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By ByongPil Lee, Changkyu Lee, Jin Gyun Park, Hyung Sub Eom, Sung-Koo Jo, Jae-Young Lee, Gilsoo Han

"A new hydrometallurgical process for nickel extraction from a low grade laterite ore such as limonite has been developed by RIST and POSCO. This POSCO Nickel Extraction Process (PosNEP) consists of five main processes: ore reduction using hydrogen as a reductant; acid leaching at atmospheric pressure and temperature; cementation by the use of reduced-ore seed; production of the main product such as ferronickel or a high purity nickel compound; and production of by-products such as cobalt and iron in the forms of cobalt sulfate and iron oxide. In addition, hydrogen produced in acid leaching and hydrochloric acid regenerated in pyrohydrolysis for iron oxide production can be reused in the process, which makes PosNEP more cost-effective. The performance of PosNEP has been proven through pilot tests, showing that this process is economically and technically viable. In this paper, basic concepts and detailed test results of PosNEP are shown.INTRODUCTIONNickel has been extracted from two types of ore, sulfide and oxide ore. Nickel and cobalt usually occur together in the ores. The principal ore mineral of the sulfide is pentlandite, (Ni,Fe)9S8, which is easily beneficiated to produce sulfide concentrates(Moats & Davenport, 2014). These concentrates are usually treated by smelting and converting to make a matte. The produced matte is then purified through either hydrometallurgical or pyrometallurgical processes to produce high-purity nickel. In general, this process for sulfide ore has been known as a more cost-effective process than that for oxide ore.The oxide ore is laterite comprised of two different ore types, saprolite and limonite. The main nickel-bearing mineral of saprolite is nickeliferrous garnierite,(Mg,Ni)6Si4O10(OH)8, and that of limonite is nickeliferrous goethite (Fe,Ni)O·OH ore (Moats & Davenport, 2014). Since the saprolite has high contents of nickel and slag formers (MgO and SiO2) and a low content of iron, it tends to be treated by a pyrometallurgical smelting process such as calcination and electric furnace techniques to produce ferronickel for use in stainless steel. In this process, the cobalt in the ferronickel does not have any economic value."

Jan 1, 2017

By P. M. Dranchuk

"""PLANET EARTH seen from space appears as a fragile and limited life-supporting system in a vast emptiness. That such a view is, in fact, an accurate one is now more widely accepted than it was not long ago, before Earth's problems of over-population, overconsumption, limited resources and environmental degradation attained the limelight. The danger is that a government and public now deluged by doomsday prophecies and bemused by equally confident reiterations that technology will cure all may hesitate in coming to grips with the problem, in the hope that, given time, it will go away."" With these words, Preston Cloud begins a recent editorial, in Science(l), in which he presents a brief resume of some of the findings of the Committee on Resources and Man of the National Academy of Science-National Research Council(20.Their report, which is based on a two-year study by an extremely competent group and consists of some 250 pages of text, is even more far-reaching and sobering than the report on Energy Resources(3). It begins by quoting Sir Macfarlane Burnet as follows:""There are three imperatives: to reduce war to a minimum; to stabilize human population, and to pre-vent the progressive destruction of the earth's irreplaceable resources.(4)"

Jan 1, 1971

By J. B. Hadaway

The operation at Phu Kham commenced design and construction in early 2006 and was commissioned in May 2008. This paper will examine and discuss the project from the inception of flow sheet development and equipment selection, equipment design and manufacture, construction, commissioning and ramp up to full production. The paper will touch on the strategies employed to achieve a short schedule and the efficient use of capital, but with the main emphasis on the grinding circuit. Various challenges during the early years of operation will be discussed including the effect of ore characteristics, including competency, on the performance of the grinding circuit. Actions to overcome these challenges and to enhance performance will also be discussed. Finally, current and future plans to improve the performance of the grinding circuit and the overall plant will be summarised.

