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By Bruce Geller

The 2005 Prospectors and Developers Association of Canada (PDAC) convention continued the upbeat mood found in 2004. The global mining industry is booming due to higher commodity prices in nearly every sector. Other factors include low commodity inventories, China’s strong resource demands, the weak U.S. dollar, the very strong Euro, global uncertainties, an almost overripe investment climate for natural resources and the highest mining exploration budgets in seven years. Even unglamorous commodities, like iron, uranium and zinc, received copious attention in talks, the investors’ exchange, the core shack and in certain hospitality suites. The following impressions were gathered at the convention and enhanced by conference handouts and some abstracts that are available on the PDAC’s Web site, www.pdac.ca. At least 119 papers were presented, almost twice last year’s number.

Jan 1, 2005

"The Antamina orebody is a geologically complex, polymetallic skarn located in the Peruvian Andes. A range of copper and copperzinc ores are campaigned separately through the concentrator producing copper and zinc concentrates as well as lead and molybdenum by-products.Ore type classification at Antamina is based on chemical assays; geological or lithological variations are not considered. Consequently, each ore type demonstrates a wide range of concentrator performance.Antamina is currently implementing a system to track ore movements from the shovel face to the concentrator. Relatively sophisticated models of run-of-mine and coarse ore stockpiles ahead of the mill will be used to account for the variable delay between mining and milling.One of the numerous benefits of ore tracking is the ability to directly associate the measured concentrator performance with a physical location in the orebody. Using existing mine planning software, three-dimensional models can be created of such performance measures as metal recovery, concentrate quality, operating cost, and reagent consumption.Such a database of information allows the true value of different ore sources to be determined. The value of an ore source is conventionally measured as metal content (individual or combined ‘equivalent’) with a cut-off grade applied to indicate some base level operating cost. However, the true value of an ore source should include dynamic factors like haulage cost, reagent use, smelter penalties, and even prevailing metal prices. If an ore source is considered from all perspectives rather than simply its potential to deliver value, the concept of ore becomes more flexible. Any ore source that reveals itself to be unprofitable can be eliminated from the mine plan or possibly blended with others to improve its value. The ability to predict mill performance, and thereby profitability, is a powerful tool.In an operation such as Antamina, where managing ore sources, campaigns, and the delivery of a variety of concentrates in a narrow timeline to customers is a daily challenge, prediction is the key to success and improved efficiency."

Jan 1, 2005

By C. Sykes, E. Turner, M. Wyart-Remy

This paper follows that of the Milos Conf, 2002 and examines the collection and reporting of SDIs in the industrial minerals industry in Europe. It compares the characteristics of the GRI Reporting Guidelines, with its Metals and Mining Sector Supplement with those of the EU DG Enterprise Scheme, launched in 2001. The particular issue of SME's and companies which are not publicly traded is examined. The pros and cons of participating in such schemes is a central theme of the paper. The paper concludes that there and many business benefits for these companies in participating and submitting their data. The European Commission Scheme is strongly recommended for companies in the sector which are SME's and not-publicly traded as well as large firms who are listed on European Stock Exchanges.

Jan 1, 2005

By Michael S. Zhdanov

One of the major problems of mineral exploration is the ability to reliably distinguish between uneconomic mineral deposits and economic mineralization. While the mining industry uses many geophysical methods to locate the mineral deposits, until recently, there was no reliable technology for mineral resources identification and characterization. The main goal of this project is to develop a new geophysical technique for subsurface material characterization, mineral exploration and mineral discrimination, based on electromagnetic methods. The proposed new technique is based on examining the spectral induced polarization effects in electromagnetic data using the modern distributed acquisition systems and advanced methods of 3-D modeling and inversion. The recovered parameters of the relaxation model will be used for the discrimination of different rocks, and in this way will provide an ability to distinguish between uneconomic mineral deposits and zones of economic mineralization using geophysical remote sensing technology (Zonge, 1976). The proposed research and development is undertaken using multi-partner collaboration between the University of Utah, four major mining companies, Kennecott Exploration, BHP Billiton World Exploration Inc., Placer Dome Inc., Phelps Dodge Exploration, and Zonge Engineering Inc., which is equipment manufacturer and service provider to the mining industry. The multi-partner collaboration between the academic institution, the University of Utah, and mining industry helps to identify the appropriate mining target and conduct the field experiment for practical demonstration of the developed new technology, which is an important part of the this project.

