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By P. N. Calder, D. B. Apel, S. D. Butt

Mine-wide (MW) microseismic systems use widely spaced transducers to determine the source location and parameters of stronger microseismic events, while high frequency (HF) systems use fewer transducers to monitor local areas for the weaker events that can precede stronger events. Previous monitoring at the Creighton Mine indicated that an HF transducer located 120 m away from an active stope recorded two types of activity in response to production blasting: the first occurring at the same time as the production blasts and associated with the passage of the direct seismic waves from the blast through the local area, and the second occurring several hours later and associated with the arrival of a slower moving stress change through the rock mass (which was identified by the mine’s MW system). Interpretations of locally increased stress levels, based on analysis of the recorded HF events, correlated with the nearby occurrence of two strong seismic events. These results were applied to a similar monitoring trail at the Kidd Creek Mine where the transient stress changes induced by several development blasts were monitored. It was observed that increases in HF activity corresponded with the occurrence of MW events near the transducer location, and that fewer HF events were recorded the longer this occurred after the blast. Local geological features appeared to influence the number and occurrence of both HF and MW events.

Jan 1, 2000

By Caroline B. Chapleau, Mélanie Proulx, Claude Bazin, Gaétan Lavoie

"Quebec Cartier Mining operates a pelletizing plant in Port-Cartier, QC. Grinding, agglomeration and pellets induration are the three main steps in the preparation of iron oxide pellets. In 1998, following different recommendations, the company increased the speed of one of its ball mill in order to increase the grinding efficiency of the machine. As expected, the increased speed lead to an increase of the power draught, which did not produce the expected increase of fineness of grind, neither its allows to increase the mill throughput. The change of behaviour of the mill could hardly be understood by comparison of discharge size distribution at initial and modified mill rotation speed. On the other hand, the use of the selection function from a population balance model provides an insight of the changes that occurred in the mill. This paper reviews the various steps required for the estimation of a grinding mill selection function. Results of the calibration to Quebec Cartier grinding mills show that the increase in the mill speed leads to higher rate of breakage of coarse particles, at the expenses of less efficient breakage of medium and fine size particles. In the case of the studied mill, breakage of coarse particles was probably not the critical step of the mill operation. INTRODUCTIONOre size reduction is the major energy consumption step in any mineral processing operations (Austin et al., 1984). Size reduction is required to either liberate valuable minerals from the gangue minerals in which they are imbedded, or to increase the specific surface of the ground material. Plant engineers continuously face the challenge to find grinding machines, operating conditions or grinding circuit flowsheet configurations that could improve the size reduction process at lower energy or m6dia consumption."

Jan 1, 2000

By J. -S. Park, H. -S. Jeon

This study has been carried out to develop a relatively simple hydrometallurgical process for recovering nickel as nickel sulfate from the spent nickel-cadmium battery residue in which cadmium was removed by vacuum distillation. This residue is composed of 36 % nickel, 20 % iron, and other metals such as cobalt. First, crushing and selective classification were performed to separate iron to produce a nickel-rich product (over 40 % nickel). This product was dissolved in sulfuric acid to obtain a nickel sulfate solution. During the dissolution, nitric acid and air were added to the system to enhance the iron oxidation reaction rate. The free acid remaining in the dissolved solution was neutralized by adding nickel carbonate. Iron was precipitated as iron hydroxide and removed from the solution. The nickel sulfate solution was then fed to a vacuum evaporator to concentrate the solution by evaporation of water and crystallized at around 45°C to obtain nickel sulfate hexahydrate. A recrystallization process could remove other impurities such as zinc and manganese.

