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By Lloyd Rowson

??Several factors have led to a review and reoptimization of the Midwest uranium deposit by AREVA Resources Canada Inc., the project operator, on behalf of the owners ??The current proposal is to mine the deposit using open pit methods and then transport the ore by truck on a dedicated road linking the Midwest site with AREVA?s McClean Lake Operation (JEB mill) for processing ??A decision has been made to begin mining the deposit by 2010 (pending regulatory approvals)

May 1, 2008

By Jay Rodgers

There has been a longstanding acceptance that burden plays a major role in the magnitude of ground vibration amplitudes generated from surface blasting. Much of the data that this belief is based upon is empirical in nature and may or may not represent an example of false inference. Recent published reports have rightly questioned the influence of burden and confinement on blast vibration amplitude, suggesting that the fracture condition of the rock mass is a better indicator. The increased investment in electronic detonators as a tool to control ground vibration amplitudes demands an understanding of vibration production detailed enough to make use of the vastly improved timing accuracy that they provide. A more accurate relationship may be found if we strip away the assumptions of the past and search for the underlying mechanism of vibration production in surface blasting. We must answer the question: What happens at or near the borehole when an explosive charge detonates that produces ground vibrations?

Jan 1, 2003

By Gabriel S. Esterhuizen, Jarek Jakubec

In 2000, Laubscher’s Mining Rock Mass Rating (MRMR) classification system was updated and published. The new system brought a few fundamental changes that were in direct response to the challenges and problems encountered when applying the classification system in the mining environment, specifically caving operations. The fundamental changes introduced into the MRMR system in 2000 were the abandonment of the Rock Quality Designation (RQD) as an input parameter, accounting for healed and cemented joints, and the concept of rock block strength. The objective of this paper is not to discuss the role and usefulness of classification systems; the fact that classification systems are widely used in every stage of mining projects speaks for itself. This paper discusses some of the experiences gained with the MRMR 2000 system in various mining projects and shows how the changes to the system have resulted in improved assessment of rock mass conditions. Issues related to core logging for rock mass assessment are also presented.

Jan 5, 2007

By George A. Morgan

There was little change in the mineral industry of Benin in 1986, as the economy remained in the grip of a regional recession exacerbated by failing oil prices, which nullified much of the income from Benin's oil production. Benin's industrial sector accounted for less than 10% of the gross domestic product (GDP), with the mineral industry providing about one-half of that total. Several major projects initiated over the last several years continued to perform and/or progress below Government expectations. These included the Save sugar refinery, the Dassa-Parakou section of the Dassa-Cotonou highway, the Benin-Togo Nangbeto hydroelectric plant, the Onigbolo cement plant, and the Semé Oilfield. Funding for these projects is the major source of the Beninese external debt, which was estimated to be over $800 million.2

Jan 1, 1988

By J. G. van der Watt

Due to increasing concerns of global rare earth element shortfalls in the near future, possible alternative sources of rare earth elements have recently become of economic interest. One such alternative is decanting acid mine water originating primarily from abandoned old mines in the Witwatersrand region of the Republic of South Africa. In this study, a novel way of rare earth element removal from the acid mine drainage was employed, making use of bentonite clay, which has very good adsorbent properties, as a rare earth element carrier material. The process can be economically viable only, if the elements can be selectively removed from the bentonite clay carrier material so as to yield reusable clay. Acid leaching was proposed to liberate the adsorbed rare earth elements from the bentonite clay. Accordingly, acid leaching experiments were performed to study the desorption of three commonly-found rare earth elements, namely neodymium, samarium, and dysprosium, from bentonite clay in the presence of sulphuric and hydrochloric acid. It was established that the three rare earth element species could be selectively removed as a group from iron, magnesium, and manganese metals through the careful manipulation of the pH. An investigation into the kinetic aspects of the rare earth element desorption process from the bentonite clay was also undertaken. The applicability of various kinetic models such as zero-order, pseudo first-order, pseudo second-order, elovich, parabolic diffusion, and power function were tested to describe the time-dependent desorption of rare earth elements from bentonite clay. It was determined that the pseudo second-order kinetic model represented the dissolution processes for neodymium, samarium, and dysprosium from bentonite clay the most accurately.