Jan 1, 2012

By W. C. Risley

IN the year 1933, workings at the No. 12 colliery, New Waterford, of the Dominion Coal Company, Limited, had advanced to a point where additional ventilation would soon be required. Furthermore, development of the mine was being .made to practically double the output of coal. Consequently, authorization was given to sink a shaft to the workings. The location selected is on the west side of the mine, about one and a half miles from the slope mouth and on the Low Point shore, some 250 feet from high-water mark. The cliff at this point is 40 feet high, with the land rising on a slope of about 5 per cent to the shaft. Figure 1 shows the location with reference to the colliery workings. The strata through which the shaft was to be sunk were pretty well known from diamond-drill borings previously made, and it was believed that water would be encountered to a depth of at least 250 feet to 300 feet. It was planned, therefore, to seal-off the water by the pumping of cement grout under high pressure. This method was considered to be the most economical means of handling the water during sinking, and would also result in a permanently dry shaft. Figure 2 shows a cross-section of the strata. The permanent shaft hoist and fan were to be electrically driven, which would necessitate the construction of a transmission line between the colliery and the shaft; therefore, it was arranged that the sinking equipment would have electric drive. As all equipment, materials used in construction, and supplies were to be hauled by truck, a roadway 1,800 feet long was required from the main highway to the site, and as heavy loads would be hauled during the fall, winter, and succeeding spring, this road was ballasted with 18 inches of clinkered material obtained from a burned culm bank one and a half miles distant. Actual field work was begun by the Company's own forces early in October. Work preparatory to sinking-in addition to the roadway and trans-mission line-included the construction of the reinforced-concrete shaft collar and fan drift connection; the permanent timber headframe (which was to be used also as the sinking headframe); the permanent reinforced-concrete building to house the shaft hoist and fan drive; and the erection of temporary buildings and installation of all equipment for sinking and lining the shaft and for cementation.

Jan 1, 1936

By R. A. Brown

RIGHT NOW the Canadian oil business is suffering from growing pains brought on by developments outside our borders. I would like, therefore, to place our industry in perspective for you in two ways. I would like first to describe it briefly and let you see it in relation to the world oil industry. Then I would like to bring it back and place it into perspective against a strictly Canadian background. Naturally, in such a discussion, it is necessary to use a certain amount of statistical material. I'll endeavour, however, to keep it to a minimum. Eleven years ago, before the discovery of Leduc, Alberta could boast of having 21,000,000 barrels of crude oil reserves. Five years ago we had 1,810,000,000 barrels. At year end, 1957, our remaining recoverable reserves totalled more than 3,000,000,000 barrels. In 1957, our potential production in Alberta reached an all-time high of 756,000 barrels a day. Unfortunately, our actual average daily production dropped from 393,000 barrels per day in 1956 to 376,000 barrels per day in 1957. And in 1958, to date, it has dropped sharply to around 300,000 barrels per day.

Jan 1, 1958

By G. P. van Greunen

"The rehabilitation of underground excavations has been undertaken as long as mining has existed. The conventional methods have proven to be dangerous, time consuming and expensive. During the construction of Styldrift Mine at Royal Bafokeng Platinum several vertical and horizontal excavations had to be rehabilitated. With a zero tolerance attitude towards working in unsafe conditions, together with a non-negotiable timeline to construct and ramp up the mine, the project team could not rehabilitate these excavations using conventional methods. This paper details the approach used to rehabilitate excavations using remote methods and how it was adapted to suit varying operating conditions and requirements - ensuring that no person ever entered an unsafe excavation before it was fully rehabilitated and safe. INTRODUCTION Styldrift Mine is an expansion project of the Royal Bafokeng Platinum group. It is located in South Africa in the North West Province some 10 km south of the Sun City resort (Figure 1). The mine consists of a twin shaft system (Main Shaft and Services Shaft). Capital construction of the shaft and associated infrastructure started in 2009 and is projected to be completed during 2020. The designed steady state production capacity of the shaft is 230 ktpm of Merensky ore. Production ramp-up commenced in 2017 with steady state production set to be achieved 36 months later in the fourth quarter 2020.Merensky Reef was intersected at a depth of 600 m below surface and the shaft design has a mean mining depth of 630 m. The project was approved for execution in 2008 on the basis of a suitable mine design and bankable feasibility study. One of the main excavations that required rehabilitation was an underground reef silo, Silo 4. It is a key piece of infrastructure on the critical path to allow steady state production at Styldrift Mine to be achieved. During construction excessive scaling within the silo along its 64m length necessitated urgent rehabilitation to be able to meet the ramp-up schedule. The criticality and urgency of these excavations prompted the project team to reduce the risk of failure while ensuring safe and cost-effective rehabilitation. This paper will focus on the rehabilitation of Silo 4 while capturing the essence of the learnings of all the excavations that were rehabilitated remotely."

