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By R. M. Graves, C. B. McKenzie, D. Barbour, D. W. Desnoyers

"The prospective Tulks volcanic belt hosts five significant massive sulfide deposits, Tulks Prospect, Tulks East, Jack's Pond, Daniel's Pond and Victoria Mine, as well as numerous showings and indications throughout its 70 km outcrop length. Regionally, the 498 Ma sequence consists dominantly of felsic pyroclastic rocks and flows with interbedded mafic volcanic units and finegrained sediments, commonly graphitic. Contemporaneous granitoid rocks occur in the south half of the belt. Rocks usually display a strong NE-SW, steeply dipping, penetrative foliation and other shear-related high-strain fabrics. Facing directions are normally northwest, although there is local evidence of folding. Sulfide bodies and their alteration systems are deformed and shape-modified in the style of ambient strain.The Tulks, Tulks East and Jack's Pond prospects appear to occupy a similar stratigraphic level, on or near the contact between a thick felsic pile and an overlying broad, conductive package of graphitic sedimentary rocks. All are pyritic deposits with well-developed footwall alteration systems. The Tulks prospect comprises four polymetallic lenses totalling 750 000 t. Three lenses constituting more than 6 000 000 t of sulfide mineralization are indicated at Tulks East but only the 210 000 t ""B"" lens contains significant base metals. Jack's Pond consists of a very extensive, zoned alteration complex in which four lenses of massive to semi-massive pyrite + chalcopyrite are known. The central part of the system, characterized by Mg chlorite and carbonate, is enveloped by pervasive sericitization and capped by intensely silicified and pyritized volcanics. The sulfide lenses are interpreted as part of the footwall zone and are beneath that part of the system most likely to hostpolymetallic massive sulfides.Daniel's Pond differs from the other prospects in such fundamental ways as metal content, associated alteration and structural setting. The deposit comprises strongly tectonized, Ag-rich, Zn-Pb mineralization distinguished by a pronounced Ba-As-Sb signature. Mineralization is confined to a narrow, north-south high-strain zone which separates unstrained mafic volcanic rocks to the east from well-foliated felsic rocks. The deposit lacks an extensive alteration halo and at its north end is associated with a lens of barren, undeformed massive pyrite.The Victoria Mine deposit, the most cupriferous of the five, is related to a moderately dipping structure that separates well-foliated Tulks volcanic rocks from an overlying, less deformed volcanic sedimentary sequence that may be as young as 462 Ma. The structure is also the locus of black chlorite, dolomite and quartz alteration. Structurally remobilized precursor sulfide mineralization is one possible source for the deposit."

Jan 1, 1993

By Hal. Oliver

MR.]. G. TRAILL: My only excuse for contributing to the discussion on Mr. Hall's interesting paper is that I had the good fortune to be employed at Noranda during those romantic years, 1927 and 1928, when construction was at its height. The mine was in course of being rapidly prepared and brought into production, and the initial difficulties in crushing-plant and smelter were being met and overcome. They were stirring days, and perhaps those members who were with the second Empire Mining and Metallurgical Congress in 1927 sensed the atmosphere of excitement and activity that prevailed. Early History. Noranda must surely possess some of the most remarkable ore-bodies known to mining men, and the story of their development is pure romance. Ed. Horne's faith in the property, and the persistence of Thomson and Chadbourne, were richly rewarded in the end, but only after some very thin times had been experienced. In those early days access to the district was by the Kenojevis river and various portages to Osisko lake, on the shores of which the mine and smelter and the town of Noranda now stand. But all the early work was done on the Chadbourne claims, more than a mile to the west; through the b~sh. I have read a log of the events of that period, and through the whole tale of hard work, discouraging developments, occasional shortages of food, and constant danger from forest fires, can be read the faith and persistence of the men in charge. The Chadbourne ore was of that well-known type which, though just too low-grade to pay (with gold at $20 per ounce), is yet sufficiently encouraging to lead one on in the hope of striking something better. It was only as a last resort that work on the Chadbourne claims was suspended and a diamond drill brought to the gossan-covered hill beside the lake. The diamond-driller told me his version (it may be exaggerated) of how the position and direction of the first hole were decided on. He was told, "You might as well set up your drill here, and drill in, say, that direction". I believe that the first hole went through the richest ore ever found at Noranda. After the drill had gone through about 150 feet of solid sulphide ore running 17 per cent copper and 4 dwt. of gold per ton, it passed into barren rock, but the diamond-driller expressed the opinion (I wonder how he knew)) that the hole would come into ore again before long.

