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The information in this document has been prepared as at February 16, 2011. Certain statements contained in this document constitute ?forward-looking statements? within the meaning of the United States Private Securities Litigation Reform Act of 1995 and forward looking information under the provisions of Canadian provincial securities laws. When used in this document, the words ?anticipate?, ?expect?, ?estimate?, ?forecast?, ?will?, ?planned?, and similar expressions are intended to identify forward-looking statements or information. Such statements include without limitation: statements regarding timing and amounts of capital expenditures and other assumptions; estimates of future reserves, resources, mineral production, optimization efforts and sales; estimates of mine life; estimates of future internal rates of return, mining costs, cash costs, minesite costs and other expenses; estimates of future capital expenditures and other cash needs, and expectations as to the funding thereof; statements and information as to the projected development of certain ore deposits, including estimates of exploration, development and production and other capital costs, and estimates of the timing of such exploration, development and production or decisions with respect to such exploration, development and production; estimates of reserves and resources, and statements and information regarding anticipated future exploration; the anticipated timing of events with respect to the Company's minesites and statements and information regarding the sufficiency of the Company's cash resources. Such statements and information reflect the Company's views as at the date of this document and are subject to certain risks, uncertainties and assumptions, and undue reliance should not be placed on such statements and information. Many factors, known and unknown could cause the actual results to be materially different from those expressed or implied by such forward looking statements and information. Such risks include, but are not limited to: the volatility of prices of gold and other metals; uncertainty of mineral reserves, mineral resources, mineral grades and mineral recovery estimates; uncertainty of future production, capital expenditures, and other costs; currency fluctuations; financing of additional capital requirements; cost of exploration and development programs; mining risks; community protests; risks associated with foreign operations; governmental and environmental regulation; the volatility of the Company's stock price; and risks associated with the Company's byproduct metal derivative strategies. For a more detailed discussion of such risks and other factors that may affect the Company?s ability to achieve the expectations set forth in the forwardlooking statements contained in this document, see the Company's Annual Report on Form 20-F for the year ended December 31, 2009, as well as the Company's other filings with the Canadian Securities Administrators and the U.S. Securities and Exchange Commission. The Company does not intend, and does not assume any obligation, to update these forward-looking statements and information. Marc Legault, a Qualified Person and the Company?s Vice-President, Project Development, reviewed the technical information disclosed herein. For a detailed breakdown of the Company?s reserve and resource position see the February 16, 2011 press release on the Company?s website. That press release also lists the Qualified Persons for each project.

May 1, 2011

By John Kazakoff, Andrew Mortimore

"Production at the remote Kumtor Gold Mine in Kyrgyzstan commenced on schedule in December 1996.The ore mined during the first few months of 1997 from the upper benches of the pit did not produce the results predicted by the feasibility study. Low metallurgical recoveries experienced at the time were cause for great concern.It soon became clear the recovery difficulties centred around the preg robbing nature of the ore.Procedures were developed to selectively stockpile highly carbonaceous low recovery ore types. Testing methods were developed in the mill to quante the preg robbing activity of the ore. Preg robbing masking agents were added to the process to reduce the preg robbing activity of the ore.The importance of coconut carbon activity relative to the preg robbing activity of the ore was realized. Every aspect of the performance of coconut carbon in circuit was evaluated and optimized to improve carbon activity.Mineralogical analyses were completed defining the deportment of gold in ore and process tailingsBy year end the recovery difficulties had been overcome and plant design production had been achieved. Process improvements continue through 1998."

