Search Documents

Cambior has been involved in the Guiana Shield since 1990, first in Guyana and then in Suriname starting in 1994. This paper presents the history of Omai Gold Mines Limited in Guyana, where commercial production started in 1993 after an investment of US $150 million. In 1995, the mine was expanded in order to increase the milling capacity to 21,000 tonnes per day. After ten years of production, approximately 3 million ounces of gold have been produced. Building on this experience, Cambior became involved in Suriname with the Rosebel Project. A US $95 million pre-production program started in the fourth quarter of 2002, and the mine should be in commercial production early in 2004.

May 1, 2003

By F. O. Verret, A. McKen, G. Chiasson

Several grindability tests were developed over the years to design grinding circuits or optimize existing operations. Each test has its own strengths and weaknesses and it is imperative to select the proper test procedure(s) to meet project deliverables and minimize the risk of a project. Pilot plant testing of large bulk samples historically constituted the traditional approach for AG or SAG design, but was gradually replaced by small-scale tests. Nowadays, conducting grindability tests requiring only a few kilos of material on several samples is a more typical approach to grinding mill design. This paper summarises the requirements and deliverables of various bench-scale test procedures, their strengths and weaknesses, and cases where AG/SAG pilot testing should still be performed.

Jan 1, 2012

By Jorge Amaya

A critical aspect of long-term open-pit mine planning consists in computing a production schedule based upon a block sequencing strategy. Such a schedule should specify when and if blocks should be extracted in such a way as to maximize NPV, while satisfying wall-slope and production capacity constraints. It is well known that this problem can be modeled with integer programming (IP). However, integer programming is not used in practice because the size of typical block models makes such problems intractable to standard IP solvers. In this article we describe a scalable IP-based methodology for solving very large (millions of blocks) instances of this problem. We show that embedding standard IP technologies in a local-search based algorithm we are able to obtain near-optimal solutions to large problems in reasonable time. This methodology has been tested in several mine wide block models.

Oct 1, 2009

Accountability for profit realized or lost, and responsibility for continued safe operation are the main impetus behind operator training. Efficiency in operation enables production at lower unit costs. An inefficient operation eats profitability of the operation, creating short term losses, and also affecting longer term viability particularly when commodity prices fluctuate and competition erodes market share. Safe operation and efficient operation are ultimately conjoined entities which may not be able to be sustained without dual effort. Training is a very valuable tool to engage operations in adopting more efficient and safe practices. Training requires time, facilities and trainers. One novel way of minimizing both the trainers and the facilities is through the use of Computer Based systems. Included amongst this are Computer based equipment simulators, following an identical philosophy as flight simulators used for pilot orientation and training for different aircraft types.

Feb 1, 2008

By J. Paraszczak

ABSTRACT: Application of teleoperated and automated (or “autonomous”) mobile equipment in under-ground metal mines represents a promising avenue for overcoming some of the challenges facing the industry. This paper addresses the overall effectiveness of autonomous loading and haulage equipment compared with conventional human-operated machines. Factors affecting availability, utilization, and production rate are explored, and an emphasis is placed on some problems and risks not present in conventional human-operated systems, as well as on the character and criticality of autonomous equipment. The need for a more in-depth analysis of factors affecting overall autonomous equipment effectiveness is stressed; these factors should be taken into consideration at the stage of feasibility studies. The paper concludes with recommendations and directions for future research.

Jan 1, 2010

By Mikael Ramström

In 2002 Atlas Copco Rock Drills AB released the new RCS technology for all of its drill rig types. RCS opened the way for a new generation of computerized drill rigs based on modern, standard PC-computer technology. Drilling accuracy, information logging and reduction in manpower in some types and serviceability, have all taken a quantum leap forward when compared with previous generations of drill rigs. The RCS (Rig Control System) is modularised and distributed is accomplished by means of CAN-bus technology. This technology, which is well proven in automobile applications, forms the communication backbone of the rig. The modularity facilitates almost unlimited possibilities for the expansion and adaptation of drill rig functions.

May 1, 2003

By Jorge Amaya

A critical aspect of long-term open-pit mine planning consists in computing a production schedule based upon a block sequencing strategy. Such a schedule should specify when and if blocks should be extracted in such a way as to maximize NPV, while satisfying wall-slope and production capacity constraints. It is well known that this problem can be modeled with integer programming (IP). However, integer programming is not used in practice because the size of typical block models makes such problems intractable to standard IP solvers. In this article we describe a scalable IP-based methodology for solving very large (millions of blocks) instances of this problem. We show that embedding standard IP technologies in a local-search based algorithm we are able to obtain near-optimal solutions to large problems in reasonable time. This methodology has been tested in several mine wide block models.