Jan 1, 1937

By E. H. Henderson

MR. R. V. NEILY stated that he had at one time operated at Goldenville. The practice and results are much the same now as in the olden days. Inside plates were then found to be a source of trouble and had been removed. At the Libbey mine, Queen's county, the sulphides carried considerable gold, and $45.00 to $60.00 per ton had been recovered from the concentrates by roasting and chlorinating. Later, concentrates were treated with bromocyanide. Following that practice, a cyanide leaching plant was installed, which did not require concentration of the tailings. Cyanidation brought a recovery of around 95 per cent, with but $300 worth of plant. In Nova Scotia, the ore of each locality presents an individual problem of its own as to treatment required. Ma. W. B. Timm stated that, in the majority of Nova Scotia gold ores, more than 75 per cent of the gold content is free-milling and, naturally, stamps are most efficient for collecting and amalgamating this gold. In Ontario and the West, they had got away from stamps, and perhaps the main reason was that the supply of battery-men, who came from Nova Scotia, had died off. Ball-mills had been installed, which required smaller space and handled large tonnage, even though, as far as amalgamation goes, the stamps were probably more efficient. If concentration is to be done, ore from stamps is usually in better shape for recovery in passing over the tables, as there is no slime. With the ball-mill, flotation is necessary. The better practice, undoubtedly, is to take out what gold is possible before it is all smashed up, as in the ball-mill, though recent developments in the ball-mill make it possible to trap and take coarse gold directly from the mill. In this way, cyanidation is speeded-up, due to saving of the time the coarse gold would take before going into solution. PROFESSOR A. E. FLYNN found it unusual in these days to read anything in favour of the stamp mill, and thanked Mr. Henderson for the excellent paper in which he upholds the stamps and backs his opinion with facts from actual operations. For the typical Nova Scotia ore, containing coarse gold, stamps are un¬excelled. It used to be said that the virtue of stamps is that they brighten the gold for amalgamation. Although this saying is almost classical, it is not true, for gold is never brighter than in the native, untouched state. Any hammering that gold gets makes it more difficult to amalgamate.

Jan 1, 1935

By Jim Richard

Introduction Electric Vehicle Controllers (EVC) and the Northern Centre for Advanced Technology (NORCAT) have created two generations of Lunar Highland Simulant ?Simulant preparation techniques and equipment resulted from drilling activities in support of Regolith and Environment Science and Oxygen and Lunar Volatiles Extraction (RESOLVE ) ?The purpose of defining the compaction process was to minimize the effect of density on drill testing This allowed other variables including drill bit geometry, auger, RPM, and thrust to be evaluated independent of density ?Density of Highland Regolith falls within a range of 1.40 to 2.29 g/cm3 (p484 Lunar Source Book)

May 1, 2013

By Minghui Li

China is the largest coal producer in the world. In 2012, the coal production in China is 3.65billion tonnes, accounting for approximately 49% of global coal production. The raw coal production in 2012 was 3.8% more than the year 2011. 56% of total raw coal has been washed. The increase in raw coal production also promotes technology to be developed and brings separation capacity become larger and larger in coal processing in China. At present, over 40 extra-large scale coal preparation plants (each plant has capacity of more than 10 Mtpa) are in operation in China, the largest one is 32.5 Mtpa. Heavy medium separation are widely used in new built coal preparation, the washing limit for thermal coal feed lower and lower, the equipment selection tends larger which brings the whole washing system simplified, the local equipment developed and manufactured are more and more used. By discussing designs of several typical thermal coal preparation plants and coking coal preparation plants in China, this thesis introduces the current design of China?s extra-large coal preparation plants, and sums up the prevailing design features and trends of extra-large coal preparation plants.

