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By C. Schmidt, M. Kohnk, C. Siemers, J. Kiese

The application of conventional titanium alloys is limited to 550°C due to their poor oxidation resistance. In addition, severe grain growth is observed in single-phase titanium alloys in long-term runs at elevated temperature leading to a degradation of their mechanical properties. In exhaust applications in automotive or aerospace engineering, products are often manufactured by cold-deformation like deep-drawing or rolling which is normally difficult in oxidation-resistant titanium alloys due to the presence of titanium-silicides. Therefore, in the current study, titanium alloys based on CP Titanium Grade 1S (soft grade) were developed showing (1) improved oxidation resistance due to a concerted addition of silicon, iron and niobium, (2) microstructure stability by the precipitation of hafnium-silicides mainly on the grain boundaries and (3) good cold-deformation properties. The industrial production route was developed so that the new class of Ti-Si-Fe-Nb-Hf-alloys is now ready for application in exhaust systems of planes or cars at minimum 800°C.

Jan 1, 2015

By Erwin L. Zodrow

THE AUTHORS welcome this timely opportunity to comment o n a paper by MacLean and Merner (" Room-and- Pillar Mining at the Prince Mine of the Cape Breton Development Corporation " , ClM Bulletin , June 1978, pp. 59-62) concerning the rock falls and their relation to "a change in the strata". First, however, it is proper to express our gratitude to the Cape Breton Development Corporation, and in particular to A. R. MacLean, for making it possible for us at the College of Cape Breton to start two new collections. The first of these is a fossil plant reference collection from the Sydney Coalfield, Cape Breton (Upper Carboniferous period) , and the second is a documentation of the role o f pyrite in the formation of hydrated sulphates (samples from No. 26 Colliery, 1-B Mine, and the Prince Mine at Point Aconi). Conditions of sedimentation in the deltaic-type basin of the Upper Carboniferous time in the Point Aconi area were such that on the (coal) swamp, now represented by the Stubbart (or Hub) seam , (a) clays of varying thickness and extent were deposited , (b) biogenetic sulphur was introduced and (c) flora were buried. These are essentially the culprit s that make rock falls possible and at the same time predictable over large areas (in the present mine). The clays lithified to become shale, and biogenetic sulphur combined with iron to become pyrite (marcasite?), which exists as nodules and in fine-grained layers.

Jan 1, 1978

By J. O. Yeboah, V. Boakye, P. A. Bepswa, M. Lombard, G. Nutor

The comminution circuit at Tarkwa Gold Mine was commissioned as a Single Stage SAG mill operated in closed circuit with hydrocyclones designed to process 4Mtpa. The circuit was later expanded by adding a secondary ball mill in closed circuit with hydrocyclones with a view to treat 12Mtpa. The change in the circuit configuration and assigning the low aspect ratio SAG mill for primary grinding application makes the Tarkwa experience unique in terms the optimisation strategy and operating philosophy. This paper reports the findings from a series of surveys performed on this plant. The surveys reported include data obtained when the SAG mill was operated as a single stage mill in closed circuit with hydrocyclones and also SABC mode under two different feed conditions. The differences in operating philosophy between the initial single stage SAG circuit and the current SAG/Ball mill circuit are discussed.

Jan 1, 2012

By L. Tejeda, J. R. Donald, R. Parra, J. Duran, P. H. Lauzon

"Crucible slag tests were employed to evaluate different refractory brick classes for the Cerro Matoso electric furnace. Comprehensive analysis was conducted to evaluate the crucible erosion and characterize any slag/refractory reaction products.The classes of refractories investigated were:•,tar-impregnated magnesia;•,rebonded fused grain magnesia-chrome;•,direct bonded magnesia-chrome;•,alumina-chrome;•,picrochromite; and•,magnesia-alumina (spinel).It was concluded that tar-impregnated MgO bricks were the most suitable for the slag chemistry and furnace environment according to corrosion and infiltration resistance. A picrochromite (MgCr2O4) brick performed exceptionally well with regards to erosion resistance, however, the slag infiltrated extensively through the brick pores. Alumina-chrome, direct bonded magnesia-chromite, and spinel (magnesia-alumina) bricks were evaluated as not suitable for use in the furnace."