Jan 1, 2019

By J. C. Underwood

"The wear performance of grinding balls under conditions of impact and abrasion is affected by their chemical composition and structure. The selection of appropriate analyses and heat treatments that will provide both abrasion and impact resistance takes into account the effects of certain elements on structure and harden-ability, as well as the over-all effect of composition and hardness penetration on the residual stress pattern developed through heat treatment. Direct quenching from forging temperatures substantially increases hardenability over that obtained in reheat-quench practices, and can be done without undue risk of damage to the ball provided that the harden-ability bears the correct relationship to ball diameter.Average volumetric hardness and percent hardened volume are convenient parameters for quantitatively expressing the response to heat treatment and indicating anticipated wear properties. A number of factors which can lead to reduced wear life as a result of material or processing problems are reviewed and illustrated."

Jan 1, 1959

By Joseph J. Larry

In hard siliceous sandstone strata overlying coal seams, roof bolting is often the bottleneck in the coal production cycle. In the past, these strata have been drilled by pneumatically operated stopers. Although slow drilling is cumbersome and uncomfortably noisy, the stoper was the most effective drill in these harder strata. However, because of the (U.S.) Coal Mining Safety Act, which limits noise levels for operating drills, FMC Mining Equipment developed the water-through-the-drill-steel method of drilling high-compressive-strength strata. Although water-through-the-drill steel had been developed earlier, the real impact of wet drilling techniques surfaced when the dual-boom roof drilling machines were installed at the Virginia-Pocahontas Division, Keen Mountain, Virginia, in 1974. This paper covers some of the technical details of the water-through- the-drill-steel design and its application.