Aug 1, 2013

By Ferrin Prince

New Gold?s New Afton mine is an 11,000 tonne per day block caving mine, located 8 km west of the city of Kamloops, British Columbia. The reserve is estimated at 52.5Mt with grades of 0.65 g/t Au and 0.93% Cu. Block caving requires a considerable amount of infrastructure development before production can begin. Each excavation had its own challenges, often further complicated by interactions with the caving stresses and fault structures. The main areas of interest were: the production crusher complex, the surface to underground infrastructure, and the footprint interaction with the faults. The ore zone at New Afton is bounded by two very weak fault zones, with large fault affected areas and associated splays. The resulting rock mass rating (RMR) is 35-50, with some areas significantly weaker due to clay infill. These conditions created a unique and decidedly difficult environment in which to develop New Afton?s infrastructure. Despite these difficulties, the mine began production on schedule in July 2012. The main production crusher for the mine is a gyratory crusher that allows for direct truck dumping, with a smaller jaw crusher in series to facilitate the initial development and production. The crusher chamber was redesigned several times to minimize the chamber volume, resulting in a 40% decrease in volume without losing functionality. After drilling and geotechnical testing, the location of the crusher was changed to eliminate the threat of fault affected ground in the area; the entire complex moved a short time before mining began on the chamber. The mining techniques used enabled tight control of the crusher pocket excavation, while also allowing for the timely completion of the chamber. The locations of the surface to underground infrastructure were tightly constrained by geology, surface infrastructure, and an existing open pit. The VR5 raise was drilled and abandoned part way through the reaming process when the drill string became stuck in fault gouge material. It was relocated and successfully completed. The VR7 raise hit a region of poor rock strength and deviated more than 11 m. Poor ground conditions caused a 130m section of the raise walls to fail. An innovative rehabilitation program was undertaken to re-establish the raise for ventilation. A surface to underground slick line was also installed to ease the material movement underground. A layout of the Extraction level was changed from herring bone to straight through drawpoints that resulted in a net reduction of 1.3 km of development. The Apex level was added to aid in the breakage over the major apex pillar and allow for geological mapping. A portion of the caving footprint is located within the footwall fault. The low strength, high clay content, and small joint spacing of the material resulted in blast-hole cut-off and drift deformation. Drift rehabilitation was a key factor in the successful development of the cave footprint. Innovative drilling and loading techniques were used to keep the holes open and to impede movement along the joint structures.