Jan 1, 1999

By W. J. Wolfe

"Quartz Hill is a large, low- to moderate-grade quartz vein stockwork porphyry molybdenum deposit, discovered in 1974 during a regional stream sediment geochemical reconnaissance survey of southeast Alaska conducted by United States Borax and Chemical Corporation. Mineralization is localized in the upper parts of an Upper Oligocene (30 Ma) composite quartz monzonite stock which is emplaced discordantly into older Cretaceous to Early Tertiary terrain of the Coast Range igneous metamorphic complex of the northwest North American Cordillera. Subsequent fault-controlled, complex multi-stage intrusion, concentrated in the core of the Quartz Hill stock, produced successive pulses of hydrothermal alteration and molybdenum mineralization at about 27 Ma. Overall, the deposit is tabular and flat-lying and well suited to open pit mining. The 0.05% MoS2 grade limit covers an area of approximately 1500 m by 2750 m and extends to a maximum depth of 520 m below surface. Details of grade distribution show two separate lobes of higher grade material within the larger low-grade deposit.A ten year program of exploration drilling, underground development, sampling and metallurgical testwork led to a 1983 feasibility study based on a resource of 1600 million tonnes grading 0.127% MoS2 at a 0.08% MoS2 cutoff The large size of the deposit and its homogeneous grade distribution, typically showing gradual outward decrease of grade, makes in pit grade selection practical at several cutoff levels. Cominco Ltd. now reports a Probable Resource of 210 million tonnes averaging 0.22% MoS2 with a further Possible Resource of 1100 million tonnes averaging 0.12% MoS:z. At low molybdenum metal prices which have persisted for 10 years since the molybdenum price spike of the late 1970s and early 1980s, the Quartz Hill deposit is sub-economic."

Jan 1, 1995

"HPGRs operate in a wide array of applications in mining and minerals. These range from relatively coarse crushing of copper and gold ores at one end of the spectrum to the processing of fine iron ore pellet feed and fine industrial mineral products at the other. Traditionally these circuits involve the treatment of relatively moist materials in pre-grinding circuits; using single stage HPGRs in open circuit or as a closed circuit operation with screening or partial product recycle. More recently, HPGR is increasingly deployed in dry grinding in combination with air classification. The high throughput demonstrated by larger HPGRs has stretched the application towards coarser size reduction duties for a number of new projects. At the same time, the basic principle of inter-particle crushing for generating a product with a high fines proportion gives ground to investigate applying the technology further towards finished product duties. The advantages that HPGR brings are clear. Multi Stage grinding enables energy efficient size reduction across more of the comminution circuit. Primary HPGR serves for a coarse grinding duty, whereas a secondary HPGR is geared towards generating a fine product for downstream processing or even a finished product. This publication summarizes some of the features of staged HPGR circuits and discusses some examples of operating and projected applications.INTRODUCTION In most HPGR applications, the grinding units are used as a single process stage, either in open circuit, such as for pebble crushing [Rose 2002, Westermeyer 2000, Van der Meer 2015] or in closed circuit with classification [Van der Meer 2009, 2012] or product recycling [Van der Meer 2010]. Where a higher plant capacity is required, the HPGRs are commonly installed in multiple lines in a parallel arrangement [Parker 2005, Koski 201, Vanderbeek 2006]. HPGRs can take a wide range of feed size distributions, and grind this down to a product with a high fines content. In general view, there is a limit on the size reduction range that even an HPGR can provide. Grinding down from a very coarse ore (e.g. 70-100 mm) to a very fine product (e.g. 100 microns range) is stretching the ability of a single stage HPGR circuit. Fine grinding generally requires a classification stage that returns the classifier oversize to the head of the HPGR circuit. From one point of view, it can be demonstrated that when recycling a large proportion of fines and middlings back to the HPGR feed results in an effective feed with an overrepresentation of middlings and fines, which will eventually reduce the grinding efficiency and consequently result in an increased recirculation mass flow [Van der Meer 2014]. From another point of view the large recycling mass puts a strain or even a limit on the capacity of present-day conveyor capacity."