Jan 1, 1999

By C De-Vitry

"The large Yandi channel iron deposit (CID) is located in the north-west of Western Australia and is currently mined via open pit methods. Drilling at Yandi is widely spaced and current estimates are mostly linear averages of the surrounding local samples. Linear estimates such as ordinary kriging (OK) based on block sizes that are significantly smaller than the dimensions of the drilling grid are less variable than the unknown reality (Armstrong and Champigny, 1989).Conditional simulation (CS) provides a series of plausible realisations that represent the actual grade variability at a small scale (eg 1 m + 1 m + 1 m). These simulations are very useful for a number of purposes, eg: optimising grade control, stockpiling and blending selection of optimal drill hole spacing assessing resource risk on contained tonnage and metal.At Yandi the major constituents of the ore (Fe, P2O5, SiO2, Al2O3 and LOI) are correlated to varying degrees. Independent CS of each assay variable will not reproduce these correlations. Reproducing the correlations (and the shape of scatterplots) is important if the simulations are used for the abovementioned purposes. This paper examines and compares various methods of CS that aim to reproduce the correlations between the assay variables.The CS methods evaluated in this paper are conditional co-simulation (CCS) using the linear model of co-regionalisation and two other, alternative multivariate simulation methods, which use min/max autocorrelation factors (MAF) or the stepwise conditional transform (SCT) to de-correlate assay variables before performing independent CS. It was found that CCS best reproduced the characteristics (histograms, variogram, scatterplots, etc) of the declustered drill hole data (Figure 1). Whilst simulation using MAF generally produced acceptable results, the method did not adequately reproduce the variance of the assay variables. The univariate statistics, histograms and experimental variograms were acceptable for simulations generated from the SCT. Bivariate statistics, cross-variograms and scatterplot reproduction for the SCT were unacceptable. The latter method produced inferior results because there were insufficient samples to obtain a reliable transform of the third assay variable in the transformation sequence.None of the abovementioned simulation methods provides good reproduction of all the scatterplots. This is due to the presence of clay pods, which cause some scatterplots to display two trends. These clay pods contain higher percentages of SiO2 and Al2O3 than the surrounding CID. The clay pods are generally smaller than the drill-grid dimensions. Thus their locations are typically unknown and they cannot be defined by manual interpretation, eg via wireframes. The locations of the clay pods were simulated via indicator CS. CCS was then performed separately for the clay pods and the CID. This significantly improved the reproduction of the correlation coefficients, the scatterplots and visually the simulation was more geologically realistic. Simulating the location of clay pods followed by CCS of assay variables is the recommended approach for simulation at the Yandi CID.CITATION:De-Vitry, C, 2013. Simulation of correlated assay variables - a case study from the Yandi Channel iron deposit, in Proceedings Iron Ore 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By D. J. Burger

This paper will highlight the system components of a successful underground mining automation project recently launched at DeBeers Finsch Mine. It will also show that integration of short-term mine planning with other upstream and downstream mining processes in the extraction of kimberlite ore from a block cave is not just critical to the future sustainability of this underground mining operation but also for profitability and cost-effectiveness. This paper will discuss the information data flow required from the mine-planning process through to production for underground block cave mining. The benefits associated with this type of integrated mine planning and automation system will be highlighted.

Jan 1, 2006

By O. F. Brown

The use of quality materials (aggregates and asphalt binder) in optimal proportions is the key to producing optimally performing hot mix asphalt (HMA). The Superpave mix design standard in the US introduced specific volumetric and binder property requirements in HMA design. Different methods for HMA constituent proportioning have been proposed in various guidelines. The design process to determine the HMA blend is currently iterative and engineers rely almost exclusively on experience. This approach is time consuming and often does not result in cost-optimal HMA mixtures. This paper introduces a mixed integer linear programming (MILP) optimization model for hot-mix asphalt constituent proportioning. The MILP model minimizes the total mix cost while satisfying all the volumetric, binder and mix property specification requirements. The model has been successfully validated with real-life example. The aggregates and binder ratios from the model were in close agreement with those from the contractor. The Bailey ratios and the gradation constraints were also satisfied. The cost of the optimal mix was $0.804/Mg less than that of the contractors?. This marginal reduction might make all the difference in an industry that is highly competitive. The MILP model also demonstrated that adding RAP to the contractor?s design would reduce the cost of the blend by $5.74/Mg. The virgin binder content was reduced by 1% because of the recycled asphalt contained in the RAP. This work represents the first successful attempt in incorporating both aggregate and asphalt performance requirements into the optimization formulation. Applying these models will ensure the minimum cost mix that meets all constraints and will increase profit margins for plant operators.

Jan 1, 2012

By J. Drelich, J. Pletka

Lost foam casting patterns are foamed polystyrene shapes glued together into the shape of the part to be cast and are coated with a refractory material consisting of a mineral mixture and binders. Prior to casting, a significant number of the patterns are damaged and inevitably land-filled. In this study, a process is developed for the recovery of foamed polystyrene from the coating and glue contaminants. The process consists of shredding, impact comminution, size classification and density separation. It is successful in separating up to 97% of the contaminants, while recovering 95% of the polystyrene.