Aug 1, 2013

By D. A. Barr

"Most of the lode and placer gold production in the Canadian Cordillera has been derived from mines and placers in the Intermontane and Omineca belts. Gold has been produced from rocks of Precambrian to Eocene age, but the preferred host environment contains Upper Paleozoic to Upper Jurassic eugeosynclinal or arc-type sedimentary and volcanic rocks adjacent to plutonic complexes which have a wide variety in both size and composition. Auriferous quartz lodes occur in fissures and shear zones which are commonly subsidiary to strong fault zones. In common with most vein-type deposits, structural complexities are an essential part of the mine environment.Gold production from the Canadian Cordillera to the end of 1978 totals 35.0 million ounces, of which 47 per cent has been produced from placer mining, principally in the Klondike and Cariboo districts. The balance has been derived from lode gold (80 per cent) and base metal (20 per cent) mines.Gold reserves in producing mines and deposits committed for production as of January 1, 1978 were 87.4 tons, or 21.6 per cent of total Canadian gold reserves contained in all types of deposits. Although more than 100 lode mines have operated in the Canadian Cordillera since the turn of the last century, over 75 per cent of the lode gold produced by 1978 was recovered from five mining camps, namely the Rossland, Hedley, Bridge River, Premier and Barkerville.The average grade of the principal producers in these camps was about 0.45 ounce of gold per ton. Individual camps yielded from 3 to 8 million tons during their operating lives, which varied from 28 to 43 years. The last of these mines ceased operating in 1971.Most of the total lode gold production has been derived from quartz veins, frequently with associated carbonate and ankerite, occupying fractured and faulted zones in Mesozoic volcanic and sedimentary rocks closely associated with a variety of intrusions. A review of the literature suggests that several deposits may have evolved by remobilization of ore constituents from earlier concordant gold-bearing formations. The principal metallic minerals in the deposits are native gold, electrum, tellurides, pyrite, arsenopyrite, pyrrhotite, sphalerite, galena and chalcopyrite.As the mineralogy suggests, many of the Cordilleran lode gold deposits have yielded important co-products or byproducts, including silver, copper, lead, zinc, cadmium and tungsten. Significant by-product gold production has also been derived from porphyry copper, volcanogenic, replacement and pyrometasomatic deposits, particularly in recent years.No major lode gold discovery has been made in the past 67 years, although little exploration activity for gold has taken place during the last 30 years. Several relatively small lode gold and gold replacement deposits have been discovered in recent years, either serendipitously (Chappelle) or on very low initial budgets (Northair and Carolin). Based on well-established precedents, one or more of these may eventually be developed into a large mine.A detailed study of the Canadian Cordillera gold deposits based on recent genetic models could prove rewarding, not only in up-dating information on their origin and depositional characteristics, but in stimulating the search for undiscovered gold deposits, in the Cordillera and other parts of Canada."

Jan 1, 1980

By Kazutoshi Haga, Batnasan Altansukh, Atsushi Shibayama, Ryuji Oinuma

"Recently, the arsenic grade in copper ores has been increasing year by year. Arsenic bearing minerals (enargite (Cu3AsS4) and tennantite (Cu12As4S13)) coexist with typical copper minerals such as chalcopyrite (CuFeS2). The removal of arsenic from copper ores that contain relatively high arsenic content is essential due to its adverse impact on the environment and the resulting economic consequences. In this study, arsenic removal and dissolution behaviour of Cu and As from enargite (Cu3AsS4) were investigated using ferric sulphate (Fe2(SO4)3) solutions containing sodium chloride under high pressure oxidation conditions. The effects of numerous parameters including the concentration of Fe2(SO4)3 and NaCl, temperature, total pressure, leaching time and particle size were studied while other variables such as pulp density and stirring speed were fixed at 100 g/L and 750 rpm. The results showed that more than 60% of the copper was dissolved in a 0.1 M ferric sulphate solution under the high pressure oxidative conditions, whereas the leaching rate of arsenic was less than 20%. SEM observation revealed that elemental sulphur was deposited on the surface of enargite forming a passivation layer and the residue was agglomerated. Those phenomena may cause a decrease in the copper leaching rate. It was found that more than 80% of copper was dissolved in the ferric sulphate solution in the presence of 0.34 M sodium chloride under the conditions optimized, whereas the dissolution of arsenic in the mixture did not exceed 2%. XRD analysis of the solid residues from the leaching experiments used ferric sulphate and mixtures of ferric sulphate and sodium chloride showed arsenic to be present as scorodite (FeAsO4).INTRODUCTION In recent years, there has been an increase of the arsenic (As) content of copper ores due to the gradual depletion of high grade copper ores. In some copper deposits, arsenic occurs in the form of minerals such as enargite and tennantite. The removal of arsenic in ores containing copper is critical to the production of pure copper and the management of the environmental challenges caused by the smelting process. Due to the environmental risk caused by arsenic emission and the deteriorated quality of the copper product, smelting of enargite concentrates is not an effective method for the extraction of copper (Padilla et al., 2010; Safarzadeh et al., 2014; Long et al., 2012). Therefore, a number of studies have been carried out to develop arsenic removal technologies from copper ores using various methods such as hydrometallurgy (Curreli et al., 2009; Tongamp et al. 2010), pyrometallurgy (Dalewski., 1999; Padilla. et al, 2012) and bio-oxidation (Ehrlich, 1964; Sasaki et al., 2010). Several hydrometallurgical leaching processes like sulphuric acid, alkaline sodium sulphide and sodium sulphate and ferric sulphate leaching have been developed to treat enargite ores and concentrates. The alkaline sodium sulphide leaching process has been developed for the removal of arsenic from enargite (Anderson, & Twidwell, 2008; Parada et al., 2014). The mechanism of the dissolution of arsenic from enargite in sodium sulphite solution is"