Jan 1, 2005

By R. K. Wharton

The paper reviews the development of European harmonised standards for fireworks, recent major incidents involving the bulk storage of fireworks which led to research funded by the European Commission, progress with the forthcoming European Regulation on pyrotechnics and potential issues relating to the certification of products within the scope of the new Regulation.

Jan 1, 2005

By C Tukel

Copper sulfate is traditionally used to activate various types of sulfide minerals. The list of users includes Falconbridge Sudbury operations, where copper sulfate solution is added to the pyrrhotite/pentlandite middlings at the scavenging stage. Results from some batch tests reported in the literature suggested that copper activation is helpful for the improvement of pentlandite recovery, especially in the difficult to float fine particle range. Any improvement in pentlandite recovery is important since it is the main nickel bearing sulfide mineral. The impact of copper sulfate for this function has been investigated. Since the focus of current investigation was the flotation behaviour of minerals at the scavenger stage, rougher flotation was kept as constant as possible at two different weight recoveries, namely 13.2 per cent and 15.5 per cent that is relevant to industrial practice. Samples taken during batch testing were extracted using DETA and flotation products from selected tests were analysed to determine the recovery by size behaviour in relation to the use of copper sulfate. Results provide significant evidence that the addition of copper sulfate to these middlings does not yield greater nickel recovery, either on an overall or specific particle size basis. It is concluded that copper sulfate is wasted in the process and that self activation behaviour of the ore at a slightly reduced pH is sufficiently significant to maintain the scavenger recovery of pyrrhotite and pentlandite at desirable levels. Results obtained from limited circuit trials have shown supporting evidence for this conclusion.

Jan 1, 2005

By John Taylor

?Introduction to Black Mountain ?Historical metal accounting practice ?Metal accounting audit ?Feed measurement ?Sample precision ?Concentrate measurment ?Current metal accounting practice ?Further refinements to the metal accounting practice

Jan 1, 2005

As a society, the retiring age of workers is increasing. Individuals are having to consider working to an older age (beyond 55 years), the reason being to æpay offÆ debt, maintain a quality of life or, as a bigger picture, because society simply cannot afford the aging population. The Government is encouraging and promoting those approaching retirement to work to an older age to alleviate the financial burden of an aging population. In a working context those aged 55 years and over accounted for ten per cent of the Australian workforce in 1998 with this age group expected to account for half of the growth in the workforce between now and 2016. For the 60 - 64 years which account for less than three per cent in 1998, this group is expected to account for 15 per cent of the growth in the same period. As a result of individuals who have worked all their lives and in some cases æphysically hardÆ, they do not fully enjoy their years of retirement as a time when they get to choose what they want to do rather than what they have to do. Of particular interest are the physical or health related conditions that individuals end up with and the restrictions that ensue resulting in an individual being incapacitated either physically or with respect to the state of their health.

Jan 1, 2005

By T. Mulpeter, G. Deschênes

Sadiola Gold Mine is an open pit operation located in Mali and owned by Anglogold Ashanti Ltd, Iamgold Corporation and the State of Mali. A conventional cyanidation process (cyanidation/CIP) treats 15,000 tpd (of a mixture of oxide and sulphide ores) at an average grade of 3 g/t Au. In 2002, the increasing tonnage of sulphides caused an increase in production costs and a decrease in gold extraction (from 95% to 70-76%). Because of the short retention time of the leach circuit (18 hours) and the refractory nature of the sulphides, gold leaching kinetics are critical. A laboratory investigation was initiated to evaluate actual plant practice and identify a means of improving the gold leaching rate. The study was conducted on a "soft" sulphide gold sample containing 4.96 g/t Au, 0.4 g/t Ag, 2.5% pyrite, 1.2% arsenopyrite, and 0.2% pyrrhotite with a P80 of 74microns. Pre-leaching significantly influenced the gold leaching rate. A short pre-leach (2 hours) performed at pH 8, a DO of 8 ppm, and with 300 g/t lead nitrate added at the start or the end, produced the preferred conditions. Pre-leaching for more than 2 hours was detrimental to gold extraction. The cyanide concentration had to be maintained at 450 ppm NaCN to reach a maximum gold extraction within the retention time of the circuit. A maximum extraction of 81.3% Au was obtained in 20 hours (leach residue at 0.97 g/t Au). A high level of dissolved oxygen in the pre-leach was not of any benefit. Extension of gold leaching beyond 20 hours indicated that all leachable gold had been extracted by that time. Plant modifications were made to allow leaching of oxides and sulphides in separate circuits. Treatment of oxide ores is now performed at a higher rate. Sulphides are processed at a lower throughput, with 300 g/t lead nitrate, to allow a retention time of 22 hours. Combined throughput remains the same, and total gold recovery has increased from 76% to 80% for an additional gold production of 16,000 ounces per year.

