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By J. Wills

The use of drilling rigs to increasingly mechanize stope drilling has been acknowledged as important for the S.A. mining industry in it ís efforts to tackle the challenges of low productivity, AIDS and an ageing driller workforce. The spin-offs of increased safety, cost-effectiveness and better mining performance provide advantages to all?from the driller to the shareholder. However, implementation or product rollout has varied from outright success to dismal failure. A study of various cases by Novatek and Anglogold TDS showed clear reasons for these differences. Whereas the successes were characterized by clear objectives, accountability, user buy-in, a commitment to make the technology work and no-nonsense reporting, these were typically absent in failed implementations. The attitude at unsuccessful mines was to ?trial? the equipment?even subconsciously, a ?trial? is a test where failure becomes an acceptable outcome. During the study it became clear that mining management are not adequately trained to manage the often-tricky rollout process. They are often also not empowered or clearly mandated to deal with the organizational, human and technical issues that must dovetail to create a success. The output of the study was to develop a basic rollout process that could be used to formally manage the implementation of new drilling technology. Creating an alignment between the mine, workforce and supplier promotes a win-win situation that will not otherwise spontaneously arise.

Jan 1, 2002

By S. K. Kawatra, S. J. Ripke

Bentonite clay is used as a binder for iron ore concentrate pelletization. Bentonites are sensitive to cations such as calcium, magnesium, sodium, and potassium that are known to be dissolved in the moisture remaining in the iron ore concentrate. These cations affect the ability of bentonite to absorb water, as measured by the plate water absorbance (PWA) test. This paper addresses the relationships between plant water chemistry and pellet strength for a wide PWA range of bentonites. Experiments were conducted to determine the effect of concentrate moisture solute chemistry and bentonite PWA value on the wet knock and wet and dry compressive strengths of iron ore pellets. Experiments used seven different types of bentonite that had PWA values ranging from 564 to 1033. Flushing plant concentrate with distilled water to remove the dissolved cations resulted in increased pellet strengths, to a widely varying degree, for each bentonite tested; wet knock values increased an average of 92% and dry compressive strength increased an average of 46%. In addition, pellet strengths were not found to be directly related to the ability of bentonite to absorb distilled water, measured by the PWA test.

Jan 1, 2002

More than 100,000 people are expected to be in Las Vegas, NV in March for ConExpo-Con/Agg 2002, the largest exhibit of its kind in the Western Hemisphere. This triennial event features equipment, services and technical sessions geared toward the global construction aggregates and ready mix concrete industries. ConExpo-Con/Agg 2002 will take place March 19-25, 2002 at the Las Vegas Convention Center. For registration information, contact the show offices, phone 800-867-6060, 414-298-4141, or 301-587-3140, Website www.conexpoconagg.com.

Jan 1, 2002

By F. Hassani, D. O’Donnell, M. Momayez, P. Guevremont

Shotcrete is a practical and economical support system in many Canadian underground mines. Although shotcrete technology has gained acceptance in the mining industry, there are some problems that have emerged with respect to quality assessment and thickness measurement of the liner. This paper presents recent tests performed with miniature seismic reflection technology (MSR) developed and patented at McGill University primarily for thickness measurement of this heterogeneous liner. MSR is also capable of providing information regarding the quality of shotcrete in terms of its mechanical properties such as modulus of elasticity and Poisson’s ratio. Work was performed on site in an underground mine in Ontario, Canada. This paper also presents the results from laboratory tests performed on fiber-reinforced and non-reinforced shotcrete panels that were used to assess the P-wave velocity in both materials. The results of these tests were used in a second site investigation. The NDT thickness measurements showed good agreement with direct thickness measurement such as coring. In addition, the MSR technology has the advantage of being more accurate and more affordable compared to other non-destructive testing (NDT) systems in the market.