Jan 1, 2016

By K. Matsuura, M. Ohno, T. Tokunaga

"Recently, weight saving of automobiles has been strongly required to solve the global environmental problems. Mg alloys are one of the promising candidates as a new material for automobile components. However, the application of the Mg alloys is limited due to their poor corrosion resistance. In the authors’ preliminary study, an Al/Mg/Al clad sheet was fabricated by hot extrusion and subsequent hot forging. The clad sheet exhibited a high corrosion resistance and excellent super plasticity. More specifically, the elongation of the clad sheet was as high as 550%.Importantly, despite that the elongation of Al itself was only 40%without cladding with Mg, the ductility of Al was greatly improved in the form of the clad sheet. In the present study, in order to clarify the mechanism of the superplastic deformation of the Al part in the clad sheet, the microstructure evolution of the Al during the tensile de formation is investigated. The tensile tests were conducted at a temperature of 573 K and at a strain rateof1.0×10-3s-1. The Al exhibited fiber-type texture at the beginning of the tensile deformation, and brass-type texture after the elongation of 50%.INTRODUCTIONMg alloys have been gaining attention because of their excellent properties e.g. light weight, good recyclability and high electromagnetic shielding. However, their practical applications have been limited due to their poor corrosion resistance. In the authors’ previous study, in order to solve this problem, Al coating on Mg alloy by hot extrusion has been proposed, and the Al-coated Mg alloy plate was fabricated(Tokunaga, Matsuura, &Ohno,2012). The plate was hot-rolled and an Al/Mg/Al clad sheet was fabricated. No cracks or debondings were observed at the Al/Mg interface. The sheet exhibited a high corrosion resistance in a comparable level as pure Al. Also, the sheet exhibited a large and uniform elongation of 550%in a tensile test at a temperature of 573 K and at a strain rate of 1.0×10-3s-1without any breakings or debondings of the Al part(Tokunaga, Matsuura, &Ohno,2014).Mg alloys have been known to exhibit a superplastic characteristic when the grain size is small. However, it is known that the pure Al does not generally exhibit the super plasticity. As mentioned above, the Al-coated Mg alloy sheet exhibited 550% of elongation in the authors’ previous study (Tokunagaet al., 2014). However, the pure Al itself showed only 40% of elongation, while the Mg alloy itself exhibited 800% of elongation. Thus, it has been demonstrated that the pure Al was super plastically elongated when it was bonded with the Mg alloy. Generally, deformation mechanism of the super plasticity of the Mg alloy is known as a grain boundary sliding. On the other hand, the mechanism of the superplastic elongation of the pure Al is still unclear. The purpose of the present study is investigation of the deformation behavior of the Al part in the Al/Mg/Al clad sheet during tensile de formation."