Jan 1, 2000

By Mike Watts

Since the first longwall panel development started in the new mining, (Southern) area, a number of roof falls have occurred in L1 and L2 gate-entries. The longwall was delayed for a total of two months due to roof falls in the gate-entries. To prevent roof falls in future gate-entries, an extensive ground control analysis has been conducted which incorporated regional horizontal stress and panel orientation, tectonic stress, roof strata, surface stream valleys, etc. Results of the analysis indicate that a combination of these factors caused the roof falls. Therefore, a Roof Instability Rating (RIR) system was constructed to predict the roof condition and identify areas where supplemental support should be implemented. The L3 gate-entries, supported by the prediction using the RIR system, have not experienced any roof problems.

Jan 1, 2000

By Michel Fontaine, Bruno St-Cyr

"The mission of the CENTRE DE RECHERCHE INDUSTRIELLE DU QUEBEC (CRIQ) is to stimulate economic development by guiding businesses in their pursuit of innovation.With a comprehensive approach to their needs, CRIQ provides businesses with expertise based on the most recent developments and insights in the fields of:Research and Development ServicesAutomation and production processesDevelopment of industrial equipmentEnvironmental biotechnologiesTesting and Product Qualification Services Industrial and Technological Information ServicesConsultancy and competitive intelligence servicesIndustrial information bankStandardization ServicesElaboration of standards and product certificationSystems registrationEXPERTISE COMPETENCE, INNOVATIONSince its founding in 1969, CRIQ has been involved in over 100,000 projects. The results of its research and development services have enabled it to build over one hundred pieces of equipment, almost all still in operation today. CRIQ has been and remains the driving force of innovation and expertise on the industrial scene, offering highly competitive solutions to a clientele from numerous industrial sectors.CRIQ became a crown corporation operating on a commercial basis on June 30, 1997. This change in its corporate structure has enabled it to put a marked emphasis on trade and implement an array of new operational practices.The formation of marketing companies with private partners, the opening up to corporate business and international markets, the new directions for internal research and the strengthening of its marketing component are among the activities CRIQ has initiated over the last fiscal year to finally reach its cruising speed."

Jan 1, 2000

By Giuliana A. Zelada

This paper reports on a study of 43 compression load tests (five fully instrumented) and ten pullout tests of auger cast-in-place (ACIP) piles in sand. Eight design methods reported in the literature were used to predict the measured pile capacities. Ultimate load capacities of the ACIP load tests were determined using two different definitions of ultimate capacity and compared with predictions. Load transfer behavior was determined from a study of the fully instrumented pile tests and compared to predicted values. Recommendations are made regarding the design approach most appropriate for these foundations and the best procedure for estimating ultimate capacity from pile load tests.

Jan 1, 2000

By M. Board, R. Pakalnis, S. Seldon, R. Brummer

The Kidd operation mines roughly 10 000 tpd of copper and zinc ore from underground and employs about 700 personnel. In the late summer and fall of 1997, major movements in the proximity of the east wall of the Kidd open pit had been observed. The Kidd pit had been mined from 1965 to 1977 to depths of 260 m (850 ft), followed by subsequent mining by underground methods to current depths in excess of 1830 m (6800 ft). The No. 1 Mine (2600 Level to pit bottom) is approximately 90% extracted, with most of the remaining reserve between 2000 and 2500 levels. Although initial concerns centred on the stability of the pit walls, the potential ramifications of the movements to the underground were recognized and measures were implemented to ensure the safety of personnel as well as to minimize the potential damage to existing operations. In late October, damage to underground operations was observed as deep as the 2000 Level. In the final assessment, the global mobilized mass was a “wedge”-shaped hangingwall block extending from surface to about 610 m (2000 ft) below surface. The “wedge” boundaries are defined by a fault and shear zone which have continuous lengths in excess of 1070 m (3500 ft); its base by shearing through the host rock mass; and its eastern face by deep tension cracks (Fig. 1). Mined and filled excavations at the western face of the “wedge” allowed mobilization of a mass in excess of 30 M tonnes. Movements in excess of 75 cm (30 in.) per day were recorded on the surface stations that preceded the complete shutdown of operations on October 29, 1997. The evaluations in the days following the shut-down were centred on mitigation of immediate and future possible negative impacts on infrastructure and mining of the remaining No. 1 Mine reserves while ensuring the safety of the operators. This effort required the rapid assessment of the potential damage of the block movement on underground infrastructure, stope access, drainage and ventilation, as well as airblast potential due to the falling of a large block into the pit near the ventilation intake at the base of the pit. These assessments were presented in a previous paper (Seldon et al., 1999). In total, the lateral movement of the block on the ground surface was over 4.3 m (14 ft). This paper describes the detailed studies performed to understand the failure mechanism and to assess the impacts on future mining in No. 1 Mine.

