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By R. A. Hill, J. D. Pitts

"Long distance slurry pipeline systems have been successfully trans-porting steam coal, iron concentrates, copper concentrates and limestone for an aggregate of nearly 60 years and nearly three billion ton-miles annually. A phosphate concentrate pipeline is nearing start-up and systems for coking coal, lead/zinc concentrates and fly ash are planned. The solids pipeline concept, first patented in the early 1900's and commercialized in the 1950's, is now a proven technology providing an economic, environmentally pleasing and safe method for long distance bulk transport.The challenge for larger tonnage and longer distance movements of solids, for traversing increasingly rugged terrain in grass roots mineral developments, for transporting untried materials and for shipping more economic forms of proven materials still remains. This has necessitated continued refinements and optimization of the technology. The economic and environmental incentives for slurry pipelines when compared to other transport alternatives has justified substantial activity in this area. The scope of planned systems in coal, iron and other minerals is indicative of the firm place slurry pipelines will have in worldwide mineral development.In this presentation, the state-of-the-art in long distance slurry pipelines is reviewed with a focus on major systems of interest to the mineral processing industry. An overview of new developments in the application of this concept is presented, and finally, a projection of the future of pipelines in mineral development both worldwide and in Canada is discussed."

Jan 1, 1978

By Lachezar Tsotsorkov

Corporate social responsibility Is a principal trend of the corporate strategy for sustainable development of Assarel-Medet JSC ? the largest Bulgarian company for open pit mining and ore processing the production activities of which date back to 1964. Sustainable development Social responsibility is considered as one of the three pillars for sustainable development, together with the economic and environmental responsibility.

Aug 1, 2013

By D. Settles, R. Rose, P. L. Dunn

"A new mineral sands operation is being developed in Georgia by Southern Ionics, Inc. (SII). Prevailing mineralogy and certain design constraints required detailed testing and circuit analysis to create a robust separation processes. The floating wet concentrator plant (WCP) and mineral separation plant (MSP) flow sheets were designed based on historical testing information and recent SII test campaigns on various composite feed samples. The flow sheets were finalized through rigorous process and orebody sequence modeling.The process uses traditional physical separation equipment; however a new MT spiral, the MG12, was selected for use on board the WCP for roughing duty. The MG12 spiral is a two-stage, twelve-turn spiral that has been proven to achieve very high recoveries of heavy minerals. The floating plant includes feed desliming operations, a central MT surge bin for optimum spiral circuit feed control and ancillary operations for concentrate and tailings handling. Scrubbed heavy mineral concentrate (HMC) is then transported to the MSP for concentration of the titanium and zirconium bearing mineral fractions.The testing, flowsheet development, and plant design will be described and explained, and a brief summary of the current project status will be given.IntroductionSouthern Ionics Inc. (SII) is a privately held chemical manufacturing company, founded in 1980 by Milton Sundbeck. SII focuses primarily on the sale of specialty and intermediate inorganic chemicals. Core markets include cement and refinery catalysts, molecular sieves, zeolites, pulp and paper, pharmaceuticals, TiO2 and water treatment. SII is built on the four cornerstones of service, quality, technology and delivery with all SII facilities ISO certified and key products used in potable water treatment certified to NSF standards. SII owns and operates its own transportation fleet and is focused on being a low cost producer, committed to safety and the environment."