Jan 1, 2018

By G. Granata, C. Tokoro, T. Kato

"The goal of this study was to evaluate the effectiveness of mechanochemical activation by planetary milling as method to enhance the recovery of cerium from rare earth ores. For this purpose, a weathered ore was first ground by planetary milling and then leached by sulfuric acid. The influence of planetary milling was investigated by assisting the experiments with X-ray absorption fine structure (XAFS) in cerium LIII-edge and inductively coupled plasma spectrometry to measure the concentration of cerium dissolved by leaching. Results showed that, by increasing the grinding time, although the particle size of the specimen increased due to agglomeration, the recovery of cerium significantly increased. This finding clearly indicated that a smaller particle size actually hinders the recovery of cerium. In particular, XAFS analysis revealed that the longer the grinding time, the more tetravalent cerium could be converted into trivalent cerium and such conversion, also called mechanochemical reaction was beneficial to the recovery of cerium. Based on the obtained results, it was confirmed that approximately 70% of cerium could be recovered by mechanochemically activated leaching of rare earth ores.INTRODUCTION Rare earth elements (REEs) are a group of 17 chemically similar metallic elements comprising lanthanides, scandium and yttrium. Since REEs have various unique physical and/or chemical properties, they have become essential materials for advanced application (Adachi, 2015). REEs used in industry are usually supplied as rare earth minerals. In the last decades, flotation, gravity separation, magnetic separation and leaching have been widely applied to recovery of REEs from rare earth minerals like monazite (Archana, Rekha, Manis, Jitendra, & Jin, 2015). Among these operations, leaching has been widely studied in the recent years to improve the state of the art (Archana, Rekha, Manis, Jitendra, & Jin, 2015; Xiao, Feng, Huang, Huang, Chen, Liu, Wang, & Long, 2016; Farzaneh, Fereshteh, & Ahmad, 2017). Aiming to enhance recovery of REEs from rare earth minerals, a possible advancement of leaching technology could be the mechanochemically activation of the ore by high-intensity milling (Alorro, 2016). In the mechanochemical activation, an improvement of the leaching performances can be achieved through high-intensity milling operations which result into a dramatic decrease of the mineral particle size with a consequent improvement of the physical kinetics of leaching. Furthermore, the high mechanical energy provided to the sample during milling can determine the rupture of the crystal structure of the mineral, thereby transforming it into a more leachable form."

Jan 1, 2017

By Eduardo A. Pérez, Alejandro R. Alonso, Rosa María Luna-Sánchez, Gretchen T. Lapidus

Rare earth elements have been widely used in various sectors, from the aerospace and steel industries, to electronic applications, particularly in displays and batteries for portable devices. The high demand for newer and better equipment, such as cell phones, tablets and lap tops, has increased the consumption of the rare earth elements and at the same time the need for its recovery from electronic wastes. For that reason, the recycling of batteries is important, principally the Ni-HM batteries, due to their elevated content of rare earths elements, in addition to the high concentrations of cobalt and nickel. The current processes are based on dissolution in strong acid solutions (sulfuric acid concentrations from 2 to 4 mol/L), and temperatures from 30 to 90°C. In the present work, electrodes from spent Ni-HM batteries were leached using 1 mol/L H2SO4, in the presence of ozone as the oxidant, where recoveries of 96% for La, Ce and Nd were obtained at room temperature. The separation of Ni and Co from the leach solutions was performed using an electrochemical reactor, after which rare earth elements were precipitated, obtaining a mixture of its hydroxides with impurities below 1%, according to EDS analysis.

