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By J. F. Papp

In the United States, chromium has been consumed in three major markets: chemical, metallurgical, and refractory. The predominant end use for chromium in the United States is in the metallurgical market as an alloying element in the production of stainless steel. In addition to being a major stainless steel-producing country, the United States is a major world producer of chromium-containing chemicals and has used substantial amounts of chromite ore for refractory applications. Chromium use is not easily further subdivided within the chemical and refractory industries because there is insufficient publicly available information to do so; however, chromium use can be subdivided among metallurgical industry uses based on the American Iron and Steel Institute (AISI) reported shipments of stainless steel by market classification (agricultural, aircraft, automotive, etc.). It is the goal of this study to determine the distribution of U.S. chromium apparent consumption among major markets in the United States. The distribution is expressed in the form of dimensionless fractions that are computed based on documented chromium consumption by major market. The distribution of chromium among markets within the metallurgical market is computed in a similar manner. Distribution factors are first computed for the major markets, then for markets that are subdivisions of the metallurgical market. The distribution of chromium among major markets has changed substantially over the time period of analysis. The fraction of chromium consumed by the metallurgical market has increased while that of the chemical and refractory markets has declined. Within the metallurgical market, the service industry market accounts for the greatest fraction of chromium consumption followed by transportation. Electrical, machinery, and fabricated products markets account for a substantial share of the metallurgical chromium consumption.

Jan 1, 2004

By N. Hmidi, T. Yalcin, M. Papadakis, B. Hilscher

Mill tailings, containing iron sulphides in particular, pose an environmental concern since they constitute a potential source of acid mine drainage which can damage vegetation, harm soil and living organisms, and contaminate groundwaters. Proper disposal of acid generating tailings is therefore an important issue that must be addressed and resolved in a satisfactory manner. Placer Dome Canada operates a 4000 t/d gold cyanidation facility at Musselwhite mine, in northwestern Ontario, where the mill tailings have been classified as acid generating. This study was conducted to explore the effectiveness of froth flotation in removing the sulphide minerals from these tailings and producing a low-sulphur, non-acid generating material that could serve as a capping material for previously deposited tailings. Laboratory semi-batch flotation tests were carried out in accordance with an experimental design procedure, and a computer simulation program was developed to facilitate the evaluation of flotation performance. In this investigation, pH, collector concentration, and airflow rate were considered as the relevant flotation variables, and their effects were examined both experimentally and by simulation. Results have demonstrated that flotation can successfully desulphurize the Musselwhite mine tailings and render them non-acid generating.

Jan 1, 2004

By C. C. Russelll, V. T. McLemore

The Metals Mining Sector of the Acid Drainage Technology Initiative (ADTI-MMS) addresses technical drainage-quality issues related to metal mining and related metallurgical operations, for future and active mines, as well as, for historical mines and mining districts. One of the first projects of ADTI-MMS is to develop a handbook describing the best sampling, monitoring, predicting, mitigating, and modeling of drainage from metal mines, pit lakes and related metallurgical facilities based upon current scientific and engineering practices. One of the important aspects of planning a new mine in today’s regulatory environment is the philosophy of designing a new or existing mine or expansion of operations for ultimate closure. The holistic philosophy taken in the ADTI-MMS handbook maintains that sampling and monitoring programs should be designed to take into account all aspects of the mine-life cycle. Data required for the closure of the operation are obtained throughout the mine-life cycle, from exploration through post-closure.

Jan 1, 2004

By Y. M. Shneerson, V. M/ Shpaer, E. E. Zhmarin, A. Y. Lapin, E. M. Vigdorchik

This paper describes studies of zinc concentrate oxidizing pressure leaching using the method of mathematical modeling. The concept of a kinetic function was taken as a basis for mathematical modeling of the leaching process. The kinetic function describes dependence of the unreacted component share OJ on the relative time x (the relative time is the ratio of the test duration and the time of complete dissolution). This kinetic function is determined in accordance with the results of batch laboratory tests. The laboratory tests have been carried out on zinc concentrate produced from Kazakhstan zinc-copper ores. Zinc concentrate consisted mainly of three types of minerals: sphalerite (70%), pyrite (13%) and chalcopyrite (10%). Oxidation reactions of sphalerite, pyrite and chalcopyrite have been considered as principal ones. The kinetic characteristics of the process (kinetic function, reaction order, activation energy, duration of complete dissolution of the concentrate components) have been calculated in the course of laboratory tests. The mathematical model was used for estimation of the main technological leaching process parameters (such as process rate, degree of metals extraction, autoclave capacity, heat balance, etc.). Mathematical modeling based on the kinetic function concept allows safe designing of metallurgical equipment and scaling the technology to industrial capacity.