Jan 1, 2012

By Francis W. Gray

Introduction Extensive undersea coal-mining has developed on both the east and west coasts of Canada, and at this time some four million tons, or 25 per cent of the total output of Canadian coal, representing a pit-mouth value of $14,000,000 per annum, is coming from coal seams lying under the sea. Of the coal now being mined in Nova Scotia, 55 per cent comes from under the sea, and this proportion is likely to increase. The Province of Nova Scotia is at this date receiving in royalties paid upon coal ?removed from undersea areas a sum exceeding $400,000 per annum. The subject is, therefore, one of special interest to the Mining Society of Nova Scotia and the Canadian Institute of Mining & Metallurgy, and while this paper will deal chiefly with undersea coal-mining in Nova Scotia, an attempt has been made to summarize the development of mining practice in the winning of undersea coal in other parts of the world, with the hope that such a recital may assist in the assessment of local problems. The connection between the mining of coal under the sea and an insular or maritime geography is obvious in regard to Great Britain, Japan, Vancouver Island, Australia, and Cape Breton Island, and also in regard to the curious conformation of Chile; the tendency towards growth of a mercantile marine and naval eminence is equally obvious where coal is mined at tidewater. But, there is the further and less favourable significance that the mining of coal under the sea is associated with poverty rather than with abundance of coal reserves.

Jan 1, 1927

By C. Kleine

Coal sorting with an x-ray-transmission (XRT) sensor has experienced a lot of development since first described by Jekinson et.al. in 1974. Powerful computers and increasingly sensitive X-ray scintillation counters enabled the development of high-performance sensor-based sorting machines. The first industrial installation of a belt-type XRT-sorting for coal is in operation since 2004. It is upgrading high quality coal from 1% ash to 0.7% ash for cathode production. In comparison to the high quality coal which is treated with a belt-type sorter, the chute type sorter has been successfully optimized for high volume coal treatment of lower quality coals. This project was funded by the German Environmental Fund (Project Nr.244444). In cooperation with the RWTH Aachen University and Isambane Processing, CommodasUltrasort(now Tomra Sorting Solutions) conducted extensive pilot test work under production conditions in 2010 for the destoning of power station coal at Arnot Power Station in South Africa. The experience gained during this pilot test phase led to an optimized, redesigned PRO Secondary XRT Chute sorter which is now in operation at a South African coal mine. This flexible semi-mobile modular destoning plant is treating a size range of -120 mm +30 mm at a throughput of 150 tph. The implementation of this plant not only reduces the ash content, abrasiveness index and sulfur content significantly, but also reduces royalties, water treatment and transport costs.

Sep 1, 2012

By P. M. Ambrose, A. C. FtELDNER

This , the twelfth annual report of research and technologic work conducted by the Bureau of Mines on coal and coal products , summarizes the research and tests conducted frah July 1, 1946, to July 1, 1947. The organic act of Congress establishing the Bureau of Mines authorized tech- nologic investigations of all phases of mining, preparation, treatment, and utilization. These investigations cover eight main fields of activ-. projects varies from time to time. The on ity. The emphase-half of the coal reservos of the world. United States These reserves are not always of the quality desired or in the place where they could best be used. It is necessary to continue research in order that increased output, greater recovery, and better quality can be main- tained under safe mining conditions. Coal comprises 98 percent of the known fuel reserves of the United States and ad eventually must take over much of the requirements now supplied by petroleum and natural gas.. The purpose of this report is to bring to the reader a resume of the work of the fiscal year. The material presented herein is based largely upon publications. In a few instances the results of research that would not otherwise be available in the immediate future are presented. For details concerning the research, it is suggested that the readers consult the publications given in the footnote references." Collected references to all Bureau of Mines publications on coal are published in a series of bibliographies. Technical Paper 576 covers 1910 to 1935; Technical Paper 639 covers 1935 to 1940; and Technical Paper 698, issued in 1947; covers' 1940 to 1945.