Jan 1, 2001

By Pfeifer H. C, Nicacio P. A D

Sinter has been used as part of the metallic charge in large-scale blast furnaces for many years with the well-known benefits in terms of productivity and fuel consumption. However, because of the high investment in a conventional sinter plant, small blast furnaces and the associated integrated mini steel plants have not taken the advantages of using sinter. Recently KTS Korf Tecnologia Siderurgica, a division of Mannesmann Demag Ltda in Brazil, has developed a mini sinter plant for which the investment is compatible with small blast furnaces. Consequently, it is of great interest to evaluate the economical impact of using sinter in such small-scale integrated steel plants. In order to compare two alternatives, ie 100 per cent ore and 70 per cent sinter in the blast furnace burden, mass and heat balances for the entire operation from sinter plant through the blast furnace and EOF-based melting shop, were performed to evaluate the final production cost of the liquid steel. It was found that, depending on the sinter feed price, substantial savings can be obtained with the use of sinter.

Jan 1, 1999

Case I- Timber Pile Test- 4 pages describe the pile driving record, the pile load test and the boring log. Case II- 24 inch square prestressed concrete pile-5 pages give details about the pile driving, the boring log, the pile driving record, and the pile load test. Case III- 12 inch square prestressed concrete pile- 5 pages describe the compilation of SPT blow counts for the whole project, the pile driving record, the pile load test and the detailed boring logs. The 70 foot long pile was driven by a Vulcan 08 pile hammer. Case IV- 12 BP 53 Steel H pile- 3 pages give the pile load test, the pile driving record and the nearest boring log. The 64 foot long pile has its tip at elevation 908 ft. and the ground is at elevation 972 ft. The contractor augered to elevation 959 ft. before driving the pile with a Conmaco 08 single acting pile hammer. The hammer had an 8000 pound ram, a rated energy of 26,000 ft-1b., and a 7 1/2 inch thick asbestos cushion. Dynamic measurements were made during driving of the test pile and measured a hammer energy equal to 12,500 foot-pounds.

Jan 1, 1988

Test Work on High Throughput Diamond Tracer Recovery from Alluvial Recovery Tailings with a Containerised Optical Sorter Under Real Production Conditions Worldwide alluvial diamond deposits are traditionally processed with dense media separation and XRF sorters, hand picking or grease tables. The test work conducted verifies the performance of an optical sorter detecting the transparency of particles for diamond recovery from the DMS concentrate, eg XRF-sorter and handpicking tailings. The containerised setup enables economically feasible, high throughput, semi-mobile setups to retreat recovery tailings from alluvial and also primary deposits. The test work has been conducted with quartz and glass particles, which are less transparent or comparably transparent, under realistic production conditions on a 600 mm belt machine with an installed electrical power of only 21 kW. The results show that 99 per cent recovery can be reached at a throughput of 10 t/h in the -8 + 2 mm fraction and at 22 t/h in the -25 + 8 mm fraction. At a throughput of 18 t/h a recovery of 88 per cent has been assessed. At a further escalation of the throughput, dust in the sorter container made sorting impossible in the coarse fraction and the recovery decreased significantly in the fine fraction. Analysis of the belt coverage indicates that higher throughputs of the coarse fraction can be fed onto the optical sorter if the dust extraction system is improved. The results are basis for the decision to conservatively feed 20 t/h of the coarse fraction and 17 t/h of the fine fraction in day to day production. The settings have been applied to sort alluvial recovery tailings in South Africa and will be applied to sort the recovery tailings of a primary deposit in Lesotho. The test work has shown that an optical sorter can be used to retreat recovery tailings with high throughputs. The compact setup of a screen and a 9 m standard container enables semi-mobile, temporary setups for small recovery tailings dumps and remote areas. In addition, sorting on transparency ensures the recovery of high value low-fluorescent diamonds.

Sep 13, 2010

By P. E. Hand

Coal is a complex heterogeneous commodity that can be mined in a number of ways and needs to be processed to a homogeneous quality that satisfies the customer?s requirements, while attempting to maximize revenues. Only a small proportion of coal is suitable for metallurgical use. Export coals cover a wide range of qualities and some coals can be used optimally in the raw state for energy production. Critical quality parameters vary and can be a combination of heat value, ash, volatiles, sulphur, phosphorus, sizing, amongst others. The level of beneficiation is generally dictated by the washability of the coal, mining contamination, and the target product quality. The steps in the coal chain covered in this paper comprise exploration, mining selections, production, the washing process, and product delivery. Many points of sampling are needed to maximize yield at the correct quality, and some of these will be described in the paper. Keywords coal chain, coal beneficiation, sampling.