Jan 1, 2018

By R. Clarkson

"Free gold particles occur in many base metal and precious metal mines throughout the world. Due to the high density and malleability of gold, large circulating loads of free gold particles can build up over time in grinding circuits. This gold is often deposited in unintended traps throughout the mineral processing system.These unidentified free gold deposits represent a serious security risk as well as an inaccessible inventory of gold. Deposits of free gold particles often remain undetected by mine management until they are accidentally discovered while repairing mill equipment.Nuclear tracers have been used to determine the free gold recovery efficiency of gravity recovery equipment, drills, and sampling equipment (Clarkson, 1994, 1995; Walsh and Rao, 1986; Walsh and Kelly, 1992). In November, 1993, the author inspected the grinding circuit at La Mine Doyon in Rouyn-Noranda, Quebec and made recommendations to recover coarse gold and to eliminate gold traps from the circuit. In 1995, the author salted mineral processing circuits with radioactive gold particles. The gamma and X-ray radiation from gold’s nuclear isotope (Au198) were detected through steel, in pipes, and in moving equipment using scintillometers. The radiotracers proved to be a safe, rapid and accurate method of identifying gold traps and improving security.Nuclear TracersWhen particles of gold are placed in a nuclear reactor, some of the gold atoms (Au197) absorb another neutron in their nucleus to form gold’s radioactive isotope (Au198). In the process of radioactive decay, this isotope emits high energy gamma rays and X-rays which are easily detected (even through steel) with scintillometers.Radioactive gold (Au198) has a very short halflife of 2.7 days. At the relatively low activity levels used for tracing, the particles remain detectable with a small hand-held scintillometer for about 10 to 14 days. After 14 days the irradiated gold is close to background levels and within two months it is essentially non-radioactive. The radiation has no effect on the recovery characteristics of the gold particles. The gold radiotracers are very safe due to their very low level of radiation, short half-life, and their inherent physical and chemical stability. However, the use and possession of even mildly irradiated gold is strictly licensed and regulated."

Jan 1, 1997

By Takahiko Okura, Chiharu Tokoro, Shunta Shibuya

Copper concentrates bearing arsenic as enargite (Cu3AsS4) or tennantite (Cu12As4S13) have disadvantage on copper smelting environmentally and economically, so those concentrates should be treated decently. In this paper, some experiments of arsenic removal from several kinds of copper concentrates by heat treatment in an inert atmosphere were discussed. In this study, several samples in which arsenic contents varied 0.18 to 8.3 wt % were heated to the temperature range of 400 °C to 700 °C under argon gas flow during 1 hour. The heat residues and volatilized materials (V.M.) were analyzed by XRD, XRF, ICP-AES, XAFS and MLA to analyze residual concentration of arsenic and residual mineral composition. Experimental results showed that arsenic removal from copper concentrates advanced in 2 steps; at the temperature range of 500 ° C to 550 °C and of 550 °C to 650 °C, respectively. MLA analysis showed that a few of arsenic in enargite was removed by 550 °C heating and a majority of it was still combined with copper and sulfur as tennantite. On the other hand, arsenic in tennantite was removed almost completely by 650 °C heating. Furthermore, a particular type of arsenic mineral, such as Cobaltite (CoAsS) still remained after heating at 700 °C.

Jan 1, 2014

By W. W. Muir

"The Baker Mine used a 100-ton per day conventional cyanide leach mill located in northern British Columbia. A production decision was made in early 1980 and the mill was on fine in April 1981.Ore reserves had been estimated at 100,000 Ions averaging 0.9 oz gold per ton and 18 oz silver per ton . Mineralization consists of electrum (Au/Ag) and acanthite (Ag2S).This paper will review plant design and focus on some problems associated with start-up and early operation with the intention of assisting other mine operators by indicating potential problem areas.IntroductionThis paper will discuss operating strategies employed at Baker which improved over-all mill performance. Also included are some ideas which could be steps toward a more efficient operation in a similar setting.Actual dore production by mine life was 37,606 oz gold and 742,117 oz silver.Figure 1 illustrates the relative stability attained over the mine life. Metal recoveries for gold and silver were 92% and 85% respectively.Safety at Baker was of prime importance because of its remote location. Baker received the Mine Safety Association ""Small Mines Award "" in two of its three operating years. At shutdown in late 1983 the mill had operated for over 850 days without a lost-time accident."