Jan 1, 2014

By P. Ashtari

Influence of Sr and Mn single and combined additions on the modification of the Fe-containing intermetallic compounds and mechanical properties of Fe-rich AA319 aluminum alloys have been investigated, The microstructural features e,g, morphology of the Fe compounds and eutectic Si has been correlated to the mechanical properties, It was demonstrated that modification of the Fe compounds from the platelet ß-Al5FeSi to the Chinese script a-Al8Fe2Si compound improves the UTS and elongation of the alloys by 10.3% and 83.9%, respectively. Moreover, the simultaneous modification of the Fe compounds and eutectic Si increases the UTS and elongation of the alloys by 15,3% and 116,1%, respectively.

Jan 1, 2005

By Yuki Tsunazawa, Sho Fukui, Chiharu Tokoro

"A milling process is one of the important unit processes in mineral processing. In the milling process, the control of particle size distribution is necessary for the later physical separation process. Since the milling process is strongly affected by the equipment designs, operation conditions and raw materials, the control for particle size distribution of milling products is mainly based on empirical rules. Recently, the discrete element method (DEM) has been widely used as an effective tool to investigate the behavior of grinding media. Although the behavior of grinding media can be accurately simulated, it is not well-established the way to predict particle size distribution after milling by the DEM simulation.The objective of this study was to develop a new method to predict particle size distribution in ball milling using the DEM simulation. To predict particle size reduction, a correlation between experiments and the simulation was investigated in various operation conditions, that is, wide range of the rotation speed and the filling ratio of grinding media. In experiments, after lime stone was ground, the average and variance of particle size distribution were evaluated using some kinds of distribution equations. In the DEM simulation, direct simulation of particle disintegration in milling process is generally very difficult because of huge computational load. Therefore, collision energy between grinding media balls orgrinding media ball and wall was used as a factor of particle disintegration.As a result, a good correlation between experiments and simulation was obtained. In addition, the particle size distribution in ball milling could be predicted using this correlation. Therefore, these results indicated that the use of the correlation between experiments and the DEM simulation was an effective approach of predicting the particle size distribution in milling process."

Jan 1, 2016

By N. Pajunen, R. Mäkikoskela

"The current state of environment has been achieved by acting linearly. At the same time, we know that transition towards circular economy cannot be made the same way that we have used to, trusting only a market economy and economic growth. Environmental improvements have been promoted, some progress has been made, but major steps towards sustainability have not been taken. Industry is now facing significant change, from process related environmental thinking to product-based environmental thinking.Engineers make decisions which have lifelong influence and even longer on environment and society. Material engineers in case of saving natural resources and increasing material cycle, have an important role to play in the transition towards sustainability. Best knowledge of minerals and materials is in the material development phase. If we want to increase the cycle of different materials, it is vital to make decisions towards circular economy in early phase of product´s life cycle.The target of this study is to promote circular economy; to increase material efficiency; to save natural resources; and to extend product lifecycles in process industry via product design and material development. In this study we have a new kind of cooperation. We combine two disciplines, engineering science and fine arts. We promote sustainability via breaking out the silos. We bring the cyclic artistic thinking into engineering science and environmental research. The new research combination makes the existing information visible in a new way, and it will change attitudes and ways to act by means other than traditional linear rationality.We have tested the new working method via the industrial case study with the chosen product: the sandwich panel of construction industry. The target of the study was to create something new from the chosen product with artistic thinking. The working method will be presented in this paper."