Jan 1, 2000

By C E. J de Ronde

Most of the world's economically significant volcanogenic massive sulphide (VSM) deposits are considered to have formed in submarine arc and backarc settings. While the Kermadec-Tonga arc is an excellent example of an intra-oceanic arc setting, it remains largely unexplored in terms of submarine mineral resources. More than half of this arc (~1400 km of the >2500-km-long feature) lies within the EEZ of New Zealand, where it is defined by at least one sub-aerial and 33 submarine volcanoes. The NZAPLUME (New Zealand American PLUme Mapping Expedition) cruise of March 1999 provided a systematic assessment ofhydrothermal activity on the southernmost 13 submarine volcanoes along the southern Kermadec arc. Using prospecting techniques based on the physical and chemical detection of hydrothermal plumes, we discovered that more than half (7 of 13) of the southern Kermadec volcanoes host one or more active hydrothermal systems at depths ranging between <200 to 1800 m. Chemical results show that the fluids discharged are compositionally diverse among volcanoes and between sites at a single volcano. Plumes over more than half of the volcanoes are gas-rich (He, CO2, H2S) relative to mid-ocean-ridge (MOR) plumes. In addition, most sites are highly enriched in Fe, yielding Fe/Mn values that far exceed those for MORs. One interpretation consistent with these observations is compositional overprinting by addition of magmatic fluids, which are typically highly enriched in gaseous and ionic components. Regardless of the source, it is clear that the ligands (HS-, Cl-) required to efficiently transport base (e.g. Cu, Zn, Pb) and precious (e.g. Au, Ag) metals to the seafloor are abundant in Kermadec arc fluids. We conclude that modem analogs of VMS deposits are likely forming at multiple sites along the Kermadec arc and within the EEZ of New Zealand.

Jan 1, 2000

By André Vien, Robert Edwards, Rob Perry

A metallurgical control application can only succeed if the system's lowest common denominator, its instrumentation and regulatory control is implemented and maintained correctly. This paper describes the basics of regulatory control implementation including some practical guidelines for instrumentation installation, operator interface design, loop tuning, and continuous loop performance analysis. Tuning and analysis techniques are illustrated by step-by-step industrial examples. A small investment in basic control pays dividends in better overall plant performance and provides a solid foundation for advanced control efforts such as expert systems.

Jan 1, 2000

By T. Shoji

"The human history is characterized by social development based on mineral and energy resources, and many conflicts to take the resources by power. This is shown by not only world wars but also many local conflicts as well as international supremacy.IntroductionThe world population after B. C. 10000, which is summarized in several papers, is approximated by four straight lines on a semilogarithmic diagram as shown in Figure 1 [l]. The annual rates of increasing are 0.0041, 0.071, 0.53, and 1.85 % from the old and young periods. The boundaries among four periods are approximately B. C. 4600, AD. 1670, and 1930. The start of the second period seems to correspond to the beginning of agriculture and cattle breeding. Precisely speaking, the usage of natural energy resources such as woods and domestic animals already began, but is inferred to have become common after the age. The third and fourth periods are characterized by the common usage of coal and oil, respectivety. Not only energy resources but also mineral resources including gold, copper, iron and others are also important for the human history.Mineral and energy resources have supported the development of the .human civilization, and have caused many conflicts because of this reason. Every day newspapers report conflicts, such as Chechnya, East Timor and Ache. We can easily point out the facts that the conflicts closely relate to mineral and energy resources. Groznyj, Capital of Chechnya, is located on the western margin of Caspian oil field. Many mineral deposits occur in Kavkaz Mountains running south of Chechnya. Subsea oil fields occur in Timor Gap located between East Timor and Australia. Ache is also one of oil fields in Indonesia. It is very difficult to state present conflicts independently of a political view of point. For this reason let us try to historically review the relation between mineral and energy resources and international domination and conflicts [2] based on many papers [3]."