Jan 1, 2014

By U. Heuer, B. Rathmann

Many mining operations have gained an impressive expertise in trouble shooting and maintenance with their existing fleet over the years. Whether it is an in-house maintenance group or an external service group - most of the systems weak points are well known and can be corrected by maintenance personnel. As some of these issues get more and more serious each year, too much time is lost in unscheduled downtime, often taking hours to be repaired and to find the failure with obsolete diagnostic tools (Fig. 1.). Many of the breakdowns result from failures that cannot be detected in advance. The maintenance system is much more reactive than preventative. The state of the art of mining equipment today uses advanced, efficient, and reliable systems for electrical drives, control and diagnostics of the machines. The demand for highly sophisticated solutions on such mining equipment is well known. Mining operators need to ensure the highest level of productivity, lowest operating costs, least maintenance and highest reliability in a drive system. The paper will introduce you to the state of the art of drives technology for dragline (Fig. 2) and shovel mining equipment (Fig. 3).

Jan 1, 2007

Fine Gravity Separation in the Reflux Classifier, Exploiting a High Shear Rate, Laminar Flow Mechanism The Reflux Classifier is used in the gravity separation of particles over a broad range of particle sizes. The device consists of a fluidised bed zone, with a system of parallel inclined channels above. The inclined channels provide a significant hydraulic advantage over conventional fluidised beds via the so-called Boycott Effect (Boycott, 1920). This paper describes a new advance in fine gravity separation based on the high shear rate and laminar flow profile that arises when closely spaced inclined channels are deployed. As reported recently (Galvin et al, 2009a), a powerful density based separation mechanism develops from this arrangement, suppressing the effects of particle size. In this paper we focus on two areas, firstly the application of the separator in the laboratory for batch fractionation of particles of varying size and density to determine the grade recovery curve and hence the liberation, and secondly the step change in separation performance achieved on a continuous steady state basis when closely spaced inclined channels are used. The variation in the separation density with particle size decreases significantly, and the Ecarte Probable Error (Ep) remains at low levels over a broad size range.

Sep 13, 2010

By M. Soleymani Shishvan

"Continuous mining systems containing multiple excavators producing multiple products of raw materials are highly complex, exhibiting strong interdependency between constituents. Furthermore, random variables govern the system, which causes uncertainty in the supply of raw materials: uncertainty in knowledge about the reserve, the quantity demanded by the customers, and the breakdown of equipment. This paper presents a stochastic-based mine process simulator capturing different sources of uncertainties. It aims to quantify the effect of geological uncertainty and its impacts on the ability to deliver contractually defined quantities and qualities of coal, and on the system efficiency in terms of utilization of major equipment. Two different areas of research are combined: geostatistical simulation for capturing geological uncertainty, and stochastic process simulation to predict the performance and reliability of a large continuous mining system.The process of modelling and simulation in this specific production environment is discussed in detail. Problem specification and a new integrated simulation approach are presented. A case study in a large coal mine is used to demonstrate the impacts and evaluate the results in terms of reaching optimal production control decisions to increase average equipment utilization and control coal quality and quantity. The new approach is expected to lead to more robust decisions, improved efficiencies, and better coal quality management.IntroductionContinuous coal mining systems containing multiple excavators producing multiple products of raw materials are highly complex and exhibit strong interdependencies between constituents. A network of conveyor belts is used for transportation of the extracted materials to different waste dumps or the coal stockpile.Optimal decision-making in short-term planning and production control are impacted mainly by geological uncertainty associated with incomplete knowledge of the coal deposit represented in the reserve block model. These uncertainties cause deviations from expected process performance. For more robust decision-making, understanding the impacts of these stochastic elements plays a key role."

Jan 1, 2016

By Grynberg H, Lindon P, Wardrop J

The Gippsland Basin is unique in Australia in that it is a major resource based industry centre within a sensitive and special environmental context supplying Melbourne, a major urban/industrial environment with most of its energy 'on-line'. The environmental effects of the supply systems are generally local and mostly affect only those who are directly or indirectly dependent on the upstream systems. The major urban metropolis which is served remains largely unaware of the environmental impacts of the system upon which it is dependent, except when specific attention is drawn to them as in the case of the Latrobe Valley Outfall, algal blooms in the Gippsland Lakes, etc. This paper discusses the environmental context within which the energy industries operate, the environmental legislative framework which applies, the likely environmental impacts and some solutions. The energy resources of the Gippsland Basin occur in an area where the physical environment exhibits a wide variety of inherent energy states in its physical and biological regimes. The off-shore regions of the oil and gas platforms has to be able to withstand the wind and wave energy generated in a shallow sea in a confined waterway lying athwart the main current and climatic stream. The coastline includes the delicately balanced quiescent environments of Corner Inlet with its 'wilderness' tourism industry and the powerful surf and long shore drift and dunes of Ninety Mile Beach.