Jan 1, 2004

I attended a funeral in West Monroe, Louisiana, for one of the best powder peddlers I’ve ever known. He started work in 1948 for Dixie Dynamite, a seismograph explosive distributor. His first job was as a truck driver, then magazine keeper and then sales re p re s e n t a t i v e . When Dixie Dynamite quit, he acted as an explosives sales agent for sometime before moving on to Kansas to be a sales rep for a distributor there. We called him the “ragin cajun” long before James Carville came on the national scene messing up things. While he was born in G e o rgia, he was a Cajun at heart. I don’t believe the old saying, “Build a better mousetrap and the world will beat a path to your door.” To me, the best products in the world need to be sold. Two examples of this are the Beta system for TV and the Apple Macintosh computers. Beta is the best system but VHS took over because the Beta people fell down on the selling job. Windows 98 is Macintosh ‘86 but again the engineers were not salesmen. Marion “Johnny” Johnson who was buried only about a half mile from his first magazine site proved that good selling is good citizenship. He could have sold any firstclass product, for he wouldn’t tolerate inferior items, and made a successful career of it, but he chose dynamite and the industry benefited from his talents.

Jan 1, 2004

By J. I. Mathis

"The failure that was utilized for developing this model was a double bench-scale failure, approximately 20 m in height, in the Misery pit at BHP Billiton’s EKATI mine site. The bench that failed was excavated in biotite schist. Due to previous problems with bench-scale toppling failures, this bench was excavated with a 70° inclined, 30 m deep preshear. Upon exposure, the wall was very clean with half-barrels commonly observed from the pre-shear operation.In August 2003, a bench failure of about 1000 t occurred in this pre-sheared biotite schist (Fig. 1). Upon examination it was noted that the foliation that paralleled and dipped at 70° into the face when excavated was approximately horizontal at the top of the failure (Fig. 2). While the failure mode itself appears complex, the failure was apparently driven by three factors:• a low-angle, low-frictional strength fault or discontinuity at the base of the failure area;• water either contributed meteorically from precipitation and/or from permafrost melt; and• foliation planes providing a viable toppling geometry once toe block motion began to occur.The above details are illustrated in Figure 3.After considerable thought and analysis, a model was postulated for the failure.It is thought that the entire failure had been triggered by displacement of a toe block (Fig. 4). This toe block is bounded on the back by foliation, the bottom by a low-angle, lowstrength fault, and the front by the bench face. Water pressures behind the bench face developed forces on the block as can be seen in Figure 5. These forces were sufficient to induce block motion. As can be seen in the relative shear strength diagram in Figure 6, only a small amount of water is necessary in the face to initiate block displacement. Note that in this figure, a simplistic piezometric pressure distribution was assumed."

Jan 1, 2004

By P Storey, B Deans, T Lancaster

Straits completed its Feasibility study on the Whim Creek Copper Project in 1996. At this stage WCCP provided Straits with an open pit mine - heap leach - SX-EW copper project to follow on from its successful Girilambone Copper Operation (GCC). Since this time Straits has continued to review WCCP investigating a number of development and production scenarios. The development of Whim Creek, early 2004 and is on schedule to commence copper production in the final quarter of 2004. On current reserves Whim Creek will produce approximately 17 000 tonnes of copper cathode per annum for three to four years, at cash costs of The paper will cover a general description of the project, the project development and key design issues. Additional construction related issues associated with the complete relocation of the GCC plant to Whim Creek will be covered in the conference presentation.

