time."

Jan 1, 2014