Jan 1, 1948

Collecting the clay fraction of active stream sediment from a flowing stream for geochemical analysis i a difficult process. One either takes a sample of dry fine-grained sediment from the stream bank (dry weather and dry sample are uncommon in parts of New Zealand and Tasmania), or dredges up a sample of sand and mud out of the stream.The latter method produces a soggy ample bag full of mud and sand, with varying amounts of gravel, depending on the size of the stream. The water can be filtered from such a sample by means of a Buchner filter funnel, but is difficult to obtain a vacuum in the bush. This problem can be solved by using a small hand- queeze bellows such as used in priming petrol pumps on outboard petrol motors. The common laboratory hand bellows is not powerful enough.A 70 mm diameter two-piece polythene Buchner filter funnel (Fig. 1) can be used. A length of rubber tubing is fitted around the inlet valve of the hand bellows and this valve is then jammed into the pipe at the bottom of the filter funnel (the polythene pipe may be trimmed with a knife to fit over the inlet valve of the bellows). The vacuum is generated and maintained by squeezing the hand bellows.The technique of collecting a sample of the clay fraction is to dredge a sample of the fine-grained active stream sediment out of the stream with a container, such as a plastic mug. The sample is agitated to get the clay fraction into suspension and the muddy suspension is then decanted into the Buchner funnel. The desired clay fraction is obtained as a thin film on the filter paper.If the "fines" are also required, a filter of nylon bolting cloth (stretched across the mouth of a short length of 80 mm diameter polythene pipe and attached by rubber bands or a concentric polythene pipe) can be placed over the mouth of the Buchner funnel and the whole sample of stream sediment...

Jan 1, 1969

By Cajsa Samuelsson, Theo Lehner

Converting and refining play a central role in the extraction of metals. Sweden has a long tradition as an experimental play ground for metallurgists, chemists and alchemists, developing new methods and technologies. Presenters of papers are usually happy in recording successful developments. But reporting failures can be as great a value as the former. In the paper experiments and experience in process development are illustrated, differences between ferrous and non-ferrous developments are highlighted and industrial learning curves are discussed. 53

Jan 1, 2009

By Shoichi Tsukuni, Akihiko Uchida, Kazuo Konishi

"In order to investigate the effect of grid-form deep mixing walls as a countermeasure for liquefaction damage to roads and private houses in Urayasu, Japan, three dynamic centrifuge model tests were conducted. Urayasu is located in the Tokyo Bay area, and private houses in the city incurred severe damage due to liquefaction during the 2011 Tohoku earthquake. In grid-form deep mixing walls design, the distance between grid-form walls is critical to prevent liquefaction. This study clarifies the relationship between the settlement of private houses and the distance between grid-form walls under the conditions that exist in Urayasu.INTRODUCTIONMany private houses in Urayasu, Japan suffered severe damages due to liquefaction during the 2011 Tohoku earthquake (Photograph 1). Fig. 1 shows the location of Urayasu and the maximum acceleration of the observed seismic waves in the Tokyo Bay area. At Urayasu, the duration of the seismic waves (hereafter called the Urayasu Wave) was about 2 min. The maximum acceleration was 1.57 m/s2 (Fig. 2), which is relatively small. The damages occurred in the land reclamation areas that consist of loose sand with an SPT-N value less than 10.To prevent liquefaction in future, it is necessary to adopt suitable countermeasures in the areas where many private houses suffered severe damages. Grid-form deep mixing walls are one such countermeasure. Fig. 3 and Photograph 2 show grid-form deep mixing walls. Walls are constructed using the deep cement mixing method. Fig. 4 shows a plane view of planned grid-form deep mixing walls for roads and existing private houses in Urayasu."

Jan 1, 2015

By Pathies Nawej Muteb, Tom Strombotne, Karl Leetmaa, Irma Gabric, Keith Darby

"Continuous control of the final grinding product size is important to optimize gold liberation for Gold Milling operations. At Meadowbank Mine an on-line Particle Size Monitor has been employed successfully to achieve the targeted final grind which leads to optimizing the gold recovery at maximum grinding circuit throughput. The live monitoring of the final product particle size leads to a maximum grinding circuit throughput every minute during the process. This paper discusses the optimal utilization of the Particle Size Monitor to assist the Mill operator to maximize the grinding circuit throughput as the milling conditions change due to variable ore processed at Meadowbank Mine. Also the paper includes the usage of the Particle Size Monitor to guarantee the final grind target at each instant of the process.IntroductionAgnico-Eagle is a Canadian-based company that Trades on the TSX & NYSE (AEM). It owns eight mines (8) operating in Nunavut, Quebec, Finland and Mexico and has more than 7,500 employees (Figure 1). 1.6 M ounces of gold were produced in 2015 and the annual average annual production from 2016 to 2018 is forecast to be approximately 1.53 million ounces of gold.The Meadowbank Mine is located in Nunavut, Canada (Figure 2). The mine opened in 2010 and from 2010 to 2014 a total of 1.8M oz of gold was produced. The milling rate is 4.2 Mt per year with an average mill throughput of 11,900 tpd or 496 tph. Average annual gold production over life of mine is expected to be 450,000 ounces. Meadowbank has 775 employees, of which 265 are Inuit or 36% of the total workforce. Estimated life of mine is 2010 to 2018. Gold production in 2015 was 381,804 oz. Meadowbank was Agnico-Eagle’s largest Gold producer in 2015."