Jan 1, 2002

The Newmont Waihi Operations are centred on the Martha mine at Waihi, New Zealand. The mine has produced over 6.6 million ounces of gold from both openpit and underground sources since operations began in 1878. The current open pit operations commenced in 1988 and in the year to 30 June 2002 produced 129,790 ounces of gold at a cash cost of USD122 per ounce. This paper provides an overview of current operations and future directions.

Jan 1, 2002

Jan 1, 2002

By K. T. Damodaran

The Chavara and Manavalakurichi placer deposits have been known since a long time for their rich reserves of heavy minerals like ilmenite, rutile, monazite etc. While detailed work has been conducted on the mineralogy and texture of the bulk placer sediments, reports on the detailed investigations on individual minerals are relatively scanty. Though, limited work pertaining to the chemistry of ilmenite has been carried out by Nair et al (1995) and Ramakrishnan et al (1997), a comprehensive study of the weathering patterns of ilmenite along the longitudinal and vertical profiles has not been, so far, undertaken. Data on the microscopic analysis of ilmenite from the southwest placers, too, is sketchy. The present work deals with the variation of the weathering undergone by ilmenite in the southwest placer deposits based on chemical and mineralogical analyses.

Jan 1, 2002

By B Rosemberg, F Lemos, A J. B Dutra

The chemistry of cyanide solutions is complex, this complexity being responsible for the ability to act as complex-forming agents in metal dissolution processes, among them gold and silver. Such ionic species are used in hydrometallurgical processes, in particular in gold extraction and electro-plating. Due to the high toxicity of cyanide, the discard of effluent from processes and/or industries demands rigorous treatment so as to minimise its concentration. Among the conventional chemical treatment of such effluents one can mention SO2/air; biological degradation; oxidation by using hydrogen peroxide; oxidation by sodium hypochlorite, etc. However, the electrolytic recycling process is also promising for cyanide recovery and offers the possibility of recycling it to the aforementioned industrial processes. Such a process does not use additional chemicals but enables direct re-utilisation to the main process aiming at adjusting the cyanide concentration.

Jan 1, 2002

By W J. Rankin

A study was carried out to compare the environmental impacts of a number of process routes for lead and zinc metal production from sulphide ores using Life Cycle Assessment methodology and based on average industry data derived from the literature. The processes investigated were:blast furnace production of lead; Imperial Smelting Process for lead and zinc production; and electrowinning of zinc with the mining and mineral processing stages common to all three routes. The effect of a number of process variables, namely ore grade, fuel source for electricity generation and efficiency of generation, on the environmental impacts was also examined. The environmental impact categories considered in the study were:total (or full cycle) energy consumption; Global Warming Potential (GWP); and Acidification Potential (AP). The results of the study show that when produced separately, zinc production is more than twice as energy intensive as lead production (viz 48 and 20 MJ/kg respectively), however when produced jointly by the Imperial Smelting process, the energy intensity of the two metals is not all that dissimilar (viz 36 and 32 MJ/kg respectively). The metal production and refining stage was found to make the greatest contribution to the overall environmental impacts for all three processes. The study also highlighted the importance of taking a life cycle approach when comparing the environmental impacts of different processes.