Jan 1, 2004

By Joseph J. Zaluski, J. Steven Gardner, Marco M. Rajkovich

The telephone rings at 3:20 a.m. An exasperated voice on the other end says, “There has been a mine explosion at Mine No. 5 and we have not heard from three units of men.” Twenty-three minutes later, the phone rings again and another panicked voice says, “There is something wrong at the slurry impoundment, the pool level has just dropped five feet and we are trying to figure out what is wrong” Thirty minutes later, the mobile phone rings. An excited security guard says, “We have reports of thick black water running down the right fork and left fork of Straight Creek and both seem to be rising in the banks.” If this is not enough excitement, the mobile phone rings again. A stressed company official says, “I just heard a report that black slurry is running out of the portals of XYZ Co. No. 2 Mine, which is adjacent to our No. 5 Mine.” Is this all some kind of dream or nightmare? More importantly, though, if this happens, what do you do? Most people think: “It can’t happen to me.” But mine explosions do happen, slurry impoundments can rupture and creeks can flood with black water causing damage to others, including competitors. A mine’s response must be quick, cool-headed, calculated and effective. This article examines the issues, concerns and ramifications of this hypothetical disaster. The authors then present a systematic crisis-management response.

Jan 1, 2004

By W. D. Gould, A. Kapoor, K. Morin, P. Bédard

This paper presents the results of a research study that is being conducted by the Mine Effluents Program, Mining and Mineral Science Laboratory (MMSL), Natural Resources Canada aimed at evaluating biotechnology processes for the treatment of nitrogen compounds such as thiocyanide (CNS) and ammonia (NH4-N) which are present in gold mill effluents. A sequencing batch reactor (SBR) technology, commonly used for the biological treatment of municipal and industrial effluents, was used in this study. In the SBR process, the micro-organisms were able to degrade CNS to NH4-N and NH4-N to nitrate (NO3-N) at operating conditions of two 12 h treatment cycles per day, with pH maintained in the 7.4 to 7.6 range, and at room temperature (approximately 21°C) and also at 12 °C. The end products of CNS and NH4-N biological oxidation were NO3-N and sulphate (SO4) that are relatively non-toxic. Partial removal of NO3-N was achieved by biological denitrification reactions in the SBR process. The SBR process effluent was measured to be non-toxic to rainbow trout based on the 96 h acute toxicity test. The microbial consortium isolated from the SBR treating a simulated effluent was able to effectively oxidize CNS and NH4-N to NO3-N in water samples (under batch conditions) collected at three mine sites located in Quebec, the Northwest Territories, and Yukon.

Jan 1, 2004

By V. D. del Valle, T. G. Joseph, J. J. Berezan

Aggressive driving patterns, rough and poorly maintained roads and pit floors, along with the occasional bump and poorly placed load from a shovel can create intense and sometimes serious vibration levels on a heavy hauler. The effects of high vibration have been shown to be of concern for the health of the operator as well as the reliability of the equipment. It is proposed that an onboard vibration warning system based on the ISO 2631-1 standard could be used to help operators reduce the vibration levels experienced in a heavy hauler. The onboard system would consist of a screen that displays the instantaneous vibration in the form of three lights: green (safe zone), yellow (cautious zone), and red (danger zone), as well as an overall vibration exposure or dose for the entire shift. With the utilization of the warning system, it is anticipated that the overall vibration levels will be decreased resulting in improved operator health, a reduction of vibration-induced maintenance, and improved haul roads through reduced impact loading and repair for localized trouble areas.

Jan 1, 2004

By P. A. Geusebroek, N. A. Duke

Abstract - The Lupin mine, located in the central Slave province just east of the western boundary of Nunavut Territory, is a world-class example of a Neoarchean-aged banded iron formation (BIF)-hosted lode-gold deposit. At the minesite the gold-mineralized Lupin BIF, separating stratigraphically underlying psammitic wacke and overlying argillaceous turbidite sequences, delineates the Lupin dome, a hammerhead-shaped F2/F3 interference fold structure occurring at the greenschist to amphibolite facies metamorphic transition within the thermal aureole of the Contwoyto batholith. Detailed paragenetic relationships indicate that peak thermal metamorphism coincided with the switch from regional D2 compression to rapid D3 unroofing of the Neoarchean orogenic infrastructure. Gold initially precipitated with pyrrhotite, replacing amphibolitic BIF at the apex of the Lupin deformation zone, separating the east and west lobes of the Contwoyto batholith. Over the course of associated prograde/retrograde metasomatic overprints, gold was further remobilized during garnet and loellingite/arsenopyrite growth in chlorite-altered selvages of late-forming ladder quartz veins. A metamorphic model of ore genesis, with gold being scavenged and transported by metamorphic fluid that was shed and structurally trapped at the amphibolite recrystallization front, is favored over the previously proposed syngenetic and exogenic models of gold concentration that have tended to polarize genetic interpretations to date.