Jan 1, 2017

By J. MacFadyen

The U.S. cement industry experienced its best year ever during 2004 in terms of production and shipments of cement. Clinker, portland and masonry cements production and shipments were up considerably. Clinker production as reported to the U.S. Geological Survey (USGS) was 87.75 Mt (96.73 million st), an increase of 5.4 percent. Gray and white portland cement production from domestic and imported clinker was estimated to be 91.6 Mt (101 million st), up 5 Mt (5.5 million st) from 2003.

Jan 1, 2005

By Ray Brainard

The Jollyville Transmission Main will be a 10.5-km- (6.5-mile)-long, 213-cm (84-in.) diameter rock tunnel. The tunnel will pass beneath the Balcones Canyonlands Preserve, which was established to protect two endangered bird species, six endangered cave invertebrates and a threatened salamander. To address the sensitive habitat that the transmission main is to pass through, the city of Austin developed an environmental commissioning (EC) process that brought together environmental engineers and scientists, the city?s project management team and the designer team to work collaboratively to meet the city?s goals of producing a cost-effective design while also protecting the environment. This paper describes the environmental commissioning process and the benefits it brought to the project and environment through some unique environmental mitigation measures to protect this sensitive area.

Jan 1, 2012

Failure of rock materials is a process of crack propagation. Crack initiation takes place when the crack tip stress intensity K reaches a critical value called fracture toughness, K1C. The rock fracture toughness is known to be affected by the surrounding environment such as temperature, confining pressure and humidity. In order to examine the effect of humidity, a series of semi-circular bend tests were performed under various water vapour pressures in a rock material that is known to be anisotropic. Water vapour promotes stress corrosion of rock and therefore the fracture toughness was found to have a decreasing trend with increasing water vapour pressure. The rate of decreasing the fracture toughness depends on the microcrack density that promotes the migration of water vapour into the rock. Also in an anisotropic rock, the fracture toughness depends on the direction of crack in relation to the anisotropy of the rock material.

Dec 6, 2010

By G. Song

"SynopsisAccording to the overlying rock strength and thickness of 10 shallow coal seams in China, the strata are classified into four types: weak and laminated strata (hereinafter referred to as WL), weak and massive strata (WM), strong and laminated strata (SL), and strong and massive strata (SM). The four types of strata, together with longwall panel height (M), panel length (L), and seam depth (H) are factors that influence the loads on hydraulic power supports. Principal component analysis was used to study the seven influencing factors. It turns out that seam depth (H) is multicollinear with WL, WM, SL, and SM. Thus the enumerated seven factors are divided into two models. In Model 1, six factors; panel height, panel length, and layer thickness of the four type strata are involved. In Model 2, three factors; panel height, panel length, and seam depth are included. Using multivariate regression analysis, two equations to calculate loads on supports are obtained for each model. The equations were applied to shallow coal seams. The equation of Model 1 is more accurate than that of Model 2, but Model 2 could be further used in deep coal seams. The equations were coded through VB programming to simplify the calculation.IntroductionTo ensure coal production in the long term, the focus of coal mining has been gradually shifted to the western areas of China in recent years due to rich coal resources in this region. Most of the coal seams in this area are shallow but the support loads are abnormally high. In these circumstances, the chock loads estimating methods used in the past do not work. If the rated working resistance of a support is larger than needed, the shield is unable to fully perform, while a lower working resistance would lead to accidents like shield crushing or even casualties. This problem is frequently found in shallow coal seams such as Shenfu-Dongsheng, Yulin, Tuha, Lingwu etc. (Zhang, 2011). Thus, to ensure safety and efficiency during mining, the estimation of support loads and selection of supports are of great significance."