Jan 1, 2016

By F. Bélanger, P. A. Fournier

"Modelling and optimization techniques used in the operation of the Detour Lake Mine leach circuit are contrasted to a 1973 review of contemporary techniques used by a major gold producer. The leach circuit at the Detour Lake Mine was modelled using a full factorial Design of Experiment of stirred tank reactor leach tests using circuit feed. Contour plots of extraction were applied in the plant to optimize addition rates of cyanide and the newly-commissioned lead nitrate system. Contour plot sections were used to understand the impact of sulphur in circuit feed at different operating dissolved oxygen concentrations. The 1973 review paper offers insight into industrially-applied modelling and optimization techniques. In particular, a mathematical model of plant data was developed using multilinear stepwise regression analysis. The model was presented using graphical representations available at the time and applied to optimize the rates of cyanide addition. Off-the-shelf software solutions of today allow mineral processors to quickly and easily visualize data, allowing them to re-allocate time and resources spent processing data to generating raw data and extracting actionable information.IntroductionModelling and optimization in mineral processing is the art of reducing reality through judicious use of assumptions to understand a process and leverage this knowledge to engineer practical solutions to metallurgical problems. Data analysis is at the core of this enterprise.While this paper showcases the modelling work done at the Detour Lake Mine (DLM), the primary objective is to pause and reflect on how far the field has progressed since the 1970’s. A snapshot of state-of-the-art gold cyanidation modelling at that time is a review paper of the Anglo American Group’s capabilities (Brittan & van Vuuren, 1973). The objective of this paper is not a play-by-play of the evolution of modelling and optimization since that time. Rather, it is a comparison of the field at two points in time.In 2016, DLM undertook an extensive bench-scale leach circuit modelling program to better understand the impact of cyanide, dissolved oxygen, lead nitrate, grind size, density, and pH on gold cyanidation (Fournier, 2016). Two major capital expenditure projects were anticipated for 2017: improvements to oxygen control and a lead nitrate distribution system. While the lead nitrate system was planned for construction, the design parameters had not yet been selected. Following the development of the model, plant trials were executed to validate aspects of the model and the methodology was expanded to address other plant issues, in particular the effect of talc chlorite and pyrrhotite in leach feed.The variables of the bench-scale study are summarized in Table 1. Dependent variables were varied using a full factorial design of experiment with two repetitions for each test condition, yielding a total of 300 tests. Test order was randomized to eliminate bias from independent variables."

Jan 1, 2018

By J. M. Mwase

The platinum group metal (PGM) industry is currently reliant on the crush-mill-float-smelt-refine route to process PGM ores. However, there are many instances where this route would not be feasible. An alternative process route has been developed which involves heap bioleaching to extract base metals followed by heap reclamation and a water wash step, leading into heap cyanide leaching to extract precious metals. This process was evaluated through test work on samples of Platreef ore using laboratory scale columns. After 304 days 75% Ni and 93% Cu were extracted in the bioleach experiment at 65°C, and after 60 days 58% Pt, 99% Pd and 90% Au in the follow-up cyanide leach experiment at 50°C. A preliminary process flow sheet has been developed around this. Analysis via a mineral liberation analyser showed that the remaining Pt was in the form of the mineral sperrylite, which appeared to be slow leaching in cyanide in comparison to the other mineral types. Analysis of cyanide effluent solution showed high levels of thiocyanate, which present an environmental risk for disposal and high consumption of cyanide. Further studies to develop the process for commercial application in the South African PGM industry are outlined.

Jan 1, 2014

By Ralph J. Holmes, David McCallum, Alan Roberts, Rolando Orense, University of Auckland, Tobias Krull, Tom Honeyands, Kenneth Williams