Jan 1, 2015

By T. Banerjee, D. Felsher, G. Leavoy

"Lake Shore Gold is engaged in commercial gold production at both the Timmins West and Bell Creek mines, located in Timmins, Ontario. Run of mine ore is processed at the Bell Creek mill which consists of a conventional gold mill flow sheet involving crushing, grinding, gravity concentration and carbon-in-leach (CIL) for gold recovery. Since 2009, the operating capacity of the mill has been upgraded from 2000 tpd tonnes per day (tpd) to over 3,000 tpd. The most recent expansion involved the installation of a low aspect ratio SAG mill to replace the secondary crusher. Without operational data on the low aspect mill, combined with a site team that was new to SAG milling, there were many challenges in achieving the target throughput from the circuit. Through the implementation of AwaRE advanced controllers, running in closed loop with PRC fragmentation cameras as well as embedded PARC modules within the Allen Bradley PLC, the site was able to rapidly develop a best operating practise and has been successful in creating a stable and consistent operational environment. The process, lessons learned and eventual solution will be reviewed in this paper.INTRODUCTIONLake Shore Gold is engaged in commercial gold production at both the Timmins West and Bell Creek mines, located in Timmins, Ontario. Run of mine ore is processed at the Bell Creek mill which consists of a conventional gold mill flow sheet involving crushing, grinding, gravity concentration and carbon-in-leach (CIL) for gold recovery. Since 2009, the operating capacity of the mill has been upgraded from 2,000 tpd tonnes per day (tpd) to 3,150 tpd. The most recent expansion involved the installation of a low aspect ratio SAG mill to replace the secondary crusher. This endeavor was split into two phases: the expansion of the back-end (Phase 1) and the front-end (Phase 2) of the mill. Phase 1 of the expansion was completed at the end of 2012 and involved enhancements and capacity addition to the leaching and adsorption circuits, which increased the mill’s capacity to 2,500 tpd. Phase 2 of the expansion commenced at the end of July 2013 and involved the expansion of the crushing and grinding circuits. The expanded front-end of the mill now has a capacity of 5,500 tpd, and processes ore from both Bell Creek and Timmins West mines. The updated flow-sheet, as shown in Figure 1, illustrates the replacement of the two-stage crushing and ball milling circuit with a single stage crusher and a low aspect ratio SAG mill."

Jan 1, 2015

By G. Styles, K. Lye, R. Tenbergen, M. Mayhew

Requirements to produce a higher bulk concentrate grade have necessitated extensive use of on-stream analyser data and computer programming to obtain the targets set for Frood Stobie Mill as required by overall milling considerations.A brief history of milling process changes associated with the changes from a low grade (3% Ni) bulk concentrate in the sixties to a high (6 to 8.5%). Nil bulk concentrate currently will be presented.The heart of the presentation will be the computer control schemes for ""self optimisation"" of the distinct flotation sections in the plant within certain restraints to achieve targets set by the mill metallurgist.

Jan 1, 1985

By G. Cordingley, A. Mwanza

Lumwana is an open pit Copper mine located in the Northwestern Province of Zambia approximately 80 km west from the provincial capital of Solwezi, approximately 300 km northwest from the Copperbelt and 700 km northwest from the national capital of Lusaka. The mine has two major Copper deposits: Malundwe and Chimiwungo. Copper mineralization includes Chalcopyrite, Bornite and Chalcocite. In addition to Copper, these deposits also contain the undesirable element Uranium contained in vein hosted and disseminated Uranite. The processing plant was designed using conventional technologies: semi-autogenous grinding (SAG) and ball mill for grinding, and mechanical cells for rougher and cleaner flotation. Soon after commissioning in early 2009, it was recognised that two stages of conventional cleaning were unable to produce plant final Copper concentrates with the desired Uranium grades. Studies have shown that a significant quantity of liberated and fine Uranium particles (up to 80-90%) is recovered with the concentrate by entrainment. Lumwana Operations sought the use of the Jameson Cell technology after observing successful implementation at other sites in rectifying similar issues. In late 2009, Jameson Cell pilot-plant test work was conducted at the site and this quickly led to the installation of a full-scale B5400/18 model into the existing cleaner circuit. Inclusion of the Jameson Cell resulted in the plant being able to effectively produce clean and saleable concentrate with Uranium contents consistently below acceptable levels. Initially designed to be used as a cleaner scalper cell at the head of the existing conventional cell circuit, subsequent operational issues with the existing recleaner cells forced reconfiguration of the cleaner circuit and reintroduced the Jameson Cell for the recleaning duty. This paper reports the Lumwana Operation from the first two years of operation where it struggled to produce a saleable concentrate with Uranium grades below 150 ppm, which is the maximum allowable limit set out in the smelting contracts, to steps taken in the subsequent years to implement a satisfactory solution. The plant can now consistently produce a clean Copper concentrate with Uranium grades well below 130 ppm and the overall improvements implemented at site have seen the overall plant recovery improve by 1.3%.