Jan 1, 2004

By J M. Santini, I C. A Streimann

Arsenic is a naturally occurring element in the environment and is toxic to biological systems. Arsenic can exist in the environment in the following redox states, arsenite (+3), arsenate (+5), arsine (-3) and elemental (0) (Oremland and Stolz, 2003). Arsenic is released into the environment by natural and anthropogenic activities such as rock weathering and ore mining, respectively. Such activities result in the release of the soluble inorganic arsenic oxyanions, arsenite and arsenate. The redox state of arsenic in the environment is influenced by a number of factors including, redox potential, pH and microorganisms (Irgolic et al, 1977; Genc-Fuhrman, Tjell and McConchie, 2004). Recently, the ability of microorganisms to influence the cycling of arsenic in the environment has attracted much attention. Microorganisms that can oxidise arsenite and reduce arsenate have been isolated and the mechanisms of arsenic metabolism are currently being investigated. The differences between arsenic resistance and arsenic metabolism are being revealed. The role of microorganisms in the release of arsenic into the environment is of particular importance with arsenic contamination of waters causing the death of millions of people worldwide, due to the consumption of contaminated water (Vasken Aposhian et al, 2003; Islam et al, 2004).

Jan 1, 2004

By P J. Clark, A W. Fisher, R G. Ford

Site characterisation of subsurface contaminant transport is often hampered by a lack of knowledge of site heterogeneity and temporal variations in hydrogeochemistry. The use of a regional-scale data compilation derived from satellite imaging is discussed with respect to directing design of site characterisation to monitor the fate of a Dense Non-Aqueous Phase Liquid (DNAPL) plume in Nevada. Evaluation of the drainage basin contributing to the groundwater flux into the study site was used to re-assess the site conceptual model and re-direct the characterisation effort. The use of highly resolved measurements of subsurface hydrogeochemistry in space and time were employed to identify the predominant biogeochemical processes controlling arsenic transport during discharge of groundwater into a pond at a site in Massachusetts. Direct-push conductivity measurements coupled with vertically-resolved sampling within the pond and adjoining aquifer demonstrated spatial and temporal variations in dissolved arsenic within groundwater and the pond water column and sediment pore water. Spatial variability was observed over the scale of centimetres to metres, and temporal variations were observed over the scales of days (following storm events) to seasons. Microbially-driven redox processes maintained anoxic conditions in groundwater and at the sediment-water interface (iron and sulfate reduction) and exerted both a direct and indirect influence on arsenic solution speciation and partitioning to surface water sediments.

Jan 1, 2004

By Naresh Koirala

The Greater Vancouver Regional District completed installation of a 2.5 Km long, 2400 mm diameter concrete sewer in Delta, British Columbia in 2000. The sewer traverses through area of peat and soft ground. The ground investigation along the sewer alignment consisted of cone penetration tests and auger drilling with standard penetration tests. The gravity sewer is supported on precast, pretensioned spun concrete piles imported from Malaysia which had never been used for a major project in North America. The capacities of the installed piles were tested using pile driving analyzer (PDA) and three static load tests. A total of 46 PDA tests were carried out during pile installation. The paper describes the pile vetting process the owner went through prior to accepting the piles for use in the project and performance of the piles. It compares the pile capacity estimated from the PDA tests with that estimated from soil mechanics methods using data from cone penetration tests and standard penetration tests. The ranges of estimated capacities calculated by different methods are discussed from design capacity selection considerations.

Jan 1, 2004

By Dennis J. Kemp

Laterite projects are found in the tropical and sub-tropical regions of the world. As a result severe meteorological situations accompany such projects, often in regions of high seismic activity and political uncertainty. Frequently, socio-economic development supported by political interest is a major driver for development, while environmental protection imposes numerous stresses on the project. This paper will review and examine the many social, environmental, technical and financial issues that a mining and extraction process is subject to during development. The options that must be evaluated will be discussed in the context of sustainable development. Issues of project standards and cultural impact through to long-term issues such as greenhouse gasses and climate change will be assessed in redirecting project environmental norms. Although a rationale for sustainable project can be developed many long- term uncertainties around issues remain. Keywords: sustainable development, communities, social issues, standards, energy, waste management, consultation, agreements