Jan 1, 2015

By Arno C. Fieldner

From July 1, 1949, to July 1, 1950, the Bureau of Mines conducted the research and technologic work on coal and coal products that is summarized in this report. The research, described in this fifteenth of a series of resumes, is presented in more detail in publications (see footnote references) that appeared during the fiscal year, though in some cases research data are given that have not been published elsewhere. Results of research in the experimental coal mine, on explosives, and on gas and dust explosions will be found in Bureau of Mines Report of Investigations 4228, Annual Report of Research and Technologic Work on Explosives, Explosions, and Flames, Fiscal Year 1950. An over-all view of our coal, oil, end natural-gas reserves was presented, and the future possibilities for the, production of synthetic liquid fuels from coal were delineated.3/

Jan 1, 1951

By Z Chang, S A. Mrozek

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Antamina, Peru is the largest Cu-Zn skarn deposit in the world. Skarn mineralisation is focused around a multiphase Miocene intrusive complex comprising at least eight distinct phases identified by cross-cutting relationships, including truncated veins, xenoliths and chilled margins. Skarn alteration and mineralisation, as observed in drill core, remain open at depths exceeding 2.2 vertical kilometres.Porphyry intrusions occur as four major phases with subphases (from oldest to youngest): P1 (a, b), P2 (a, b), P3 (a, b) and two dykes of uncertain timing named Oscarina-1 and Oscarina-2. P1a is a hornblende-biotite quartz diorite porphyry with pervasive K-alteration, local endoskarn and 30–40 per cent sheeted quartz veins, all of which obscure original igneous textures. P1b dacite porphyry is a minor unit with <10 per cent phenocrysts and <3 per cent quartz veins. P1b cuts P1a; P2 dykes cut both units. P2a porphyritic biotite quartz monzonite contains K-feldspar megacrysts up to 4 cm long, local K-alteration and 2–80 per cent quartz stockwork veins. P2b biotite monzonite porphyry contains approximately 50 per cent phenocrysts and typically <10 per cent quartz veins. P3a (brown groundmass porphyry) and P3b (coarse phenocryst porphyry) are minor in volume and extent, and both cut P2 bodies. Oscarina dykes comprise two separate but parallel bodies. Oscarina-1 is a feldspar-phyric rhyolite porphyry, while Oscarina-2 is an intensely chloritised andesite porphyry. Oscarina-1 has a U-Pb (laser ablation inductively coupled mass spectrometry (LA-ICP-MS)) age of 10.1 ± 0.1 Ma, whereas P2 U-Pb zircon ages (LA-ICP-MS) range from 10.0 ± 0.2 Ma to 9.9 ± 0.3 Ma.All the intrusive phases contain quartz veins, with P1a and P2a having the most intensive K-alteration and most abundant quartz veins ± endoskarns. Each phase may have contributed to mineralisation at the right depths and within favourable wall rocks (ie marble) during uplift of the Antamina structural block. Therefore, a model of multiple intrusions during continuous uplift explains the vertically extensive (>2.2 km) skarn and mineralisation at Antamina.CITATION:Mrozek, S A, Chang, Z and Meinert, L D, 2015. A model for the intrusive sequence and Cu-Zn skarn formation at the Antamina deposit, Peru , in Proceedings PACRIM 2015 Congress, pp 423–430 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Harlan A. Walker

This paper on the mines of El Potosi Mining Co. is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts of North America. Grateful acknowledgment is made of the helpful suggestions and criticisms offered by the management, together with the assistance of the mining staff in preparing maps and drawings and of C. L. Thornburg, mine geologist, in preparing the section on geology.

Jan 1, 1934

By William M. Gleason

Hard times continued to plague the industry when the calendar rolled over to 2000. During 1999, the United States economy had grown vigorously, capping the longest economic expansion in United States history. However, the mining industry was not so fortunate. Commodity prices remained in a slump in the “new-economy” that was fueled by excitement and speculation about the power of the Internet during the infancy of the Information Age. Much of the investment money that once went to mining and exploration was now headed to the world of virtual gold mines. SME President Donald E. Ranta implemented new technology into his plans for SME. His two major goals were new membership growth and to foster the establishment of the comprehensive Internet presence for the Society’s technical information. His strategic priorities included enhancing the quality and quantity of publications, programs, meetings and short courses. “The Internet is the vehicle that will advance the priorities,” he said.

Jan 1, 2007