Jan 1, 2014

By Marius Jacobs

"Safety performance in many companies and even industries has stalled in the few years. Accidents rates are at a "plateau" and yet, serious accidents and fatality rates are not. In more dramatic cases, such as in the BP Texas disaster, organizations that have "exemplary" safety statistics, suddenly have a catastrophic or multi-fatality event occurring. Other classic examples are the Piper Alpha disaster and NASA’s Challenger and Columbia disasters and even the Chernobyl nuclear reactor. Looking into the root causes of these accidents provides an insight into the events and deficiencies that led up to the accident, but what are the common features in the organization’s mindset? What characterizes these organizations’ decision-making, their approach to safety and to risk and are there specific cultural features that can be delineated? The research and review presented in this paper covers a period since 1994, which started in the Australian resource industry and since then covered international events. The features of these organizations are summarized as the seven deadly delusions, based on extensiveresearch since 1997 of organizations that suffered unexpected disasters.The Piper Alpha Oil Rig disaster in the North Sea, on the 6 July 1988, was one of the most pivotal events in safety around the world. It changed the thinking and focus of governments, whole industries and led to numerous books and papers. It resulted in new legislation, textbooks and a critical self-examination by the oil and gas industry.In short, an explosion and fire occurred when a pipe started leaking gas and ignited. A temporary flange, with no safety valve, was used to block off this pipe during a maintenance operation the previous shift. The permit to advise operators not to start the pumps on this line was misplaced and lost. Several deficiencies, problems and system failures coincided. A key factor was that the water deluge system was inoperable at the time and failed to extinguish the large fire that erupted, followed by an even larger gas explosion. The accommodation unit, situated on top of the oil rig, was the main "killing field" - most men gathered here to await instructions (which never came) and where they died from smoke inhalation. Later, a large explosion of the gas pipeline from an adjoined rig exploded and killed more people.The line of events and the associated system failures are all very relevant in the analysis of the accident, and provide the only insight into what caused the accident. But much "further back", inside the organization’s culture, lurks more dark matter. The first inclination is to ask what was "deficient" in the culture. Did they not care enough about safety, or about their people? Did they have a culture where production decisions were more important than safety considerations? Did they ‘coerce’ supervisors and employees to ignore safety precautions or did they just "fly by the seat of their pants"?Not surprisingly, it is very difficult to identify the true nature of the culture in that business because in such an aftermath of death and destruction, no one dare say that the safety culture was a ‘positive one, focused and caring’ or that the company was doing well in safety and that this is only a freak accident. Indeed, there were many deficiencies in the organization’s systems and procedures, such as the permit to work system.But there are some niggling questions: How is then that the Piper Alpha Oil Rig was actually considered the company’s most productive and safest oil rig in the North Sea? Why would this rig win a safety competition, 6 months before the disaster, with the deficient permit as its most outstanding successful system?"

Jan 1, 2014

By Chris Larsen, Carole Fortin, Dave Scott, Curtis Deredin, Ian Orford, Jean Guy Gauthier, Andy Trusiak, Lyne Côté, Mike Cooper