Oct 1, 2009

By D. Milne

Laser profilometers exist for obtaining very accurate two and three dimensional profiles of joint surfaces. The application of this technology is not commonly applied to the collection of field data on discontinuity surface roughness. Rugged and portable field devices are not commonly used and the value of the possible field data that can be collected has not been well recognised. This paper reviews commonly used field techniques for assessing discontinuity roughness, discusses the value of this data and presents a new laser profilometer design for field application.

May 1, 2009

Abstract: ?The paper will review the perspective of Scotia Capital on financing mines, mining projects and mining companies in today's world of major increases in commodity prices, increases in capital and operating costs, shifts in foreign exchange rates, and increasing scrutiny of mining's social license ?Focus on debt financing alternatives Key Assumptions: ?Assume financing a mining asset (i.e. not an exploration play) ?Exploration is generally financed with equity ?private placements or public offerings on an idea

May 1, 2006

By Felix D. Klebe

Efficient, high volume, mine load out operations have evolved in recent years to include more sophisticated control systems that integrate with mission critical equipment such as weighing systems. Traditional weighing systems often involve static weighment of individual railcars and either manual or serial transmission of scale data to a database application. In recent years integration of railcar or truck weight data into a loadout operation via direct PLC or Ethernet communication between the weighing terminal and the loadout control system has been realized. Furthermore, use of dynamic railcar weighing where railcars are automatically weighed while moving has increased productivity in a variety of mining applications.

May 1, 2008

By Tom Brady

A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is to incorporate weak rock masses (such as are associated with operations in the Carlin Trend in Nevada) into existing design relationships. The original database that led to most of the empirical design relationships presently employed in hard-rock mining was derived from fair-to-good-quality rock. In this study, the relationship between weak rock quality and opening design (nonentry/entry methods) is being investigated. The common factor in all mines is a weak back or wall. This work attempts to provide tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2003

By Willie Manfrey, Richard Klimpel

This paper describes the effects of slurry viscosity on the selection-for-breakage and breakage distribution parameters in the wet grinding of cres. A series of experimental tests were run on laboratory scale ball mills. Slurry viscosities were modified by varying the solids/water ratio with and without the presence of selected chemicals. Very consistent and predictable correlations are shown to exist. The grinding parameters were calculated using a computerized back -calculation technique developed by Klimpel and Austin. Industrial scale circuit calculations and preliminary plant trial data suggest that considerable increases in throughput and/or fineness of grind can he achieved through the judicious use of chemical additives.

Jan 1, 1977

By Lisa J. Renaud

For generations, the mining industry has been committed to work toward developing new technology that can improve safety and increase production. Now with a more environmentally conscious society and tighter environmental regulations, a natural progression for the industry is to develop and take-on ?green? or environmentally friendly technologies. Not only could this improve the sustainability of operations, but could also reduce the long-term environmental impact footprint that is left behind. Algae represent a new frontier in research and development. As discussed specifically in this paper, algae, specifically microalgae, can be used for the production of biodiesel and other green chemicals by exploiting carbon dioxide and waste heat contained within process off-gasses. The potential positive benefits of this approach in terms of contribution to community and the environment are significant, and the focus of our research and development on microalgae production technology.

Oct 1, 2010

By Robert J. McCarthy

Many technologies have been adopted over the last half century for the haulage of material from open pit mining operations. Some of the technologies utilized include rail, off-highway trucks, conveyors, and slurry pipelines - each having its unique application and benefits. Over time, truck haulage has become the primary means of surface mine material movement, though recently it has been plagued by problems of tire shortages, high diesel fuel costs, labour shortages, and carbon emissions. This paper focuses on In-Pit Crushing and Conveying (IPCC) as a competitor to truck haulage which has the potential to solve many of these problems. An overview of the available technology is presented along with measures required to overcome perceptional if not physical barriers to implementing this technology in modern open pit mines.