Jan 1, 2004

By 12670

The Cigar Lake project will develop the world’s second largest high-grade uranium deposit. The Cigar Lake Phase 1 orebody contains approximately 226 million pounds U3O8 at an average grade of 20.7% U3O8. The mine, to be operated by Cameco Corporation, will use a unique water jet boring mining method to cut previously frozen ore. A distinctive ore handling design is required to handle the highgrade ore slurry exiting the mining machines. The ore will be crushed and ground underground, with the ore slurry then pumped to surface. Loaded into purpose-designed containers on tractor-trailer units, the ore slurry will be trucked to Cogema Resources Incorporated’s McClean Lake mill. McClean Lake will leach all of the ore. Forty-three percent of the resulting uranium solution will remain at McClean Lake for processing into yellowcake. The other 57% of the uranium solution will be shipped to Cameco’s Rabbit Lake mill for processing into yellowcake there. Detailed design for the Cigar Lake project is now underway. Barring regulatory or market delays, production could start up as soon as early 2006.

Jan 1, 2004

By H. K. Lin, J. L. Oleson

The purpose of this study is to develop a mathematical model to describe the oxidation of cyanide with SO2as proposed in the Inco process. This research employed a direct method for measuring the change in cyanide concentration with respect to time as effected by varying concentrations of SO2, copper and pH. Developing this model may be applicable in determining optimum conditions in a process well known and used in the mining industry. It was determined that the reaction is first-order with respect to cyanide, SO2and [Cu+2].The reaction order is 0.15, or zeroth order with respect to [H+] at pH range from 8.0 to 9.5.The activation energy, Ea, is 21.6 kJ/mol. The overall rate equation, as determined through this study is: [ ]

Jan 1, 2004

By Houyuan Liu

A new process was developed to recover nickel and cobalt by leaching laterite ore at atmospheric pressure and.95"-105" C. The nickel-containing goethite in limonite was first leached with sulphuric acid to liberate over 90% of nickel, cobalt and iron. The dissolved iron was then precipitated as Ni-free goethite by the additioil of saprolite. The acid released during iron precipitation as goethite was simultaneously used as lixiviant to leach saprolite to recover more nickel. With this process the limonite and saprolite were essentially converted into goethite-, gypsum- and silica- containing tailings. Twenty bench scale tests and two campaigns of pilot plant operation were carried out at BHP Billiton's Newcastle Technology Centre (NTC) from January to August 2002. The overall nickel and cobalt extractions were 81 to 90% and 91 to 100% respectively. The average plant availability was 99%. The advantages of this process over existing processes include high plant availability, high consistency, robustness and simplicity of the operation.

Jan 1, 2004

The current boom being experienced by mining, coupled with a shortage of professionals, will mean those in the industry will have many choices. It may be easy to become carried away and run with the highest bid or the biggest promise. Without planning, however, the ærightÆ opportunity may be missed and there may be some long-term consequences. There are many choices of paths in the industry to suit work preferences, life cycles and to achieve a balanced life. People in mining have changed jobs and companies frequently û which means new leaders need to take greater responsibility in charting their own direction. Career options need to be carefully assessed and aligned to personal values and preferences. Emphasis is given on gaining site experience early on.This paper examines strategies for career planning, which incorporate life cycles, education and what is meant by a balanced lifestyle. Two tools are identified as being helpful in ensuring strategies can be successfully executed. They are ævisioningÆ and æinfluenceÆ.To make the mining industry more attractive, we need more creative solutions around advances in technology and organisation of work. It also needs the input and leadership of new entrants in to the industry to assist in its survival. New leaders are encouraged to voice a vision and effectively influence their companies. New leaders have little authority and need to learn how to effectively influence. We as a mining industry need to listen, be open-minded and give it a go.

Jan 1, 2004

Leaving the relatively simple life on a uni student and venturing off in to the outside working world is a big step. There are two paths to follow, the æContikiÆ style graduate program where you pick up your new lease vehicle and set forth on two to three years of planned activities, or can pack everything into one bag, stick a copy of æthe rough guideÆ in your pocket, and set off on your own graduate adventure. I took the path less travelled.The less followed method of developing yourself isnÆt for everybody. Parts of the journey are difficult and sometimes it feels hopeless, but itÆs all a learning experience. Along the way you might not get to all the graduate ætourist stopsÆ like dragline, truck-shovel, or drill and blast. But youÆll see most of them and pick up a lot more of the local culture such as people management, operational knowledge, quality control, and the black arts of project financial management.

Jan 1, 2004