Jan 1, 2002

By G. M. J. van Heerden

Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering) degree The Union Section of Anglo Platinum is situated ±18 km west of the town of Northam on the north-western rim of the Bushveld Igneous Complex. Both the Merensky and UG2 reefs are mined. Support of the Merensky stoping areas with rock bolts is specifically problematic due to the stoping width restrictions varying around 90 cm. The installation equipment of in-stope rock bolts and the effectiveness thereof in the Merensky stoping areas was critically evaluated. In order to do this a background research on the need for better on-the-face support had to be conducted. The need for improving the rock bolt drilling and the equipment had to be investigated and the financial implications and justifications for the improved equipment examined. To conduct the search an overall study was done on the rockfalls and safety aspects throughout the platinum industry in South Africa and specifically Union Section. It was found that most of the rock falls in the Merensky stoping areas of which ± 70% are less than 1.2 m in thickness generally occurs within 4 m from the face and causes ± 60% of the in-stope injuries. Serious shortcomings had been identified with respect to the airleg, rock drill machine and the drill steels used in the drilling of the rock bolt holes. Through experimentation, using a testing frame built for this purpose on surface and with the co-operation of mine staff and suppliers, a number of possible modifications were identified and tested. This resulted in the final product with which it was possible to drill a 1.2 m hole in the hangingwall of the stopes ranging with an angle to the hanging from 90° for a 90 cm stoping width and 67° for a 80 cm stoping width. It is confidently concluded that this system will effectively improve the total face support and result in a substantial reduction of rock falls and consequently the occurrence of injuries and fatalities in the Merensky stoping areas. The installation of rock bolts on the face with the modified drilling equipment will increase the direct support, but the system has a potential of a substantial reduction in the profile stick support density and an increase in productivity in the stoping areas due to fewer occurrences of rock falls. It was finally concluded that effective modifications to the drilling equipment for rock bolt in-hole drilling could be made and the installation thereof in the stope face is adequately justified.

Jan 1, 2002

By Takuya Shinagawa

After vitrification of the residues from a municipal solid waste incinerator, the vitrified products can be used as a construction material, and the dust can be used as raw materials for the non- ferrous industry. The NKK electric-resistance furnace is operated under a reducing atmosphere, and heavy metals such as zinc and lead in the ash vaporize to form dust. Also, dust from the NKK electric-resistance ash melting furnace is composed of water insoluble zinc and lead components and water soluble NaCl and KCI. This is why, The concentration of zinc and lead in the dust after washing is sufficiently high for the dust to be used as a raw material for the zinc and lead industry. NKK developed a heavy metal recovery process in which zinc and lead in the dust are reclaimed as a raw material for smelting by making the best use of the characteristics of the dust.

Jan 1, 2002

By D. Stone

"The Beal Mountain mine near Anaconda, Montana, is an interesting case history of a mine that has continued operations despite several large pit wall failures over a period of approximately 10 years. The largest event involved some 3.9 million tons of rock that has moved steadily at a rate of about 0.05 ft/day since 1992. This paper documents the geotechnical instrumentation and monitoring programs implemented at Beal to provide the company with a comfortable baseline that supported ongoing operations. The success and failure of a variety of stabilization measures will be discussed, along with typical instrumentation responses for several significant events. The success of Beal Mountain serves as a good model for mines faced with serious geotechnical challenges."

Jan 1, 2002

By M. Fustic, A. H. Paul

The geology of the Muskeg River Oil Sands Mine is described to demonstrate how geologic modeling aided in resource evaluation and material characterization during the feasibility and construction stages. Bitumen is hosted in the clastic sediments of the Cretaceous McMurray Formation which is informally divided into members representing the fluvial, estuarine and marine environments of this transgressive sequence. Lithofacies mapping of drill core provides further detail to classify materials as resource type, for extraction suitability and for construction suitability. Geologic interpretation provides tools for the engineers to produce effective mine plans and for the operators to execute them during mine development.

Jan 1, 2002

By W. E. Roscoe

"Mineral exploration properties are those on which an economically viable mineral deposit has not yet been discovered. Such properties are bought, sold, optioned and joint ventured on the basis of their perceived potential for the existence and discovery of a viable mineral deposit. The intrinsic value of an exploration property is therefore based on the exploration potential. One measure of the exploration potential is the amount that can be justified to spend on exploration for a viable deposit.The appraised value method uses a cost approach to value exploration properties. It is based on the premise that an exploration property is worth the meaningful past exploration expenditures plus warranted future costs to test remaining exploration potential. Results of past exploration work are analyzed in order to retain only those past expenditures that are productive in terms of identifying remaining potential. Warranted future costs comprise a reasonable exploration budget to test that potential."