Jan 1, 1992

By Rudolph P. Frizzi

Quality control is essential for augered cast-in-place (ACIP) piles (also known as continuous flight auger (CFA) piles outside the United States) and drilled displacement (DD) piles since the pile is constructed below the ground surface out of the direct sight of the personnel constructing and inspecting the pile. ACIP piles are being successfully constructed to support high-rise structures, hospitals, arenas and stadiums, mass transit systems, and power and industrial facilities. The use of DD pile technology is also gaining ground in the United States, typically utilizing proprietary systems such as Omega (currently utilized by Richard Goettle Inc., and LG Barcus and Sons, Inc.), Berkel, and DeWal (currently utilized by Morris-Shea). Different types of ACIP/DD pile installation equipment are shown in Figures 1 and 2. ACIP piles are installed into granular and cohesive soils, and soft rock to lengths currently approaching 130 ft (39.5 m), with diameters up to 24 to 36 inches (610 to 915 mm), and sustaining design loads approaching 900 kips (4000 kN). Current DD pile installation equipment in the United States is capable of installing up to 79-ft-long (24 m) piles with diameters ranging from 12 to 18 inches (305 mm to 460 mm).

Jan 1, 2004

By Scott A. Shuey

Keywords: E-Waste, Pyrometallurgy Many might think addressing the issue of e-waste is a new area of study. Electronics disposal has been discussed in some circles for at least the past 25 years. The recycling of electronic waste (e-waste) tends to be a rather complex undertaking when considering the intimate bonding of materials in the average printed circuit board. The development of a recycling process is further complicated when considering the wide variety of products being generated under the heading of ?electronics.? Focusing only on the primary constituents (polymers, Cu, Al, Fe, etc.) tends to lead one to fairly simple flowsheets. Ignoring trace elements, and the various halide species generated, will lead process engineers down a development path that is sure to cause material handling issues. Researchers at Colorado School of Mines are modeling the complex chemistry that exists within the body of e-waste?comprising 39 of the known elements. An understanding of the systems thermodynamic behavior will result in the development of a more robust, long-term process for the recovery of valuable materials from the e-waste stream.

Jan 1, 2005

By S. R. Gilbert, C. O. Bounds, R. R. Ice

"Many ores are upgraded to produce auriferous sulphide concentrates (principally pyrite) which are not amenable to direct cyanidation. Often these refractory gold-bearing concentrates contain undesirable elements such as arsenic, antimony, etc., which present environmental and/or processing problems. The pretreatment techniques most often considered for processing these concentrates prior to cyanidation include roasting, pressure oxidation, chemical oxidation, pre-aeration, and recently, bacterial oxidation. In this paper, the technical performance and economics of bacterial pre-oxidation vs the classical roasting approach for treating a specific auriferous pyrite concentrate are compared. The results provide flow sheets, preliminary operating and capital cost estimates, and rates of return for the two processes and demonstrate the potential advantages of bacterial pre-oxidation. IntroductionThe increased attention that gold has received in the last ten years has prompted mining companies to look for lower grade orebodies. Many of these low-grade ores do not respond well to conventional direct cyanidation recovery techniques. As free-milling ores decline, gold is sought in refractory environments which, ultimately, drive up the treatment costs.There are a number of reasons for a gold ore to be termed refractory, most of which can be identified by thorough mineralogical examination. The mineralogical occurrence of gold can, to a great extent, impact the method by which the ore is treated and, consequently, the capital and operating costs. Gold in a refractory ore can often occur as discrete particles locked in a host of silicate or carbonate gangue, or associated with sulphides or sulphosalts. Depending on its particle size, gold can be liberated and recovered by mechanical size reduction such as regrinding. This approach is most effective for gold in the 10 - 50 micron range. Gold can also be associated with clay, iron hydroxides, or other minerals which tend to coat the gold surface and inhibit the penetration of the cyanide solution, resulting in poor plant recovery. Because of their resistance to cyanide dissolution, gold tellurides and other refractory gold minerals are also responsible for losses to the tailings. For these reasons, it is paramount that the mineralogical occurrence of the gold be thoroughly and accurately determined before selecting a final process flowsheet."