Jan 1, 2005

By Shimi Tzobery, John E. Shamma, Samuel Swartz, Gary B. Hemphill

The trapezoidal tapered ring method has made significant progress in recent years for shielded-TBM projects, excavating tunnels with high overburden, strict water tightness criteria, and multiple curve alignments. The selection of compatible tapered rings is critical for successful advancement of the tunnel, assuring efficient installation of rings, as well as prevention of ring damage and excessive leakage. Using experience from the Arrowhead Tunnels Project, this paper describes guidelines for ring selection in tunnel curves, geometric analyses that comply with criteria principals, and provides techniques developed to determine the appropriate relative key position.

Jan 1, 2005

By Guangyi Sun

Wall rock classification method for coal mine support is the main factor affecting mine support. It is greatly affected by the combined effect of randomness, fuzziness and human being's incomplete knowledge. There are several coal rock classification methods. Using different rock classification methods the same engineering rock mass can be classified into different classification leading to different construction practices.

Jan 1, 2005

By P. Sauriol

This work addresses the design challenges and demonstrates the capabilities of a novel water transfer factor measurement apparatus. Several measurement concepts were screened on the basis of their water transfer factor accuracy using Monte-Carlo generated virtual experiments. The most promising measurement concept was assembled and tested to assess its actual measurement accuracy. For these concept validation experiments, the polymer electrolyte membrane fuel cell was simulated by adjusting the water injection rate to corresponding levels. Combining the anode and cathode measurements, the water transfer factor accuracy was typically better than 0.01. Real-time measurements of the water transfer factor on both anode and cathode sides of a polymer electrolyte membrane fuel cell were achieved. The anode and cathode side measurements were in good agreement with each other; however the anode side measurements were generally more reproducible. A parametric study showed that stream humidification plays an important part in the water transfer across the membrane electrode assembly. Finally the water transfer factor along the channel of a 300cm2 co-current fuel cell was obtained by using a series of six 50cm2 sub cells. The results were in good agreement with predictions from a recently proposed model.

Jan 1, 2005

The implementation of a process information management system (PIMS) is to provide a single online, real-time information system. This system provides a unique and completely open view for everyone, based on the key business drivers. It is structured around the three key concepts: process, maintenance and stocks. It combines numerous applications and provides accessibility to common tools and reports, through a web-based user interface, for every one from the floor operator to the General Manager. This æunique and commonÆ view displays raw, online process information that provides a quick health check of the operation at a glance, highlighting areas that require further investigation. The system is based on a hierarchical system of views, from the overview of the whole plant flow sheet to the more detailed operational shop view. It provides a synthetic view between continuous and batch operations, enabling the tracking of each batch produced. The batch view displays the critical batch components, and a comparison with each component of an ideal batch. This enables detailed analysis of each batch to identify areas of improvement. The information system will consist of an online reconciliation of stocks and flow data. This enables focus on the recovery of each process unit on a regular basis. This paper discusses the design strategy for the Process Information Management System, to ensure a unique and open view on the key business drivers is achieved and implemented successfully.