Jan 1, 2002

By L. Shevenell, L. Stillings

The Acid Drainage Technology Initiative-Metal Mining Sector (ADTI-MMS) has established a Pit Lake Committee to enhance the science and understanding for the long-term management of pit lakes. Participation in this new committee is from members of federal and state agencies, industry, and academia, including numerous individuals representing 10 states. Work has begun on a pit lake literature search and review, database, classification, and sampling and monitoring procedures document. Coordination with the International Network for Acid Prevention (INAP) has been established. Future work will include preparing a prediction and assumption verification document, a report identifying variables upon which water quality is dependent, and an applied remediation technologies document, including an evaluation of the effects of backfilling.

Jan 1, 2002

By Rob Famlield, Gavin Yuill, William Birch

The Blasting Research Group at the University of Leeds, in the United Kingdom, continues to be highly active in the area of the environmental impact of blasting. In recent years a major part of this research has been concerned with the use of linear superposition. This technique relies upon the assumption that all the holes in a blast produce identical vibration signals. Previous work at the University has shown that this assumption is not sufficiently robust to be generally applicable. This is due to a number of factors of which the key variable appears to be dynamic confinement

Jan 1, 2002

By N. Samman, S. N. Lau

"A series of new, grease-based, solvent free open gear lubricants were developed to meet the demanding service requirements of mining equipment. The use of these products has resulted in better performance under conditions of temperature extremes and in terms of longer component lives. They have gained widespread acceptance within the mining communities for such applications as the lubrication of mining shovels, draglines and ball mills.These products are WHMIS non-controlled and are environmentally acceptable. The benefits and advantages of using this type of product to lubricate mining equipment as well as the field evaluation and experience will be discussed."

Jan 1, 2002

By Felix Cheng

Extensions to the Convention Centre in Adelaide, South Australia consisted in part of construction over the existing railway system comprising nine rail lines and passenger platforms. Vibro-pile (Aust) won the design and construct tender with a solution comprising over 500 cast insitu concrete piles. The pile types were 500 to 900mm diameter non-displacement CFA piles and 400mm diameter displacement V-piles. The V-pile is a cast insitu screw pile developed by Vibropile (Aust) Pty Ltd. Both pile types were installed with minimal noise and vibration required for the project, while the displacement V-pile had the advantage over the CFA pile by developing the same pile capacity but with a smaller diameter and with minimal spoil. The latter was important in alleviating spoil removal problems near the railway tracks and disposal of potentially contaminated spoil. The results of dynamic compression load testing and static lateral load testing indicated that the performance of a 400 mm V-pile was equivalent to a 500 mm CFA for this site. The lateral load testing indicated that the surficial soils have a major influence on the load-deflection response, but despite the site containing up to 4 m of filled ground, the piles were found to carry the required lateral loads satisfactorily.

Jan 1, 2002

By Kazimierz Gwizdala

In the paper the method for estimation of settlement of vertically loaded piles in a group is presented. The method is generally based on the hybrid procedure with non-linear solution for single piles and with interaction between them for the low-strain shear modulus. Some attention is paid to the influence of deformation and strength parameters used in calculations. The applied model is verified in the framework of the research programme carried out recently in the Geotechnical Department of Gdansk Technical University. It concerns monitoring and analysing the settlements of the existing structures on piles. A comparison of calculation and measurements results for two tested buildings is presented as an example.

Jan 1, 2002

By William R. Yernberg

The combined 75th Annual Minnesota Section of SME meeting and 63rd Annual University of Minnesota Mining Symposium was held April 9 and 10, 2002, in Duluth, MN. This year’s theme was “Keys to the Future: Imagination, Innovation and Technology.” The meeting consisted of plenary and technical sessions and a special General Manager’s Session. The technical paper presentations included concurrent mining and mineral processing sessions. In the General Manager’s Session, representatives from the region’s taconite operations presented the current status, concerns and future plans for each of their operations.

Jan 1, 2002