"Upon successful commissioning of the Stage Grinding Project (Cormier et. al., 2002), process improvements predicted through pilot plant testing were obtained in several flotation circuits, resulting in higher grades and recoveries for zinc and lead concentrates. Subsequent to establishing new baseline operating conditions from the Stage Grind Project implementation, additional opportunities were identified, and through the application of Six Sigma methodologies further gains were made. Six Sigma improvement projects were carried out in the copper-lead, zinc, lead upgrading and bulk flotation circuits. The overall performance increase resulting from incremental improvement projects has been substantial.Most remarkably, given the operational maturity up to the late 1980’s, the Brunswick concentrator team has continued to deliver a steady stream of major improvements over the past fifteen years. While senior managers and their programs have changed several times, there have been some critical constants over the long run. Common elements have been a commitment to team work, a commitment to recruit and maintain technical personnel, a structured business improvement framework supported organizationally by senior management, and focus on a few priority initiatives rather than trying to fix everything at once.The paper briefly discusses the longer term setting and then endeavors to illustrate, with examples, how improvements are presently achieved by applying the Six Sigma quality program.INTRODUCTIONThe Noranda Inc. Brunswick Mine, located near Bathurst, New Brunswick, is one of the world’s larger lead/zinc mines. Milling of ore began in 1964 from the No. 12 orebody, with an expansion in 1966 to accommodate ore from the No. 6 mine. In excess of 100 million tonnes have been milled to date. The concentrator employs differential flotation to produce lead, zinc, copper, and lead/zinc bulk concentrates. The ore is massive sulphide, with approximately 20% valuable minerals, 60% pyrite and 20% silicates."

Jan 1, 2005

By H. Ito, T. Takasu

Effects of a mechnochemical treatment to oxide Ni ores have been investigated to enhance the extractive ratio of Ni from them in acid leaching process. High intensity grinding by a planetary boll mill showed strong effect to enhance the extractive ratio of Ni, for example , 10% of extractive ratio of Ni in sulfuric acid leaching(0.05mo1/1,at room temperature) increased to more than 90% with 60min. of planetary boll milling. Effects of additives(sulfur and some oxidants) on the mechnochemical treatment have also studied. Sulfur showed almost no effect to enhance the total Ni extractive ratio but increases the selectivity of Ni extraction. More than a half of Ni could be extracted by water when Ni ore was grinded at addition of Na2S207 in the milling treatment. Some effects of mechnocemical treatments to Ni ore are summarized in this paper.

Jan 1, 2005

By Niklas Frank

Ore and waste transports form an integral part of any mining operation and represents a substantial portion of the mine´s total operating cost. Mine layout, truck fleet and size, production rates, haulage distances, shift schedules, maintenance strategies etc. are all important and not at all static variables. They all change during the life of a mine and interact in a dynamic way. It is therefore essential for the successful mine management to constantly analyse and optimise the mine's transport systems. Önnerlöv has recently conducted a life-of-mine haulage simulation project for Zinkgruvan Mining, a medium sized, underground zinc producer, located approximately 60 kilometers south of Örebro, Sweden. The main objective of the project was to analyse and optimise the investments required to provide ore and waste haulage under changing conditions over an +10- years period: Deepening of the mine, increased production rates, changed mine layout, changed truck fleet etc. A large number of scenarios has been tested in the simulation model in order to identify the "lowest cost per ton" solution. This paper comprises an introduction of Zinkgruvan Mining and a brief background to the actual project, a description of the simulation model, project conclusions and some useful hands-on tips for mining engineers and project managers how to run a successful simulation project.

May 1, 2003

By Dave Rose, David G. Meadows, Mike Westendorf

"Copper Mountain’s concentrator was commissioned in May 2011. The circuit consists of a 34’ x 20’ EGL SAG mill, a Raptor 900 pebble crusher and two 24’ x 39’6” ball mills. Each mill is equipped with a 2 x 8500 HP dual pinion drive system. The plant was designed to process 1585 mtph of SAG feed. From startup, the mill struggled to meet the required production rates. Over time, a major initiative that involved blasting and fragmentation, optimization of the SAG mill in terms of discharge grates, ball size and slurry density, and operation of up to three mobile pre-crushing plants resulted in significant increases in throughput. In parallel, a number of modeling tools, including JK SimMet, were run based on plant benchmarking exercises. Samples collected at the mine site during ramp up confirmed the very competent nature of the ore with drop weight - A*b values of less than 24 being recorded on a variety of plant feeds and lithologies. After due consideration including demonstration of proof of concept, a new pre-crushing circuit incorporating an XL2000 cone crusher and associated screening equipment was designed, constructed and commissioned at the site in August 2014. This paper reviews the history of the original circuit design, the various optimization steps taken and impacts, together with the final pre-crushing circuit and net results.IntroductionThe Copper Mountain Mine is located approximately 20 km south of Princeton, British Columbia, Canada (refer to Figure 1). The region has a long history of copper mining dating back to 1923. The Copper Mountain camp occurs in the 'eastern volcanic belt' of the Nicola Group (Monger, 1989). It is an alkali copper-gold deposit in which the volcanic strata are intruded by early Jurassic dykes, sills, irregular plugs and zoned plutons (Woodsworth et al., 1992). The stratified rocks are relatively fresh with slight metamorphism in the local contact regions."