Jan 1, 1985

By Yufeng Yao, Robert P. Lowell

Abstract - Conductive heat flow anomalies associated with hydrothermal sulfide mounds on the seafloor have been studied. Sulfide mounds tend to focus conductive heat flow because sulfide minerals have a greater thermal conductivity than country rock. The topography of the mound above the seafloor, however, leads to a reduction of heat flow, particularly near the center of the mound. Because the focusing effect is constant, whereas the topographic effect decreases with distance away from the center, the focusing effect dominates toward the edges of the mound. The magnitude of these effects depends upon the conductivity contrast and the height/radius aspect ratio of the mound. Conductive heat flow anomalies at sulfide mounds also result from fluid circulation within the edifice. For the active and relict mounds at the TAG hydrothermal field, which have an aspect ratio of approximately 0.3 and a conductivity contrast of 3, the heat flux through the center of the mound should be roughly 70% of the background heat flux. The maximum effect of heat flow focusing is to increase the heat flux by about 30% above background. By comparing these effects with conductive heat flow data at TAG, we find that advective processes dominate conductive heat flow at both the active and relict mounds. Advective circulation can also give rise to much larger lateral and vertical temperature gradients than would result from conduction alone.

Jan 1, 1999

By D. Saramak, Z. Naziemiec

"Chalcedonite is an unique rock due to the relatively small area of its occurrence. It also possesses multi-raw-material features therefore it should be given a special protection aiming at its complete and optimal utilization. It is the natural sedimentary rock and the only mine in Poland, located in Inowlodz, where the opencast mining from “Teofilow” deposit is carried out.Chalcedonite mainly consists of cryptocrystalline and microcrystalline chalcedony together with small amounts of autogenous and detrital quartz. The chalcedony itself is a fairy common mineral and many forms of its occurrence is known, some of them are semi-precious minerals. Among the most popular ones following can be found: agate, bloodstone, onyx, carnelian, chrysoprase. Many countries own chalcedony deposits: Australia, Brazil, India, Canada, Namibia Russia, South Africa. However chalcedony in its pure form does not occur in the mentioned chalcedonite rock. The pores, which take usually from 5% to 25% of volume and have sizes smaller than 0.5 mm, are the characteristic feature of all chalcedonite forms. The paper presents some crucial problems of its processing together with most significant directions of its applications. New method of chalcedonite enrichment based on densimetric separation (patented in Poland) is presented. Results of investigation show that the obtained products can increase quality of concrete and filter grits."

Jan 1, 2016

By A. W. White

Introduction To discuss all the technical details of incorporation laws, security laws, underwriting procedures, codes, and ethics-as laid down by varous associations -would be impossible in the time which has been allotted to me. My remarks, therefore, will be made in a very general way and will naturally be coloured with experiences which my firm and I have had. There is a common expression that "money makes the mare go". I hardly have to mention here that the best prospect in the country is of very little value unless its prospects can be developed-and this requires large capital expenditures. The art and problems surrounding the raising of this money is a long and interesting story. Since by its very nature mining is risky, the appraising of its risks in the many phases of its development programme is continuous. Very few men-if any-and very few corporations -if any -can afford to take all the risk of mining. Because of taxation policies-and the very scheme of present-day living -the truth of this statement can be seen throughout the whole industry by a close examination of the records. Since this is so, it is essential that the mechanics of distributing risk on a sound, and equitable basis be known to those engaged in the business and to the investor or spectator who proposes to risk his funds in the industry. Perhaps the greatest stimulant to modern business activities has been the creation of corporate bodies. It is evident, from the number of charters being granted by various jurisdictions, that this method of doing business is becoming more and more important. A limited company -or corporation-can be defined as a fictitious person existing solely in contemplation of the law.

Jan 1, 1951

By Mario A. Morin

Mine design, planning and scheduling is a very complex, iterative process comprising several interrelated and interdependent activities. Understanding how this process works, identifying the critical pieces of information and the decisions to be made is key to initiating business process improvements (BPI) or business process reengineering (BPR) activities. Fundamental to most BPI and BPR work is some form of systems analysis. Structured Analysis is a powerful systems analysis technique that is well suited for modeling and analyzing complex process activities. Through a series of diagrams, this paper presents a vertical slice through the analysis work performed for formally describing the underground hardrock mine design and planning process. These diagrams illustrate how simple graphic constructs can be used to decompose the most complex situations into easily understandable diagrams that facilitate understanding, communication, improvement and reengineering.