Jan 1, 2000

By A. E. Dabbagh

Saudi Arabia’s mineral potential offers development target that compliment the national effort to diversify the income of this oil and gas economic based nation. Ma’aden, a joint stock company with paid-up capital of US$1 billion, has from its inception in 1997, actively developed in-house engineering and management skills to transform the Arabian shield’s mineral potential into such real projects. Gold mine operating facilities of 100,000 oz/yr underground and 50,000 oz/yr open pit are de-scribed, as well as 3 targets, two of which are underdevelopment; Al Hajar (3,000 tpd at 2.5 gpt Au)and Al Amar (5,000 tpd at 20 gpt Au). Emphasis is also on exploitation of phosphate rock and down-stream fertilizer products, based on the Kingdom’s107,000 sq. km. northern basin geological reserve. Al Jalamid, the prime target, represents 216 million tonnes of these P2O5 reserves. Saudis and expatriates, together, lead international engineering companies and contractors operating and developing these facilities.

Jan 1, 2000

By Robert Jakiel

The following paper is being presented to provide an understanding of the Deep Soil-Cement Mixing (DMM) performed at Contract C09A7 at the Fort Point Channel Site (FPC), for the I-90/I-93 Interchange of the Central Artery/Tunnel Project (CA/T), Boston, MA. The paper is written as a summary of the DMM from the DMM Contractor's perspective. The summary provides technical information and practical observations that are currently considered to be state-of-the art knowledge within the soil mixing industry. The observations and information are being provided by Robert L. Jakiel, Chief Engineer of SMW Seiko, Inc., who was the DMM Project Manager and Project Engineer for the A7 Joint Venture at FPC. The DMM was started in April of 1996 and completed in December 1999. The various acronyms and terminology used to describe the soil mixing are found in a section at the end of the paper.

Jan 1, 2000

Determining the controls of high-grade mineralisation at Vera Nancy requires careful data collection and assessment on a global and specific deposit basis. The techniques developed over 60 years ago to analyse structure, grade and width data are just as applicable today and can be enhanced using modern geological modelling software. High ore grades at Vera Nancy are controlled by both the primary geometry of the mineralised structure and the intersections of the main mineralised veins with subordinate splay veins. The main mineralised structure dilated as a consequence of extensional tectonics while the splays acted as conduits bringing oxidising surficial fluids into mixing zones precipitating high gold grades. Near-mine exploration is focussed on identifying zones of vein flexure and splay interaction to locate the relatively small high-grade shoots. Data modelling in a 3D environment is an essential process for understanding the geometry of the system being explored.