Jan 1, 2016

By A. Pratt

Portland cement is primarily used to solidify backfill in underground mine workings and it represents a major cost in mining operations. CANMET-MMSL has invented an alternative binder technology that does not contain any amount of Portland cement and is made using waste materials, such as development rock and smelter slag. The technology has been successfully tested with many types of base metal and ferrous slag. Research conducted in collaboration with several mining operations in Canada has shown that the CANMET-MMSL binder has considerable potential as a replacement for Portland cement in mine backfill. An integral part of the overall mining operation, backfill is used for two main purposes: safety and environmental remediation. Depending on the mining method used, backfill provides a working surface, stabilizes stope and pillar walls, as well as the surrounding rock mass, and controls caving of stope backs. There are several benefits associated with the replacement of Portland cement in backfill, including reductions in (i) the footprint by placement of slag waste underground, (ii) the environmental effects and long term liability resulting from disposal and containment of slag waste on surface such as acid rock drainage, (iii) GHG as a result of reduced Portland cement usage (the production of 1 ton of Portland cement produces 1 ton of GHG), and (iv) the significant costs associated with reduced Portland cement usage.

May 1, 2010

By P. Kolodziejczyk

Mining seismicity can be harmful both under and on the surface. ? Tremors are not totally damaging, but destructive to buildings and infrastructure, especially in highly urbanized regions, such as Upper Silesia in Poland ? Destroy the social appreciation, trust and support for mining industry ? To prevent or reduce these effects, engineers and scientists develop methods allowing prediction of ground shaking intensity near buildings and various losses that can result from it Evaluation and prediction of mining tremor?s damaging influence on buildings is usually solved with two steps: ? Estimation of local ground shaking intensity (based on known attenuation relation) and classification into one of several predefined intensity intervals ? Apply supposed relation between the shaking intensity interval and qualitatively defined damaging effects to express predicted effects This makes a mixed quantitative/qualitative procedure, difficult to analyze or optimize

Aug 1, 2013

By B. M. Coombes

The McCracken and Stacey (1989) method of assessing geotechnical risk for largediameter raisebored shafts has been the basis for most Australian pre-construction raisebore investigations for the past 20 years. At the time of its publication, the McCracken and Stacey (M&S) Method did not include a database of raisebore diameter and rock mass conditions versus actual performance. It did, however, provide a chart that quantified geotechnical risk in terms of proposed shaft diameter and the raisebore rock quality index, QR. Two parameters, RQD/Jn and Jr/Ja were identified as being critical to raisebore stability, but the contribution of these to overall raisebore stability was not quantified. Peck and Lee (2008) published a database of raisebore performance from Australian case histories. Raisebore diameter and ground conditions, in terms of a Lower Bound QR value, were presented for 50 cases versus raisebore performance. This paper updates the database with further case histories and corrected SRF values. This paper further evaluates the reasons for the variable raisebore performance for similar RSR values. For all case histories, three parameters, RQD/Jn, Jr/Ja and Jw/SRF are investigated to assess their influence on raisebore performance.