May 1, 2002

By Kr. N. Karparov

Measurements made with high precision GPS landmarks and geotechnical radar Reutech MSR- 300 associated with the observed movements in the north face of Assarel Mine, where on a horizontal distance of 50 m, 2 groups of landmarks indicated different deformation behavior. Measurements are made in order to confirm the applicability of the radar system in regions of complex geotechnical conditions. The standard deviation of each landmark is used as an accuracy standard between the separate measurements of the deformation vectors made by the high-precision GPS system for each landmark. A very good correlation between the displacement vectors can be seen based on the measurements made with the high-precision GPS system and the measurements made by the radar system MSR-300. Geological, engineering geological and hydro-geological conditions of the area of concern are discussed in this paper. The measured deformations and the FLAC/SLOPE analysis show similar results. In the paper is discussed their local character and their sensitivity to other geotechnical and hydro geological conditions.

Aug 1, 2013

By V. Bruned, K. Mohamed, A. Michaut

Orano Mining Somaïr uranium treatment plant (Niger) uses a pugging-curing process to leach uranium. Sulfuric acid, nitrates and water are added to the finely grinded ore in a rotary drum to leach uranium bearing minerals and solubilize uranyl sulfate ions. Reagents, sulfuric acid and nitrates, are the main OpEx of this process step. The economical optimization of their addition requires a thorough knowledge of the ore behavior in solution with these reagents. Orano Mining technical direction and Somaïr laboratories developed a model to predict the curing process uranium recovery surface with a limited number of parameters. Experimental laboratory work to fit the model needs to be done for each type of ore which can require a lot of metallurgical tests and would be time consuming. In order to optimize the required number of tests, an innovative experience plan was designed in parallel to the development of this model reducing the required number of tests to only eight. Once the parameters of the models are correctly fit, the comparison between the estimated values and the actual values for the uranium recovery is excellent (less than 0.5% error in average). Associated with an updated cost model of the curing process, this new recovery model helps the plant operator find the best set of reagents to maximize curing process profitability in the Somaïr plant day after day.

Jan 1, 2020

By W. Baranek

The paper describes activities undertaken for intensification of copper cathodes production in electro-refining plants of the Polish copper smelters: 'Legnica', `Glogów I' and `Glogów II'. In the 'Legnica' smelter, Outokumpu?Wenmec machine was used for preparation of copper anodes. Intensive studies were conducted in order to optimise copper electro-refining conditions. As the result of them, spacing between the electrodes was reduced to 99 mm, which enabled placing forty-one cathodes in each tank and increasing amperage from 10.8 to 13.0 kA. This modification resulted in the increase of electro-refining capacity to 103,000 tons/y. Intensification of the copper production at `Glogów II' by 18,000 tons/y became possible after development of new electro-refining procedures, including application of a regime of changes in electrolyte level during the cathode cycle, implementation of the changes in location of starting sheets relative to anodes, and in dimensions of the sheets, and modification in the shape of the anodes. Similar works have been performed at `Glogów I', which were concentrated mainly on defining of a new method of anodes preparation, modification of their geometry, determination of optimum current density, composition of a set of inhibitors and of a method of their introducing. The implemented solutions resulted in the increase in electro-refining capacity at `Glogów I' from 207,000 to 240,000 tons/y.

Jan 1, 2007

By A. Khan

The purpose of this paper is to demonstrate the value of identifying and optimizing throughput constraints by utilizing a Constraint Model. This will be achieved by first understanding the overall concept of Operational Excellence, Continuous Improvement and Theory of Constraints as practiced within Vale Canada Limited. Next, the value of utilizing a Constraint Model is demonstrated by primarily identifying constraints. The applications in utilizing Constraint Models will be demonstrated, including the primary benefit of identifying constraints. The remainder of the paper will focus on how to properly setup a Constraint Model using discrete simulation (regardless of simulation software). Benefits of understanding the severity of constraints and movement of the bottleneck will be recognized. The paper will conclude with the summary of real applications within Vale Canada Limited.

Aug 1, 2013