"The safe ocean transport of bulk commodities like iron ore, coal, nickel ore, manganese ore and bauxite by large bulk ships is vitally dependent on the stability of the cargo under the influence of wave induced ship motion. Safety standards are set by such bodies as the International Maritime Organisation (IMO) with recommended tests for the assessment of bulk commodities. Since the 1960s, the bulk cargo code (BC Code) commenced defining methods to determine the Transportable Moisture Limit (TML) for transportation of bulk commodities. By the latter part of the 1960s, three TML test methods were defined, namely the Flow Table, Proctor-Fagerberg and Penetration tests. All three tests were predominantly aimed at determining TML values for mineral concentrates.More recently, bulk commodity producers, Maritime Organisations and Port Authorities worldwide have been investigating whether commodity based TML methods better reflect realistic safe ship transportation than the current concentrate based TML test methods. In these investigations, the relationship between the mineralogical and particulate parameters of specific commodities with respect to cargo stability and moisture retention has provided insights into the development of tailored TML test methods. To this end, an AMIRA International project (P1097) undertaken by CSIRO, TUNRA Bulk Solids, the University of Newcastle and the University of Auckland assisted the IMO Technical Working group to investigate the relationship between iron ore fines characteristics and a new TML test specific for iron ore fines bulk cargoes.A review of the three standard concentrate based TML methods and characterisation studies of iron ore fines, as well as cyclic triaxial testing to determine liquefaction resistance, resulted in the development of a modified Proctor-Fagerberg method for determining the TML of iron ore fines. Of particular importance in determining TML is mineral composition, porosity, particle density and allowing time for moisture equilibration."

Jan 1, 2016

By Michael Moser, Brighty Dutta, David Dreisinger

"Molybdenum is widely used in the industries as an alloying element in the manufacture of steels and super alloys. The widespread use of the element encourages a growing need to develop extraction processes for recovery from both primary and secondary sources. The Solvay Group has developed a solvent extraction reagent named CYANEX®600 for the recovery of molybdenum from acidic solutions originating from both low grade (e.g. copper solvent extraction raffinates, smelter dusts and slags) and high grade (molybdenite) molybdenum sources. CYANEX®600 is a purified form of CYANEX®272 with the active component bis(2,4,4- trimethylpentyl)phosphinic acid. The extraction behavior of CYANEX®600 towards molybdenum in sulphuric acid medium was evaluated. The uptake of molybdenum increased with the increase in concentration of CYANEX®600. The approximate stoichiometry of the extracted complex was: Mo: CYANEX®600 = 1:2. Efficient back-extraction could be achieved with 0.1 M disodium EDTA and 0.1 M (NH4)2CO3, thus providing the option of recyclability of the extractant. The detailed back-extraction studies are currently under progress to find out the possible option for complete transfer of Mo(VI) to the aqueous phase so that high purity Mo salts could be precipitated from the molybdate solutions.INTRODUCTION Molybdenum (Mo) is one of the world’s valuable metals and is highly sought after by researchers due to its versatile mechanical, thermal, chemical properties. Swedish scientist Carl Wilhelm Scheele demonstrated molybdenite to be a mineral sulfide in 1778. Peter Hjelm successfully isolated dark metal powder from the mineral sulphide and named it as ‘Molybdenum’ in 1782 (Gupta, 1992). Molybdenum is a refractory metal of silver gray appearance and is an important alloying element used in the manufacture of steels and super alloys. Molybdenum compounds are widely used in formulation of catalysts (Gupta, 1992). Molybdenum occurs in nature only in chemical combination with other elements. Several molybdenum bearing minerals have been identified, but the only one of commercial significance is molybdenite (MoS2). As molybdenum is a strategic metal for the industrial sector, its widespread use acts as a factor for depletion of the natural resources. Hence, there is growing need to develop extraction procedures for its recovery from both primary and secondary sources. United States, China, Chile, Canada, Peru, and Mexico are listed as the main producers by the U.S. Geological Survey, 2016 (U.S. Geological Survey, Mineral Commodity Summaries, January 2016)."