Jan 1, 1979

By John N. Ludden, Maurice Rive, Hillar Pintson

"Quelques soixante-dix-sept plutons présents dans la Sous-Province de Pontiac et dans la partie centrale de la Sous-Province de I’Abitibi ont fait I ’objet d’une reconnaissance systématique. Ils ont été regroupes en huit suites plutoniques majeures et trois suites mineures à partir de critères géologiques et petro logiques. Parmi les suites majeures, quatre représentent I' activité intrusive la plus ancienne dans la région. L’une d' entre e/les est représentée par deux complexes anorthosito-gabbroi' ques lites et les trois autres comprennent les orthogneiss dioritiques a leucotonalitiques et les intrusions dons la composition varie de diurétique et granodioritique à leucotonalitique. Leur mise en place peut être pretectonique a syn ou tarditectonique; certains plutons sont synvolcaniques. Quelques data/ions U! Pb effectuées à propos de ces roches donnent des âges s' étalant entre 2 718 et 2 694 MA. Les données géochimiques indiquent la présence des deux lignées magmatiques, tholemique et calcoalcaline bien qu’il n'y ait aucune évidence de relations entre elles dans I' espace et dans le temps. Ces suites magmatiques différentes peuvent provenir soit d’une croute tholemique impliquée dans un processus de subduction soit directement du manteau.Les trois autres suites majeures comprenant des monzodiorites, des granodiorites et des monzonites ainsi que les deux suites mineures comprenant des syenites correspondent à un évènement intrusif plus jeunesse déroulant entre2 694 et2 680 MA. Ces roches sont syn, tarti a post tectoniques et sont enrichies en alcalins, Ba, Sr et terres rares legeres par rapport aux quatre suites précédentes. Leurs caractères chimiques prop res suggèrent qu' e/les proviennent d' une source différente par rapport à celle precedemment citee.La derniere suite plutonique majeure correspond a un monzogranite leucocrate, riche en pegmatite, également syn a tard tectonique, dont I' age n' est pas connu avec précision. ll représente le seul granite ""vrai"" de la région et dérive d’une anatexie soit des meta sédiments soit des granodiorites-tonalites plus anciennes. La troisième suite plutonique mineure correspond a quatre stocks de granodiorite porphyrique qui n’ont pas été étudiés en détail.ABSTRACTSevenly-sevenplutons have been identified in the east-centra/part of the Abitibi Subprovince and adjacent Pontiac Subprovince. These have been subdivided, on the basis of geological and petrological criteria, into eight major and three minor plutonic suite. Four of the major suite, which represent the oldest intrusive activity in the area, range in composition from dioritic-leucotonalitic orthogneisses to diorite-granodiorite/leucotonalite and include two layered anorthosite- gabbro complexes. Their time of emplacement ranges from pretectonic to syn-late-tectonic and some plutons are synvolcanic. U-Pb zircon ages for these rocks range from 2 718 to 2 694 Ma. Geochemical data indicate the presence of both calc-alkaline and tholeiitic magma series for these rocks although there is no evidence time and space relationships between the two. The different magma series also suggest the derivation of these rocks from two sources, either from subduced tholeiitic crust or directly from the mantle. Three major monzodiorite-granodiorite, monzonite, and two minor syenite suites comprise a younger inlrusive event ranging from 2 694 to 2 680 Ma in age. These rocks are syn-, late- to post-tectonica and, compared to the above four plutonic suites, are enriched in alkalis, Ba, Sr and light Rare Earth Elements.Their distinctive geochemistry suggests that these rocks were derived from a different source region than for the older plutonic suites. The remaining major plutonic suite consists of leucocratic, pegmatite-rich, monzogranite-granodiorite. These rocks are also syn- to late-tectonic but their ages are not known with precision. They are the only ""true"" granites in the area and were derived by the partial melting of either older"

Jan 1, 1990

By J. -F. Blais, M. -O. Simonnot, P. Charbonnier, J. Mocellin, Université de Lorraine INRA, G. Mercier

"Huge amounts of air pollution scrubber sludge have been generated during ferromanganese production using blast furnace. These residues have been historically deposited in ponds near steel making plants. They are very rich in zinc, manganese and lead (5 to 40 %) and also contain aluminum and iron. Considering the market value of these metals, brownfield sites can now be used as secondary resources. These ponds also have to be cleaned up to meet the environmental regulations.We have developed a hydrometallurgical process to recover Zn, Mn and Pb in order to produce valuable compounds of Mn and Zn and recover the final Pb residue by pyrometallurgy. The Zn and Mn compounds need to be pure enough to be economically valuable. Batch laboratory tests were carried out to determine suitable selective leaching conditions. The investigated operating conditions were acid concentration, pulp density and temperature. Optimal conditions to maximize zinc extraction (100 %) and manganese extraction (95.9 %) were found using sulfuric acid and sodium metabisulfide. The final residue contained 14.8 to 23.8 % of Pb. Then, Zn was recovered in the form of ZnO or ZnS by precipitation and Zn metal by electrowinning, while Mn was recovered as MnCO3 with a fairly acceptable concentration of impurities.INTRODUCTIONFerromanganese has been produced by pyrometallurgy in much of Western Europe for centuries. Use of wet scrubber to remove pollutant and dust particles from gas stream was common for most of these operations. Those residues contain high concentration of Zn, Mn and Pb. They have been left to decant in settling ponds installed close to the steel production plants. They now constitute heavily contaminated artificial soils. Those sludges are so contaminated with Zn, Mn and Pb that they can be used for metal production. Currently, no method is available to decontaminate these residues and recover Zn, Mn and Pb. Therefore, an approach considering these brownfield sites as secondary resource is in development. Doing so would achieve two goals, decontaminate the site and produce metals.. (Huot, Faure, Biache, Lorgeoux, Simonnot, & Morel, 2014a; Huot, Simonnot, Marion, Yvon, De Donato, & Morel, 2012; Huot, Simonnot, Watteau, Marion, Yvon, De Donato, & Morel, 2014b)."