Jan 1, 1988

By G. Castillo, G. Thies, C. Bissue

"Newmont’s Phoenix mine began gold production in 2006 and has since experienced difficulties in reaching design throughput due to variability in ore hardness. In 2010, a debottlenecking study was conducted, generating multiple options to increase throughput of the existing Phoenix Mill through a series of phased expansions. An option was selected in early 2011 to increase the current concentrator capacity by approximately 25% through two phases. The first phase of the project was the installation of a secondary crushing and screening circuit in order to reduce SAG feed size from a P80 of 6 inches to 2 inches. The second phase focuses on downstream unit operations in the concentrator aiming to relieve existing bottlenecks such as flotation. This paper analyzes the design, commissioning, and operation of a recently installed SAG Pre-crush circuit (Phase 1). The design discussion will focus on concept development, flowsheet design, design criteria, process models, design limitations, and control philosophy. Discussion on the integration of operating data and flowsheet into design during engineering will be presented. Actual operating data of major equipment is gathered from the commissioning and operation of the circuit and compared to the initial design models. Conclusions will be drawn on equipment design factors used during engineering, and the success of model integration into operation. The paper concludes on the successes of the project and where improvements can be made during design.INTRODUCTIONThe Phoenix mine is located within 25 miles of the town of Battle Mountain, Nevada. The mill processes copper, silver, and gold ore. Production started in 2006 and has since struggled to reach the designed tonnage of 33,600 stpd due to the variability in ore hardness. In production year 2010-2011, the Phoenix mill average daily throughput of 33,000 stpd. In 2008, a larger primary crusher (FLS 60/89 gyratory crusher) was installed to operate in parallel with the originally supplied primary crusher (Metso 50/65 gyratory crusher), in order to provide additional capacity upfront in the circuit so that the primary crushing circuit could keep up with the mill.In 2010, a mill debottlenecking study was completed to assess the various options that could be implemented to increase the current mill capacity. The study was completed in late 2010 and contained four tonnages that Phoenix could achieve through various expansion scenarios. A single option was selected in early 2011 to increase the mill capacity from 33,000 stpd to 48,000 stpd. The selected option looked at a four phased expansion that would increase the capacity of the Phoenix mill and address the mill’s current bottlenecks:"

Jan 1, 2013

By Hemingway P, Boag J

Major operating aspects of the Mary Kathleen Uranium Ltd. treatment plant are discussed with partkular reference to those which are peculiar to this operation.Problems associated with the production of a penalty free uranium oxide product are examined and the methods developed to overcome them are described in detail.INTRODUCTIONMary K,athleen Uranium Ltd. is the largest of the Australian uranium producers. The flow-sheet is based on fine grinding, standard sulphuric acid leach, ion exchange concentration, and magnesia precipitation of the final product, with certain modifications introduced as the result of pilot plant investigations at the South Australian Department of Mines Research Laboratories in Adelaide.The plant commenced operations in June, 1958, attained design tonnlige of 1,120 tons per day in September of that year and has since operated continuously with a throughput in excess of 1,000 tons per day. Pilot plant recommendations generally have been followed, and predicted results have been attained. The only exception has been the silica and rare earth content of the product produced during the early months of operation. Considerable modification of the early resin regeneration techniques resulted in the reduction of the silica content of the product to within specification limits. Research work in the ion exchange section has also resulted in the reduction of the rare earth content of the product to below specification levels. All product now being produced is completely within the agreed specification limits of impurities.

Jan 1, 1961

By M. T. Styles, E. Condliffe, R. C. Leake, R. J. Chapman, D. J. Bland

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Quantitative point analysis and microchemical mapping identified 52 different types of mineral in inclusions, usually ranging in size from 5 to less than 1 micrometre, inherited from source bedrock. A combination of grain chemistry, heterogeneity and inclusions provides a grain signature reflecting the type and history of source mineralisation. Several grains from an alluvial site are needed, to allow for bedrock variation and the presence of inclusions in only 10-20% of grains. A total of 1 530 grains obtained from 30 localities in Scotland were of ten types, two of them minor variants. Two types in the Highlands may be related to centres of Caledonian igneous activity, but the most widespread is likely to have been of deep-seated origin and structurally controlled. Gold in the Ochil Hills is probably from a source associated with Devonian andesitic activity. In the Southern Uplands, grain types reflect two separate episodes of mesothermal lode gold mineralisation and relationships with Permian red beds/mafic volcanics and with Tertiary dykes

Jun 19, 1905