Jan 1, 2005

By Scott Chesman

Increased TBM performance is leading the way for resurgence in tunneling activity in NYC. Tunnels will be excavated in the same geologic formations as previously excavated D&B tunnels whose construction records are providing valuable insight into the prediction of rock mass behavior. This report compares an eight mile stretch of NYC Water Tunnel #2 with the recently excavated eleven mile stretch of the TBM driven Water Tunnel #3. Comparisons of the type and amount of rock support installed as well as water inflows and grout quantities are made. Rock mass characteristics specific to TBM performance are also evaluated.

Jan 1, 2005

By Paul Hewitt, Tim Smirnoff

Design and construction of the Epping to Chatswood Rail Line tunnels in Sydney, Australia required an innovative approach to define hydrogeological properties of the Sydney Hawkesbury Sandstone and provided an insight into the hydraulic behaviour of fractured sedimentary rocks. To meet restrictive water inflow and infiltration criteria both the pre-treatment of zones of fractured or highly jointed rock, and waterproofing using an interior spray on membrane for the finished drained tunnels and stations was required. Methods typically used to address the interaction of groundwater and tunnels in the Sydney Basin are demonstrated by case histories from major design-build tunnel projects.

Jan 1, 2005

This paper reviews ore pass practice in some Canadian mines in Quebec and Ontario. In particular it reviews ore pass configuration, flow control mechanisms and monitoring practice. A review of the type of problems encountered and the tools to restore flow is also presented.

Jan 1, 2005

By Andrew Wessman

Keywords: Recycling, Electrodeposition, Recovery, Dilute, Dissolved Metal Ions In order to facilitate the recovery of pure metals from solutions containing a mixture of dissolved metal ions, a pulsed electrodeposition method was developed. Using this method, it is possible to selectively remove metal ions from solution based upon the electrochemical potential of the particular ion desired. The use of pulsed electrodeposition rather than direct current electrodeposition creates an electrodeposited material with better morphology, increases electrical efficiency of the process, and avoids problems with short circuiting between electrodes. Using this method, it is possible to recover dissolved metal ions in a purified form in one simple step, and therefore maximizes recovery of the metal ions while obtaining them in a saleable form. This method is likely to be useful in improving the recycling process for numerous complex metal mixtures and alloys.

Jan 1, 2005

By Ronald E. Heuer

A 1995 RETC paper of similar title presented a method for estimating rock tunnel water inflow based on semi-empirical correlations with borehole water pressure tests. Since that time the author has found the method to be very useful, and it has been used by others in the industry. This current paper is an update which is intended to: A. More clearly explain assumptions and limitations of the method. B. Describe some case history examples. C. Respond to questions which have been raised; and extend the method to other considerations including distribution of inflow along the tunnel, panning requirements, interpretation of tunnel probe hole water inflow, and estimation of potential effectiveness of pre-excavation grouting to reduce water inflow.

Jan 1, 2005

By P. K. Naik, B. Das

Flotation studies were carried out to recover carbon values from blast furnace flue dust containing ~30.34% carbon, 4.6% volatile matter (VM), and 65.03% ash. The variables chosen for the experiments were dispersant (sodium hexametaphosphate), pH, collector (diesel oil), and frother (MIBC). The experiments were designed according to a 24 full factorial design method and regression equations for the recovery of carbon and product grade were determined from the data. Experiments were performed to optimize recovery and grade using the steepest ascent method. The maximum recovery of carbon was 90.0% with a concentration of 56.5%, whereas the maximum obtainable grade of carbon was 66.35% with 50.45% recovery.

Jan 1, 2005

"The application of telerobotics to mining is currently being introduced into production systems around the world. Mining companies in Canada, Sweden, South Africa, and Australia have tended to lead the international charge to this form of technology for mining. While this introduction is taking place, a few basic questions have yet to be answered. How many machines can a single operator run? How many types of machines can a single operator run?A Canadian Research Chair in Robotics and Mine Automation has been established at Laurentian University to investigate these questions and many more through a series of experiments in a telerobotics laboratory that connects Laurentian teleoperation workstations to model mining machines at Cambrian College’s eDome. The laboratory supports many experiments allowing researchers to physically run multiple robot scenarios differing the numbers and types of machines at one quarter scale. Further experiments are being designed to investigate the potential for managing time delays in telerobotics. This paper describes the laboratory, experiments, and some preliminary results."

Jan 1, 2005