Jan 1, 2016

By C. O. Stee

Introduction The property of Siscoe Gold Mines, Limited, is located on an island of three hundred and forty acres in lake Kienawisik, about fifty-two miles east of Noranda and forty-three miles south of Amos, Quebec. Lake Kienawisik is a part of the Harricanaw drainage system and is crossed by the main line of the Canadian National railway at Amos. This waterway is navigable for boats with a draught of six to eight feet. Diesel engines have been the source of power at the property since milling operations were commenced in January, 1929. The power plant as first designed and built was for a milling capacity of 100 tons. Two Polar-Atlas units, each of 200 h. p., comprised the original installation. With the growth of the 'mine, more engines were added until, at the present time, there is installed at the Siscoe what is rated the largest Diesel plant at any mining property in Canada. Definition of a Diesel 'The Diesel engine is an internal combustion engine which works with liquid fuel introduced after, and independently of, the air charge at a time when communication between the cylinder and the outside atmosphere is cut off, and which ignites the fuel by compression-beat and stored combustion-heat unassisted by heat sources outside the cylinder itself while the engine is in stable operating condition"(1).

Jan 1, 1934

By Robert D. McKellar, Luke Frawley, Okrasa. Richard

"The resource industries in Canada are facing increasing global competition and stringent environmental regulations. This has made it essential for companies to lower operating costs wherever possible. Electrical energy rep-resents one variable cost that may be better managed and utilized, providing the user with lower operating costs, improved productivity and better yields.The utility industry is also facing changes in the way it must do business. Utilities in North America are facing the prospect of deregulation that will eliminate the monopoly they have traditionally held. This will force them to strive for lower operating costs, to maintain a competitive position and to improve customer ser-vice so as to maintain their customer base.Ontario Hydro has been working with industry for several years. Many opportunities for cost savings have been identified involving energy efficiency, process improvements and the use of new electro technologies. One useful service that the utility can offer industry is to increase the awareness of potential opportunities suited to their operations. This paper will provide an overview of some of the projects that have been implemented and those that are presently being evaluated. An electronic data-base of electro technology applications that is under development will also be described."

Jan 1, 1996

By Robert Lee

"International competition is presenting the Canadian steel industry with a major challenge. While Canadian companies have invested in new technology, research and development, activity by Canadian industry, in general, lags significantly behind that of its major competitors. While OECD countries increased their research and development spending during the 1980s, Canada's R&D funding levels have changed little since the early 1970s and have actually dropped since 1986, despite greater public discussion on the issue. This fact is reflected in the relatively slower pace of innovation in the Canadian steel industry, despite the efforts of both government and industry.In addition, there are a number of factors that undermine the competitiveness of the Canadian steel industry, in particular in relation to the United States. Among these are higher interest rates, labour costs and tax rates, as well as an overvalued Canadian dollar. Canadian steel companies are thus feeling the full impact of the current economic recession. This recession, combined with recent strikes, have, for example, caused serious losses for Algoma and Stelco.In spite of these objective difficulties, the Canadian steel industry has been able to survive and continues to strive for a leadership position in the world market. Since World War II, heavy investment in new technology has allowed the industry to upgrade its facilities and increase productivity, while at the same time improving quality and reducing pollution. This last point is particularly important in view of public insistence on improvements to the quality of the environment. Over the next decade, this technological innovation must be maintained and intensified if industry is to meet the challenge of international competition and attain a leadership position."