Jan 1, 2000

By Wolfgang G. Brunner

The closing of the gap in the European waterway- net is one of the big and challenging traffic projects following the German reunification. The water canals in the North German plain connect the Rhine river, the border between Germany and France, with the Oder, the German border river to Poland. As early as in the 30's of the 19th century the planning and construction of a ship- lift and a canal bridge started, in order to close this last big gap in the system between the Mittelland Canal and the Elbe- Havel Canal near Magdeburg. This main waterway connects the West of Germany, known for its coal mines and steel mills, with the capital Berlin, and from there it goes on into Poland. The building activities started in 1934 but came to a complete stop in 1942 because of the war. The communist government in East Germany was not interested in continuing this huge project, including the ship lock Rothensee, the canal bridge crossing the river Elbe, the former border river between West and East Germany, and the lock Hohenwarthe due to lack of political backing along with low construction capacity. Now this important project is in progress and this report describes the special foundation techniques used on the great ship lock Hohenwarthe. Hohenwarthe is a double- bay ship lock of considerable scale, which is notable for recirculating water rather than letting it flow. It includes 44 800 m2 ( 481 720 sq. ft) of up to 55 m ( 180 ft) deep cut- off walls, ground water control, 1248 bored piles with a depth of 22 m ( 72 ft ) serving as foundation and 28 000 m ( 91 864 ft) of soil densification with vibroflotation equipment for ground improvement. In the year 2003 the project shall be completed and all ships can travel from the West to the East through Germany without expensive and time- consuming detours through other canals and locks.

Jan 1, 2000

By T. Tamagawa, N. S. Fu, I. Iwasaki, M. Kobayashi

A 3-stage fluidizing bed process of chlorination, selective oxidation and sulfur chloride conversion was tested for processing of a chalcopyrite concentrate. It was found that the use of excess oxygen was essential to a stable operation in the oxidation reactor. The oxygen-excess gas will inevitably cause the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and the selective oxidation steps with separate flow paths of the fluidizing gases, thereby preventing the passage of oxygen-excess gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratory-scale fluidizing bed setup.

Jan 1, 2000

By K. Gie Tan, Frank Wright

"Misty Mountain Gold Limited (MGL - TSE VSE, MGLCF - NASDAQ) of Vancouver, owns the Harmony Gold Project located in the Queen Charlotte Islands of British Columbia. The deposit contains a mineable reserve of 2.3 million ounces of gold, at a 1.2 g/t cut-off and an average grade of 2.1 1 g/t Au.Discovered in 1970 and frequently investigated by previous owners, full-scale production has not yet occurred because of the complex metallurgy of the deposit. Recent process studies that were completed in six months at Process Research Associates Ltd. (PRA) of Vancouver resulted in significant improvements to the project viability. The work involved detailed mineral processing studies aimed at achieving a marketable concentrate. An option for bio-oxidation and cyanidation to allow on-site dor6 production was also investigated.The main findings at PRA followed the front-end recovery of finely divided free gold (Au) by gravity concentration. Approximately 20% of Au reported to less than 0.2% of the mass, resulting in a grade exceeding 500g/t Au. The resulting gravity tailing provided a uniform feed for flotation evaluation. The optimization of this step allowed for a reasonable primary grind size of 80% passing (&) 50pm. Efficient slime’s rejection was made possible by flotation at a reduced pulp density, and pre-oxidized sulphides were reactivated with Na,S. The regrinding of the bulk flotation concentrate followed by up to five stages of cleaning resulted in a combined gravity + flotation product of 50g/t Au with 82% recovery in less than 4% of the feed mass.Further studies indicated that the flotation concentrate was amenable also to tank bio-oxidation. At 65% sulphide oxidation the gold recovery improved from less than 70% to 90% by cyanide extraction using CIL (carbon in leach). This compares to less than 45% gold recovery from whole-ore cyanidation in several previous studies. Heap leaching may also be considered for lower grade material. PRA’s methodical approach and consistent results dispelled the uncertainty about predicting the material behavior for the Harmony Property."