May 1, 2011

By S. Bellec, A. Berton

"Usually, steady state mass balances are used for the design of mineral processing plants. However, this tool does not take into account the impact of process inputs variability nor does it evaluate process transient behaviours between stationary states, such as mill start-up and shutdown. The use of advanced simulations enables the integration of dynamic behaviours in process design decision-making by highlighting situations that are undetectable by using only steady state mass balances. Applying these simulation tools to brown field projects allows the simulator performances to be calibrated and validated on actual plant data before it is used as a prediction tool for the modified plant.Three (3) simulators were implemented at the design stage of a major upgrade project for an ore processing plant in order to assess process behaviours under different production scenarios. These simulators were built to evaluate the impacts on major elements such as mine production, ore stockpile, concentrator production as well as water demand. A validation of individual equipment models was performed whenever sufficient measured data was available. The simulators were then used to study the impact of ore variability (grade, hardness, throughput), to assess day-to-day production special events, and to evaluate the true stockpiles live capacity.The use of a stochastic simulator for equipment sizing allowed a more precise sizing of many pieces of equipment and avoided important expenses in the fresh water pumping system. The dynamic simulator also confirmed that the water in place system would suffice, even in the most demanding production scenario. Finally, the stockpile simulator allowed an important production bottleneck to be quantified and then made possible the assessment of various practical solutions for the stockpiling-reclaiming issues.Post start-up, process data underlines the fact that using advanced simulation tools was useful to mitigate process-related risks associated to the plant expansion, showing generally accurate prediction and adequate equipment sizing, leading to smooth process commissioning. The presented methods are part of what is now routine in Soutex’s participation in both greenfield and brownfield projects."

Jan 1, 2015

By A. J. Williams

"Conventional base metal milling practice normally consists of crushing, grinding and cyclone classification followed by flotation. It is the authors' belief that the commencement of flotation after cyclone classification leads to inferior metallurgical results and that implementation of flotation of grinding mill discharges can result in increased recovery due to reduced overgrinding, reduced activation of contaminating minerals and improved dewatering circuit results due to the production of coarser concentrates.The concept of recovering minerals from the discharge of grinding mills is not new! Gold concentrators have utilized jigs and flotation cells while iron ore plants have employed magnetic separators to recover gold and magnetite respectively from the discharge of grinding mills. More recently, a Reichert cone has been used to recover sulphide and oxide base metal minerals from screened rod mill discharge. 1To the authors' knowledge, the first application of flotation of base metal minerals from the discharge of a production plant grinding mill was at the Lake Dufault concentrator of Corpor'1tion Falcon bridge Copper. Located 10 miles north of Noranda, Quebec the Lake Dufault concentrator commenced operations in August, 1964.The installation of flot11tion cells in the Lake Dufault grinding circuit proved so successful that an identical system was installed in the Manibridge concentrator of Falconbridge Nickel Mines Limited. Located 90 miles southwest of Thompson, Manitoba the Mamibridge concentrator commenced operations in June, 1971 and due to exhaustion of economic ore reserves discontinued production in May 1977."

Jan 1, 1984

By Gary Anderson

??Privately Held Corporation ??Incorporated in Delaware, May of 2002 ??HQ in Malvern, PA (just outside Philly) ??Approx 40 employees ?9 Field Engineers ?MSHA Certified ?10 Development/NOC Engineers ?Site Survey/Site Design ?RF Engineers ??Standards Based ?IEEE 802.11 ??Commercial Off the Shelf (COTS) ?Gateworks, Ubiquity, Atheros, Linux Based ??Technology was developed and inspired by the lack of communications during the terrorist attacks of Sept. 11, 2001

May 1, 2009

By Tassos Grammatikopoulos, Gary Pearse, Massoud Aghamirian, Charlotte Forstner, Stephen Mackie