Jan 1, 1991

By R. A. McGuire

THE recorded production of the Sheep Creek camp from 1900, when the Yellowstone Mining Company first put its mill into operation, to the present day is in excess of $17,500,000. Of this total, $2,500,000 can be attributed to the early period from 1900 to 1916, at which time increased costs of labour and material due to the Great War forced abandonment of any operations on a large scale for a number of years. Since the camp was revived in 1929, at which time the Reno mine started large-scale operations, and the early 'thirties', when the increased price of gold induced the commencement of operations on other properties in the district, total gross production has been in excess of $15,000,000. In addition to the above totals, intermittent shipments were made by lessees and small operators, principally during the period of inactivity from 1916 to 1929, but no records of this production are available. The Sheep Creek camp would rank fifth in the Province-behind Rossland, Portland Canal, Bridge River, and Hedley-in gross gold production, but, because of relatively inexpensive mining and milling costs, would occupy a more prominent position in regard to total dividends paid. Operating mines at the present time include Reno Gold Mines, Gold Belt Mining Company, Kootenay Belle Gold Mines, and Sheep Creek Gold Mines. Each one of these companies, with the exception of Kootenay Belle, represents a consolidation of several smaller properties, all of which were in existence for a number of years prior to 1929. These four companies, at the present time, own, or hold options on, practically all the important claims in the district with the exception of a very few claims and fractions still held by private owners.

Jan 1, 1942

By Maurice Lauzon

"Aerial surveys of the open pits have been conducted regularly at Lake Asbestos of Quebec, Ltd. -a subsidiary of American Smelting and Re-fining Company -since 1958. Ground controls are supplied by Lake Asbestos, and a topographic map of the pits at a scale of 1 in. to 50 ft., with 2-foot contour intervals, is obtained by aerial photography. The information from the topographic map is then transferred by the Lake Asbestos engineering staff to sections from which the volumes removed are calculated. Considering the size and complexity of the operation, this system has proved to be the cheapest, fastest and most accurate way of determining the quantities of rock and overburden removed. More than 11,000,000 tons of ore and waste are mined each year in three different pits. Further-more, the nature, shape and extent of the orebodies make it necessary to mine on many (up to eight) benches of a pit during a single year. In addition, there are sections of the pits where it is impossible or un-safe to survey the crest of some benches by standard ground methods. For these reasons, the tonnages obtained by truck count are checked and adjusted by aerial survey. These surveys are now taking place every six months. With this system, it is possible for a two-man surveying crew to look after all field work in the mine area."

Jan 1, 1967

By B. Simonian

"The Mount Milligan mine, located in central British Columbia, began operation in September 2013 with a design nameplate capacity of 62,500 dry metric tonnes per day, using a conventional SABC grinding circuit followed by bulk sulphide flotation. Over the last few years, many changes have been implemented in order to debottleneck and optimize the comminution circuit to meet and exceed the nameplate design capacity as well as improve the metal recovery of the flotation circuit. This paper discusses changes, grouped into mechanical modifications, projects, and operational changes. The implementation of these changes as well as ongoing challenges and potential solutions will also be discussed.INTRODUCTION The Mount Milligan mine began production in the fall of 2013. It is a conventional truck-shovel open pit gold and copper mine and concentrator with a 62,500 tpd design capacity copper-gold flotation processing plant. The average head grades for the life of mine are 0.18% Cu and 0.39 g/t Au. At full capacity, the mine produces an average 400 dry tonnes per day of copper-gold concentrate containing approximately 21.5% Cu and 50-60 g/t Au. Current mine life is 21 years. This paper will discuss a selection of the operational, engineering, and administrative changes that have been made at the site since the publication of An Update on Reaching Nameplate Throughput and Continuous Improvement at Mount Milligan (Yue, 2017). PLANT FLOWSHEET CONFIGURATION Run-of-mine ore is crushed through a 60-110 gyratory crusher to a top size of seven inches. Up to 100% of the gyratory crusher product is diverted to the secondary crushing circuit by a moveable gate. The material diverted to the secondary crushing circuit is fed to a vibrating double-deck screen. The screen oversize is placed on a surge pile and reclaimed by four vibrating feeders to feed two 1250 kW standard head cone crushers in open circuit. The screen undersize is combined with the crusher discharge and returns to the conveyor feeding the coarse ore stockpile along with primary crusher product that by-passes the diverter gate."