May 1, 2011

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

By I. Bakry

Uncertainty is an inherent characteristic of construction projects. Neglecting uncertainties associated with different input parameters in the planning stage could well lead to misleading and/or unachievable project schedules. The objective of this paper is to present a new approach towards scheduling repetitive construction projects while accounting for uncertainty. The paper presents an algorithm that quantifies anticipated delays resulting from different sources of uncertainty in the form of fuzzy time buffers. Through inserting the time buffers in strategic places in a time schedule, the algorithm provides protection against those main anticipated delays. The presented algorithm comprises two integrated components, a scheduling component responsible for producing a basic Linear Scheduling Method (LSM) schedule with deterministic activity durations, and a buffer component that handles fuzzy buffers sizing and insertion. The presented algorithm offers four different buffer insertion techniques covering different cases of interrelations between successive activities. The algorithm is implemented in a spreadsheet application, which automates calculations, yet allows users to fine tune the algorithm to fit the project at hand. With a focuses on highway construction projects as an example of repetitive construction projects, this paper accounts for sources of uncertainty such as weather, site conditions, change orders and equipment related delays. A hypothetical case is studied and explained to further demonstrate how the proposed algorithm works.

Aug 1, 2013

By Yan Jie

The oxygen-enriched bottom-blowing continuous converting process for copper matte was recently developed by the China-ENFI Engineering Corporation. The first commercial plant based on this technology was successfully commissioned at the Yuguang smelter in China in March 2014. The present paper describes this new continuous converting process and compares technical characteristics with other continuous converting processes including: Kennecott-Outokumpu flash converting, the Mitsubishi Process, the Noranda Converter and TSL continuous converting. The bottom-blowing oxygenated continuous converter with competitive capex and opex costs is seen as an attractive alternative to the Peirce-Smith converter.

Jan 1, 2014

By Fathi Habashi

New technology first introduced by Nippon Steel Corporation at Kitakyushu in Japan in 1976 now used at a number of plants in other countries, known as dry quenching of coke, uses nitrogen in a closed circuit to avoid environmental emissions. In addition, heat is recovered in the form of steam, from the red-hot coke. In steel plants oxygen is used extensively and therefore by-product nitrogen from air liquefaction can be effectively utilized in this way.

Jan 1, 2014

By Steve Simard

Suite aux excellents résultats, obtenus avec la technologie des détonateurs électroniques dans des chantiers longs trous de grandes dimensions, nous avons décidé d?étendre cette technologie dans les ouvertures, dans le dynamitage de piliers et dans différents chantiers complexes. Cette technologie nous a permis d?effectuer l?abatage de chantiers avec un très grand nombre de trous sans détériorer le terrain. L?équation est bien simple avec les détonateurs électroniques, plus gros sont les dynamitages moins de fois les épontes se font ébranler, moins de blocs d?effondrement se retrouvent dans les points de soutirages entre les dynamitages et plus la fragmentation est meilleure. La flexibilité d?opération que nous avons obtenu avec les détonateurs électroniques est difficilement quantifiable, mais elle nous a permis de maintenir notre rythme de production mensuelle même avec certains chantiers complexes. Il est bien certain que l?utilisation des détonateurs conventionnels a encore sa place dans une mine conventionnelle comme Beaufor, mais l?utilisation des détonateurs électroniques a aussi sa place dans certaines situations spéciales. Pour terminer, bien que la technologie des détonateurs électroniques soit encore dispendieuse, nous pensons encore l?utiliser pour optimiser certains dynamitages et ainsi maintenir notre flexibilité d?opération.

Oct 1, 2004

By S. F. Dudka, T. Dang, M. L. Wong

Abstract - The Nui Phao W-F-Cu-Au-Bi deposit is located in one of the poorest regions of northern Vietnam. The deposit is currently undergoing a pre-feasibility study by Tiberon Minerals Ltd., with a view to developing what would be the largest WO3 mine and one of the five largest fluorite mines in the world. The project is being planned in close compliance with World Bank and national guidelines for environmental and social protection. Development of the mine is anticipated to bring the following benefits: remediation of serious pre-existing environmental conditions (natural and anthropogenic heavy metal contamination and acid rock drainage); provision of employment and training, and thereby wealth, to local communities; significant tax and royalty payments to government, which will be reinvested as social spending; and development of municipal and industrial infrastructure to build sustainable post-mining communities. The role of governments at all levels is critical in guiding and facilitating this process. This paper was written prior to development of the mine, and relays the intentions of the developers. Future studies will be needed to evaluate the degree of attainment of sustainable development objectives, both during mine operation and after closure.

Jan 1, 2003