"SGS Minerals Services (Lakefield, Ontario site) has conducted a number of developmental and pilot programs that examined methods for the beneficiation, extraction and recovery of lithium from a variety of spodumene containing hard rock sources. An overview of the beneficiation programs is presented separately by Aghamirian, Mohns, Grammatikopoulos, Imeson & Pearse (2011). The focus of this discussion will be the hydrometallurgical steps involved in producing a high grade lithium carbonate (Li2CO3) sample from the spodumene concentrate. SGS has applied the standard Li2CO3 hydrometallurgical flow sheet to a number of spodumene concentrates and has determined that all of these samples respond in a similar manner to the process and produce a final product having a Li2CO3 grade of >99.5%. The standard process is sufficiently robust to accommodate the observed variability in the concentrates that have been tested. Advantage of one spodumene deposit over another will thus be gained through process optimization and innovation. Optimization at the beneficiation stage and at the hydrometallurgical stage must be considered. Some aspects of the process optimization of the hydrometallurgical flow sheet will be presented.INTRODUCTION The current activity in the exploration, development, and mining of lithium based minerals is due in large part to the key role that this metal plays in the rechargeable battery industry (U.S. Geological Survey, 2011). Lithium battery technologies are widely applied in a range of portable electronic consumer products. The expanding development and production of hybrid and fully electric vehicles has contributed to the increased interest in finding and developing new lithium sources in order to meet the expected demand from the lithium battery industry. Lithium may be sourced from continental brines (sub-surface salars), hard rock minerals (pegmatite, spodumene), hectorite clay deposits, geothermal brines and oilfield brines. Currently the majority of the lithium products are produced from Li brines. The four major lithium producing countries are Chile, Australia, China, and Argentina (U.S. Geological Survey, 2009; Roskill, 2009). These countries accounted for 97.6% of the total lithium produced in 2010."

Jan 1, 2012

By G. R. Dunning, M. R. Wilson

"Abstract - The early Paleozoic accretionary tectonic regime that was established along the Laurentian margin of the Newfoundland Appalachians provided a favorable setting for shear-hosted gold mineralization along a major terrane suture, the Baie Verte-Brompton Line. The Stog’er Tight prospect is one of several mesothermal-style gold occurrences hosted by shear zones within accreted ophiolites and oceanic arc terranes on the Baie Verte Peninsula. It is an epigenetic, stratabound deposit that is confined to shallow-level gabbro sills within the volcanic cover sequence of the allochthonous Point Rousse ophiolite complex. Gold mineralization at Stog’er Tight is associated with hydrothermal mineral assemblages represented by chlorite-calcite, sericite-ankerite, red albitepyrite (±Au) and chlorite-magnetite alteration zones. Gold occurs with pyrite within the intensely altered gabbro, along the margins of syn- to late-shear, quartz-rich, replacement veins.The Stog’er Tight gabbro served as a rigid body conducive to shear deformation and fluid penetration, whereas, its high Fe-Ti oxide content induced fluid oxidation and gold-pyrite precipitation. Hydrothermal alteration involved progressive CO2, S, Na, and LILE metasomatism, along with significant enrichments in the REE, HFSE, and Th in the high-grade ore zone. Temperatures of vein formation and alteration are constrained by oxygen isotope thermometry to be between 250°C and 480°C. Isotopic compositions of vein quartz from the Stog’er Tight prospect are uniform (??O = +12.5 ± 1‰) and fall within the range cited for many shear-hosted, auriferous quartz veins.A U-Pb zircon igneous age of 483 +3/-2 Ma for the Stog’er Tight gabbro is consistent with its stratigraphic correlation with other Ordovician ophiolitic and volcanic arc/back-arc assemblages in Newfoundland. The U-Pb age of a rare variety of hydrothermal zircon recovered from the high-grade ore zone directly constrains the timing of gold mineralization to 420 ±5 Ma, in accord with a major orogenic episode of Silurian age that produced many of the magmatic and metamorphic rock suites in north-central Newfoundland. Our results are consistent with a post-peak metamorphic, late-magmatic model for gold mineralization that occurred during the waning stages of Silurian orogenesis, driven by emplacement of I-type granitoid intrusions into the crust."

Jan 1, 2000

By James Ransford Dankwah

This work investigates the effect of waste plastics addition on the reduction of iron oxide by sawdust. Composite pellets of iron oxide containing sawdust (SD), high density polyethylene (HDPE) and blends of SD/HDPE were fired under argon in a horizontal tube furnace at temperatures between 1300 and 1500 °C. Reduced samples were weighed after 10 minutes of reduction and the extent of reduction was calculated from the measured oxygen contents of the compact. The results showed improved extent of reduction when SD was blended with HDPE. The highest extent of reduction was achieved at SD:HDPE ratio of 2:3.

Jan 1, 2014