Jan 1, 2019

By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American?s suite of specifications for gearless mill drives (?GMDs?). These specifications are based on experiences in both Anglo American?s and others? operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Jan 1, 2012

By R. Viljoen, K. Manns

"The mining industry instinctively follows rule-of-thumb design velocities often based on very simplistic theoretical “economic velocity” optimization calculations to determine airway sizes. Although these are important building blocks in ventilation planning it should be recognized that mines are far more complex and various, often opposing factors, are at play. Therefore, it is important that each ventilation situation be analyzed on a case-by-case basis to determine the best-fit solution for an operation. The ventilation design process should not necessarily be constrained by theoretical optimal economic velocities that become rules-of-thumb. In some cases, this could lead to unrealistic infrastructure requirements and exorbitant capital expenditure. This type of design often lacks corporate support leading to a scenario where no ventilation upgrades are implemented. Economic velocities typically consider the cost of power, development costs and operational risk. These typical rules-of-thumb work reasonably well as a starting off point when considering feasibility of greenfield projects. For established mines that are looking at expansion these rules may not be appropriate due to capital expenditure constraints or geotechnical ground conditions. The theoretical optimum should be reviewed in the case of an established mine where existing infrastructure could perhaps be maximized. For example, the geotechnical risk of large diameter raises at depth may require multiple small diameter raise to maintain the theoretical economic velocity. If a mine has a life of less than 5 years, then the cost of power is an insignificant proportion of the total owning cost. For these mines, operating the ventilation raises at an increased velocity to avoid a complicated and expensive capital upgrade might be the more appropriate option, even though it opposes the traditional rules-of-thumb. Mines which are capital constrained may be better off accepting a higher operating cost for the interim or settle for minor infrastructure upgrades rather than run the risk of the entire ventilation upgrade not being approved at all. This paper explores a number of examples derived from case studies undertaken by the authors for several deep mechanized mining projects in Australasia. The examples explore conditions under which higher than the economic norm would be applicable."

Jan 1, 2019

By Stopford Brunton

For many years it has been accepted as axiomatic that the greater number of 'veins' or 'leads' in the gold districts of Nova Scotia are of the 'interbedded' type. The corollary to this hypothesis is that the vein or lead will have a continuous hanging-wall of one kind of rock, and a continuous footwall of the same or another kind of rock; but the essential point is that the foot and hanging walls are, according to this theory, both continuous and of uniform composition throughout; and that the vein or lead conforms to the bedding of the adjacent strata. With regard to the deposition of the gold in the rocks, the probability is that the key of the problem is contained in a statement by E. R. Faribault, of the Geological Survey of Canada: "The combined effect of cleavage, jointing, and stratification is to cause the rocks, especially the quartzites, to break into rhombohedral blocks". It is essential to comprehend that the rocks of the Province are no doubt folded into anticlines and synclines; but also it must be fully realized that the gold deposits and pay-shoots do not depend so much upon these as upon the fractures resulting from the disturbance caused by the intrusion of granite masses, and controlled by the combined effect of cleavage, jointing, and stratification. These fractures would form the channels through which the ore-bearing vapours and solutions would rise, and at the junctions of these fractures, where the fracturing was greatest, the easiest passages would be afforded to the ore carriers, with the result that the ore-shoots would be found at or near the intersections of fractures. It is a significant fact that in at least thirteen different districts throughout the Province, operators have at various times remarked upon the occurrence of rich ore at the intersection of 'leads,' 'veins,' 'beds,' etc.

Jan 1, 1928

By M. Kuyumcu

After German reunification the mining industry in former East Germany was profoundly restructured. Beside privatization of profitable companies the public sector took over responsibility for the mining operations to be shut down. Therefore state-owned companies cope with technical, ecological, and social challenges. The rehabilitation and reclamation has to rededicate former mining areas to new use and provided new jobs as well. In the lignite mining districts there are around 100,000 ha of mining area, a mining caused disturbance to the groundwater balance and to the system of surface water bodies of approx. 390,000 ha. They are called the largest landscape construction site in Europe. In addition to the results and diverse experience achieved over the past 23 years, a description will follow of our new challenges and of an outlook on remaining tasks. This article will describe the financing, as well as aspects of the jobcreation policy arising from lignite industry remediation.

Aug 1, 2013