Jan 1, 2000

By Fuzail Siddiqui

"The SIDMIN program aims at filling the mineral processor’s need to know the deportment of ‘minerals of interest’ not just ‘elements of interest’ that pass through the processing plants. Generally, chemistry is used as a tool of routine monitoring on site. Mineralogy, which is relatively much slower, is used more as a tool of research and post mortem investigations and these services are usually provided by a distant facility. The SIDMIN program enables site management to receive chemical and quantitative mineralogical reports on their critical samples daily, simultaneously and affordably.The author developed the SIDMIN program at ZCCM Nchanga Division where it continues to be a powerful tool for monitoring the efficiency of operations. Outlines are given of procedures for quick sample preparation and quantification of significant minerals in process samples. A specimen report is presented, which shows the format of reporting the contributions of individual minerals to metal losses at critical stages of the circuit. It is shown that SIDMIN provides timely information to management, about trends and abrupt changes in the quality of ore, and its processing, in a way never achievable by chemical analyses alone. This greatly helps in resolving the age-old problem of ‘bad ore’ or ‘bad operations’ on a day-by-day basis. For example increase in copper mica in the feed indicates excessive ore dilution during mining. Increased loss of free sulphides was traced to insufficient reagent conditioning time at the Concentrator. Persistent losses of leachable oxides at the Tailings Leach Plant were traced to inadequate leach residence time.SIDMIN is affordable because it can be implemented using basic optical microscopes, minimal quantities of micro-chemical reagents and custom trained site staff who demonstrate good colour perception and an ability to follow laid down procedures consistently."

Jan 1, 2000

By L. P. James, W. W. Atkinson

Utah has produced about one billion troy oz. (31.7M tonnes) of silver, more than any U.S. state except Idaho. Several very high grade ore systems, now closed, occur within large polymetallic limestone-hosted districts related to plutonic complexes. These Utah mines fed several major lead smelters for nearly a century. Interaction of magmatic chloride-rich fluids with carbonate rocks localized significant bonanzas within these districts. A low sulfidation state was produced in the fluids by their passage through limestones. The Bingham porphyry mine has also yielded more byproduct silver than other porphyry copper-gold systems. Away from exposed intrusive rocks, some large silver-only systems occur in Mesozoic sandstone and in caldera-related veins in volcano sedimentary rocks. Thick permeable latest-Proterozoic basement meta quartzite sequences present beneath western Utah may have been important, as perhaps they were in the Coeur d’Alene district of Idaho, in providing chloride and silver-rich ore fluids. However, it is clear that specific Tertiary magmatic events played an essential role in the evolution of the Utah silver-rich metallogenic province. The largest silver districts in the state are genetically related to porphyritic plutonic rocks.

Jan 1, 2000

By D Mee

The Western Mining site at Olympic Dam, near the community of Roxby Downs in South Australia is one of the largest orebodies of its type in the world. It contains known reserves of over 10.6 M tonne of copper, with economic secondary metals including uranium, silver and gold. In 1996, an expansion project was commenced to increase mine production approximately threefold, to produce 200 000 tonnes pa of copper, 4600 kg pa of uranium oxide, 3600 kg pa of gold and 50 000 kg pa of silver. This expansion included both underground mining and surface processing investment. Because of the scale of operations, it was decided that ore should be transported underground by a railway system. In July 1997, ALSTOM Automation and Control Limited (then Cegelec Australia Limited), was awarded the contract to deliver a control system to manage and automate the rail haulage system for Western MiningÆs Olympic Dam Mine, as part of this major upgrade and extension project. This paper explains the overall design and the approach taken to implement route selection, route locking, train interlocking and track topology using normal industrial control equipment such as Programmable Logic Controllers. Included is a discussion of how this automation has improved the productivity of the haulage system by more than 15 per cent.

Jan 1, 2000

By Edgardo Salas M

El presente texto describe la geología del yacimiento polimetálico de Iscaycruz. Dicha mina está situada en el distrito de Pachangara, provincia de Oyón, al norte del departamento de Lima, donde predominan los sulfuros de zinc, confinados al ámbito de la formación calcárea Santa, tanto en el piso como en el techo.Su mineralización corresponde al tipo de reemplazamiento hidrotermal, conformado por minerales de zinc, plomo, plata y cobre; y se encuentra formando mantos en las calizas de la formación Santa.

Apr 26, 1999