Jan 1, 2017

By H. Feldheiser

Acid resistant brick linings are state of the art for anti-corrosion linings in tanks for high pressure acid leaching (HPAL) treatment. The design of these brick linings has to take into account the almost non-elastic behaviour of the brick lining inside a relatively highly elastic steel vessel. There must be tools and data available to determine for the steel vessels the thermal growth plus the pressure expansion and for the brick lining the linear thermal expansion and the chemical swell. Thermal shocks and pressure drops are not regular operating events but their negative influence on the lifetime of a brick lining has to be a part of the engineering study. Finite Element (FE) models as well as a lot of research and development on brick lining materials is the only way to find a path through the complex engineering work for pressure vessels.

Jan 1, 2004

By Rui Wang, Engang Wang, En Jiang, Anyuan Deng, Xingwu Zhang, Fei Wang

In this paper, the rectangular strands of Incoloy 800 superalloy were fabricated with a pilot vertical continuous caster in Northeastern University, China. In the processing, an electromagnetic stirring (EMS) is applied on the secondary cooling zone to control the solidifying structure and segregation of elements in the strands. The solidification structure of Incoloy 800 superalloy strands were investigated at different electric parameters and casting parameters. The research results show that the EMS can effectively restrain the dendrite growth and increase the ratio of equiaxed grains in Incoloy 800 superalloy strands as applied a suitable electric parameters and cooling condition in the process of continuous casting. The evolution of dendrite crystallization in Incoloy 800 alloy strands from the surface to its center during the solidifying process was investigated with and without EMS.

Jan 1, 2014

By Harold J. Rose

"A VETERAN newspaperman once summed up a lifetime of observation and experience in these words:""What man can imagine, man can do"".That statement might well serve as the theme of a talk on research potentials of the coal industry or any other industry. It is not my intention today to make a series of predictions of things to come. Experience of the past few decades has shown that long-range predictions made be-fore engineering groups usually fall short of the mark; that is, the actual technical achievements in any period tend to surpass the boldest predictions that any responsible engineer would have made, say twenty years earlier.Instead, I will point out some recent accomplishments or refer to research that is in progress or now being planned in order to suggest important trends to be expected in the next few years. Based on this rapidly increasing tempo of achievements you can make your own extrapolations into the future."

Jan 1, 1959

By A. Dave Mackintosh

The Current demand for potash has pushed world prices to record levels and allowed Saskatchewan producers to operate at maximum capacity. Several years of strong demand has resulted in a permitting rush not seen since the 1960?s. Even though Saskatchewan has a huge potash resource, mining and processing constraints will limit the areas of economic development. Introduction In 1969 M. E. Holter prepared a report ?The Middle Devonian Prairie Evaporite of Saskatchewan?, published by the then Dept. of Mineral Resources. Holter?s report has remained the bible of geologists working in potash ever since. It is astounding that a report written before there was really much potash mining history in the province, is as valid today as when it was first published. This paper re-iterates much of Holter?s report and adds a little mining experience to essentially confirm the importance of his work.

May 1, 2008

By W. L. Murphy

The Star Lake property, located 115 km northeast of La Ronge, Saskatchewan is underlain by metamorphosed andesitic tuffs and flows which have been intruded by the dioritic to granitic Star Lake Pluton. Gold mineralization on the Star Lake property was first discovered at Ru h Lake by E. Beveridge in 1959 and by M. and E. Hird in 1961. In 1960 E. Partridge discovered Kahn 18 and Kahn 28. In 1982 the SMDC-Starrex joint venture completed geophysical and geochemical urveys including magnetics, VLF, IP/Resistivity, vegetation, bulk till and oil sampling, followed by drill testing of pecific targets. To date the most ignificant depo it is the 21 Zone which contain drill indicated reserves of 230,000 tons grading 0.5 oz/ton Au . The 21 Zone con ists of quartz with 5-10% (locally > 30%) drusy pyrite, minor chalcopyrite and trace amounts of scheelite, chalcocite and arsenopyrite. The 21 Zone is enclosed by a 25-50 m wide band of mylonitized monzonite. The mylonite occurs in the central portion of a 300 m wide northeasterly trending zone of brittle deformation .

Jan 1, 1986